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Ion traps offer the opportunity to study fundamental quantum systems with high level of accuracy highly decoupled from the environment. Individual atomic ions can be controlled and manipulated with electric fields, cooled to the ground state of motion with laser cooling and coherently manipulated using optical and microwave radiation. Microfabricated ion traps hold the advantage of allowing for smaller trap dimensions and better scalability towards large ion trap arrays also making them a vital ingredient for next generation quantum technologies. Here we provide an introduction into the principles and operation of microfabricated ion traps. We show an overview of material and electrical considerations which are vital for the design of such trap structures. We provide guidance in how to choose the appropriate fabrication design, consider different methods for the fabrication of microfabricated ion traps and discuss previously realized structures. We also discuss the phenomenon of anomalous heating of ions within ion traps, which becomes an important factor in the miniaturization of ion traps.

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Using an optical biosensor based on a dual-peak long-period fiber grating, we have demonstrated the detection of interactions between biomolecules in real time. Silanization of the grating surface was successfully realized for the covalent immobilization of probe DNA, which was subsequently hybridized with the complementary target DNA sequence. It is interesting to note that the DNA biosensor was reusable after being stripped off the hybridized target DNA from the grating surface, demonstrating a function of multiple usability. © However, some of these demonstrated optical biosensors have limitations for real-time hybridization studies and monitoring hybridization kinetics. Here we implement an optical biosensor based on a dualpeak long-period fiber grating (LPFG) for detecting biomolecular interactions at a silica-liquid interface with the advantages of high sensitivity, real-time monitoring, and reusability. To achieve high-sensitivity detection of the designed biomolecular interaction, the most sensitive LPFG structures should be used. It has been reported that the coupling condition of LPFGs with relatively short periods are close to the dispersion turning points, resulting in conjugate dual-peak cladding modes that are extremely sensitive to external perturbations [9,10]. Several dual-peak LPFGs with a relatively small period ͑ϳ160 m͒ were UV inscribed in H 2 -loaded SMF-28 fibers employing the point-by-point method and a frequency-doubled Ar laser. All the gratings were annealed at 80°C for 48 h to stabilize their optical properties. Figure 1 shows the spectral evolution of a 30 mm long LPFG with a period of 161 m during the UV inscription process. It is clear that with increasing UV exposure the conjugate dual peaks were increasing in strength and moving close to each other as the coupling condition approached the dispersion turning point.The ability of LPFGs to couple light from the fiber core mode to cladding modes allows optically detecting the change in refractive index at the grating surface. This thus provides an optical detection method to monitor biochemical and biomolecular interactions. Figure 2 shows the basic scheme of the functionalization of a LPFG as a DNA-array biosensor. Silanization is a process for modification of the glass surface to adsorb biomolecules. The LPFG surface is first silanized, followed by the activation of cross linkers to facilitate the immobilization of probe DNA and then to be used to monitor in situ the hybridization of targeted DNA. The DNA hybridization process modifies the refractive index of the LPFG surface, thus resulting in its spectral shift. By demodulating the spectral shift, the designed DNA hybridization can be monitored with high sensitivity.All the biochemical experiments were performed in a fume cupboard. To minimize the bend cross sensitivity, the dual-peak LPFG with a 161 m period was placed straight in a V-groove container on a Teflon plate, and all the chemicals and solvents were added and withdrawn from the container by carefully pipetting.Prior ...

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Back in 2003, we published ‘MAX’ randomization, a process of non-degenerate saturation mutagenesis using exactly 20 codons (one for each amino acid) or else any required subset of those 20 codons. ‘MAX’ randomization saturates codons located in isolated positions within a protein, as might be required in enzyme engineering, or else on one face of an α-helix, as in zinc-finger engineering. Since that time, we have been asked for an equivalent process that can saturate multiple contiguous codons in a non-degenerate manner. We have now developed ‘ProxiMAX’ randomization, which does just that: generating DNA cassettes for saturation mutagenesis without degeneracy or bias. Offering an alternative to trinucleotide phosphoramidite chemistry, ProxiMAX randomization uses nothing more sophisticated than unmodified oligonucleotides and standard molecular biology reagents. Thus it requires no specialized chemistry, reagents or equipment, and simply relies on a process of saturation cycling comprising ligation, amplification and digestion for each cycle. The process can encode both unbiased representation of selected amino acids or else encode them in predefined ratios. Each saturated position can be defined independently of the others. We demonstrate accurate saturation of up to 11 contiguous codons. As such, ProxiMAX randomization is particularly relevant to antibody engineering.

This version is available from Sussex Research Online: http://sro.sussex.ac.uk/38820/ This document is made available in accordance with publisher policies and may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the URL above for details on accessing the published version. Copyright and reuse:Sussex Research Online is a digital repository of the research output of the University.Copyright and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable, the material made available in SRO has been checked for eligibility before being made available.Copies of full text items generally can be reproduced, displayed or performed and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. We present the design and operation of an ytterbium ion trap experiment with a setup offering versatile optical access and 90 electrical interconnects that can host advanced surface and multilayer ion trap chips mounted on chip carriers. We operate a macroscopic ion trap compatible with this chip carrier design and characterize its performance, demonstrating secular frequencies >1 MHz, and trap and cool nearly all of the stable isotopes, including 171 Yb + ions, as well as ion crystals. For this particular trap we measure the motional heating rate ṅ and observe an ṅ ∝1/ω 2 behavior for different secular frequencies ω. We also determine a spectral noise density S E (1 MHz) = 3.6(9) × 10 −11 V 2 m −2 Hz −1 at an ion electrode spacing of 310(10) µm. We describe the experimental setup for trapping and cooling Yb + ions and provide frequency measurements of the 2 S 1/2 ↔ 2 P 1/2 and 2 D 3/2 ↔ 3 D[3/2] 1/2 transitions for the stable 170 Yb + , 171 Yb + , 172 Yb + , 174 Yb + ,a n d 176 Yb + isotopes which are more precise than previously published work.

This study aims to compare the sensitivity of whole-body MRI with bone scintigraphy in the detection of bone metastases in patients with renal cancer. A prospective study was carried out in 47 patients with renal cancer (mean age 62 years, range 29-79 years). All patients had assessment of the skeleton with whole-body bone scintigraphy (with technetium-99m methylene diphosphonate) and whole-body MRI (coronal T(1) weighted and short tau inversion recovery sequences). The number and sites of bony metastases were assessed on each imaging investigation independently. Sites of extra-osseous metastasis on MRI were also noted. The imaging findings were correlated with other imaging modalities and follow-up. 15 patients (32%) had bone metastases at 34 different sites. Both scintigraphy and MRI were highly specific (94% and 97%, respectively), but the sensitivity of MRI (94%) was superior (p = 0.007) to that of scintigraphy (62%). MRI identified more metastases in the spine and appendicular skeleton, whereas scintigraphy showed more lesions in the skull/facial and thoracic bones. MRI identified extra-osseous metastases in 33 patients (70%), these were mainly lung and retroperitoneal in site. Whole-body MRI is a more sensitive method for detection of bone metastases in renal cancer than bone scintigraphy, and also allows the assessment of soft-tissue disease.