Search

A heterogeneous NiO catalyst was prepared by a precipitation process using nickel nitrate with oxalic acid and tested for heterogeneous oxidation of benzoic acid (BA) in the presence of peroxymonosulfate (PMS). It was found that the synthetic NiO is highly effective in heterogeneous activation of PMS to produce sulfate radicals ( SO 4 · - ) and hydroxyl radicals (· OH), and also presents stable performance in the heterogeneous activation of PMS for BA degradation. Physicochemical properties of the NiO catalyst were characterized by several techniques, such as thermogravimetric analysis, Brunauer-Emmett-Teller, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. It was found that NiO and NiOOH were formed on the synthetic NiO catalyst and were stably distributed on the catalyst surface. Nearly 95% decomposition could be achieved in 30 min at the conditions of 500 ml 20 μM BA solution, 0.25 g catalyst, and [PMS]:[BA] = 30:1. The heterogeneous reactions, the effects of PMS concentration, and catalyst dosage on the BA degradation were investigated. The heterogeneous BA degradation reactions followed first-order kinetics. Additionally, quenching experiments proved that the dominant radical in the solution was · OH. The experiments results also showed that this approach is effective for the degradation of many other pollutants (such as tetracycline hydrochloride, 2, 4-dichlorophenol, Acid orange 7, rhodamine B, and methyl red). PRACTITIONER POINTS: A novel NiO material was fabricated for degradation of benzoic acid. The synthetic NiO catalyst comprised active NiO and NiOOH. The main radical for benzoic acid removal rate was · OH. A plausible mechanism for catalyzed degradation of the benzoic acid was proposed.

Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) are universal molecular engines that drive membrane fusion. Particularly, synaptic SNAREs mediate fast calcium-triggered fusion of neurotransmitter-containing vesicles with plasma membranes for synaptic transmission, the basis of all thought and action. During membrane fusion, complementary SNAREs located on two apposed membranes (often called t- and v-SNAREs) join together to assemble into a parallel four-helix bundle, releasing the energy to overcome the energy barrier for fusion. A long-standing hypothesis suggests that SNAREs act like a zipper to draw the two membranes into proximity and thereby force them to fuse. However, a quantitative test of this SNARE zippering hypothesis was hindered by difficulties to determine the energetics and kinetics of SNARE assembly and to identify the relevant folding intermediates. Here, we first review different approaches that have been applied to study SNARE assembly and then focus on high-resolution optical tweezers (OTs). We summarize the folding energies, kinetics, and pathways of both wild-type and mutant SNARE complexes derived from this new approach. These results show that synaptic SNAREs assemble in four distinct stages with different functions: slow N-terminal domain (NTD) association initiates SNARE assembly; a middle domain (MD) suspends and controls SNARE assembly; and rapid sequential zippering of the C-terminal domain (CTD) and the linker domain (LD) directly drive membrane fusion. In addition, the kinetics and pathway of the stage-wise assembly are shared by other SNARE complexes. These measurements prove the SNARE zippering hypothesis and suggest new mechanisms for SNARE assembly regulated by other proteins. This article is protected by copyright. All rights reserved.

Aim The aim of this study was to assay the clinical characteristics of persistent ectopic pregnancy (PEP) and its influence on ongoing pregnancy. Methods We retrospectively reviewed 2498 patients who received salpingostomies as primary management for ectopic pregnancies from January 2004 to December 2009, using medical records and telephone inquiries. Clinical characteristics of the 52 patients (2.08%) who were diagnosed with PEP after salpingostomy were compared with those who received satisfactory treatment. The odds ratios and 95% confidential intervals were calculated for each variable by univariate and (for significantly different factors) multivariate analysis. Results Preoperatively, patients with PEP after salpingostomy significantly differed from the non-PEP patients in gestational age, mass size and pelvic adhesiolysis. Serum β-human chorionic gonadotropin levels in PEP patients were monitored after surgery, which had declined by 28.31% on postoperative day (POD) 4, 40.22% on POD 7, 51.46% on POD 10 and 53.43% on POD 21. Repeat ectopic pregnancy (REP) tended to occur more frequently in PEP patients (PEP: 5 cases, 10.20%; non-PEP: 4 cases, 2.80%; P = 0.034). Multivariate analysis showed that pelvic adhesions and PEP were the strongest independent predictors of REP. Conclusion Gestational age, mass size and pelvic adhesions were significantly correlated with PEP. PEP was an independent prognostic factor for REP. However, a multicenter study is needed to support and extend our findings.

