Selectfluor-Mediated Electrophilic Annulation of 2-Alkynyl Biaryls with Diorganyl Diselenides.

A general and efficient method for the synthesis of various selanyl phenanthrenes/polycyclic heteroaromatics through the electrophilic annulation of 2-alkynyl biaryls with diorganyl diselenides under metal-free and mild conditions was established. The sulfanyl phenanthrene was also obtained in moderate yields.

Modifying a D-A-π-A-D HTM system for higher hole mobility by the meta-substitution strategy to weaken the electron-donating ability of the donor unit: a DFT study.

Tuning the electron-donating ability (EDA) of the donor units of hole transporting materials (HTMs) is an efficient strategy to modulate the optoelectronic properties of HTMs. Based on this strategy, we first theoretically investigated the effects of the EDA of donor units on D-A-π-A-D architectural HTMs. The results show that the enhanced EDA of the donor unit leads to larger hole reorganization energy and poorer molecular stability of HTMs. In contrast, meta-substitution of side groups is an effective strategy to reduce the EDA of the donor unit. We found that the application of the meta-substitution strategy in the D-A-π-A-D system not only successfully improves the molecular stability, but also achieves higher hole mobility by promoting the electronic coupling between the molecular dimers and decreasing the hole reorganization energies simultaneously. Studies on interfacial properties indicate that intermolecular coupling also synergistically enhances the interfacial charge extraction performance and reduces carrier recombination. In conclusion, by utilizing the meta-substitution strategy to reduce the EDA of donor units on D-A-π-A-D architectural HTMs, we successfully designed four superior performance HTMs mD1, mD2, mD3, and mD4.

Fracture strength of custom-fabricated Celay all-ceramic post and core restored endodontically treated teeth.

BACKGROUND: The increased use of all-ceramic crown provides a rationale for tooth-colored core. Due to superior mechanical properties, Vita Celay infiltration ceramic developed for crown and bridge works presents the potential for fabricating all-ceramic posts and cores in one piece. This study was conducted to compare the fracture strength of endodontically treated teeth which were thereafter given different types of posts and cores and crowns restoration, respectively. The evaluated post-and-core systems are: custom-fabricated Celay all-ceramic post-core, custom cast metal post-core, and prefabricated stainless steel post (Parapost) with and without 2.0 mm dentine ferrule. METHODS: Sixty freshly extracted human maxillary central incisors were endodontically treated and randomly divided into five groups with 12 samples each. Group A: Celay ceramic post-cores restored teeth with 2.0 mm dentine ferrule. Group B: Celay ceramic post-cores restored teeth with no dentine ferrule. Group C: cast metal post-cores restored teeth with 2.0 mm dentine ferrule. Group D: cast metal post-cores restored teeth with no dentine ferrule. Group E: prefabricated post and composite cores restored teeth with 2.0 mm dentine ferrule. All teeth were restored with Celay ceramic crowns. Each specimen was subjected to a load at a 45-degree angle to the long axis on MTS 810 material testing machine until failure, at crosshead speed of 0.02 cm/minute. Analysis of variance followed by the Newman-Keuls pairwise multiple comparison tests were used to compare the results of the groups tested. RESULTS: There was a statistically significant difference among the five groups (P < 0.01). Celay ceramic post-cores restored teeth with 2.0 mm dentine ferrule [(758.35+/-19.26) N] and cast metal post-cores restored teeth with 2.0 mm dentine ferrule [(756.63+/-66.22) N] had a significantly greater mean fracture strength than the other three groups in which no significant difference was observed. The 2.0 mm dentine ferrule could cause significant fracture resistance alteration of Celay post-core restored teeth. CONCLUSIONS: When covered with Celay ceramic crowns, Celay post-cores restored teeth with 2.0 mm dentine ferrule and cast metal post-cores restored teeth with 2.0 mm dentine ferrule have similar fracture strength. There was a statistically significant difference between the fracture resistance of Celay post-core restored teeth with and without 2.0 mm dentine ferrule.

[Adsorbable organic halogen compounds and bio-toxicity in hospital wastewater treatment].

