Photocatalytic Activation of Saturated C–H Bond Over the CdS Mixed-Phase Under Visible Light Irradiation

Selective activation of saturated C–H bond in hydrocarbons to produce high-value-added chemicals is of great significance for chemical synthesis and transformation. Herein, we present a facile procedure to achieve Ni-doped CdS nanoparticles with mixed (cubic and hexagonal) phases, as well as its application to the photocatalytic activation of saturated primary C–H bond of toluene and its derivatives. The photocatalytic oxidation rate of toluene into benzaldehyde of formation reached up to 216.7 μmolh−1g−1 under visible light irradiation. The excellent photocatalytic performance of Ni(II)-doped CdS [Ni(II)/CdS] can be attributed to its unique structural assembly with cubic and hexagonal phases and also the addition of Ni ions, together taking effect in promoting the separation of photogenerated charge carriers. The possible reaction mechanism for the photocatalytic selective oxidation is illustrated in this work. The band width of the as-prepared mixed phase CdS is reduced, which can effectively expand the response range and improve photocatalytic performance

A Nonaqueous Approach to the Preparation of Iron Phosphide Nanowires

Previous preparation of iron phosphide nanowires usually employed toxic and unstable iron carbonyl compounds as precursor. In this study, we demonstrate that iron phosphide nanowires can be synthesized via a facile nonaqueous chemical route that utilizes a commonly available iron precursor, iron (III) acetylacetonate. In the synthesis, trioctylphosphine (TOP) and trioctylphosphine oxide (TOPO) have been used as surfactants, and oleylamine has been used as solvent. The crystalline structure and morphology of the as-synthesized products were characterized by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The obtained iron phosphide nanowires have a typical width of ~16 nm and a length of several hundred nanometers. Structural and compositional characterization reveals a hexagonal Fe2P crystalline phase. The morphology of as-synthesized products is greatly influenced by the ratio of TOP/TOPO. The presence of TOPO has been found to be essential for the growth of high-quality iron phosphide nanowires. Magnetic measurements reveal ferromagnetic characteristics, and hysteresis behaviors below the blocking temperature have been observed

New approaches in the diagnosis and treatment of latent tuberculosis infection

With nearly 9 million new active disease cases and 2 million deaths occurring worldwide every year, tuberculosis continues to remain a major public health problem. Exposure to Mycobacterium tuberculosis leads to active disease in only ~10% people. An effective immune response in remaining individuals stops M. tuberculosis multiplication. However, the pathogen is completely eradicated in ~10% people while others only succeed in containment of infection as some bacilli escape killing and remain in non-replicating (dormant) state (latent tuberculosis infection) in old lesions. The dormant bacilli can resuscitate and cause active disease if a disruption of immune response occurs. Nearly one-third of world population is latently infected with M. tuberculosis and 5%-10% of infected individuals will develop active disease during their life time. However, the risk of developing active disease is greatly increased (5%-15% every year and ~50% over lifetime) by human immunodeficiency virus-coinfection. While active transmission is a significant contributor of active disease cases in high tuberculosis burden countries, most active disease cases in low tuberculosis incidence countries arise from this pool of latently infected individuals. A positive tuberculin skin test or a more recent and specific interferon-gamma release assay in a person without overt signs of active disease indicates latent tuberculosis infection. Two commercial interferon-gamma release assays, QFT-G-IT and T-SPOT.TB have been developed. The standard treatment for latent tuberculosis infection is daily therapy with isoniazid for nine months. Other options include therapy with rifampicin for 4 months or isoniazid + rifampicin for 3 months or rifampicin + pyrazinamide for 2 months or isoniazid + rifapentine for 3 months. Identification of latently infected individuals and their treatment has lowered tuberculosis incidence in rich, advanced countries. Similar approaches also hold great promise for other countries with low-intermediate rates of tuberculosis incidence

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

N,N′-[(2E,3E)-Butane-2,3-diylidene]bis[4-fluoro-2-(1-phenylethyl)aniline]

The title molecule, C32H30F2N2, a product of the condensation reaction of butane-2,3-dione and 4-fluoro-2-(1-phenylethyl)aniline, is located about an inversion centre. In the asymmetric unit, the dihedral angle between the planes of the benzene and phenyl rings is 84.27 (5)°. Neither hydrogen bonding nor aromatic stacking is observed in the crystal structure

