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The 3-GeV rapid cycling synchrotron (RCS) of the Japan Proton Accelerator Research Complex (J-PARC) was commissioned in October 2007, and successfully accomplished 3 GeV acceleration on October 31. Six run cycles through February 2008 were dedicated to commissioning the RCS, for which the initial machine parameter tuning and various underlying beam studies were completed. Then since May 2008 the RCS beam has been delivered to the downstream facilities for their beam commissioning. In this paper we describe beam tuning and study results following our beam commissioning scenario and a beam performance and operational experience obtained in the first commissioning phase through June 2008.

Simultaneous productions of high-purity CaCO 3 (calcium carbonate) and amorphous nanosized SiO 2 -rich (silica-rich) gel from waste concrete powder remain quite challenging, and thus the high-value added utilization of waste concrete powder is significantly limited. A novel technology involving a combination of alkaline treatment and carbonation, has been proposed for the greatly enhanced utilization of waste concrete powder. Through alkaline treatment, CaCO 3 and SiO 2 -rich gel formed during carbonation of concrete powder were transformed into Ca(OH) 2 (calcium hydroxide) and Na 2 SiO 3 (sodium metasilicate), respectively. Subsequently, Ca(OH) 2 and Na 2 SiO 3 were separated. As a result, CaCO 3 with a high purity of 98.54% and amorphous nanosized SiO 2 -rich gel were obtained via carbonation, and the recovery ratio of CaCO 3 was 81.46%. Furthermore, the concrete powder exhibited a high CO 2 (carbon dioxide) uptake efficiency of 0.24g CO 2 /g. 30.31 Mt CaCO 3 and 2.77 Mt SiO 2 -rich gel productions as well as 38.54 Mt CO 2 emission reduction could be realized via recycling a quarter of annually generated waste concrete powder worldwide., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Al oxo-hydroxide clusters, synthesized through the hydrolysis of Al 3+ solutions, are expected to bridge the gap between metal-aqua complexes and bulk metal oxides/hydroxides. These clusters exhibit remarkable diversity in structure and composition, controlled by modulating the basicity of the solution and use of capping ligands. While anionic metal-oxo clusters, such as polyoxometalates, have been extensively studied since the early 20th century, cationic metal-oxo clusters, including those of aluminum, have gained interest more recently due to their high reactivity and potential for various applications. We explore their molecular structures and assembly into various forms, including ionic crystals, amorphous solids, and hybrid materials, for applications such as adsorption, coagulation, and catalysis. Furthermore, we present future perspectives, emphasizing molecular design, scalable synthetic methods, and expanded functional applications, particularly in energy and environmental sciences, where these clusters are expected to demonstrate significant potential., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Polyoxometalates (POMs) are recognized for their diverse structures and catalytic properties, yet their organometallic salts have not been thoroughly investigated. In this study, we synthesized salts of a Keggin-type POM with cationic sandwich complexes featuring various substituents, [ X ] 2 [SMo 12 O 40 ] [ X = Ru(C 5 H 5 )(C 6 H 5 R); R = H ( 1a ), Me ( 1b ), Bu ( 1c )], [Co(C 5 H 5 ) 2 ( 2 ), and Co(C 5 Me 5 ) 2 ( 3 )]. These salts exhibited similar structural characteristics, with each anion surrounded by 10 cations, forming two-dimensional sheet arrangements through O···O anion-anion contacts, except for the salt of 1c , which exhibited one-dimensional contact owing to the larger cation substituent. Additionally, [ 2 ](THA)[Mo 6 O 19 ], [ 3 ] 2 [Mo 6 O 19 ], and [ 3 ](THA)[SMo 12 O 40 ], containing the Lindqvist-type POM [Mo 6 O 19 ] and/or tetrahexylammonium (THA) cation, were obtained, with the packing structure of [ 3 ] 2 [Mo 6 O 19 ] closely resembling that of [ X ] 2 [SMo 12 O 40 ]. Solvate crystals of [ 1a ] 3 [PMo 12 O 40 ] were also prepared. [ 1a ] 2 [SMo 12 O 40 ] exhibits an electrical conductivity σ of 1.4 × 10 -7 S cm -1 at 373 K, which is 2 orders of magnitude higher than those of (THA) 2 [SMo 12 O 40 ] and [ 1a ]PF 6 .

