Hyperspectral microscopy is an advanced visualization technique that combines hyperspectral imaging with state-of-the-art optics and computer software to enable the rapid identification of materials at the micro- and nanoscales. Achieving this level of resolution has traditionally required time-consuming and costly electron microscopy techniques. While hyperspectral microscopy has already been applied to the analysis of bulk materials and biologicals, it shows extraordinary promise as an analytical tool to locate individual nanoparticles and aggregates in complex samples through rapid optical and spectroscopic identification. This technique can be used to not only screen for the presence of nanomaterials, but also to locate, identify, and characterize them. It could also be used to identify a subset of samples that would then move on for further analysis via other advanced metrology. This review will describe the science and origins of hyperspectral microscopy, examine current and emerging applications in life science, and examine potential applications of this technology that could improve research efficiency or lead to novel discoveries.
The future of work embodies changes to the workplace, work, and workforce, which require additional occupational safety and health (OSH) stakeholder attention. Examples include workplace developments in organizational design, technological job displacement, and work arrangements; work advances in artificial intelligence, robotics, and technologies; and workforce changes in demographics, economic security, and skills. This paper presents the Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health's Future of Work Initiative; suggests an integrated approach to address worker safety, health, and well‐being; introduces priority topics and subtopics that confer a framework for upcoming future of work research directions and resultant practical applications; and discusses preliminary next steps. All future of work issues impact one another. Future of work transformations are contingent upon each of the standalone factors discussed in this paper and their combined effects. Occupational safety and health stakeholders are becoming more aware of the significance and necessity of these factors for the workplace, work, and workforce to flourish, merely survive, or disappear altogether as the future evolves. The future of work offers numerous opportunities, while also presenting critical but not clearly understood difficulties, exposures, and hazards. It is the responsibility of OSH researchers and other partners to understand the implications of future of work scenarios to translate effective interventions into practice for employers safeguarding the safety, health, and well‐being of their workers.
Nanomaterials are increasingly prevalent throughout industry, manufacturing, and biomedical research. The need for tools and techniques that aid in the identification, localization, and characterization of nanoscale materials in biological samples is on the rise. Currently available methods, such as electron microscopy, tend to be resource-intensive, making their use prohibitive for much of the research community. Enhanced darkfield microscopy complemented with a hyperspectral imaging system may provide a solution to this bottleneck by enabling rapid and less expensive characterization of nanoparticles in histological samples. This method allows for high-contrast nanoscale imaging as well as nanomaterial identification. For this technique, histological tissue samples are prepared as they would be for light-based microscopy. First, positive control samples are analyzed to generate the reference spectra that will enable the detection of a material of interest in the sample. Negative controls without the material of interest are also analyzed in order to improve specificity (reduce false positives). Samples can then be imaged and analyzed using methods and software for hyperspectral microscopy or matched against these reference spectra in order to provide maps of the location of materials of interest in a sample. The technique is particularly well-suited for materials with highly unique reflectance spectra, such as noble metals, but is also applicable to other materials, such as semi-metallic oxides. This technique provides information that is difficult to acquire from histological samples without the use of electron microscopy techniques, which may provide higher sensitivity and resolution, but are vastly more resource-intensive and time-consuming than light microscopy.
Additive manufacturing (AM), often called 3-D printing, is becoming a prominent part of modern industry due to its usefulness in accelerating product development and prototyping, as well as producing complex and precision parts. [1] AM is a collection of processes for creating products by selectively joining small amounts of material based on a computeraided design file. [2,3] This approach yields several advantages to industry: shortened production cycles, reduced tooling costs, reduced waste material, easier product customization, novel design options, and new possibilities in distribution and fulfilment. [3][4][5][6][7] AM has already impacted automotive, aerospace, medical device, and electronics manufacturing; [1,4] is expected to grow in biomedical applications; [8,9] and has found its way into construction, [10] offices, schools, and libraries. [11,12] Despite dramatic growth in applications and adoption, there has been a relatively minimal amount of academic literature published on the potential implications of AM for worker safety and health. While many forms of AM share some similarities with existing technologies, changes in materials, instrumentation, applications, and work organization can create potential hazards that are either sufficiently distinct as to warrant renewed consideration, or are entirely new. The challenges may resemble those of nanotechnology, where the mixture of old and new processes, novel environments, and the pace of change made characterization of hazards and assessment of risk ongoing challenges. [13] The challenge to academic researchers, industrial designers, and occupational safety and health personnel will be developing knowledge of AM potential hazards, exposure assessment methods, and controls; and to propagate that knowledge throughout the industry. Doing so will require foundational knowledge in the basic principles of AM processes and the context in which AM is conducted. Herein, those processes will be briefly described, various potential hazards identified, and several aspects of AM implementations discussed.
