Mechanism for Local-Atomic Structure Changes in Chalcogenide-based Threshold-Switching Devices.

Threshold-switching devices based on amorphous chalcogenides are considered for use as selector devices in 3D crossbar memories. However, the fundamental understanding of amorphous chalcogenide is hindered owing to the complexity of the local structures and difficulties in the trap analysis of multinary compounds. Furthermore, after threshold switching, the local structures gradually evolve to more stable energy states owing to the unstable homopolar bonds. Herein, based on trap analysis, DFT simulations, and operando XPS analysis, it is determined that the threshold switching mechanism is deeply related to the charged state of Se-Se homopolar defects. A threshold switching device is demonstrated with an excellent performance through the modification of the local structure via the addition of alloying elements and investigating the time-dependent trap evolution. The results concerning the trap dynamics of local atomic structures in threshold switching phenomena may be used to improve the design of amorphous chalcogenides.

Recovery of non-metallic useable materials from e-waste.

Tremendous amounts of electric and electronic wastes (e-waste) are generated daily, and their indiscriminate disposal may cause serious environmental pollution. The recovery of non-metallic materials from e-waste is a strategy to not only reduce the volume of e-waste but also avoid pollutant emissions produced by indiscriminate disposal of e-waste. Pyrolysis, sub/supercritical water treatment, chemical dissolution, and physical treatment (e.g., ball milling, flotation, and electrostatic separation) are available methods to recover useable non-metallic materials (e.g., resins, fibers, and various kinds of polymers) from e-waste. The e-waste-derived materials can be used to manufacture a large variety of industrial and consumer products. In this regard, this work attempts to compile relevant knowledge on the technologies that derive utilizable materials from different classes of e-waste. Moreover, this work highlights the potential of the e-waste-derived materials for various applications. Current challenges and perspectives on e-waste upcycling to useable materials are also discussed.

Selective recovery of caprolactam from the thermo-catalytic conversion of textile waste over γ-Al2O3 supported metal catalysts.

The massive generation of synthetic textile waste has drawn considerable attention. Landfilling/incineration of textile waste has been widely made. To abate the environmental burdensome from the conventional management processes, a thermo-catalytic conversion was used for rapid volume reduction of textile waste and simultaneous valorization by recovering textile monomer in this study. Stockings were chosen as a model feedstock. Because stockings consisted of nylon with other contents, different products (caprolactam (nylon monomer), imines, cyclic dimers, and azepines) were recovered. The yield of caprolactam from the thermal conversion at 500 °C was 53.6 wt%. To selectively enhance the caprolactam yield, catalytic pyrolysis was done using γ-Al2O3 supported metal catalysts (Ni, Cu, Fe, or Co). γ-Al2O3 itself increased the caprolactam yield up to 69.0 wt% via a based-catalyzed reaction of nylon depolymerization and intramolecular cyclization. Under the presence of metal catalysts, the caprolactam yield increased up to 73.3 wt%. To offer desired feature of green chemistry, CO2 was adopted as reactive gas. Under the CO2-mediated catalytic pyrolysis, caprolactam yield was enhanced up to 77.1 wt% over Cu/Al2O3 (basis: stocking mass). Based on the net content of nylon in the stockings, the yield of caprolactam was deemed 95.3 wt%. This study proves that textile waste (stocking) and CO2 are useful resources for recovery of nylon monomer, which can reduce the waste generation with simultaneous recovery of value-added product.

Enhanced Osteogenesis of Dental Pulp Stem Cells In Vitro Induced by Chitosan-PEG-Incorporated Calcium Phosphate Cement.

The use of bone graft materials is required for the treatment of bone defects damaged beyond the critical defect; therefore, injectable calcium phosphate cement (CPC) is actively used after surgery. The application of various polymers to improve injectability, mechanical strength, and biological function of injection-type CPC is encouraged. We previously developed a chitosan-PEG conjugate (CS/PEG) by a sulfur (VI) fluoride exchange reaction, and the resulting chitosan derivative showed high solubility at a neutral pH. We have demonstrated the CPC incorporated with a poly (ethylene glycol) (PEG)-grafted chitosan (CS/PEG) and developed CS/PEG CPC. The characterization of CS/PEG CPC was conducted using Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The initial properties of CS/PEG CPCs, such as the pH, porosity, mechanical strength, zeta potential, and in vitro biocompatibility using the WST-1 assay, were also investigated. Moreover, osteocompatibility of CS/PEG CPCs was carried out via Alizarin Red S staining, immunocytochemistry, and Western blot analysis. CS/PEG CPC has enhanced mechanical strength compared to CPC, and the cohesion test also demonstrated in vivo stability. Furthermore, we determined whether CS/PEG CPC is a suitable candidate for promoting the osteogenic ability of Dental Pulp Stem Cells (DPSC). The elution of CS/PEG CPC entraps more calcium ion than CPC, as confirmed through the zeta potential test. Accordingly, the ion trapping effect of CS/PEG is considered to have played a role in promoting osteogenic differentiation of DPSCs. The results strongly suggested that CS/PEG could be used as suitable additives for improving osteogenic induction of bone substitute materials.

