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Organic solid-state emissive materials have recently gained significant attention for their optoelectronic properties, leading to the design of various optical devices and sensors. Achieving highly efficient solid-state fluorescence is challenging. Moreover, understanding a structure–property relationship is crucial for designing and improvising solid-state emitters. Herein, we have synthesized different compounds having p-bis(2,2-dicyanovinyl)benzene as a core structure and varied the substitution position and linker length. However, after several batches of failed crystallization for a few analogues, microcrystal electron diffraction (MicroED) and synchrotron were used for structure elucidation that helps in better understanding the solid-state emission behavior of the synthesized organic fluorophores. During the analysis, MicroED helps us to characterize a novel polymorph of 4,4′-biphenyldicarboxaldehyde (starting material for BP-1and BP-2) and an intermediate product of BP-2, i.e., monoaldehyde derivative, from a powdered mixture. Based on the structural analysis, it was observed that π–π interactions and C–H···O/N interactions play a dominant role in tuning the photophysical properties of these organic fluorophores.

Here we report thermally-induced and long-duration jumping phenomena in a toluene-solvated crystal of zinc(II) tetraphenylporphyrin. The crystal splits into pieces along with a jumping phenomenon by cooling after heating over its desolvation temperature. Interestingly, the jumping phenomenon was observed for more than a few minutes after the thermal stimulus. Microscope observations, thermal analyses, and X-ray crystallographic studies revealed that the long-duration jumping phenomenon is due to a stepwise stimulation: accumulation of thermally-induced strain by coexisting the solvated and unsolvated crystal structures, i.e. pseudo-polymorphs, in the crystal and release of the strain triggered by time, i.e. gradual spontaneous desolvation at the ambient conditions. Our findings based on the stepwise approach demonstrate that time can work as a stimulus for jumping molecular crystals and demonstrate their designability by introduction of strain as an artificial modification.A long-duration crystal-jumping phenomenon as a pseudo-chronosalient effect is demonstrated in a single crystal of zinc(II) tetraphenylporphyrin by a stepwise stimulation approach, i.e. introduction of strain to a crystal via thermal desolvation which results in the coexistence of pseudo-polymorphic crystal structures and release of the strain triggered by gradual spontaneous desolvation.

Crystal structures strongly depend on intermolecular interactions and molecular structures. Sterically bulky molecules sometimes have a problem in their close packing and form voids which can be filled by small or thin molecules, for example, solvent molecules and alkyl chains, in the crystalline state. Herein, we investigate molecular assembly manners of salts with both sterically bulky and conformationally flexible moieties: alkyldiammonium triphenylacetates. Discrete, one-dimensional, and two-dimensional connections of hydrogen-bonding supramolecular columns were found in the salts with short, middle, and long alkyl chains with trans/gauche conformations, respectively. The result demonstrates potential applicability of the conformational flexibility of alkyl chains to crystal designs in crystal engineering.

In contrast to the versatile superelastic deformability in superelastic alloys, organic single crystals make superelastic deformation mechanically well defined due to the strong anisotropy of component molecules and their packing manners, while the purposful design of superelasticity in multiple directions has not been achieved. Herein, we demonstrate perpendicularly oriented dual superelasticity in an organic single crystal of 2,7-dibromo-9,9-diphenylfluorene. Although the two superelastic deformations are based on mutually different molecular movements and their twin interfaces and bending directions orient perpendicularly, they have a common twin axis corresponding with the axis of molecular C2symmetry. Our findings will contribute to the design of directional deformability of organosuperelastic crystals by symmetry-based crystal engineering.

Specific kinds of alloys, so-called shape-memory alloys (SMAs), show superelasticity. Their mechanism has been known as slight atomic rearrangement by keeping relative positional relationships. Contrary to this, not only molecular rearrangement but also orientational and conformational changes are involved in superelasticity in molecular single crystals. Herein, we investigate superelasticity correlated with molecular bending in a crystal formed by a one-dimensional hydrogen-bonding supramolecular chain of pimelic acid. Because of the structural analogy of the supramolecular chain and polyethylene as one of the linear covalent polymers, the bending mechanism has a possibility of being applied to the similar deformability in the crystalline polymer solids. According to single-crystal X-ray structural analyses, the superelasticity based on mechanical generation and spontaneous dissipation of a thermodynamically unstable phase is induced by bending of the molecular chains along with a normal stress effect based on conformation changes via precession movement.

