Cover Picture: Recoding the Genetic Code with Selenocysteine (Angew. Chem. Int. Ed. 1/2014)

Curing of degraded MAPbI3perovskite films

Perovskite films were prepared using a one-step solution deposition. Such films degrade over time because of the ambient humidity. Curing of degraded films through X-ray, UV and electron beam irradiation is demonstrated.

Aerosol construction of multi-shelled LiMn2O4 hollow microspheres as a cathode in lithium ion batteries

Novel multi-shelled LiMn₂O₄ hollow microspheres have been successfully prepared by a facile aerosol spray pyrolysis route through the controlled combustion of carbon species. These microspheres show a superior specific capacity and a good rate capacity in LIBs.

A DNA tetrahedron-based molecular beacon for tumor-related mRNA detection in living cells

We report a DNA tetrahedron-based molecular beacon for tumor-related TK1 mRNA detection in living cells, where the target sequence can induce the tetrahedron from contraction to extension, resulting in fluorescence restoration.

Enhancing the carrier thermalization time in organometallic perovskites by halide mixing

Non-adiabatic molecular dynamics simulations of non-radiative relaxation dynamics of charge carriers in hybrid perovskites show that the carrier relaxation time can be considerably increased by halide mixing.

Mechanism study on the photocatalytic efficiency enhancement of MoS2 modified Zn–AgIn5S8 quantum dots

Heterostructure photocatalysts based on MoS₂ modified environment friendly Zn–AgIn₅S₈ quantum dots were developed exhibiting high photocatalytic activity, where enhanced charge transfer to MoS₂ was observed not only from the quantum dots but also from the dyes.

Synergistic effects from graphene oxide nanosheets and TiO2 hierarchical structures enable robust and resilient electrodes for high-performance lithium-ion batteries

A strong synergistic effect from TiO₂ hierarchical structure and GO is demonstrated for morphology control and enhanced lithium ion storage.

High performance electrochemical capacitor materials focusing on nickel based materials

Of the two major capacitances contributing to electrochemical storage devices, pseudo-capacitance, which results from the reversible faradaic reactions, can be much higher than the electric double layer capacitance.

Controllable doping of nitrogen and tetravalent niobium affords yellow and black calcium niobate nanosheets for enhanced photocatalytic hydrogen evolution

Yellow (N-doped) and black (N-/Nb⁴⁺-codoped) [Ca₂Nb₃O₁₀]⁻ nanosheets with molecular thickness were fabricated by liquid exfoliation of selectively doped KCa₂Nb₃O₁₀ perovskite.

Mesoporous carbon derived from vitamin B12: a high-performance bifunctional catalyst for imine formation

Mesoporous carbon derived from natural vitamin B₁₂ is applied for the first time in organic synthesis and exhibits exceptionally high dual activity for imine formation via the cross-coupling of alcohols with amines and the self-coupling of primary amines.

Two in one: switchable ion conductivity and white light emission integrated in an iodoplumbate-based twin chain hybrid crystal

A [Pb₂I₆]_∝ twin chain hybrid crystal shows novel switchable ion conductivity arising from the structural phase transition and color-tunable photoluminescence attributed to the broadband semiconductor emission of twin chain.

