49,404 research outputs found
Applications Of Microspectroscopy, Hyperspectral Chemical Imaging And Fluorescence Microscopy In Chemistry, Biochemistry, Biotechnology, Molecular And Cell Biology
Full text linkChemical imaging is a technique for the simultaneous measurement of spectra (chemical information) and images or pictures (spatial information)^1,2^. The technique is most often applied to either solid or gel samples, and has applications in chemistry, biology^3-8^, medicine^9,10^, pharmacy^11^ (see also for example: Chemical Imaging Without Dyeing), food science, Food Physical Chemistry, Biotechnology^12,13^, Agriculture and industry. NIR, IR and Raman chemical imaging is also referred to as hyperspectral, spectroscopic, spectral or multi-spectral imaging (also see micro-spectroscopy). However, other ultra-sensitive and selective, chemical imaging techniques are also in use that involve either UV-visible or fluorescence microspectroscopy
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Visualizing Chemistry: The Progess and Promise of Advanced Chemical Imaging
Full text linkThe field of chemical imaging can provide detailed structural, functional, and applicable information about chemistry and chemical engineering phenomena that have enormous impacts on medicine, materials, and technology. In recognizing the potential for more research development in the field of chemical imaging, the National Academies was asked by the National Science Foundation, Department of Energy, U.S. Army, and National Cancer Institute to complete a study that would review the current state of molecular imaging technology, point to promising future developments and their applications, and suggest a research and educational agenda to enable breakthrough improvements in the ability to image molecular processes simultaneously in multiple physical dimensions as well as time. The study resulted in a consensus report that provides guidance for a focused research and development program in chemical imaging and identifies research needs and possible applications of imaging technologies that can provide the breakthrough knowledge in chemistry, materials science, biology, and engineering for which we should strive. Public release of this report is expected in early October
The Chemistry of Imaging Probes
No full textOver the past decades, the field of molecular imaging has been rapidly growing involving multiple disciplines such as medicine, biology, chemistry, pharmacology and biomedical engineering. Any molecular imaging procedure requires an imaging probe that is an agent used to visualize, characterize and quantify biological processes in living systems. Such a probe typically consists of an agent that usually produces signal for imaging purpose, a targeting moiety, and a linker connecting the targeting moiety and the signaling agent. Many challenging problems of molecular imaging can be addressed by exploiting the great possibilities offered by modern synthetic organic and coordination chemistry and the powerful procedures provided by conjugation chemistry. Thus, chemistry plays a decisive role in the development of this cutting-edge methodology. Currently, the diagnostic imaging modalities include Magnetic Resonance Imaging (MRI), Computed Tomography (CT), Ultrasound (US), Nuclear Imaging (PET, SPECT), Optical Imaging (OI) and Photoacoustic Imaging (PAI). Each of these imaging modalities has its own advantages and disadvantages, and therefore, a multimodal approach combining two techniques is often adopted to generate complementary anatomical and functional information of the disease. The basis for designing imaging probes for a given application is dictated by the chosen imaging modality, which in turn is dependent upon the concentration and localization profile (vascular, extracellular matrix, cell membrane, intracellular, near or at the cell nucleus) of the target molecule. The development of high-affinity ligands and their conjugation to the targeting vector is also one of the key steps for pursuing efficient molecular imaging probes. Other excellent reviews, text and monographs describe the principles of biomedical imaging, focusing on molecular biology or on the physics behind the techniques. This Research Topic aims to show how chemistry can offer molecular imaging the opportunity to express all its potential
Facile hyperpolarization chemistry for molecular imaging and metabolic tracking of [1-13C]pyruvate in vivo
No full textHyperpolarization chemistry based on reversible exchange of parahydrogen, also known as Signal Amplification By Reversible Exchange (SABRE), is a particularly simple approach to attain high levels of nuclear spin hyperpolarization, which can enhance NMR and MRI signals by many orders of magnitude. SABRE has received significant attention in the scientific community since its inception because of its relative experimental simplicity and its broad applicability to a wide range of molecules, however in vivo detection of molecular probes hyperpolarized by SABRE has remained elusive. Here we describe the first demonstration of SABRE-hyperpolarized contrast detected in vivo, specifically using hyperpolarized [1-13C]pyruvate. A biocompatible formulation of hyperpolarized [1-13C]pyruvate was injected into healthy Sprague Dawley and Wistar rats, and metabolic conversion of pyruvate to lactate, alanine, pyruvate-hydrate, and bicarbonate was detected. Measurements were performed on the liver and kidney at 4.7 T via time-resolved spectroscopy and chemical-shift-resolved MRI. In addition, whole-body metabolic measurements were obtained using a cryogen-free 1.5 T MRI system, illustrating the utility of combining lower-cost MRI systems with simple, low-cost hyperpolarization chemistry to develop scalable, next-generation molecular imaging
Coordination chemistry of amide-functionalised tetraazamacrocycles: structural, relaxometric and cytotoxicity studies
Full text link25/09/2012MEB. Author version attached, OK to publis
Quantum dot enabled thermal imaging of optofluidic devices
No full textQuantum dot thermal imaging has been used to analyse the chromatic dependence of laser-induced thermal effects inside optofluidic devices with monolithically integrated near-infrared waveguides. We demonstrate how microchannel optical local heating plays an important role, which cannot be disregarded within the context of on-chip optical cell manipulation. We also report on the thermal imaging of locally illuminated microchannels when filled with nano-heating particles such as carbon nanotubes.</p
All-cis 1,2,3,4,5,6-hexafluorocyclohexane is a facially polarized cyclohexane