Flavonoid Glycosides Inhibit Sortase A and Sortase A-Mediated Aggregation of Streptococcus mutans, an Oral Bacterium Responsible for Human Dental Caries.

Three flavonoids were isolated from dried flowers of Sophora japonica using repetitive column chromatography and high-performance liquid chromatography. The flavonoids were identified as rutin (1), quercetin-3'-O-methyl-3-O-α-L-rhamnopyranosyl(1 → 6)-ß-D-glucopyranoside (2), and quercetin (3) on the basis of spectroscopic analysis and comparison of values reported in the literature. These compounds inhibited the action of sortase A (SrtA) from Streptococcus mutans, a primary etiologic agent of human dental caries. The onset and magnitude of inhibition of saliva-induced aggregation of S. mutans treated with compound 1 was comparable to that of untreated S. mutans with a deletion of the srtA gene.

Streptococcus mutans sortase A inhibitory metabolites from the flowers of Sophora japonica.

A new maltol derivative (2) along with three known maltol derivative (1) and flavonol glycosides (3 and 4) were isolated from the dried flowers of Sophora japonica. Based upon the results of combined spectroscopic methods, the structure of new compound (2) was determined to be maltol-3-O-(4'-O-cis-p-coumaroyl-6'-O-(3-hydroxy-3-methylglutaroyl))-ß-glucopyranoside, an isomer of 1. These compounds strongly inhibited the action of sortase A (SrtA) from Streptococcus mutans, a primary etiologic agent of human dental caries. The onset and magnitude of inhibition of the saliva-induced aggregation in S. mutans treated with compound 2 (4×IC50) were comparable to the behavior of untreated srtA-deletion mutant.

Consenting Practice of ENT Trainees: To What Extent Is Trainee Involvement Disclosed?

AIM: To assess to what extent ENT trainees disclose their involvement in operations to their patients when obtaining consent. BACKGROUND: It is not clear how the trainees are conducting the consenting process, although it could lead to a medico-legal conflict. DESIGN AND PARTICIPANTS: A 6-question questionnaire was sent via email to 22 ENT trainees in Northern Deanery, and 14 ENT registrars in Yorkshire Deanery. MAIN OUTCOME MEASURES: Seniority of the participants. Disclosure of the main operating surgeon and trainee involvement in the consenting process. Influence of operation complexity in trainee involvement disclosure. RESULTS: The response rate was 69%. Of the respondents, 46% consistently informed patients about trainee involvement in operations. Only 28% felt the complexity of operations influenced their decision to disclose trainee involvement. Subgroup analysis showed there was no statistically significant difference between junior and senior trainees in trainee involvement disclosure. If the trainees informed patients about who the operator would be, it was more likely for them to also disclose their own involvement. Many trainees also felt that the 'no guarantee of a particular surgeon' clause in the National Health Service consent form implied possible trainee involvement even if they did not specify it verbally. CONCLUSION: The rate of trainee involvement disclosure is not related to the seniority of trainee or complexity of operations, but is related to operator disclosure. This may suggest trainee involvement disclosure is not dependent on the level of confidence of trainees but on the approach and attitude towards the consenting process.

Bioactive Metabolites from the Fruits of Psoralea corylifolia.

Twenty-four metabolites, including seven new compounds (1-7), were isolated from the dried fruits of Psoralea corylifolia. On the basis of combined spectroscopic and chemical analysis, the new compounds were determined to be six flavonoids (1-6) and a meroterpenoid (7). The absolute configurations of the natural products obtained, including the previously undetermined 16 and 17, were assigned by several methods, such as NOE spectroscopy, optical rotation, and CD spectroscopy. Several of these compounds exhibited moderate inhibitory activity toward Staphylococcus mutans-derived SrtA (2, 6, and 16) and significant stimulation of SIRT1 activity (2, 3, and 15).