History of Antibiotics Research

For thousands of years people were delivered helplessly to various kinds of infections, which often reached epidemic proportions and have cost the lives of millions of people. This is precisely the age since mankind has been thinking of infectious diseases and the question of their causes. However, due to a lack of knowledge, the search for strategies to fight, heal, and prevent the spread of communicable diseases was unsuccessful for a long time. It was not until the discovery of the healing effects of (antibiotic producing) molds, the first microscopic observations of microorganisms in the seventeenth century, the refutation of the abiogenesis theory, and the dissolution of the question "What is the nature of infectious diseases?" that the first milestones within the history of antibiotics research were set. Then new discoveries accelerated rapidly: Bacteria could be isolated and cultured and were identified as possible agents of diseases as well as producers of bioactive metabolites. At the same time the first synthetic antibiotics were developed and shortly thereafter, thousands of synthetic substances as well as millions of soil borne bacteria and fungi were screened for bioactivity within numerous microbial laboratories of pharmaceutical companies. New antibiotic classes with different targets were discovered as on assembly line production. With the beginning of the twentieth century, many of the diseases which reached epidemic proportions at the time-e.g., cholera, syphilis, plague, tuberculosis, or typhoid fever, just to name a few, could be combatted with new discovered antibiotics. It should be considered that hundred years ago the market launch of new antibiotics was significantly faster and less complicated than today (where it takes 10-12 years in average between the discovery of a new antibiotic until the launch). After the first euphoria it was quickly realized that bacteria are able to develop, acquire, and spread numerous resistance mechanisms. Whenever a new antibiotic reached the market it did not take long until scientists observed the first resistant germs. Since the marketing of the first antibiotic there is a neck-on-neck race between scientists who discover natural or develop semisynthetic and synthetic bioactive molecules and bacteria, which have developed resistance mechanisms. The emphasis of this chapter is to give an overview of the history of antibiotics research. The situation within the pre-antibiotic era as well as in the early antibiotic era will be described until the Golden Age of Antibiotics will conclude this time travel. The most important antibiotic classes, information about their discovery, activity spectrum, mode of action, resistance mechanisms, and current application will be presented.

Palladium-modified functionalized cyclodextrin as an efficient and recyclable catalyst for reduction of nitroarenes

A kind of palladium-modified functionalized cyclodextrin catalytic system was synthesized and characterized. It showed high activity in the reduction of nitroarenes with the absence of sodium borohydride in water at room temperature.

White light emission by controlled mixing of carbon dots and rhodamine B for applications in optical thermometry and selective Fe3+detection

Controlled mixing of rhodamine B with fluorescent carbon dots derived from β-carotene resulted in a white light emitting mixture that could be used for optical thermometry and Fe³⁺ion detection in water.

Palladium catalyzed domino reaction of 1,4-disubstituted 1,2,3-triazoles via double C–H functionalization: one-pot synthesis of triazolo[1,5-f]phenanthridines

A palladium catalyzed domino reaction of 1,4-disubstituted triazoles involving homo- and heterocondensation is presented. The approach provides a simple, straight forward and a facile route to access triazolo[1,5-f]phenanthridines in high yields.

Two photochromic methylated nicotinohydrazide iodoargentate hybrids

Two methylated nicotinohydrazide iodoargentate hybrids have been synthesized via modulating organic/inorganic ratio, which exhibit rare structure-dependent electron-transfer (ET) photochromism.

Facile synthesis of Sn/MoS2/C composite as an anode material for lithium-ion batteries with outstanding performance

A Sn/MoS₂/C composite has been synthesized using a simple hydrothermal method with stable electrochemical performance.

Effects of nitrogen-dopants on Ru-supported catalysts for acetylene hydrochlorination

A series of N-doped spherical active carbons were synthesizedviathe pyrolysis of melamine in activated carbon, and used as a support to prepare Ru-based catalysts for an acetylene hydrochlorination reaction.

Fluorescence sensing of glucose using glucose oxidase incorporated into a fluorophore-containing PNIPAM hydrogel

We present a new composite material composed of pH sensitive fluorescent dyes in a poly(N-isopropylacrylamide)-based hydrogel and incorporating glucose oxidase (GOx), which provides a platform for fluorescence sensing of glucose.

Cobalt salophen complexes for light-driven water oxidation

Earth-abundant molecular complexes have been found to be excellent catalysts for the light-driven water oxidation reaction.

Solar and visible light photocatalytic enhancement of halloysite nanotubes/g-C3N4 heteroarchitectures

The charged surface of HNTs allows efficient charge separation and increased pollutant adsorption, enhancing the overall photocatalytic performance of the HNTs/g-C₃N₄ heteroarchitectures.