Adsorbable organic halogen compounds (AOX) exist persistently in the aquatic environment, and accumulate in the food chain. Some of them are toxic for humans and other organisms. However, hospital wastewater is considered as an important source of AOX in municipal wastewater. The aim of this study was to evaluate the generation of AOX both in a raw hospital wastewater and the effluent from a membrane sequencing batch reactor, also the effect of cR t value and the bio-toxicity were investigated. The results show that the removal of AOX in the hospital wastewater is 63.6% after treated by the membrane sequencing batch reactor, and the contribution of membrane rejection accounts for 14.5%. The concentration of AOX in the raw hospital wastewater is much higher than that of the effluent from membrane sequencing batch reactor at the same value of cR t for its higher chlorine-demands. Along with the increasing of cR t value, the fitting curves of AOX present exponential growth for the raw hospital wastewater, while linearity relation for the effluent from membrane sequencing batch reactor. To meet the requirement for indicative microorganism (fecal coliform) in the Discharge Standard of Water Pollutants for Medical Organization (GB 18466-2005), the demands of cR t value for the raw hospital wastewater and the effluent from membrane sequencing batch reactor are 5.5 (mg x h)/L and 0.0075 (mg x h)/L respectively, the bio-toxity by acute toxicity test with Daphnia magna are 40.39 microg/L (K2Cr2O7) and 8.96 microg/L (K2Cr2O7), and correspondingly the concentration of AOX produced are 607.1 microg/L and 102.5 microg/L.

The reverse posterior interosseous flap and its composite flap: experience with 201 flaps.

OBJECTIVE: To introduce our experiences of using the reverse posterior interosseous flap and its composite flap. METHODS: In the series of 201 cases, the fasciocutaneous flap was used to cover skin defects over the distal 1/3rd forearm, wrist and hand in 174 cases. The composite flap with the vascularised ulna bone graft was used to reconstruct the thumbs in 11 cases, and with the vascularised tendon graft was used to repair tendon defects with skin defects in 16 cases. The size of the ulna graft was 3-6cm in length and 1-2cm in width. The 4-7cm tendon graft was obtained from the extensor digiti quinti or extensor carpi ulnaris. The size of the flaps ranged from 5cmx4cm to 16cmx10cm. RESULTS: One flap failed completely. Of the other 200 flaps which survived 16 cases had venous congestion and had partial necrosis at the distal end. The size of the necrotic area ranged from 1 to 4cm in length. Ninety-three patients were followed up for at least 6 months, and included 10 patients with composite flaps. Generally, the flap matched the surrounding skin. But 10 cases had a lipectomy. The sensibility did not recover or achieved S1 within 6 months. For the extensor tendon defect, the function of finger extension was nearly normal and tenolysis was not required. In contrast, tenolysis was required after the flexor tendon reconstruction. However, these patients refused surgery. The bone grafts were healed in 3 months. The reconstructed thumb looked abnormal and lacked normal sensibility, although the patients used them. The linear scar line was conspicuous over the dorsum of the forearm. CONCLUSION: The reverse posterior interosseous flap is a reliable method to cover skin defects over the distal 1/3rd of the forearm, the wrist and hand. The composite flap with a vascularised tendon graft is an optimal reconstructive option for any extensor tendon loss (III zone) associated with a skin defect. Using the composite flap with a vascularised bone graft or combined with the digital neurovascular flap is another way to reconstruct the thumb.

Vascularized capitate transposition for advanced Kienböck disease: application of 40 cases and their anatomy.

Based on anatomic study, the vascularized capitate transposition to replace excised necrotic lunate was designed and applied in 40 cases of advanced Kienböck disease. It includes excision of the necrotic lunate and proximal shift of the vascularized capitate. The blood supply of the transposed capitate is provided by the dorsal branch of the anterior interosseous artery. Bone union occurred radiographically, and no postoperative capitate necrosis occurred in all cases after 6 weeks. Twenty-three cases were followed up for 1 year. No residual wrist pain existed in the range of motion, but limited residual wrist pain existed in labor work. The arc of motion ranged on average from 35 degrees of flexion to 45 degrees of extension. The grip power of the affected hand reached on average 70% compared with the contralateral. The authors conclude the vascularized capitate transposition is a reliable alternative for advanced Kienböck disease.