Recurrence rate of cholesteatoma with autoclaved incus autograft.

OBJECTIVE: To study the long-term recurrence rate of cholesteatoma with autoclaved incus autograft. STUDY DESIGN: Prospective observational study between 1994 and 2009. The incus remnants were autoclaved at 134°C for 24 minutes at 205 kPa. The mean follow-up duration was 65.5 months, with a minimum follow-up duration of 31 months and a maximum follow-up duration of 186 months. SETTING: Secondary referral center in a district general hospital. PATIENTS: Thirty-seven cases of cholesteatoma treated with canal wall down mastoidectomy with primary ossicular reconstruction with autoclaved incus autograft were included. The age range of the patients was from 11 years to 67 years. The mean age was 38 years. Fifty-four percent was male, and 46% was female. INTERVENTIONS: Therapeutic and rehabilitative--to treat and improve the patients' hearing loss secondary to cholesteatoma by using autoclaved autologous incus. MAIN OUTCOME MEASURES: Primary end point is the recurrence rate of cholesteatoma with a mean follow-up period of more than 5 years. Secondary end point is the audiometric outcome with air-bone gap (ABG) and air conduction improvement. RESULTS: No recurrence of cholesteatoma was observed. No graft extrusion was seen. Preoperative mean ABG was 29.8 dB. Postoperative mean ABG was 25.6 dB at the final review, with the air conduction improvement at final review at 4.2 dB. CONCLUSION: Autoclaving the incus remnant harvested from cholesteatomatous middle ear cleft is a safe and effective method to prepare an incus autograft for primary ossicular reconstruction.

Long-term safety and efficacy of radiofrequency ablation in the treatment of sleep disordered breathing: a meta-analysis.

Radiofrequency ablation (RFA) is used in the treatment of sleep disordered breathing (SDB), particularly in the alleviation of snoring. The literature provides evidence that the short-term results are promising; however, the long-term efficacy is a matter of contention. In this article, we present the results of a literature search of studies that use RFA in the treatment of SDB which have a follow-up time of greater than a year. RFA was found to be a safe technique with minimal morbidity. The overall Visual Analogue score from six studies showed the overall mean improvement to be 4.3 (confidence intervals 3.4-5.12). Apnea Hypopnea Index (AHI), improved significantly in five of the studies analysed. Epworth Sleepiness Score (ESS), improved significantly in six of the studies analysed. In conclusion, the evidence suggests that RFA for SDB results in a significant improvement in follow-up times of at least a year. Since RFA can be applied in a clinic setting and leads to minimal disruption to daily life, this treatment option can be considered for those unwilling to participate in the more traditional surgical options for SDB.

Sortase A inhibitory metabolites from the roots of Pulsatilla koreana.

Three new lignans (3, 4, and 6) along with eight known lignans and phenyl propanoids were isolated from the dried roots of Pulsatilla koreana, an oriental folk medicine. Based upon the results of combined spectroscopic and chemical methods, the structures of new compounds were determined to be lignan glycosides. Included among the known compounds are three compounds (5, 7, and 8) isolated first time from this plant as well as two compounds (2 and 11) previously reported only as synthetic derivatives. These compounds significantly inhibited the action of Sortase A from Streptococcus mutans OMZ65, an isolate from human oral cavity.

Unilateral non-Hodgkin's lymphoma of the frontal sinus presenting as Pott's puffy tumour.

Malignant lymphoma of the paranasal sinuses and nasal cavity is very rare and can mimic those of infectious, non-lymphomatous neoplastic and granulomatous process in their initial presentation, thus delaying its diagnosis. This report describes a case of unilateral frontal sinus B-cell lymphoma presenting as Pott's puffy tumour. Key features to differentiate the two conditions are discussed. A 61-year-old woman presented with 4 weeks history of a gradually enlarging right-sided forehead swelling, which was smooth and firm with no tenderness, fluctuation or overlying skin changes. Initial computed tomography (CT) of the paranasal sinuses revealed a mildly opacified right frontal sinus with an overlying soft tissue swelling. A repeat CT scan one week later showed evidence of osteomyelitis of the medial wall of the right frontal bone and orbit, suggesting diagnosis of Pott's puffy tumour. A third CT scan was performed as the swelling continued to enlarge despite antibiotics, which demonstrated a collection over the frontal sinus. No pus was found from a frontal sinus trephine. Histopathologic analysis of the frontal sinus biopsy showed diffuse large B cell lymphoma. The patient was treated successfully with 6 cycles of chemotherapy. In conclusion, it is not easy to differentiate Pott's puffy tumour from frontal sinus lymphoma at their initial presentation. With clearer understanding of both conditions, we can raise the index of suspicion among clinicians of the possibility of frontal sinus lymphoma even when evidence of osteomyelitis is present, therefore prompting earlier tissue biopsies for confirmation of diagnosis.