An electron-transfer photochromic metal–organic framework (MOF) compound with a long-lived charge-separated state and high-contrast photoswitchable luminescence

A new photochromic MOF compound exhibits a charge-separated state with lifetime exceeding the reported values of the analogues and a luminescence contrast higher than those of most known pyridine derivative-based photochromic compounds.

Acidic pH-induced charge-reversal nanoparticles for accelerated endosomal escape and enhanced microRNA modulation in cancer cells

pH-Induced charge-reversal nanoparticles incorporating microRNA (miRNA) were engineered through a single-step self-assembly of polyelectrolyte complexes.

An amphiphilic PEG-b-PFPE-b-PEG triblock copolymer: synthesis by CuAAC click chemistry and self-assembly in water

A new PEG₂₀₀₀-b-PFPE₁₂₀₀-b-PEG₂₀₀₀ amphiphilic triblock copolymer that undergoes self-assembly into micelles in water was synthesized by copper(i)-catalyzed alkyne–azide cycloaddition (CuAAC).

Nickel stabilized by triazole-functionalized carbon nanotubes as a novel reusable and efficient heterogeneous nanocatalyst for the Suzuki–Miyaura coupling reaction

The synthesis of a MWCNT-grafted nickel catalyst through “click” reaction of azide-functionalized carbon nanotubes with propargyl alcohol, for the Suzuki–Miyaura coupling reaction.

An efficient titanium foil based perovskite solar cell: using a titanium dioxide nanowire array anode and transparent poly(3,4-ethylenedioxythiophene) electrode

The light-weight perovskite solar cell is prepared by employing TiO₂ nanowire (TNW) arrays on the Ti foil substrate as the electron collection layer and using a highly transparent PEDOT on the ITO/PEN substrate as the hole transporting layer.

A Low-Temperature, Solution-Processable, Cu-Doped Nickel Oxide Hole-Transporting Layer via the Combustion Method for High-Performance Thin-Film Perovskite Solar Cells

Low-temperature, solution-processable Cu-doped NiOX (Cu:NiOx ), prepared via combustion chemistry, is demonstrated as an excellent hole-transporting layer (HTL) for thin-film perovskite solar cells (PVSCs). Its good crystallinity, conductivity, and hole-extraction properties enable the derived PVSC to have a high power conversion efficiency (PCE) of 17.74%. Its general applicability for various elecrode materials is also revealed.

Total syntheses of five uvacalols: structural validation of uvacalol A, uvacalol B and uvacalol C and disproval of the structures of uvacalol E and uvacalol G

Uvacalols are novel carbasugars belonging to the family of C7-cyclitols, and are isolated from the roots of the medicinal plant, Uvaria calamistrata. In this study, we report the first syntheses of five uvacalols starting from a cheap and easily available chiral pool starting material, D-mannitol, in their optically pure form. D-Mannitol was converted to the alkene 2 through a series of regioselective and chemoselective transformations by following our previously reported strategies. Alkene 2 was converted to the enal 5 through a series of protective group manipulations. Enal 5 was converted to the diene 6 by the addition of vinyl magnesium bromide. Ring closing metathesis of the diene 6 using Grubbs’ second generation catalyst installed the core cyclohexenyl unit. Through several iterative and selective manipulations of various hydroxyl groups, uvacalol A, uvacalol B, uvacalol C, uvacalol E and uvacalol G were synthesized. A comparison of the (1)H NMR and (13)C NMR data of these synthesized molecules with the reported data, revealed that the reported structures of uvacalols A–C are correct and those of uvacalols E and G are wrong.