A charge-transfer (CT) interaction stabilizes molecular assemblies and can form a useful supramolecular synthon in crystal engineering. Herein we demonstrate preparation of a chiral single crystal showing twinning-based organosuperelasticity by forming a CT complex of an achiral donor–acceptor type Schiff base: N-(2,3,4,5,6-pentafluorophenyl)-1-phenylmethanimine. Pseudo-180° symmetry of a single-component CT complex originating from an antiparallel molecular assembly is the key to mechanical twinning. The chiral crystallization induced by CT interactions is also noteworthy because of the potential development of materials showing CT-based functions coupled with chirality.

Despite the general conception of brittleness, organic single crystals composed of various kinds of molecules can show ferroelasticity by mechanical twinning. This is attributed to flexibilities in molecular structures, e.g., conformation, and noncovalent bonds, e.g., length and angle. Herein, we find ferroelasticity by mechanical twinning mediated by water of crystallization in a single crystal of a zwitterion: sulfanilic acid monohydrate. Shaping of an organic single crystal is demonstrated ferroelastically from linear to bent shape and from contracted to elongated shape. Rotation of sulfonate anions along with recombination and changes in lengths and angles in flexible hydrogen bonds of small water molecules helps ferroelastic mechanical twinning. Our findings demonstrate designability of mechanically twinnable organic crystals from the viewpoints of organic chemistry and crystal engineering based on hydrogen bonds.

In diffusion-less plastic deformation, crystalline materials deform without losing crystallinity by keeping the relative positions of atoms and/or molecules. The deformation in a direction-independent manner is achieved in polycrystalline inorganic materials comprised of isotropic spherical atoms. On the other hand, single crystals especially constructed by anisotropic molecules are expected to show anisotropic responses in the deformation. Herein we demonstrate anisotropic mechanical behaviors in a single crystal of 3-methyl-4-nitrobenzoic acid: shear direction-dependent selectivity between superelasticity and ferroelasticity. Superelasticity in two opposite directions based on two-way, mechanically induced phase transition is also noteworthy. These behaviors are unprecedented in so-called shape-memory alloys and characterize the multiplicity of organosuperelasticity and organoferroelasticity from the viewpoint of anisotropy in mechanical deformation.

Slip deformability to multiple directions results in development of moldability and processability of solids as well as applications to solid lubricants. On the other hand, strict deformation in a defined manner, and direction is applicable to mechanical devices demanding precise movements. Herein we report multilayer slip deformation in a two-dimensional direction linearly without losing crystal integrity in a lamellar single crystal of 5-fluorouracil.

Superelasticity—diffusion-less plastic deformation with spontaneous shape recoverability—has been applied to practical uses due to its unique mechanical characteristics, e.g., reversible deformability over elastic limit, and thermally induced shape recovery, the so-called shape-memory effect. For shaping shape-memory alloys showing superelasticity, they are aged under severe conditions unsuitable for organic materials, e.g., heating over several hundred degrees Celsius for several minutes to hours. Here we demonstrate shaping of a chiral organosuperelastic single crystal by quick shape-memorization processing at a temperature between 20 and 170 °C. Different from conventional shape-memory alloys, superelasticity of the crystal shows a small negative temperature dependence. Inversion of a polar direction and helical axis, induced by superelastic deformation in a crystal structure with a polar point group symmetry of 2, is also noteworthy from the viewpoint of polarity-based functions. The unveiled deformability will pave the way for development of organic crystalline materials, e.g., damping materials and structural materials, in soft robots.

The formation of two-component supramolecular polymers can lead to high supramolecular designability by a combination of different kinds of components in addition to the development of thermal and physical properties. These features are suitable for screening mechanical properties of low molecular crystals. Herein, we demonstrate ferroelasticity in a co-crystal of pimelic acid and 1,2-di(4-pyridyl)ethane, which form a one-dimensional supramolecular polymer by hydrogen bonds in the single crystalline state. The crystal showed a permanent biased ferroelastic hysteresis loop as a mixture of ferroelasticity and superelasticity, which is attributable to multiple crystallographically independent molecules.

Under the concept of supramolecular chemistry and crystal engineering, cocrystallization is one of the most widely used approaches for developing physical and other properties of crystals. Herein we report the first organoferroelastic cocrystal comprising oxalic acid and 4-chlorobenzamide showing a ferroelastic hysteresis loop, while single crystals of both of the components are non-ferroelastic.

