Blockchain technology is based on the idea of a distributed, replicated, and immutable digital ledger that enables parties to conduct business in a trustful and transparent way without the need for a central authority or intermediary. Its most popular application thus far is in payment system applications, e.g., bitcoin. This disruptive technology is expected to contribute significant business value to multiple industry sectors, including supply chain management (SCM), where it can provide greater visibility, accountability and trust in interorganizational business collaboration. In this article, we review some fundamental concepts of Hyperledger Fabric, one of the most mature permissioned blockchain implementations. Further, we use the context of a food supply chain to highlight key design and implementation challenges for blockchain, and provide a strategic assessment of its prospects. Our aim is to dispel misguided notions and myths about blockchain as a silver bullet for all businesses. We believe it is important to penetrate the hype to allow a more realistic understanding of this technology. Blockchain is a high‐cost, high‐overhead storage medium. It is viable only when its higher cost is counterbalanced by the set of benefits that are identified by a careful and thorough analysis of the business. Thus, it will be used mainly for storing important data related to interorganizational transactions among partners where trust is lacking and provenance and visibility are critical. Our paper offers enterprises a systematic way to understand the real costs and risks of blockchain adoption. The insights gained in the SCM context also apply to other areas such as financial services and healthcare that could leverage the full potential of blockchain technology.

Because a variety of human-related activities, engineer-ed nanoparticles (ENMs) may be released to various environmental media and may cross environmental boundaries, and thus will be found in most media. Therefore, the potential environmental impacts of ENMs must be assessed from a multimedia perspective and with an integrated risk management approach that considers rapid developments and increasing use of new nanomaterials. Accordingly, this Account presents a rational process for the integration of in silico ENM toxicity and fate and transport analyses for environmental impact assessment. This approach requires knowledge of ENM toxicity and environmental exposure concentrations. Considering the large number of current different types of ENMs and that those numbers are likely to increase, there is an urgent need to accelerate the evaluation of their toxicity and the assessment of their potential distribution in the environment. Developments in high throughput screening (HTS) are now enabling the rapid generation of large data sets for ENM toxicity assessment. However, these analyses require the establishment of reliable toxicity metrics, especially when HTS includes data from multiple assays, cell lines, or organisms. Establishing toxicity metrics with HTS data requires advanced data processing techniques in order to clearly identify significant biological effects associated with exposure to ENMs. HTS data can form the basis for developing and validating in silico toxicity models (e.g., quantitative structure-activity relationships) and for generating data-driven hypotheses to aid in establishing and/or validating possible toxicity mechanisms. To correlate the toxicity of ENMs with their physicochemical properties, researchers will need to develop quantitative structure-activity relationships for nanomaterials (i.e., nano-SARs). However, as nano-SARs are applied in regulatory applications, researchers must consider their applicability and the acceptance level of false positive relative to false negative predictions and the reliability of toxicity data. To establish the environmental impact of ENMs identified as toxic, researchers will need to estimate the potential level of environmental exposure concentration of ENMs in the various media such as air, water, soil, and vegetation. When environmental monitoring data are not available, models of ENMs fate and transport (at various levels of complexity) serve as alternative approaches for estimating exposure concentrations. Risk management decisions regarding the manufacturing, use, and environmental regulations of ENMs would clearly benefit from both the assessment of potential ENMs exposure concentrations and suitable toxicity metrics. The decision process should consider the totality of available information: quantitative and qualitative data and the analysis of nanomaterials toxicity, and fate and transport behavior in the environment. Effective decision-making to address the potential impacts of nanomaterials will require considerations of the relevant environ...

A concise total synthesis of nannocystin Ax, a natural depsipeptide recently isolated from myxobacteria, has been accomplished. By following a convergent strategy, the target molecule was assembled from three fragments. Each fragment can be synthesized expeditiously from readily achievable compounds. The key elements in this total synthesis feature Kobayashi's remote asymmetric induction with vinylketene silyl N,O-acetal, Roush's asymmetric crotylboration of aldehyde, Mitsunobu's esterification and macrocyclization via Stille cross-coupling.

A series of high-density double-and single-shelled ZnO/CdSe/CdTe, ZnO/CdTe/CdSe, ZnO/CdTe and ZnO/CdSe nanocable arrays were synthesized as photoanodes by an electrodeposition method using ZnO nanorod arrays as cores. For ZnO/CdSe/CdTe nanocable arrays, the uniform CdSe and CdTe nanoshells were composed of zinc-blende phase nanocrystals with a respective average size range of 10-20 nm and 7-15 nm, and formed a compact and continuous interface in between. Based on the band offset of the bulk material before contact and the interfacial Fermi level shift after contact, the energy level alignments at the CdSe/CdTe and CdTe/CdSe interface were deduced for the double-shelled nanocable arrays. The CdTe/CdSe interface of the ZnO/CdTe/CdSe nanocables has a negative band offset of À0.16 eV whilst for ZnO/CdSe/CdTe nanocables, the band edge of CdTe lies above CdSe with a conduction band offset of 0.16 eV at the CdSe/CdTe interface. Such a stepwise band alignment, together with the compact interface, fewer grain boundaries along the radial direction, and the fast transfer rate along the axial direction of the nanocables, makes the ZnO/CdSe/CdTe nanocable arrays photoanode have a saturated photocurrent of $14.3 mA cm À2 . This is under the irradiation of AM1.5G simulated sunlight at 45 mW cm À2 , which is greatly higher than ZnO/CdTe/CdSe, ZnO/CdSe or ZnO/ CdTe nanocable arrays.