Synthesis of Single-Crystalline Tungsten Ditelluride (WTe2) Nanostructures Using Eutectic Metal Alloys

Department of Materials Science EngineeringBeyond graphene, group-VI transition metal dichalcogenides (TMDs) which is compound of transition metal and chalcogen have recently attracted much attention and mechanically exfoliated flakes of two-dimensional TMDs hold great promise due to their rich variety of properties. As a member of the TMDs family, tungsten ditelluride (WTe2), which has a stable distorted octahedral phase (1T’) among several polymorphs, are appealing because of their unique properties such as an unusual magnetoresistance and quantum spin Hall effect. In an effort to synthesize WTe2 nanostructures, researchers have tried to develop many growth techniques. Nonetheless, there remains considerable difficulty in obtaining high-quality WTe2 nanostructures due to a high equilibrium vapor pressure of tellurium at growth temperatures and a weak binding energy of W-Te than other chalcogens. Here, we suggest a novel facile method to realize the synthesis of single-crystalline WTe2 nanostructures using eutectic metal alloys. In our work, we studied on the role of eutectic metal alloys and its behavior on synthesis parameters and more details will be presented. In addition, the as-synthesized WTe2 nanostructures can be easily transferred to different substrates and/or solutions as well as successfully formed on desired substrate without the needs for a further transfer process. The transfer-free formation of WTe2 nanostructures can be adopted to research the novel properties of WTe2 nanostructure without any degradation of the intrinsic characteristics. Moreover, feasibility of synthesis for MoTe2 nanostructure as a member of the layered TMDs family was evaluated through our methods. We expect that the emergence of new type of transition metal telluride nanostructures will create exciting prospects for further technical devices and applications in nano-electronics, catalysts and other fields.ope

Archaeological resource management in South Korea: developing a holistic management planning model for buried archaeological sites

As the standard of living rose in South Korea a wider range of people became interested in archaeological heritage and its management. Specifically, since the 1990s, rescue archaeology became an issue of wider social concern: there was a paradigm shift from simply the protection of archaeological sites, under pressure from development, to the use of sites as a social resource. This transformation presented a number of challenges regarding unexcavated archaeological sites in the planning process, decision-making on preservation in-situ (as opposed to ‘preservation by record’), and the nature of display or reburial. This research aimed to develop a management planning model to face these challenges. The research focused on archaeological sites, partly because of their ability to engage social issues in contemporary South Korea, and partly because of the complexity of managing the resource, due to the ‘invisibility’ of unexcavated archaeology and the often fragile nature of the remains. In order to build this model, the research explored international theories and approaches, and set these within the context of South Korean Archaeological Resource Management, to produce an intellectual framework. The research explores four broad topics – who, why, what, and how – through complex issues such as identity, ownership, participation, assessment, conservation/protection, interpretation and presentation. The model involves principles for management (including participatory planning, transparent assessment of values, and defined management strategies). This leads to a road map for planning: Stage 1 (Identifying) explores activities such as team building, documentation and vision, under the principle of participatory planning; Stage 2 (Assessment) approaches the assessment of values and significance, and the role of decision-making and governance, using principles of transparency; Stage 3 (Responding) develops approaches to creating management strategies, specific to time and spatial scales; and Stage 4 (Reviewing and Revision) investigates the processes of monitoring and review, within a flexible framework

Functional analysis of the fructooligosaccharide utilization operon in \u3ci\u3eLactobacillus paracasei\u3c/i\u3e 1195

