Broadening the catalytic region from the cavity to windows by M₆L₁₂ nanospheres in cyclizations

Supramolecular cages have received tremendous attention as they can contain catalysts that exhibit confinement effects in the cavity, leading to excellent performances. Herein, we report an example wherein the catalytic region is extended from the cage cavity to the windows, and investigate its confinement effect by utilizing the Pd6LAu12 cage that contains rigidly fixed and isolated gold complexes at the windows. Pd6LAu12 exhibit three features of particular interest while assessing their properties in gold-catalyzed cyclization reactions. First, the catalysts experience a cage effect as they display higher reactivity and selectivity compared to the monomeric analogue, as a result of substrate pre-organization at the windows. Second, the metal complexes are physically separated by the cage structure, preventing the formation of less active dinuclear gold complexes making it more stable under hydrous conditions. Third, the cage windows present the characteristics of enzymatic catalysis via Michaelis-Menten-type mechanism analysis. This contribution presents an alternative way to engineer supramolecular catalysts through extending the catalytic region.</p

Absence of Dipole Transitions in Vortices of Type II Superconductors

The response of a single vortex to a time dependent field is examined microscopically and an equation of motion for vortex motion at non-zero frequencies is derived. Of interest are frequencies near $\Delta^{2}/E_{F}$, where $\Delta$ is the bulk energy gap and $E_{F}$ is the fermi energy. The low temperature, clean, extreme type II limit and maintaining of equilibrium with the lattice are assumed. A simplification occurs for large planar mass anisotropy. Thus the results may be pertinent to materials such as $NbSe_2$ and high temperature superconductors. The expected dipole transition between core states is hidden because of the self consistent nature of the vortex potential. Instead the vortex itself moves and has a resonance at the frequency of the transition.Comment: 12 pages, no figure

Evolutionary Characterization of the Pandemic H1N1/ 2009 Influenza Virus in Humans Based on Non-Structural Genes

The 2009 influenza pandemic had a tremendous social and economic impact. To study the genetic diversity and evolution of the 2009 H1N1 virus, a mutation network for the non-structural (NS) gene of the virus was constructed. Strains of the 2009 H1N1 pandemic influenza A virus could be divided into two categories based on the V123I mutation in the NS1 gene: G1 (characterized as 123 Val) and G2 (characterized as 123 Ile). Sequence homology analysis indicated that one type of NS sequence, primarily isolated from Mexico, was likely the original type in this pandemic. The two genotypes of the virus presented distinctive clustering features in their geographic distributions. These results provide additional insight into the genetics and evolution of human pandemic influenza H1N1

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Different loading rates of photocatalysts Co3O4/C3N4 were prepared by calcination method. Their photocatalytic performances were evaluated by the degradation of methyl blue under visible light irradiation. The results show that the introduction of Co3O4 significantly improves the optical absorption properties of C3N4, which is beneficial to the separation of photogenerated electrons and holes on the surface of catalyst. The prepared Co3O4/C3N4 for visible photocatalytic degradation of methyl blue has higher catalytic efficiency than that of pure C3N4 or pure Co3O4. The best cobalt loading rate was 30% when the concentration of methylene blue was 40 mg/L. Recycling rate of 30% Co3O4/C3N4 composite catalyst was studied. After 4 cycles, the degradation rate was only slightly decreased from 86.8% to 82.8%, indicating the catalyst with good photostability and repeatability.nbs

Brown Carbon Aerosol in Urban Xi’an, Northwest China: TheComposition and Light Absorption Properties

Light-absorbing organic carbon (i.e., brown carbon or BrC) in the atmospheric aerosol has significant contribution to light absorption and radiative forcing. However, the link between BrC optical properties and chemical composition remains poorly constrained. In this study, we combine spectrophotometric measurements and chemical analyses of BrC samples collected from July 2008 to June 2009 in urban Xi&#39;an, Northwest China. Elevated BrC was observed in winter (5 times higher than in summer), largely due to increased emissions from wintertime domestic biomass burning. The light absorption coefficient of methanol-soluble BrC at 365 nm (on average approximately twice that of water-soluble BrC) was found to correlate strongly with both parent polycyclic aromatic hydrocarbons (parent-PAHs, 27 species) and their carbonyl oxygenated derivatives (carbonyl-OPAHs, 15 species) in all seasons (r(2) &gt; 0.61). These measured parent-PAHs and carbonyl-OPAHs account for on average similar to 1.7% of the overall absorption of methanol-soluble BrC, about 5 times higher than their mass fraction in total organic carbon (OC, similar to 0.35%). The fractional solar absorption by BrC relative to element carbon (EC) in the ultraviolet range (300-400 nm) is significant during winter (42 +/- 18% for water-soluble BrC and 76 +/- 29% for methanol-soluble BrC), which may greatly affect the radiative balance and tropospheric photochemistry and therefore the climate and air quality

Assessment of the Quality of Reporting in Abstracts of Randomized Controlled Trials Published in Five Leading Chinese Medical Journals