ABSTRACTRice with double mutation of starch synthase IIIaand branching enzyme IIb(ss3a/be2b) has much higher amounts of apparent amylose and resistant starch (RS) than usual varieties. In this study, we conducted two randomized, single-blind, crossover trials to investigate the effect of single ingestion of two processed foods composed of ss3a/be2bmutant rice on postprandial blood glucose and insulin response in healthy adults, compared to those of usual cultivar. In trial 1, of ingestion of rice crackers, the incremental area under the curves of glucose (IAUCglc) and insulin (IAUCins) in RS group was significantly lower than in the control group. In trial 2, of the ingestion of cooked rice, IAUCglc in the RS group was significantly lower than in the control group. These results showed that the ss3a/be2b-mutant rice cracker and cooked rice having high RS can attenuate postprandial blood glucose and insulin response.

Controlling chiral crystallization, which remains one of the biggest challenges in crystal engineering, brings enormous advantages in material sciences, especially chiral industries. This work demonstrates that chiral crystallization is controllable by designing structures of 2-fold helices, which affect the manner of interhelical interactions. Here we show an example of chiral crystallization by using achiral primary ammonium carboxylates having simple chemical structures: naphthyl and tert-butyl groups. Their crystal structures were precisely investigated by focusing on hydrogen-bonded 2-fold helices along with theoretical calculations. Consequently, a key role of interhelical CH/π contacts in chiral crystallization was found to be not attracting but arranging chiral 2-fold helices. More importantly, a clear difference was found in densities of 2-fold helices and their stacking between chiral and achiral crystals.

The applicability of advanced graph set analysis and solid-state vibrational circular dichroism (SD-VCD) spectroscopy to the characterization of supramolecular chirality has been demonstrated. Recrystallization of R-(+)-1-phenylethylammonium 1-naphthoate affords two polymorphic crystals: one is composed of hydrogen-bonded (HB) 2-fold helices with helicity, while the other contains HB clusters with topological chirality. Handedness and origins of the chirality were crystallographically characterized by advanced graph set analysis. SD-VCD measurements were then recorded for these polymorphic crystals using the VCD spectrometer PRESTO-S-2007, which we developed. Unique VCD spectra were observed because of the difference in features of the chiral supramolecular structures. Enhancement of VCD signals depending on dimensionality of the supermolecules is especially noteworthy. Generality of 2-fold helices, demonstrated by statistics from the Cambridge Structural Database, and geometrical characteristics and theoretical simplicity of the HB clusters, because of their finite number of components connected by closed-hydrogen bonding networks, allowed them to become reasonable representative examples for chiral supermolecules.

Electrochemical intercalation behaviors of lithium ions into graphene-like graphite (GLG) were investigated at high cell voltages. The interlayer spacing of GLG started to increase at much higher cell voltages than that needed for graphite. It stepwisely increased at a decrease in the cell voltages, indicating the staging phenomenon. The thermodynamic considerations suggested that the strong interaction between oxygen atoms introduced in GLG and lithium ions is responsible for the formation of intercalation compounds of desolvated lithium ions. The interlayer distance of GLG was more important than the content of oxygen in it for the decreased separation energy of carbon layers and, accordingly, for the onset voltage of the intercalation of lithium ions into it. The intercalation of desolvated lithium ions into GLG was achieved even in an electrolyte solution containing dimethoxyethane in which solvents are co-intercalated into graphite.

In this study, a novel phenomenological model is developed to predict the etching yields of SiO2and SiNxsubstrates by fluorocarbon and hydrofluorocarbon ions. The CF layer thickness and reactive layer chemistry are described, which significantly affect the etching yields. The study focuses on the dependence of the atomic component of the ion and the incident ion energy of the ion on the etching yield. Some assumptions enable the calculation of ion etching yields in a short turn-around-time. The proposed model can predict the etching yields of other larger species at higher incident ion energies. The obtained simulation results are in good agreement with the experimental data. The optimal etching ions for high aspect ratio etching are comprehensively investigated using the proposed model, providing a better understanding of the differences in the underlying material and the atomic component of the ion.

Superelasticity is characterized by unique mechanical behavior, i.e., spontaneous shape recoverability by diffusionless plastic deformation and has been considered to be a property of specific alloys, so-called shape memory alloys, from its discovery in 1932. The discovery of superelasticity in an organic crystal in 2014, so-called organosuperelasticity, paved the way for functionalization of superelastic materials based on molecular design. In this context, achieving superelasiticity using various kinds of organic compounds and elucidation of its mechanism are inevitable. Here we show superelasticity in a single crystal of a derivative of sterically bulky cyclophanes: 4,5,7,8,12,13,15,16-octafluoro[2.2]paracyclophane. Crystallographic studies indicated interconversion of two centrosymmetric crystallographically independent molecules by changing molecular orientations in the crystalline state in twinning superelasticity. Our findings will contribute to propose one of the useful approaches for designing organosuperelastic materials.