Polyoxometalates (POMs), anionic nanosized oxoclusters that can be considered as fragments of metal oxides, have been extensively studied for their diverse composition and structure, showing promise in various fields such as catalysis and electronics. Proton conduction, relevant to catalysis and electronics, has attracted interest in materials chemistry, and POM anions are advantageous in terms of their proton carrier density and mobility. Recently, polar POMs have attracted attention for their unique ferroelectric behaviors, yet they have been little studied with regard to proton conduction, as their polarity has generally been believed to have a negative impact. Here, we propose that polar POMs can be used to align polar proton carriers, such as H 2 O and polymers, to construct efficient proton-conducting pathways. In this study, we present ionic crystals composed of polar Preyssler-type POMs ([X n + (H 2 O)P 5 W 30 O 110 ] (15- n )- , X n + = Ca 2+ , Eu 3+ ) and K + exhibiting ultrahigh proton conductivity surpassing 10 -2 S cm -1 , which is required for practical applications. In contrast, ionic crystals with nonpolar Preyssler-type POMs show an order of magnitude lower proton conductivity. Structural and spectroscopic studies combined with theoretical calculations reveal that proton carriers align with the aid of staggered arrays of polar POMs, forming a hydrogen-bonding network favorable for proton conduction. This study integrates molecular chemistry by the design of POMs and solid-state chemistry by exploring long-range proton conduction mechanisms, offering novel insights for future materials design.

The metal-organic frameworks (MOFs) attract interest as potential catalysts whose catalytic properties are driven by defects. Several methods have been proposed for the defects-inducing synthesis of MOFs. However, the active species formed on the defective sites remain elusive and uncharacterized, as the spectroscopic fingerprints of these species are hidden by the regular structure signals. In this work, we have performed the synthesis of ZIF-8 MOF with defect-inducing procedures using fully deuterated 2-methylimidazolate ligands to enhance the defective sites' visibility. By combining 1 H and 31 P MAS NMR spectroscopy and X-ray absorption spectroscopy, we have found evidence for the presence of different structural hydroxyl Zn-OH groups in the ZIF-8 materials. It is demonstrated that the ZIF-8 defect sites are represented by Zn-OH hydroxyl groups with the signals at 0.3 and -0.7 ppm in the 1 H MAS NMR spectrum. These species are of basic nature and may be responsible for the catalytic activity of the ZIF-8 material., (© 2024 Wiley-VCH GmbH.)

To control three-dimensional (3D) cell spheroid formation, it is well-known the surface physicochemical and mechanical properties of cell culture materials are important; however, the formation and function of 3D cells are still unclear. This study demonstrated the precise control of the formation of 3D cells and 3D cell functions using diblock copolymers containing different ratios of a zwitterionic trimethylamine N -oxide group. The diblock copolymers were composed of poly( n -butyl methacrylate) (PBMA) as the hydrophobic unit for surface coating on a cell culture dish and stabilization in water, and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) as the precursor of N -oxide. The zwitterionic N -oxide converted from 0 to 100% using PDMAEMA. The wettability and surface zeta potential varied with different ratios of N -oxide diblock copolymer-coated surfaces, and the amount of protein adsorbed in the cell culture medium decreased monotonically with increasing N -oxide ratio. 3D cell spheroid formations were observed by seeding human umbilical cord mesenchymal stem cells (hUC-MSCs) in diblock copolymer-coated flat-bottom well plates, and the N -oxide ratio was over 40%. The cells proliferated in two-dimensions (2D) and did not form spheroids when the N -oxide ratio was less than 20%. Interestingly, the expression of undifferentiated markers of hUC-MSCs was higher on surfaces that adsorbed proteins to some extent and formed 50-150 μm spheroids in the range of 40-70% of N -oxide ratio. We revealed that a moderately protein-adsorbed surface allows precise control of spheroid formation and undifferentiated 3D cells and has potential applications for high-quality spheroids in regenerative medicine and drug screening.