BACKGROUND: Clear, transparent and sufficiently detailed abstracts of randomized trials (RCTs), published in journal articles are important because readers will often base their initial assessment of a trial on such information. However, little is known about the quality of reporting in abstracts of RCTs published in medical journals in China. METHODS: We identified RCTs abstracts from 5 five leading Chinese medical journals published between 1998 and 2007 and indexed in MEDLINE. We assessed the quality of reporting of these abstracts based on the Consolidated Standards of Reporting Trials (CONSORT) abstract checklist. We also sought to identify whether any differences exist in reporting between the Chinese and English language version of the same abstract. RESULTS: We identified 332 RCT abstracts eligible for examination. Overall, the abstracts we examined reported 0-8 items as designated in the CONSORT checklist. On average, three items were reported per abstract. Details of the interventions (288/332; 87%), the number of participants randomized (216/332; 65%) and study objectives (109/332; 33%) were the top three items reported. Only two RCT abstracts reported details of trial registration, no abstracts reported the method of allocation concealment and only one mentioned specifically who was blinded. In terms of the proportion of RCT abstracts fulfilling a criterion, the absolute difference (percentage points) between the Chinese and English abstracts was 10% (ranging from 0 to 25%) on average, per item. CONCLUSIONS: The quality of reporting in abstracts of RCTs published in Chinese medical journals needs to be improved. We hope that the introduction and endorsement of the CONSORT for Abstracts guidelines by journals reporting RCTs will lead to improvements in the quality of reporting

Application of magnifying narrow-band imaging endoscopy for diagnosis of early gastric cancer and precancerous lesion

<p>Abstract</p> <p>Background</p> <p>Gastric carcinoma is the second commonest cause of cancer deaths worldwide. Early detection and diagnosis of gastric cancer in the stomach is important for improving the prognosis of gastric cancer. This retrospective study was designed to investigate the value of magnifying narrow-band imaging (NBI) in the diagnosis of precancerous lesions and early gastric cancer.</p> <p>Methods</p> <p>This study included 122 patients who were diagnosed with early gastric cancer or precancerous gastric lesions by endoscopy. The patients underwent an examination with conventional endoscopy, magnifying NBI, and magnifying chromoendoscopy. Images resolution was evaluated, and the morphology, pit patterns and blood capillary forms of lesions were analyzed. The presence of gastric carcinoma and high grade intraepithelial neoplasia in the biopsy samples was considered as a positive pathological result, which is used to assess accuracy of endoscopic diagnosis.</p> <p>Results</p> <p>For image resolution, magnifying NBI and magnifying chromoendoscopy were significantly superior to magnifying conventional endoscopy in morphology, pit pattern and blood capillary form (P < 0.01), and magnifying NBI was significantly superior to magnifying chromoendoscopy in blood capillary form (P < 0.01). IV, V₁, and VI type of gastric pit pattern were detected in 14 cases, 43 cases, and 17 cases in patients with high grade intraepithelial neoplasia, respectively. V₁and VI type of gastric pit pattern were detected in 9 cases and 39 cases in patients with early gastric cancer, respectively. The presence of irregular minute vessels and variation in the caliber of vessels was found in 109 cases. The accuracy, sensitivity, specificity, false positive rate and false negative rate for diagnosis of early gastric cancer and precancerous gastric lesions were 68.9%, 95.1%, 63.1%, 24.5%, and 32.4% for conventional endoscopy, 93.6%, 92.7%, 94.5%, 5.7%, and 6.9% for magnifying NBI, and 91.3%, 88.6%, 93.2%, 13.2%, and 21.48% for magnifying chromoendoscopy, respectively.</p> <p>Conclusions</p> <p>This study demonstrates that magnifying NBI is superior to conventional endoscopy in the diagnosis of early gastric cancer and precancerous gastric lesions, and can be used for screening early malignancies of the stomach.</p

Quantum entanglement and disentanglement of multi-atom systems

We present a review of recent research on quantum entanglement, with special emphasis on entanglement between single atoms, processing of an encoded entanglement and its temporary evolution. Analysis based on the density matrix formalism are described. We give a simple description of the entangling procedure and explore the role of the environment in creation of entanglement and in disentanglement of atomic systems. A particular process we will focus on is spontaneous emission, usually recognized as an irreversible loss of information and entanglement encoded in the internal states of the system. We illustrate some certain circumstances where this irreversible process can in fact induce entanglement between separated systems. We also show how spontaneous emission reveals a competition between the Bell states of a two qubit system that leads to the recently discovered "sudden" features in the temporal evolution of entanglement. An another problem illustrated in details is a deterministic preparation of atoms and atomic ensembles in long-lived stationary squeezed states and entangled cluster states. We then determine how to trigger the evolution of the stable entanglement and also address the issue of a steered evolution of entanglement between desired pairs of qubits that can be achieved simply by varying the parameters of a given system.Comment: Review articl

Symmetry and topology in antiferromagnetic spintronics

Antiferromagnetic spintronics focuses on investigating and using antiferromagnets as active elements in spintronics structures. Last decade advances in relativistic spintronics led to the discovery of the staggered, current-induced field in antiferromagnets. The corresponding N\'{e}el spin-orbit torque allowed for efficient electrical switching of antiferromagnetic moments and, in combination with electrical readout, for the demonstration of experimental antiferromagnetic memory devices. In parallel, the anomalous Hall effect was predicted and subsequently observed in antiferromagnets. A new field of spintronics based on antiferromagnets has emerged. We will focus here on the introduction into the most significant discoveries which shaped the field together with a more recent spin-off focusing on combining antiferromagnetic spintronics with topological effects, such as antiferromagnetic topological semimetals and insulators, and the interplay of antiferromagnetism, topology, and superconductivity in heterostructures.Comment: Book chapte