Structure, optical and magnetic properties of Ni@Au and Au@Ni nanoparticles synthesized via non-aqueous approaches

National Natural Science Foundation of China [50701036]; National Basic Research Program of China [2012CB933103]; National Outstanding Youth Science Foundation of China [50825101]Although the combination of magnetic and noble metals in core-shell nanoparticles is very useful in many applications, the preparation of magnetic-noble bimetallic core-shell nanoparticles with uniform shells remains a great challenge due to large mismatch of crystal lattices between magnetic and noble metals. Herein we present non-aqueous methods for combing Au and Ni in nanoscale to form a core-shell structure. Ni@Au nanoparticles were prepared via an injection-quenching process in which Au precursors decomposed and formed closed shells on pre-formed Ni seeds synthesized in oleylamine, whereas Au@Ni nanoparticles were obtained in a one-step reaction involving a seed-catalyzed mechanism. The formed core-shell structure was confirmed by high-angle annular dark-field imaging along with the analyses of energy-dispersive X-ray spectroscopy and high-resolution transmission electron microscopy. UV-Visible absorption spectroscopy and superconducting quantum interference device magnetometer were used to characterize the optical and magnetic properties of the as-prepared bimetallic core-shell nanoparticles. Through the adjustment of growth conditions, Ni@Au and Au@Ni nanoparticles with different core or shell dimensions and morphologies were obtained, which offers an important means to tailor their optical and magnetic properties for multiple practical applications

Nickel-Doped Excess Oxygen Defect Titanium Dioxide for Efficient Selective Photocatalytic Oxidation of Benzyl Alcohol

In this study, a novel composite Ni-OTiO₂ was prepared by doping nickel and introducing excess oxygen defects in TiO₂. The as-synthesized Ni-OTiO₂ particles were characterized by scanning electron microscopy, X-ray diffractino, transmission electron microscopy, Fourier transform infrared spectroscopy, differential reflectance spectroscopy, photoluminescence, photoelectrochemistry, and X-ray photoelectron spectroscopy. When employing Ni (1%)-OTiO₂ as photocatalyst, the conversion of benzyl alcohol (BA) was up to 93% by 1 h irradiation derived from a 300 W xenon lamp, which is ∼8-times higher than that using pure TiO₂. Moreover, while being irradiated with the 300 W xenon lamp (using a filter, λ > 420 nm), the Ni (1%)-OTiO₂ conducted photocatalytic system can give 86% conversion of BA to benzaldehyde within 1 h. Specifically, during photocatalysis, a peroxo group and nickel ion act as the electron carrier, promoting the separation of the electron–hole pair. It is considered that the highly improved photocatalytic ability after modification of pure TiO₂ is ascribable to the synergistic effect of excess oxygen defects and nickel doping in TiO₂

Defect Engineering in CuS<i>_x</i>/COF Hybridized Heterostructures: Synergistic Facilitation of the Charge Migration for an Efficacious Photocatalytic Conversion of CO₂ into CO

The photocatalytic CO2 reduction reaction (CO2RR) provides an attractive approach to tackling environmental issues. To actualize the optimal catalytic efficiency, one efficacious strategy is to rationally modulate the charge migration for the adopted heterogeneous catalysts. Herein, by virtue of a one-step hydrothermal method, Cu2S nanospheres and defect-rich Cu2S (CuSx) nanosheets are wrapped by a triazine-containing covalent framework (TP-TA COF), resulting in CuSx/TP-TA and Cu2S/TP-TA. Owing to the heterojunction construction that suppresses the carrier recombination, both hybridized structures present enhanced charge migration in comparison to that of their corresponding sulfides and COF constituents. It is worth emphasizing that CuSx/TP-TA proffers a significantly greater photocurrent than Cu2S/TP-TA. The subsequent photocatalytic reduction of CO2 also exhibits an apparently higher CO evolution rate, about 2.8 times higher than the Cu2S/TP-TA photocatalyst. The above evident improvement owes much to the heterostructure establishment between CuSx and TP-TA COF, as well as the synergistic effect provided by the defect engineering for CuSx, both of which are able to enhance the separation efficiency of photoinduced carriers. Our work sheds light on the rational construction of heterogeneous structures between organic and inorganic photocatalysts, which emphasizes the possible synergistic effect of defect centers for enhancing photocatalytic performance