Olanzapine (OLN), an antipsychotic drug, is one of the most widely studied pharmaceutical materials. Although OLN and most of their multicomponent solids are highly crystalline, some of their molecular salts are difficult to crystallize and optimization takes a long time. After several batches of failed crystallization, we applied mechanochemistry and microcrystal electron diffraction (MicroED) for structure elucidation. This combined approach was successful not only in structure determination of the drug molecule but also in characterizing traces of impurity present in a bulk solid. This study demonstrates that the combined approach is fast and efficient for structure elucidation of pharmaceutical materials when generation of suitable single crystals is challenging.

We present the first spectropolarimetric observations of a candidate of super-Chandrasekhar mass Type Ia supernova (SN): SN 2009dc. The observations were performed at 5.6 and 89.5 days after the B-band maximum. The data taken at the later epoch are used to determine the interstellar polarization. Continuum polarization is found to be small (<0.3%), indicating that the explosion is nearly spherically symmetric. This fact suggests that a very aspherical explosion is not a likely scenario for SN 2009dc. Polarization at the Si II and Ca II lines clearly shows a loop in the Q-U plane, indicating a non-axisymmetric, clumpy distribution of intermediate-mass elements. The degree of line polarization at the Si and Ca lines is moderate (0.5% +- 0.1% and 0.7% +- 0.1%, respectively), but it is higher than expected from the trend of other Type Ia SNe. This may suggest that there are thick enough, clumpy Si-rich layers above the thick 56Ni-rich layers ([?]1.2 M ). The observed spectropolarimetric properties, combined with the photometric and spectroscopic properties, suggest that the progenitor of SN 2009dc has a super-Chandrasekhar mass, and that the explosion geometry is globally spherically symmetric, with clumpy distribution of intermediate-mass elements.

The 2007 Chuetsu-oki earthquake occurred just west off the coast of Kashiwazaki in Niigata Prefecture, Central Japan on July 16, 2007. The permanent GPS network (GEONET) clarifies the coseismic displacement as a thrust faulting whose compressional axis lies in the NW-SE direction. Interferometric analysis of synthetic aperture radar (SAR) images acquired by “Daichi” satellite (ALOS) maps a detailed spatial pattern of the displacement toward the satellite for both ascending and descending orbits. Peak-to-peak displacement reaches approximately 400 mm in the descending orbit interferometric (In)SAR data. Repeated precise leveling shows uplift near the northeast part of the aftershock area and subsidence near the southwestern part. We construct a preliminary fault model by inverting the observed deformation. The preferred model consists of two segments of rectangular faults whose moment magnitude is 6.7 in total. From only the used geodetic data on land, it is difficult to determine which plane in two conjugate planes of the focal solution was ruptured. It is important to consider the effect of a heterogeneous medium and variable slip on the faults as well as other geophysical data to determine the fault model with confidence.

We have developed a new method for the treatment of stomach lesions in early gastric cancer, which we refer to as laparoscopic intragastric full-thickness excision under flexible endoscopic control. In this procedure, the diseased lesion of the gastric wall is pulled inwards and removed under endoscopy and laparoscopy guidance. A lesion in the anterior wall of the stomach, for which a direct percutaneous transgastric puncture can be performed, is a good indication for laparoscopic intragastric full-thickness excision, similarly to the lesion-lifting method. The purpose of the study is to describe the surgical techniques in the procedure and to assess the clinical relevance of the approach.

We investigate the luminosity functions of Lyman break galaxies (LBGs) at z ~ 4 and z ~ 5 based on optical imaging data obtained in the Subaru Deep Field project. Three samples of LBGs in a contiguous area of 875 arcmin2 are constructed. One consists of 3808 LBGs at z ~ 4 down to i' = 26.85 selected with the B-R versus R-i' diagram. The other two consist of 539 and 240 LBGs at z ~ 5 down to z' = 26.05 selected with two kinds of two-color diagram: V-i' versus i'-z' and R-i' versus i'-z'. The adopted selection criteria are proved to be fairly reliable by spectroscopic observations. We derive the luminosity functions of the LBGs at rest-frame ultraviolet wavelengths down to MUV = -19.2 at z ~ 4 and MUV = -20.3 at z ~ 5. We find clear evolution of the luminosity function over the redshift range 0 [?] z [?] 6, which is accounted for solely by a change in the characteristic magnitude M*. We examine the evolution of the cosmic star formation rate (SFR) density and its luminosity dependence over 0 [?] z [?] 6. The SFR density contributed from brighter galaxies is found to change more drastically with cosmic time. The contribution from brighter galaxies has a sharp peak around z = 3-4, while that from fainter galaxies evolves relatively mildly with a broad peak at earlier epochs. Combining the observed SFR density with the standard cold dark matter model, we compute the cosmic SFR per unit baryon mass in dark halos, that is, the specific SFR. The specific SFR is found to scale with redshift as (1 + z)3 up to z ~ 4, implying that the efficiency of star formation is on average higher at higher redshift in proportion to the cooling rate within dark halos, while this is not simply the case at z [?] 4.

