DJL

“ … Cross-cultural collaboration, when it works, is synergistic, and brings understanding between partners that neither is likely to be able to develop alone. There are people in the world that know something, but nobody knows everything. International collaborations in science bring together and capitalize on the dispersal of knowledge and resources across the globe, and the human desire to advance knowledge …” Read more in the Editorial by Joseph S. Francisco.

Here we present a nuclear forensic study of uranium from German nuclear projects which used different geometries of metallic uranium fuel.3b,d, 4 Through measurement of the ²³⁰Th/²³⁴U ratio, we could determine that the material had been produced in the period from 1940 to 1943. To determine the geographical origin of the uranium, the rare-earth-element content and the ⁸⁷Sr/⁸⁶Sr ratio were measured. The results provide evidence that the uranium was mined in the Czech Republic. Trace amounts of ²³⁶U and ²³⁹Pu were detected at the level of their natural abundance, which indicates that the uranium fuel was not exposed to any major neutron fluence.

En route to nuclear reactors: When the first self-sustained nuclear chain reaction was initiated in 1942, projects focusing on the technical application of nuclear fission had also been launched in Germany. Two historic samples of uranium have now been studied in order to determine the source and age of the material and whether it had been exposed to any major neutron fluences.

“… Fifty years ago, out of the ashes of the Second World War, the German Chancellor, Konrad Adenauer, and the Israeli Prime Minister, David Ben-Gurion, initiated the establishment of diplomatic relations between Germany and Israel. This special issue commemorates the fruitful and mutually enriching long-term collaborations between Israeli and German scientists … Read more in the Editorial by Helmut Schwarz, Itamar Willner, and Ilan Marek.

Most recently, much attention has been devoted to 1T phase MoS₂ because of its distinctive phase-engineering nature and promising applications in catalysts, electronics, and energy storage devices. While alkali metal intercalation and exfoliation methods have been well developed to realize unstable 1T-MoS₂, but the aqueous synthesis for producing stable metallic phase remains big challenging. Herein, a new synthetic protocol is developed to mass-produce colloidal metallic 1T-MoS₂ layers highly stabilized by intercalated ammonium ions (abbreviated as N-MoS₂). In combination with density functional calculations, the X-ray diffraction pattern and Raman spectra elucidate the excellent stability of metallic phase. As clearly depicted by high-angle annular dark-field imaging in an aberration-corrected scanning transmission electron microscope and extended X-ray absorption fine structure, the N-MoS₂ exhibits a distorted octahedral structure with a 2a ₀ × a ₀ basal plane superlattice and 2.72 Å Mo–Mo bond length. In a proof-of-concept demonstration for the obtained material's applications, highly efficient photocatalytic activity is achieved by simply hybridizing metallic N-MoS₂ with semiconducting CdS nanorods due to the synergistic effect. As a direct outcome, this CdS:N-MoS₂ hybrid shows giant enhancement of hydrogen evolution rate, which is almost 21-fold higher than pure CdS and threefold higher than corresponding annealed CdS:2H-MoS₂.

Gram-scale aqueous synthesis of 1T-MoS₂ , highly stabilized by intercalated ammonium ions, is demonstrated. In combination with X-ray absorption spectra and atomic structure observations, the correlation between microstructure and stable metallic phase is revealed, agreeing with density functional calculations. More interestingly, highly efficient hydrogen evolution is achieved by hybridizing the 1T-MoS₂ with semiconducting CdS nanorods.

Recently bendable and flexible optoelectronics have attracted more attentions on display technology and concaved or curvy photovoltaic devices owing to the flexibility and softy in layered materials. The bending photoluminescence (BPL) and surface photovoltaic effect of a thin multilayer InSe 2D crystal are demonstrated here by using PL and surface photovoltage (SPV) experiments. The BPL result of InSe (t ≈ 30 nm) shows an enhancement in light intensity with respect to that of the other flat PL measurement owing to the spreading of emission solid angle for the irradiant Se-In-In-Se basic units under concaved upward condition. The band edge structure of multilayer InSe is analyzed. The SPV measurement of an In mesh-coated InSe microplate demonstrates that the Schottky-type solar cell converts sunlight starting from ≈1 eV with the auxiliary of surface states on InSe. An initially formed In-InSe Schottky solar cell (surface area of ≈2 mm² and thickness of ≈85 μm) is also tested. The testing result shows a photovoltage of V ≈ 24 mV can be generated from the Schottky solar cell under the illumination of Hg lamp with power density of P ≈ 0.83 mW cm⁻². All the experimental results demonstrate flexible light-emission capability and “1 eV” photoelectric conversion capacity existed in the 2D multilayer ε-InSe.

The bending photoluminescence (BPL) and surface photovoltaic effect of a thin multilayer InSe 2D microplate crystal are demonstrated. The BPL result shows an enhancement in light intensity (×6) with respect to that of the other flat PL measurement for InSe. A small area of In-InSe Schottky solar cell is also tested. The testing result shows a photovoltage of V ≈ 24 mV was generated from the Schottky solar cell under the illumination of Hg lamp.

A majority of the photo-responsive drug-delivery systems that are currently being studied require a complicated synthesis method. Here, we prepare a near-infrared responsive, photothermally controllable, drug-delivery carrier by a simple mixing and extraction process without the incorporation of toxic chemicals. A blend of doxorubicin (DOX), an anticancer drug, and a phase-change material (PCM) are loaded onto the mesoporous structure of silica-coated graphene oxide (GO@MS) to form a waffle-like structure, which is confirmed by various physicochemical analyses. The cytotoxicity of DOX/PCM-loaded GO@MS (DOX/PCM-GO@MS) against HeLa cells is 50 times higher than that of free DOX, and this improved activity can be attributed to the photothermal effectiveness of GO@MS. Additionally, the cytotoxicity and uptake mechanism of the PCM-based material are analyzed by flow cytometry. Taken together, our results suggest an enormous potential for spatio-temporal control in photothermally responsive drug-delivery systems.

A photo-thermoresponsive drug nanocarrier is easily prepared by the introduction of a thermo-sensitive medium (PCM) and an anticancer drug onto mesoporous silica-coated graphene oxide. As PCM is highly sensitive to temperature changes just above body temperature, the photothermal effect of graphene oxide induced by irradiation with NIR facilitates the rapid release of the drug with significantly increased cytotoxicity and enhanced imaging in vitro.