Controllable assembly of well-defined monodisperse Au nanoparticles on hierarchical ZnO microspheres for enhanced visible-light-driven photocatalytic and antibacterial activity

A high-efficiency visible-light-driven photocatalyst composed of homogeneously distributed Au nanoparticles (AuNPs) well-defined on hierarchical ZnO microspheres (ZMS) via a controllable layer-by-layer self-assembly technique is demonstrated. The gradual growth of the characteristic absorption bands of Au loaded on ZnO in the visible light region with an increasing number of assemblies indicates the enhancement of the light harvesting ability of the ZMS/Au composites as well as the reproducibility and controllability of the entire assembly process. Results on the photoelectrochemical performance characterized by EIS and transient photocurrent response spectra indicate that the ZMS/Au composites possess increased photoinduced charge separation and transfer efficiency compared to the pure ZMS film. As a result, the hybrid composites exhibited enhanced decomposition activity for methylene blue and salicylic acid as well as antibacterial activity in killing S. aureus and E. coli under visible light irradiation. It can be noted that well-distributed Au components even at a rather low Au/ZnO weight ratio of ∼1.2% also exhibited extraordinary photocatalysis. Such a facile and controllable self-assembly approach may be viable for preparing high-performance visible-light-driven ZMS/Au photocatalysts in a simple and controllable way, and consequently, the technology may extend to other plasmon-enhanced heterostructures made of nanostructured semiconductors and noble metals for great potential application in environmental protection.

Electrospun interconnected Fe-N/C nanofiber networks as efficient electrocatalysts for oxygen reduction reaction in acidic media

One-dimensional electrospun nanofibers have emerged as a potential candidate for high-performance oxygen reduction reaction (ORR) catalysts. However, contact resistance among the neighbouring nanofibers hinders the electron transport. Here, we report the preparation of interconnected Fe-N/C nanofiber networks (Fe-N/C NNs) with low electrical resistance via electrospinning followed by maturing and pyrolysis. The Fe-N/C NNs show excellent ORR activity with onset and half-wave potential of 55 and 108 mV less than those of Pt/C catalyst in 0.5 M H₂SO₄. Intriguingly, the resulting Fe-N/C NNs exhibit 34% higher peak current density and superior durability than generic Fe-N/C ones with similar microstructure and chemical compositions. Additionally, it also displays much better durability and methanol tolerance than Pt/C catalyst. The higher electroactivity is mainly due to the more effective electron transport between the interconnected nanofibers. Thus, our findings provide a novel insight into the design of functional electrospun nanofibers for the application in energy storage and conversion fields.

Split aptamer mediated endonuclease amplification for small-molecule detection

A novel, highly sensitive split aptamer mediated endonuclease amplification strategy for the construction of aptameric sensors is reported.

Synthesis of Ir(III) complexes with Tp(Me2) and acac ligands and their reactivity with electrophiles

The reaction of the bis(ethylene) complex [Tp(Me2)Ir(C2H4)2] () (Tp(Me2) = hydrotris(3,5-dimethylpyrazolyl)borate) with an excess of 2,4-pentanedione (acetylacetone, Hacac) at 70 °C produced a mixture of the Ir(iii) complex [Tp(Me2)Ir(acac)(C2H5)] () as a major product (67% yield) and two other side complexes [Tp(Me2)Ir(acac)(H)] () and [Tp(Me2)Ir(C9H14O2)] () in 20 and 13% yields, respectively. According to the proposed reaction mechanism and DFT calculations, complexes and are generated from an 18e(-) intermediate [Tp(Me2)Ir(C2H4)(acac)(C2H3)] () which undergoes either hydrogen insertion or β-hydride elimination followed by the subsequent loss of a molecule of ethylene. The lowest yielding complex which features a 2-iridafuran is presumably generated from an unusual thermal coupling between one vinylic and one acac moiety. The availability of the acidic α-proton of the acac ligand was tested by the treatment of complex with Br2 and Cu(NO3)2 rendering the substitution complexes [Tp(3-Br,Me2)Ir(3-Br-acac)Br] () and [Tp(Me2)Ir(3-NO2-acac)(C2H5)] () in good yields. The series of heteroleptic iridium(iii) compounds display air and moisture stability and have been characterized by NMR, IR, and elemental analyses, and, in the case of , and , by single-crystal X-ray diffraction analyses.