We report an extensive search for Lya emitters (LAEs) at z = 6.5 in the Subaru Deep Field. Subsequent spectroscopy with Subaru and Keck identified eight more LAEs, giving a total of 17 spectroscopically confirmed LAEs at z = 6.5. Based on this spectroscopic sample of 17, complemented by a photometric sample of 58 LAEs, we have derived a more accurate Lya luminosity function of LAEs at z = 6.5, which reveals an apparent deficit at the bright end of ~0.75 mag fainter L*, compared with that observed at z = 5.7. The difference in the LAE luminosity functions between z = 5.7 and 6.5 is significant at the 3 s level, which is reduced to 2 s when cosmic variance is taken into account. This result may imply that the reionization of the universe has not been completed at z = 6.5. We found that the spatial distribution of LAEs at z = 6.5 was homogeneous over the field. We discuss the implications of these results for the reionization of the universe.

We present the properties of Ly$\alpha$emitters (LAEs) at $z=5.7$in the Subaru Deep Field. A photometric sample of 89 LAE candidates was constructed from narrow-band data down to $\mathit{NB816} = 26.0$(AB) in a continuous $725 \,\mathrm{arcmin}^2$area. Spectra of 39 objects satisfying the photometric selection criteria for LAEs were obtained with Subaru and Keck II Telescopes, among which 28 were confirmed LAEs, one was a nearby galaxy, and eight were unclassified. We also obtained spectra of another 24 NB816-excess objects in the field, identifying six additional LAEs. We find that the Ly$\alpha$luminosity function derived from the photometric sample is reproduced well by a Schechter function with $L^\star = 7.9^{+3.0}_{-2.2} \times 10^{42} \,\mathrm{erg} \,\mathrm{s}^{-1}$and $\phi^\star = 6.3^{+3.0}_{-2.0} \times 10^{-4} \,\mathrm{Mpc}^{-3}$for $\alpha =-1.5$(fixed) over the whole luminosity range of $L \simeq 3 \times 10^{42} \hbox{--} 3 \times 10^{43} \,\mathrm{erg} \,\mathrm{s}^{-1}$. We then measured the rest-frame Ly$\alpha$equivalent widths for the confirmed LAEs, to find that the median among the 28 objects satisfying the photometric selection criteria is $W_{0}^{\mathrm{i}} = 233 \,{Å}$. We infer that 30%-40% of LAEs at $z=5.7$exceed $W_{0}^{\mathrm{i}} = 240 \,{Å}$. These large-EW objects probably cannot be accounted for by ordinary star-forming populations with a Salpeter IMF. We also find that LAEs with fainter far-UV luminosities have larger EWs. Finally, we derived the far-UV luminosity function of LAEs down to $M_{\mathrm{UV}} \simeq-19.6$using the photometric sample, and compared it with that of Lyman-break galaxies (LBGs). We find that as high as about 80% of LBGs at $z \sim 6$have $W_{0}^{\mathrm{i}} \ge 100 \,{Å}$, in sharp contrast to lower-$z$counterparts.

We explored the clustering properties of Lyman break galaxies at z = 4 and 5 with an angular two-point correlation function on the basis of the very deep and wide Subaru Deep Field data. We confirmed the previous result that the clustering strength of LBGs depends on the UV luminosity in the sense that brighter LBGs are more strongly clustered. In addition, we found an apparent dependence of the correlation function slope on UV luminosity for LBGs at both z = 4 and 5. More luminous LBGs have a steeper correlation function. The bias parameter was found to be a scale-dependent function for bright LBGs, whereas it appears to be almost scale-independent for faint LBGs. Luminous LBGs have a higher bias at smaller angular scales, which decreases as the scale increases. To compare these observational results, we constructed numerical mock LBG catalogs based on a semianalytic model of hierarchical clustering combined with high-resolution N-body simulation, carefully mimicking the observational selection effects. The luminosity functions and the overall correlation functions for LBGs at z = 4 and 5 predicted by this mock catalog were found to be almost consistent with the observation. The observed dependence of the clustering on UV luminosity was not reproduced by the model, unless subsamples of distinct halo mass were considered. That is, LBGs belonging to more massive dark halos had steeper and larger amplitude correlation functions. With this model, we found that LBG multiplicity in massive dark halos amplifies the clustering strength at small scales, which steepens the correlation function. The hierarchical clustering model could therefore be reconciled with the observed luminosity dependence of the correlation function if there is a tight correlation between UV luminosity and halo mass. Our finding that the slope of the correlation function depends on luminosity could be an indication that massive dark halos hosted multiple bright LBGs.