A scalable process to the insecticide Isoclast manufactured by Dow AgroSciences LLC is described. The process involves the de novo construction of a fully elaborated pyridine sulfide using enamine-mediated cyclization followed by two efficient and inexpensive oxidations to introduce the sulfoximine.
Optimization of the route to the sap-feeding insecticidal candidate tyclopyrazoflor featuring [3 + 2] cyclization of 3-hydrazinopyridine·2HCl and methyl acrylate is described. The key impurities in the [3 + 2] cyclization were identified and successfully controlled after optimization. The hazards associated with oxidation of an intermediate pyrazolidin-3-one using the incompatible combination of potassium persulfate and N,N-dimethylformamide (DMF) were avoided by using potassium ferricyanide in the presence of potassium hydroxide in water. The two elimination impurities in the ethylation step to produce tyclopyrazoflor were successfully minimized using ethyl iodide in the presence of cesium carbonate in DMF at 0 °C. The overall yield for this seven-step synthesis of tyclopyrazoflor was improved from 10% to 41% after the optimization detailed herein.
Treatment of a variety of substituted 2‐aminobenzonitriles with formic acid under strong acid catalysis provides the corresponding quinazolin‐4(1H)‐ones in good yield. A potential reaction pathway is described.
This report describes nucleophilic fluorination of 3 and 5-substituted picolinate ester substrates using potassium fluoride in combination with additive promoters. Agents such as tributylmethylammonium or tetraphenylphosphonium chloride were among the best additives investigated giving improved fluorination yields. Additionally, the choice of additive promoters could influence the potential formation of new impurities such as alkyl ester exchange. Other parameters explored in this study include additive stoichiometry, temperature influence on additive degradation, solvent selection, product isolation by solvent extraction, and demonstration of additive recycling. ■ INTRODUCTIONAryl fluorides are extremely important structural motifs that are featured prominently in pharmaceuticals, agrochemicals, organic materials, and biological imaging agents. 1 An increasing number of fluorine-containing biologically active molecules have been developed for pharmaceutical and agrochemical applications ( Figure 1). Despite rising pharmaceutical and agrochemical prevalence, the selective fluorination of arenes remains a difficult task. As a result, significant recent efforts have focused on the development of new synthetic procedures for the formation of C Aryl −F bonds. 2,3 Halex reactions are a class of nucleophilic substitutions where a carbon−halogen bond (C−X 1 ) is converted to new and different carbon−halogen (C−X 2 ). For this study, halex reactions specifically refer to the conversion of aryl−Cl bonds to aryl−F bonds using a nucleophilic fluoride source. Halex reactions, typically run in polar aprotic solvents, require extreme temperatures (greater than 150°C) largely due to the poor solubility of metal fluoride salts such as cesium fluoride (CsF) and potassium fluoride (KF). 4 KF is much more economical than CsF but usually less reactive. Traditionally, common halex substrates require an electron-withdrawing group to activate the aryl ring towards nucleophilic attack. These factors often present challenges for developing efficient fluorination methods for aromatic and heteroaromatic motifs.Recently, our efforts have focused on the development of mild, selective methods to fluorinate aromatic systems. One strategy developed in our laboratories utilizes the combination of copper triflate Cu(OTf) 2 and KF to convert a variety of aryl potassium trifluoroborates to the corresponding fluorinated products in good yield. 5 This methodology has a wide range of functional group compatibility (Figure 2). Additionally, we developed methodology for high yielding fluorination of heteroarenes utilizing adaptations to the anhydrous tetrabutylammonium fluoride (TBAF) protocol. 6 Unique to this adaptation was the ability to premix some of the heteroarene substrates with tetrabutylammonium cyanide before adding hexafluorobenzene, thus enabling in situ generation of anhydrous TBAF. This strategy telescoped the fluorination procedure into a single one pot process. Overall, the anhydrous TBAF agent exhibited good solubility in a wide rang...
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