Structural analysis of hierarchically organized zeolites

Advances in materials synthesis bring about many opportunities for technological applications, but are often accompanied by unprecedented complexity. This is clearly illustrated by the case of hierarchically organized zeolite catalysts, a class of crystalline microporous solids that has been revolutionized by the engineering of multilevel pore architectures, which combine unique chemical functionality with efficient molecular transport. Three key attributes, the crystal, the pore and the active site structure, can be expected to dominate the design process. This review examines the adequacy of the palette of techniques applied to characterize these distinguishing features and their catalytic impact.

Electrochemical nanoprobes for the chemical detection of neurotransmitters

Neurotransmitters, acting as chemical messengers, play an important role in neurotransmission, which governs many functional aspects of nervous system activity. Electrochemical probes have proven a very useful technique to study neurotransmission, especially to quantify and qualify neurotransmitters. With the emerging interests in probing neurotransmission at the level of single cells, single vesicles, as well as single synapses, probes that enable detection of neurotransmitters at the nanometer scale become vitally important. Electrochemical nanoprobes have been successfully employed in nanometer spatial resolution imaging of single nanopores of Si membrane and single Au nanoparticles, providing both topographical and chemical information, thus holding great promise for nanometer spatial study of neurotransmission. Here we present the current state of electrochemical nanoprobes for chemical detection of neurotransmitters, focusing on two types of nanoelectrodes, i.e. carbon nanoelectrode and nano-ITIES pipet electrode.

Characterization of Novel Fusaricidins Produced by Paenibacillus polymyxa-M1 Using MALDI-TOF Mass Spectrometry

Paenibacillus polymyxa-M1 is a potent producer of bioactive compounds, such as lipopeptides, polyketides, and lantibiotics of biotechnological and medical interest. Genome sequencing revealed nine gene clusters for nonribosomal biosynthesis of such agents. Here we report on the investigation of the fusaricidins, a complex of cyclic lipopeptides containing 15-guanidino-3-hydroxypentadecanoic acid (GHPD) as fatty acid component by matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). More than 20 variants of these compounds were detected and characterized in detail. Mass spectrometric sequence analysis was performed by MALDI-LIFT-TOF/TOF fragment analysis. The obtained product ion spectra show a specific processing in the fatty acid part. GHPD is cleaved between the α- and ß-position yielding two fragments a and b, one bearing the end-standing guanidine group and another one comprising the residual two C-atoms of GHPD with the attached peptide moiety. The complete sequence of all fusaricidins was derived from sets of bn- and yn-ions. The fusaricidin complex can be divided into four lipopeptide families, three of them showing variations of the amino acid in position 3, Val or Ile for the first and Tyr or Phe for families 2 and 3, respectively. A collection of novel fusaricidins was detected differing from those of families 1-3 by an additional residue of 71 Da (family 4). LIFT-TOF/TOF fragment spectra of these species imply that in their peptide moiety, an Ala-residue is attached by an ester bond to the free hydroxyl group of Thr4. More than 10 novel fusaricidins were characterized mass spectrometrically.

An enzyme-free and amplified colorimetric detection strategy via target-aptamer binding triggered catalyzed hairpin assembly

Here we introduce an enzyme-free and colorimetric detection strategy for small molecule adenosine. The approach is based on the adenosine-aptamer binding triggered liberation of an initiator strand that consecutively catalyzes DNA hairpins hybridized from singles to couples. These couples induce gold nanoparticles assembled via crosslinking, which could be visualized by a color change.

A microfluidic platform with digital readout and ultra-low detection limit for quantitative point-of-care diagnostics