We carried out a search for globular clusters in M82 by taking advantage of the relatively high resolution imaging and deep spectroscopic capabilities provided by the Faint Object Camera And Spectograph (FOCAS) on the Subaru Telescope. Since M82 is a late-type galaxy, its globular cluster system provides a basis for comparison with the globular cluster system of our Galaxy or that of M31. The archetypal starburst galaxy M82 also constitutes an ideal target for studying the relation between galaxy interactions, starbursts, and globular cluster formation. First, we performed an imaging survey to pick up globular cluster candidates using the color-magnitude selection method. Follow-up spectroscopic observations were carried out for 29 globular cluster candidates using the multiobject spectroscopic mode of FOCAS. In the central 6' diameter region of M82, we found two bona fide globular clusters and three young star clusters in our first attempt at optical searching for globular clusters in M82. The estimated age of young star clusters is [?] 1 Gyr, which is consistent with or lower than the age derived by infrared photometry. Two bona fide globular clusters should have formed at the epoch of M82's formation. Some of the young star clusters identified in M82 are likely to have been produced during the tidal-interaction episode with M81.

We present new results of a deep optical imaging survey using a narrow band filter (NB921) centered at ${\lambda = 9196 \,\mbox{Å}}$together with $B, V, R, i^\prime$, and $z^\prime$broadband filters in the sky area of the Subaru Deep Field, which has been promoted as one of legacy programs of the 8.2m Subaru Telescope. We obtained a photometric sample of 58 $\mathrm{Ly}\,\alpha$emitter candidates at $z \approx 6.5 \hbox{--} 6.6$among $\sim 180$strong NB921-excess ($z^\prime-\mathit{NB921} \gt 1.0 z^\prime-\mathit{NB921} > 1.0$) objects together with a color criterion of $i^\prime-z^\prime \gt 1.3 i^\prime-z^\prime > 1.3$. We then obtained optical spectra of 20 objects in our NB921-excess sample, and identified at least nine $\mathrm{Ly}\,\alpha$emitters at $z \sim 6.5 \hbox{--} 6.6$, including the two emitters reported by Kodaira et al. (2003, PASJ, 55, L17). Since our $\mathrm{Ly}\,\alpha$-emitter candidates are free from strong amplification of gravitational lensing, we are able to discuss their observational properties from a statistical point of view. Based on these new results, we obtained a lower limit of the star-formation rate density of $\rho_\mathrm{SFR} \simeq 5.7 \times 10^{-4} \,h_{0.7} \,{{{M}_{\odot}}} \,\mathrm{yr}^{-1} \,\mathrm{Mpc}^{-3}$at $z \approx 6.6$, being consistent with our previous estimate. We discuss the nature of star-formation activity in galaxies beyond $z=6$.

The Subaru Deep Field (SDF) project is a program of Subaru Observatory to carry out a deep galaxy survey over a blank field as large as $34' \times 27'$. The program consists of very deep multi-band optical imaging, near-infrared imaging for smaller portions of the field, and follow-up optical spectroscopy. The major scientific goals of the project are to construct large samples of Lyman-break galaxies at $z \simeq 4 \hbox{--} 5$and Lyman alpha emitters at $z \simeq 5.7$and 6.6, and to make detailed studies of these very high-redshift galaxy populations. In this paper, we describe the optical imaging observations and data reduction, presenting mosaicked images and object catalogs in seven bandpasses. The optical imaging was made through five broad-band filters, $B$, $V$, $R$, $i'$, $z'$, and two narrow-band filters, NB816 ($\lambda_{\mathrm{c}} = 8150 \,{Å}$) and NB921 ($\lambda_{\mathrm{c}}=9196 \,{Å}$) with almost 10 hour integrations for each band. The limiting magnitudes measured at $3 \,\sigma$on a $2^{\prime\prime}$aperture are $B=28.45$, $V=27.74$, $R=27.80$, $i'=27.43$, $z'=26.62$, $\mathrm{NB816} = 26.63$, and $\mathrm{NB921}=26.54$in the AB system. The object catalog constructed for each of the seven bands contains more than $10^5$objects. The galaxy number counts corrected for detection incompleteness and star-count contributions are found to be consistent with previous results in the literature. Mosaicked images and catalogs of all the bands have been made open to the public on 2004 October 1 on the SDF project website.1

