Molecule-Enhanced Electrocatalysis of Sustainable Oxygen Evolution Using Organoselenium Functionalized Metal-Organic Nanosheets

Remolding the reactivity of metal active sites is critical to facilitate renewable electricity-powered water electrolysis. Doping heteroatoms, such as Se, into a metal crystal lattice has been considered an effective approach, yet usually suffers from loss of functional heteroatoms during harsh electrocatalytic conditions, thus leading to the gradual inactivation of the catalysts. Here, we report a new heteroatom-containing molecule-enhanced strategy toward sustainable oxygen evolution improvement. An organoselenium ligand, bis(3,5-dimethyl-1H-pyrazol-4-yl)selenide containing robust C-Se-C covalent bonds equipped in the precatalyst of ultrathin metal-organic nanosheets Co-SeMON, is revealed to significantly enhance the catalytic mass activity of the cobalt site by 25 times, as well as extend the catalyst operation time in alkaline conditions by 1 or 2 orders of magnitude compared with these reported metal selenides. A combination of various in situ/ex situ spectroscopic techniques, ab initio molecular dynamics, and density functional theory calculations unveiled the organoselenium intensified mechanism, in which the nonclassical bonding of Se to O-containing intermediates endows adsorption-energy regulation beyond the conventional scaling relationship. Our results showcase the great potential of molecule-enhanced catalysts for highly efficient and economical water oxidation.

[Application of lymph node labeling with carbon nanoparticles by preoperative endoscopic subserosal injection in laparoscopic radical gastrectomy]

Objective: To evaluate the application value of carbon lymph node tracing technique by preoperative endoscopic subserosal injection in laparoscopic radical gastrectomy. Methods: From June 2013 to February 2015, seventy eight patients with gastric cancer were enrolled and randomly divided into trial group and control group. Subserosal injection of carbon nanoparticles around the tumor was performed by preoperative endoscopic subserosal injection one day before the operation in trial group, while the patients routinely underwent laparoscopic gastrectomy in control group. Results of harvested lymph nodes, postoperative complications were compared between the two groups. Carbon nanoparticle-related side effect was also evaluated. Results: The average number of harvested lymph node in trial group was significantly higher than that in control group (35.5±8.5 vs 29.5±6.5, P<0.05). The rate of overall black-dyed harvested lymph node was 74.7% (1 035/1 386) in trial group, the black-dyed lymph node rate in D1 lymph node was 80.1%, which was significantly higher than that in D2 lymph node (69.8%, χ²=19.38, P<0.01). When comparing the lymph node with and without black-dyed in trial group, the rate of metastasis lymph node was significantly higher in lymph node with black-dyed (17.3% vs 4.0%, χ²=38.67, P<0.01). There was no significant difference in postoperative complications rate between two group (trial group 10.2%; control group 12.8%, χ²=0.00, P>0.05), and no carbon nanoparticle-related side effect was observed. Conclusion: Given a higher harvested lymph node number and a similar rate of complications, preoperative endoscopic subserosal injection of carbon nanoparticles was safe and feasible.

Improved production of transgenic Dioscorea zingiberensis (Dioscoreaceae) by Agrobacterium tumefaciens-mediated transformation

The establishment of high-efficiency Agrobacterium-mediated transformation techniques could improve the production of Dioscorea zingiberensis, a medicinal species with a high diosgenin content. We co-cultivated embryogenic calli induced from mature seeds with A. tumefaciens strain EHA105. A binary vector, pCAMBIA1381, which contains the gfp and hpt genes under the control of the ubiquitin promoter and the CaMV 35S promoter, respectively, was used for transformation. Pre-culture, basic medium, acetosyringone, and bacterial density were evaluated to establish the most efficient protocol. The optimal conditions consisted of MS medium without CaCl(2) for pre- and co-cultivation, three days for pre-culture, addition of 200 μM AS, and an OD(600) of 0.5. The transgenic plants grown under selection were confirmed by PCR analysis and Southern blot analysis. This protocol produced transgenic D. zingiberensis plants in seven months, with a transformation efficiency of 6%.