No full textThis work was generously supported by the Engineering and Physical Sciences Research Council (EPSRC) and the European Research Council (ERC).The highest-energy stereoisomer of 1,2,3,4,5,6-hexafluorocyclohexane, in which all of the fluorines are ‘up’, is prepared in a 12-step protocol. The molecule adopts a classic chair conformation with alternate C–F bonds aligned triaxially, clustering three highly electronegative fluorine atoms in close proximity. This generates a cyclohexane with a high molecular dipole (μ = 6.2 D), unusual in an otherwise aliphatic compound. X-ray analysis indicates that the intramolecular Fax···Fax distances (∼2.77 Å) are longer than the vicinal Fax···Feq distances (∼2.73 Å) suggesting a tension stabilizing the chair conformation. In the solid state the molecules pack in an orientation consistent with electrostatic ordering. Our synthesis of this highest-energy isomer demonstrates the properties that accompany the placement of axial fluorines on a cyclohexane and the unusual property of a facially polarized ring in organic chemistry. Derivatives have potential as new motifs for the design of functional organic molecules or for applications in supramolecular chemistry design.Peer reviewe
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Advanced optical imaging methods for investigating manuscripts
No full textThis paper gives an overview of advanced optical imaging methods relevant to the study of manuscripts. While some of the methods covered are well established, others are very much in active development. ‘Optical’ in this context is loosely defined to cover the near ultraviolet, visible and the near infrared part of the electromagnetic spectrum. Optical imaging methods are in general non-destructive and can be applied in situ. They are non-invasive if care is taken to ensure a safe dosage of illumination during the imaging process. The examples given in this paper are biased towards work that the author has been involved in. This is by no means a comprehensive review. The aim of the paper is to illustrate how advanced optical imaging techniques can assist in the investigation of manuscripts
The Integration of a Community Service Learning Water Project in a Post-secondary Chemistry Lab
Full text linkCommunity Service Learning (CSL) is an experiential learning approach that integrates community service into student projects and provides diverse learning opportunities to reduce interdisciplinary barriers. A semester-long chemistry curriculum with an integrated CSL intervention was implemented in a Canadian university to analyze the potential for engagement and positive attitudes toward chemistry as a meaningful undertaking for 14 post-secondary students in the laboratory as well as for their 400 K-12 student partners in the community. Traditionally, introductory science experiments typically involve repeating a cookbook recipe from a lab book, but this CSL project allowed the post-secondary and K-12 students to work collaboratively to determine the physical and chemical properties and total dissolved solids in the water fountains from the K-12 students' schools. Post-instructional surveys were completed by all learners and were analyzed using a mixed methodological approach with both quantitative and qualitative analyses. The expected audience that may be interested in this study are those involved in teaching chemistry in higher education and at the K-12 level as well as those interested in service learning, community and civic engagement, experiential learning, and development of transferable skills in chemistry. The results demonstrate that both groups of students report favorable engagement and attitudes towards learning chemistry and higher self-confidence levels on performing lab skills after the activity. Furthermore, both groups of students expressed interest in exploring future projects, which is indicative of the positive impact of CSL and the mutual benefits of the partnership.articl
Hydrazine Derivatives as a Platform for Site-Specific Labelling of Peptides for in vivo Molecular Imaging of Disease
Full text linkThe 6-hydrazinonicotinyl group, known as HYNIC, is an attractive bifunctional coupling agent for preparing 99mTc-labeled peptides and proteins for medical imaging. Peptides are useful for imaging disease states such as cancer and inflammation because they take advantage of a distinct cellular target, such as a receptor, being present on the cell. Receptors are often over expressed on tumour cells. Peptides will bind to their receptors with high specificity and affinity. There is a recognized need to create well-de?ned polymer probes for in vivo and clinical PET and SPECT imaging to guide the development of new generation polymer therapeutics. In general the amount of radionuclide used in radiopharmaceuticals is small, so attaching the radionuclide to a polymer ensures that the radionuclide will be highly concentrated in the radiopharmaceutical. The number of binding sites is increased with the copolymer making it a viable choice for radiolabelling applications. The chances of successfully imaging the point of interest are therefore increased.
This thesis presents the synthesis of various HYNIC analogues that are capable of chelating technetium-99m in order to be attached to an amino acid and incorporated into a peptide sequence via solid phase peptide synthesis (SPPS) to image site-specific targets. While 6-HYNIC has been widely used, 2-HYNIC has not, and as such both of these were used in the synthesis of a number of derivatives. These derivatives were characterised by 1H and 13C NMR, FT-IR and melting point data was obtained for comparison with literature. A number of derivatives were successfully synthesised and purified with the aim of binding these to copolymer chains.
This work also presents the synthesis of a bifunctional copolymer (POEGMA-co-PAMA) which is biocompatible and can be attached to a HYNIC group and subsequently a peptide. This copolymer was synthesised using a controlled living radical polymerisation technique called Reversible Addition Fragmentation chain Transfer (RAFT). This technique was chosen due to its ability to synthesise polymers with predetermined molecular weights of complex architectures whilst maintaining control over polydispersity. Copolymers of varying compositions were synthesised and analysed by GPC and NMR. This method (once optimised) would allow for the copolymer to be labelled with technetium-99 for SPECT, providing an alternative bioconjugate synthetic route
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