An overview of the current status of the 8.2 m Subaru Telescope constructed and operated at Mauna Kea, Hawaii, by the National Astronomical Observatory of Japan is presented. The basic design concept and the verified performance of the telescope system are described. Also given are the status of the instrument package offered to the astronomical community, the status of operation, and some of the future plans. The status of the telescope reported in a number of SPIE papers as of the summer of 2002 are incorporated with some updates included as of 2004 February. However, readers are encouraged to check the most updated status of the telescope through the home page, http://subarutelescope.org/index.html, and/or the direct contact with the observatory staff.

We performed deep $K'$-band imaging observations of 2 massive clusters, MS 0451.6$-$0305 at $z = 0.55$and MS 0440.5$+$0204 at $z = 0.19$, for searching counterparts of the faint sub-mm sources behind these clusters, which would provide one of the deepest extremely red object (ERO) samples. Comparing our near-infrared images with optical images taken by the Hubble Space Telescope and by the Subaru Telescope, we identified 13 EROs in these fields. The sky distributions of EROs are consistent with the previous results, that there is a sign of strong clustering among detected EROs. Also, the surface density with corrected lensing amplification factors in both clusters are in good agreement with that derived from previous surveys. We found 7 EROs and 3 additional very red objects in a small area ($\sim 0.6 \,\mathrm{arcmin}^{2}$) of the MS 0451.6$-$0305 field around an extended SCUBA source. Many of their optical and near-infrared colors are consistent with dusty star-forming galaxies at high redshifts ($z \sim 1.0 \hbox{--} 4.0$), and they may be constituting a cluster of dusty starburst galaxies and/or lensed star-forming galaxies at high redshift. Their red $J-K'$colors and faint optical magnitudes suggest they are relatively old massive stellar systems with ages ($ \gt 300$mega years) suffering from dust obscuration. We also found a surface-density enhancement of EROs around the SCUBA source in the MS 0440.5$+$0204 field.

The authors compared serum methyldigoxin MDx levels in digitalized patients by enzyme immunoassay EIA using antiMDx 3′hemisuccinate BSA antiserum antiserumI with commercial antidigoxin antiserum antiserumII. The usefulness of a phenyl boric acid PBA column for pretreatment of the serum samples was also investigated. The assay using antiserumI demonstrated good accuracy and precision in the concentration range of 0.5 to 5 ngmL. When the specificities of antiserumI and antiserumII were assessed by crossreactivity studies with various related compounds, antiserumI was much more specific for MDx antiserumII. Using a phenyl boric acid PBA column, MDx, and digoxigenin, which exhibits a negligible crossreactivity, were separated from serum, including MDx and its metabolites. The recovery tests of MDx using antiserumI with a PBA column in human serum were satisfactory and no interference of metabolites of MDx was observed. Mean MDx concentrations in serum samples n 30 from digitalized patients by EIA using antiserumI with PBA column, antiserumI, and antiserumII were 1.06, 1.30, and 1.74 ngmL, respectively. These results indicate that our EIA system using antiserumI with a PBA column for pretreatment of serum samples is useful to more precisely measure the unchanged type of MDx in patients.

We performed a deep optical imaging survey using a narrow-band filter (NB921) centered at $\lambda = 9196 \,$Å together with $i^\prime$and $z^\prime$broadband filters covering an $814 \,\mathrm{arcmin}^2$area of the Subaru Deep Field. We obtained a sample of 73 strong NB921-excess objects based on the following two color criteria:$z^\prime-\mathit{NB}\,921 \gt 1$$z^\prime-\mathit{NB}\,921 \gt 1$and $i^\prime-z^\prime \gt 1.3$$i^\prime-z^\prime \gt 1.3$. We then obtained optical spectroscopy of nine objects in our NB921-excess sample, and identified at least two Ly$\alpha$emitters at $z=6.541 \pm 0.002$and $z=6.578 \pm 0.002$, each of which shows the characteristic sharp cutoff together with continuum depression at wavelengths shortward of the line peak. The latter object is more distant than HCM-6A at $z=6.56$, which is the most distant known object that has been found so far. These new data allow us to estimate the first meaningful lower limit of the star-formation rate density beyond redshift 6; $\rho_\mathrm{SFR} \sim 5.2 \times 10^{-4} \,{{{M}_{\odot}}} \,\mathrm{yr}^{-1} \,\mathrm{Mpc}^{-3}$. Since it is expected that the actual density is several times higher than this value, our new observation reveals that a moderately high level of star formation activity already occurred at $z \sim 6.6$.