The fosABCDXE operon encodes components of a putative fructose/mannose phosphoenolpyruvate-dependent phosphotransferase system (PTS) and a β- fructosidase precursor (FosE) that are involved in the fructooligosaccharide (FOS) utilization pathway of Lactobacillus paracasei 1195. The presence of an N-terminal signal peptide sequence and a LPQAG cell wall anchor motif at the C-terminal region of the deduced FosE precursor amino acid sequence predicted that the enzyme is cell wall-associated, indicating that FOS may be hydrolyzed extracellularly. In this study, cell fractionation experiments demonstrated that the FOS hydrolysis activity was contained exclusively in the cell wall extract of L. paracasei previously grown on FOS. In contrast, no measurable FOS hydrolysis activity was detected in the cell wall extract from the isogenic fosE mutant. Induction of β-fructosidase activity was observed when cells were grown on FOS, inulin, sucrose, or fructose, but not glucose. A diauxic growth pattern was observed when cells were grown on FOS in the presence of limiting glucose (0.1%). Analysis of the culture supernatant revealed that glucose was consumed first, followed by the longer chain FOS species. Transcription analysis further showed that the fos operon was expressed only after glucose was depleted in the medium. Expression of fosE in a non-FOS-fermenting strain, Lactobacillus rhamnosus GG, enabled the recombinant strain to metabolize FOS, inulin, sucrose, and levan

Optic neuritis caused by aspergilloma within Onodi cell pyomucocele in a 62-year-old woman

Onodi cells are anatomical variants of the posterior ethmoidal cells, which are greatly pneumatized laterally, and to some degree superiorly, to the sphenoid sinuses. Th e clinical importance of the Onodi cell is that it contains the optic canal and lies in close proximity to the optic nerve. Although the incidence of Onodi cell pathologies such as mucocele is extremely low, they may cause ophthalmological complications due to the close anatomical proximity between the Onodi cell and the optic nerve. Optic neuritis caused by aspergillosis of the Onodi cell, presenting in the Emergency Department as an aspergilloma within a pyomucocele, has not been reported previously. Here, we describe the fi rst such case; the aspergilloma within the pyomucocele was completely removed via surgical endoscopy

Accuracy and Efficacy of Ultrasound-Guided Pes Anserinus Bursa Injection

The term “pes anserinus tendinobursitis (PATB)” is generally used to describe the inflammatory condition of pes anserinus bursa (PAB). Ultrasound (US) is widely used as a diagnostic and therapeutic tool to improve the assessment and management of joints and soft tissues. We performed the study to prove the accuracy and efficacy of US-guided injections in patients with PATB by comparing blind interventions. Forty-seven patients were randomly assigned to an US-guided and a blind injection group. The patients in the US-guided group were given injections under sonographic visualization. Otherwise, in the blind group, injections were provided in the conventional technique without any sonographic guidance. After the management, the accuracy of the injections was assessed by identifying the injectate location using the US. Treatment efficacy was evaluated using the visual analog scale (VAS) of knee tenderness. The US-guided group showed that the injectates were located at the PAB accurately in all participants, whereas the blind group revealed that the materials were found to be at the bursa side only in 4 out of 22 patients. VAS scores of the US-guided group significantly improved compared to the blind group. In conclusion, US-guided PAB injections are more accurate and efficacious than blind approaches

Prevalence of Inducible Clindamycin Resistance in Staphylococcal Isolates at a Korean Tertiary Care Hospital

Clindamycin resistance in Staphylococcus species can be either constitutive or inducible. Inducible resistance cannot be detected by the conventional antimicrobial susceptibility test. In this study, we determined the prevalence of inducible clindamycin resistance in staphylococcal isolates at a Korean tertiary care hospital. Between February and September 2004, 1,519 isolates of Staphylococcus aureus and 1,043 isolates of coagulase-negative staphylococci (CNS) were tested for inducible resistance by the D-zone test. Overall, 17% of MRSA, 84% of MSSA, 37% of MRCNS, and 70% of MSCNS were susceptible to clindamycin. Of the erythromycin non-susceptible, clindamycin-susceptible isolates, 32% of MRSA, 35% of MSSA, 90% of MRCNS, and 94% of MSCNS had inducible clindamycin resistance. Inducible clindamycin resistance in staphylococci was highly prevalent in Korea. This study indicates importance of the D-zone test in detecting inducible clindamycin resistance in staphylococci to aid in the optimal treatment of patients