Quantitative assays are of great importance for point-of-care (POC) diagnostics because they can offer accurate information on the analytes. However, current POC devices often require an accessory instrument to give quantitative readouts for protein biomarkers, especially for those at very low concentration levels. Here, we report a microfluidic platform, the digital volumetric bar-chart chip (DV-chip), for quantitative POC diagnostics with ultra-low detection limits that are readable with the naked eye. Requiring no calibration, the DV-chip presents a digital ink bar chart (representing multiple bits composed of 0 and 1) for the target biomarker based on direct competition between O2 generated by the experimental and control samples. The bar chart clearly and accurately defines target concentration, allowing identification of disease status. For the standard PtNP solutions, the detection limit of the platform is approximately 0.1 pM and the dynamic range covers four orders of magnitude from 0.1 to 1000 pM. CEA samples with concentrations of 1 ng mL(-1) and 1.5 ng mL(-1) could be differentiated by the device. We also performed the ELISA assay for B-type natriuretic peptide (BNP) in 20 plasma samples from heart failure patients and the obtained on-chip data were in agreement with the clinical results. In addition, BNP was detectable at concentrations of less than 5 pM, which is three orders of magnitude lower than the detection limit of the previously reported readerless digital methods. By the integration of gas competition, volumetric bar chart, and digital readout, the DV-chip possesses merits of portability, visible readout, and ultra-low detection limit, which should offer a powerful platform for quantitative POC diagnostics in clinical settings and personalized detection.

Hierarchical nanosheet-constructed yolk-shell TiO₂ porous microspheres for lithium batteries with high capacity, superior rate and long cycle capability

A hierarchical nanosheet-constructed yolk-shell TiO2 (NYTiO2) porous microsphere is synthesized through a well-designed, one-pot, template-free solvothermal alcoholysis process using tetraethylenepentamine (TEPA) as the structure directing reagent. Such a yolk-shell structure with a highly porous shell and dense mesoporous core is quite advantageous as an anode material for lithium ion batteries (LIBs). The outer, 2D nanosheet-based porous (15 nm) shell and the nanocrystal-based inner mesoporous (3 nm) core provide a stable, porous framework, effective grain boundaries and a short diffusion pathway for Li(+) and electron transport, facilitating lithium insertion/extraction. The voids between the core and the shell can not only store the electrolyte due to capillary and facilitate charge transfer across the electrode/electrolyte interface but also buffer the volume change during the Li(+) insertion/extraction. As a result, NYTiO2 demonstrates excellent Li(+) capacity with outstanding cycle performance and superior rate capability at different rates for >700 cycles, retaining a 225 mA h g(-1) reversible capacity after 100 cycles at 1 C. In particular, the reversible capacity can still be maintained at 113 mA h g(-1) after 100 cycles at 10 C. We also observe the formation of homogeneously distributed 5-10 nm Li2Ti2O4 nanocrystallites on the surface of the nanosheets during the discharge-charge process. The synergy of the yolk-shell structure with dual mesopores in the shell and core and the Li2Ti2O4 nanocrystallites endow the hierarchical NYTiO2 with high reversible capacity, excellent rate capability and outstanding cycle performance.

Light Weight and Flexible High-Performance Diagnostic Platform

A flexible diagnostic platform is realized and its performance is demonstrated for early detection of avian influenza virus (AIV) subtype H1N1 DNA sequences. The key component of the platform is high-performance biosensors based on high output currents and low power dissipation Si nanowire field effect transistors (SiNW-FETs) fabricated on flexible 100 μm thick polyimide foils. The devices on a polymeric support are about ten times lighter compared to their rigid counterparts on Si wafers and can be prepared on large areas. While the latter potentially allows reducing the fabrication costs per device, the former makes them cost efficient for high-volume delivery to medical institutions in, e.g., developing countries. The flexible devices withstand bending down to a 7.5 mm radius and do not degrade in performance even after 1000 consecutive bending cycles. In addition to these remarkable mechanical properties, on the analytic side, the diagnostic platform allows fast detection of specific DNA sequences of AIV subtype H1N1 with a limit of detection of 40 × 10(-12) m within 30 min suggesting its suitability for early stage disease diagnosis.

Stereoselective chlorothiolation of artemisinin-derived C-10 oxa terminal alkynes

A mild and efficient strategy is explored on the highly sensitive artemisinin-derived C-10 oxa terminal alkynes. Several novel artemisinin-derived (E)-2-chloroalkenyl sulfides (20) have been synthesized by using this protocol to study their anticancer activities.