Colony Assay for Antibody Library Screening: Outlook and Comparison to Display Screening

Recombinant monoclonal antibodies are established by screening the antibody libraries. To obtain antibodies with a high specificity and affinity, an efficient screening process with a highly diverse library including low background signals is necessary. One of the most extensively used methods is the phage display method. Although phage display screening is a powerful tool for enriching clones from vast libraries, it is not easy to identify single clones with an antigen recognition function only through several rounds of biopanning. The application of colony assays for screening antibody libraries can identify clones with a high reliability by a direct observation of the antibody-antigen binding during the screening process; however, the size of the library that can be dealt with is limited. This chapter describes the colony assay as a current screening technology used in recombinant monoclonal antibody production, the possible problems in this method, and discusses the outlook for this technology

An ytterbium quantum gas microscope with narrow-line laser cooling

We demonstrate site-resolved imaging of individual bosonic $^{174}\mathrm{Yb}$ atoms in a Hubbard-regime two-dimensional optical lattice with a short lattice constant of 266 nm. To suppress the heating by probe light with the $^1S_0$-$^1P_1$ transition of the wavelength $\lambda$ = 399 nm for high-resolution imaging and preserve atoms at the same lattice sites during the fluorescence imaging, we simultaneously cool atoms by additionally applying narrow-line optical molasses with the $^1S_0$-$^3P_1$ transition of the wavelength $\lambda$ = 556 nm. We achieve a low temperature of $T = 7.4(1.3)\ \mu\mathrm{K}$, corresponding to a mean oscillation quantum number along the horizontal axes of 0.22(4) during imaging process. We detect on average 200 fluorescence photons from a single atom within 400 ms exposure time, and estimate the detection fidelity of 87(2)%. The realization of a quantum gas microscope with enough fidelity for Yb atoms in a Hubbard-regime optical lattice opens up the possibilities for studying various kinds of quantum many-body systems such as Bose and Fermi gases, and their mixtures, and also long-range-interacting systems such as Rydberg states.Comment: 14 pages, 6 figure

Resonant Control of Interaction Between Different Electronic States

We observe a magnetic Feshbach resonance in a collision between the ground and metastable states of two-electron atoms of ytterbium (Yb). We measure the on-site interaction of doubly-occupied sites of an atomic Mott insulator state in a three-dimensional optical lattice as a collisional frequency shift in a high-resolution laser spectroscopy. The observed spectra are well fitted by a simple theoretical formula, in which two particles with an s-wave contact interaction are confined in a harmonic trap. This analysis reveals a wide variation of the interaction with a resonance behavior around a magnetic field of about 1.1 Gauss for the energetically lowest magnetic sublevel of ${}^{170}$Yb, as well as around 360 mG for the energetically highest magnetic sublevel of ${}^{174}$Yb. The observed Feshbach resonance can only be induced by an anisotropic inter-atomic interaction. This novel scheme will open the door to a variety of study using two-electron atoms with tunable interaction.Comment: 5 pages, 5 figure

Effects of laser wavelength and density scalelength on absorption of ultrashort intense lasers on solid-density targets

Hot electron temperatures and electron energy spectra in the course of interaction between intense laser pulse and overdense plasmas are reexamined from a viewpoint of the difference in laser wavelength. The hot electron temperature measured by a particle-in-cell simulation is scaled by $I$ rather than $I \lambda^2$ at the interaction with overdense plasmas with fixed ions, where $I$ and $\lambda$ are the laser intensity and wavelength, respectively.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

A New Find of a Prboscidean Fossil from Nagano Prefecture, Central Japan

Article信州大学理学部紀要 6(1): 37-44(1971)departmental bulletin pape