We present new optical images ($B, V$, and $\mathrm{H}\alpha$) of the archetypical starburst/superwind galaxy M 82 obtained with the 8.2 m Subaru Telescope to reveal new detailed structures of the superwind-driven nebula and the high-latitude dark lanes. The emission-line nebula is decomposed into (1) a ridge-dominated component comprising numerous filament/loop sub-structures whose overall morphology appears as a pair of narrow cylinders, and (2) a diffuse component extended over much wider opening angle from the nucleus. We suggest that these two components have different origins. The ridge-dominated component appears as a pair of cylinders rather than a pair of cones. Since this morphological property is similar to that of hot plasma probed by soft X-ray, this component seems to surround the hot plasma. On the other hand, the diffuse component may arise from dust grains which scatter stellar light from the galaxy. Since inner region of this component is seen over the prominent “X”-shaped dark lanes streaming out from the nuclear region and they can be reproduced as a conical distribution of dust grains, there seems to be a dusty cold outflow as well as the hot one probed by soft X-ray and shock-excited optical emission lines. If this is the case, the presence of such high-latitude dust grains implies that neutral gaseous matter is also blown out during the course of the superwind activity.

The Faint Object Camera and Spectrograph (FOCAS) is a Cassegrain optical instrument for the Subaru Telescope. Its capabilities include $6^\prime \phi$FOV direct imaging, low-resolution spectroscopy ($R=250 \hbox{--} 2000$with ${0\rlap {.}{}^{\mathrm {\prime \prime }}4}$slitwidth), multi-slit spectroscopy and polarimetry. We describe the overall design of FOCAS, its observing functions, and the performance verification procedures that have been carried out.

We discuss the properties of galaxies around the radio galaxy 3C 324 at $z=1.2$based on $BVRIK^\prime$multi-band imaging data. We have applied a photometric-redshift technique to objects in the 3C 324 field, and identified 35 objects as plausible cluster members. We have found that red and luminous members are concentrated in a small region enclosed by a circle of 40$^\prime$radius (0.33Mpc at $z=1.2$for $\Omega_0 = 0.3, \lambda_0 = 0.7, H_0 = 70 \,\mathrm{km} \,\mathrm{s}^{-1} \,\mathrm{Mpc}^{-1}$cosmology) from the 3C 324 galaxy. The 3C 324 cluster is probably much more compact in size compared with the local clusters. We constructed a $K^\prime$-band luminosity function of the cluster members and fitted a Schechter function, and found the characteristic magnitude to be $K^{\ast\prime}_\mathrm{AB} = 20.2 \pm 0.6$. This value is consistent with the extrapolation of the pure passive evolution seen for $z \lt 1$clusters. We have identified eight bright galaxies which form a red color–magnitude sequence. The slope of the sequence is consistent with the passive evolution model down to $K^{\prime}_\mathrm{AB} \lt 22$; we also found that there is no clear age variation in these bright red galaxies. However, seven out of these eight galaxies exhibit a significant excess in the rest UV light with respect to the passive evolution model. This may suggest that the massive early-type galaxies in this high-redshift cluster are still forming stars to some extent. We have confirmed a truncation of the color–magnitude sequence at $K^{\prime}_\mathrm{AB}\sim22$; faint passively-evolving galaxies may not yet be present in this cluster at $z \sim 1.2$. The overall color distribution of the cluster members, selected by the photometric redshift technique, is found to be very broad. We derived the fraction of blue galaxies in this cluster following a definition of Butcher and Oemler (1984, AAA 038.160.068), and obtained $f_\mathrm{B} = 0.39 \pm 0.28$, which is higher than that for $z \lt 1$clusters. This indicates that the star-formation activity of this cluster is, on the average, higher than that of lower redshift counterparts.

We present the results of deep $K^\prime$- and $J$-band imaging of the field of a proto-cluster region near the radio galaxy 53W002 at $z=2.390$with the Subaru Telescope. The data were analyzed together with deep optical and near-infrared (NIR) images taken with the Hubble Space Telescope to investigate the properties of ten optically compact emission-line galaxies and candidates. Excluding the three objects which may contain active galactic nuclei, many are faint or undetected at $K^\prime$($\lambda_\mathrm{rest} \approx 6000 \,{Å}$), and are therefore revealed to be intrinsically small starbursting objects. On the other hand, we detect few objects with colors and magnitudes expected for quiescent massive galaxies at $z=2.4$in the field.