Cyclic Bis-1,3-dialkylpyridiniums from the sponge Haliclona sp.

Eight novel cyclic bis-1,3-dialkylpyridiniums, as well as two known compounds from the cyclostellettamine class, were isolated from the sponge Haliclona sp. from Korea. Structures of these novel compounds were determined using combined NMR and FAB-MS/MS analyses. Several of these compounds exhibited moderate cytotoxic and antibacterial activities against A549 cell-line and Gram-positive strains, respectively. The structure-activity relationships of cyclostellettamines are discussed based on their bioactivities.

In vitro sortase A inhibitory and antimicrobial activity of flavonoids isolated from the roots of Sophora flavescens.

A series of flavonoids (1-14) was isolated from the roots of Sophora flavescens. We evaluated their ability to inhibit both microbial growth and sortase A, an enzyme that plays a key role in cell wall protein anchoring and virulence in Staphylococcus aureus. Most prenylated flavonoids (7-13) displayed potent inhibitory activity against gram-positive and gram-negative bacteria except E. coli, with minimum inhibitory concentrations values ranging from 4.40 to 27.7 µM, and weak or no activity against fungal strains tested. Kurarinol (6) was a potent inhibitor of sortase A, with an IC(50) value of 107.7 ± 6.6 µM. A preliminary structure-activity relationship, including essential structural requirements, is described.

In vitro Na+/K+-ATPase inhibitory activity and antimicrobial activity of sesquiterpenes isolated from Thujopsis dolabrata.

A series of sesquiterpenes and hinokitiol-related compounds (1-15) was isolated from the essential oil of Thujopsis dolabrata Sieb. et Zucc. var. hondai Makino, and their structures were determined by combined spectroscopic analyses. The inhibitory effects of these compounds on microbial cell growth and Na(+)/K(+)-ATPase were evaluated in vitro. It was found that (-)-elema-1,3,11(13)-trien-12-ol (5), α,ß,γ-costol (8), and chamigrenol (11) inhibit the activities of Na(+)/K(+)-ATPase, with IC(50) values of 11.2 ± 0.11, 12.2 ± 0.09, and 15.9 ± 0.54 µg/mL, respectively. Thujopsene (1), cedrol (9), γ-cuparenol (10), and chamigrenol (11) showed potent antibacterial activity, with MIC values in the range of 25-50 µg/mL, and ß-thujaplicin (12) exhibited a broad spectrum of antibacterial and antifungal activity. These results indicate that these isolated compounds are promising candidates for the development of potent Na(+)/K(+) ATPase inhibitors and antimicrobial agents.

Posttranscriptional crossregulation between Drosha and DGCR8.

The Drosha-DGCR8 complex, also known as Microprocessor, is essential for microRNA (miRNA) maturation. Drosha functions as the catalytic subunit, while DGCR8 (also known as Pasha) recognizes the RNA substrate. Although the action mechanism of this complex has been intensively studied, it remains unclear how Drosha and DGCR8 are regulated and if these proteins have any additional role(s) apart from miRNA processing. Here, we report that Drosha and DGCR8 regulate each other posttranscriptionally. The Drosha-DGCR8 complex cleaves the hairpin structures embedded in the DGCR8 mRNA and thereby destabilizes the mRNA. We further find that DGCR8 stabilizes the Drosha protein via protein-protein interaction. This crossregulation between Drosha and DGCR8 may contribute to the homeostatic control of miRNA biogenesis. Furthermore, microarray analyses suggest that a number of mRNAs may be downregulated in a Microprocessor-dependent, miRNA-independent manner. Our study reveals a previously unsuspected function of Microprocessor in mRNA stability control.