A rotating-compensator based reflectance difference spectrometer for fast spectroscopic measurements

We present a new type of reflectance difference (RD) spectrometer for fast spectroscopic measurements based on a rotating-compensator (RC) design. The instrument uses a 1024 element Si photodiode linear array for simultaneous multiwavelength detection. High quality RD spectra covering a spectral range from 1.5 to 4.5 eV can be acquired within a few seconds. A detailed description of the working principle, the instrumentation, and the algorithms used for data collection and reduction is presented, followed by a discussion of errors introduced by lamp instability and optical imperfections of the compensator. Finally, to demonstrate the performance of the new RCRD spectrometer, we illustrate its application for the in situ, real-time monitoring of the initial stages of organic thin film growth of para-sexiphenyl (p-6P) on the Cu(110)-(2 x 1)O surface.

Morphology changes of nanocrystals induced by a small amount of water in the composite-hydroxide-mediated approach

The influence of water on morphology and structure of nanomaterials synthesized by the composite-hydroxide-mediated (CHM) approach has been systematically investigated. A small amount of water would affect the morphology and size, while a large amount of water would affect not only the morphology, but the structure of nanomaterials. The experimental results indicate that the nanocrystals prefer anisotropic growth and form more regular shape by the CHM route to hydrothermal synthesis.

Retardation correction for photoelastic modulator-based multichannel reflectance difference spectroscopy

The wavelength dependence of the retardation induced by a photoelastic modulator (PEM) is a central issue in multichannel modulator-based spectroscopic ellipsometry and reflectance difference spectroscopy (RDS), where the optical signal is detected simultaneously at different wavelengths. Here we present a refined analysis of the modulator crystal's retardation and its effect on the signal quality. Two retardation correction schemes that take into account the actual wavelength dependence of the stress-optic coefficient are introduced. It is demonstrated experimentally that both methods provide a better correction than the procedure currently used in multichannel RDS. We define quality factors to evaluate the actual performance of the multichannel detection system as compared with a wavelength adaptive single-channel experiment. These quality factors thus provide a useful guideline for choosing the appropriate PEM retardation or reference wavelength in a multichannel experiment.

Size-Manipulable Synthesis of Single-Crystalline BaMnO3and BaTi1/2Mn1/2O3Nanorods/Nanowires

We report a size-manipulable synthesis of single-crystalline nanorods/nanowires of barium manganite (BaMnO(3)) and barium titanium manganite (BaTi(1/2)Mn(1/2)O(3)) by using the composite-hydroxide-mediated approach. The synthesis cleanly yields nanorods with a hexagonal perovskite structure. Typical nanorods have widths ranging between 50 and 100 nm, and the lengths can be easily controlled by time and temperature or by adding a small amount of water during the synthesis process. Resistance measurement shows that a phase transition happened at 58 K on BaMnO(3). The photoluminescence spectrum of BaTi(1/2)Mn(1/2)O(3) presents two emission peaks at wavelengths of 465 and 593 nm, corresponding to blue and green fluorescence. The ability to synthesize nanorod manganites of a desired length should enable detailed investigations of the size-dependent evolution of magnetism, magnetoresistance, nanoscale phase separation, and realization of a nanodevice of magnetic sensors.

[Expression of WT1mRNA: relation to histology in Wilm's tumor]

The mRNA expression of WT1 gene was examined by Northern blot and Dot blot hybridization in 13 Wilm's tumors of varying histology, 2 normal kidneys (1 and 5 years of age) and 1 fetal kidney (5 months of gestation).

RESULTS

(1) WT1 gene expression was much higher in fetal kidney than in normal kidney of children; (2) Wilm's tumors which were predominantly epithelial or blastemal expressed high amounts of WT1mRNA, whereas predominantly stromal tumors expressed low amounts (P < 0.01). The data suggests that (1) there is a relationship between WT1 gene expression and cellular differentiation in kidney development; (2) low level expression of WT1mRNA results in disruption of cell differentiation and development of Wilms' tumor which shows stromal-predominant histology.

[Experimental study on mechanism of steroid-induced avascular necrosis of femoral head]

The authors adopted an animal model to observe the pathogenic mechanism of steroid-induced avascular necrosis of the femoral head. Sixty-four white rabbits were divided into two groups: hydrocortisone acetate (8 mg/kg) was hypodermically given to 48 experimental animals and 0.32 mg/kg of normal saline to 16 rabbits for control. Two groups of animals were fed and kept in the same condition. The results showed that application of the steroid drug could produce fat degeneration and necrosis of osteocytes and fat embolism in the small blood vessels of the femoral head. The abnormal hypertrophied fat cells in the bone marrow compressed small veins in the femoral head resulting in blood stasis of the capillaries, thus growth and regeneration of the capillary were inhibited.