This study seeks to evaluate the potential benefits of high doses of ambroxol treatment for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) by conducting a meta-analysis based on randomized controlled trials (RCTs). We searched the Pubmed, Embase, China National Knowledge Infrastructure, and Wanfang databases through December 2013. Only RCTs evaluating high doses of ambroxol (≥15 mg/kg or 1000 mg/day) treatment for patients with ALI/ARDS were selected. We included 10 RCTs involving 508 patients. Adjuvant treatment with high doses of ambroxol increased PaO(2)/FiO(2) (weight mean differences [WMD] = 69.18, 95% confidence intervals [CI]: 41.71-96.65), PO(2) (WMD = 11.74, 95% CI: 8.50-14.99), and SaO(2) (WMD = 2.15, 95% CI: 1.60-2.71) compared with usual treatment. Treatment with high doses of ambroxol appeared to reduce serum tumor necrosis factor-α level (WMD -7.92 µg/L; 95% CI, -10.94 to -4.9) and interleukin-6 level (WMD = -20.65 µg/L, 95% CI: -24.74 to -16.55) and to increase serum superoxide dismutase level (WMD = 19.07 NU/mL, 95% CI: 6.16-31.97). The findings suggest that treatment with high doses of ambroxol appears to improve PaO(2)/FiO(2), PO(2), and SaO(2), and the benefits might be related to ambroxol's anti-oxidant and anti-inflammatory properties.

This paper examines the effect of short-sale constraints on the stock price manipulation of an insider, who is subject to mandatory disclosure rules. We show that the privately informed insider may manipulate by trading against his or her information when short selling is banned. We find that stock price movement is asymmetric in the sense that prices fall by a larger percentage than they rise. In addition, we prove that removing short-sale constraints increases price volatility. Finally, we explore the welfare implications of short-sale constraints.

A ligand-free Pd/Al(OH)3 nano-catalyst which is prepared by one-pot three-component method using Pd(PPh3)4, tetra (ethylene glycol), and aluminum tri-sec-butoxide exhibits excellent catalytic activity in Stille cross-couplings of (Het)aryl chlorides, arenediazonium tetrafluoroborate salts with phenyltributylstannane, respectively, and Kumada couplings of (Het)aryl chlorides with various Grignard reagents. More importantly, these two processes show excellent functional group compatibility with moderate to good yields and they are also versatile with respect to not only (Het)aryl chlorides, but also diazonium salts, and heteroaryl Grignard reagents. The nano-catalyst could also be recycled and reused 5 times without loss of activity and decrease of yield.

Early detection of resistance to platinum-based therapy is critical for improving the treatment of ovarian cancers. We have previously found that increased expression of annexin A3 is a mechanism for platinum resistance in ovarian cancer cells. Here we demonstrate that annexin A3 can be detected in the culture medium of ovarian cancer cells, particularly these cells that express high levels of annexin A3. Levels of annexin A3 were then determined in sera from ovarian cancer patients using an enzyme-linked immunosorbent assay. Compared with those from normal donors, sera from ovarian cancer patients contain significantly higher levels of annexin A3. Furthermore, serum levels of annexin A3 were significantly higher in platinum-resistant patients than in platinum-sensitive patients. To gain insight into the mechanism of secretion, the ovarian cancer cell lines were examined using both transmission electron microscopy and immunoelectron microscopy. Compared with parent cells, there are significantly more vesicles in the cytoplasm of ovarian cancer cells that express high levels of annexin A3, and at least some vesicles are annexin A3-positive. Moreover, some vesicles appear to be fused with the cell membrane, suggesting that annexin A3 secretion may be associated with exocytosis and the release of exosomes. This is supported by our observation that ovarian cancer cells expressing higher levels of annexin A3 released increased numbers of exosomes. Furthermore, annexin A3 can be detected in exosomes released from cisplatin-resistant cells (SKOV3/Cis) by immunoblotting and immunoelectron microscopy.

ATP‐dependent chromatin remodelling complexes use the energy of ATP hydrolysis to reposition and reconfigure nucleosomes. Despite their diverse functions, all remodellers share highly conserved ATPase domains, many shown to translocate DNA. Understanding remodelling requires biophysical knowledge of the DNA translocation process: how the ATPase moves DNA and generates force, and how translocation and force generation are coupled on nucleosomes. Here, we characterize the real‐time activity of a minimal RSC translocase ‘motor’ on bare DNA, using high‐resolution optical tweezers and a ‘tethered’ translocase system. We observe on dsDNA a processivity of ∼35 bp, a speed of ∼25 bp/s, and a step size of 2.0 (±0.4, s.e.m.) bp. Surprisingly, the motor is capable of moving against high force, up to 30 pN, making it one of the most force‐resistant motors known. We also provide evidence for DNA ‘buckling’ at initiation. These observations reveal the ATPase as a powerful DNA translocating motor capable of disrupting DNA–histone interactions by mechanical force.