Metal-organic framework (MOF) glasses have emerged as a new class of organic-inorganic hybrid glass materials. Considerable efforts have been devoted to unraveling the macroscopic dynamics of MOF glasses by studying their rheological behavior; however, their microscopic dynamics remain unclear. In this work, we studied the effect of vitrification on linker dynamics in ZIF-62 by solid-state 2 H nuclear magnetic resonance (NMR) spectroscopy. 2 H NMR relaxation analysis provided a detailed picture of the mobility of the ZIF-62 linkers, including local restricted librations and a large-amplitude twist; these details were verified by molecular dynamics. A comparison of ZIF-62 crystals and glasses revealed that vitrification does not drastically affect the fast individual flipping motions with large-amplitude twists, whereas it facilitates slow cooperative large-amplitude twist motions with a decrease in the activation barrier. These observations support the findings of previous studies, indicating that glassy ZIF-62 retains permanent porosity and that short-range disorder exists in the alignment of ligands because of distortion of the coordination angle.

Materials for Cs + adsorption continue to be important for the treatment of various solutions. Metal-organic frameworks (MOFs) with large specific surface areas promise adsorption properties for various gases, vapors, and ions. However, the utilization of MOFs for alkali ion capture, specifically, Cs + capture is still in its infancy. Herein, MOFs are hybridized with polyoxometalates (POMs) to study the effect of i) MOF type, ii) POM type, and iii) POM loading amounts on Cs + capture. In particular, the composite of ZIF-8 and [α-PMo 12 O 40 ] 3- (PMo 12 /ZIF-8) adsorbed Cs + ions effectively when compared to pristine ZIF-8. In addition, the reduction of Mo within the POM from Mo VI to Mo V by ascorbic acid during the Cs + uptake process doubled the Cs + uptake capacity of PMo 12 /ZIF-8. This observation can be attributed to the increased overall negative charge of the POM facilitating Cs + uptake to compensate for the charge imbalance. Hybridization with other MOFs (MIL-101 and UiO-66) largely suppresses the Cs + uptake, highlighting the importance of hydrophobicity in Cs + capture. Furthermore, PMo 12 /ZIF-8 led to an outstanding Cs + uptake (291.5 mg g -1 ) with high selectivity (79.6%) from quinary mixtures of alkali metal cations even among other representative porous materials (Prussian blue and zeolites)., (© 2023 The Authors. Small published by Wiley‐VCH GmbH.)

Ag clusters with a controlled number of atoms have received significant interest because they show size-dependent catalytic, optical, electronic, or magnetic properties. However, the synthesis of size-controlled, ligand-free, and air-stable Ag clusters with high yields has not been well-established. Herein, it is shown that isostructural porous ionic crystals (PICs) with redox-active polyoxometalates (POMs) can be used to synthesize Ag clusters via electron transfer from POMs to Ag + . Ag clusters with average numbers of three, four, or six atoms emitting blue, green, or red colors, respectively, are formed and stabilized in the PICs under ambient conditions without any protecting ligands. The cluster size solely correlates with the degree of electron transfer, which is controlled by the reduction time and types of ions or elements of the PICs. Thus, advantages have been taken of POMs as electron sources and PICs as scaffolds to demonstrate a convenient method to obtain few-atom Ag clusters., (© 2023 The Authors. Small published by Wiley-VCH GmbH.)

3D structured cells have great drug screening potential because they mimic in vivo tissues better than 2D cultured cells. In this study, multi-block copolymers composed of poly(2-methoxyethyl acrylate) (PMEA) and polyethylene glycol (PEG) are developed as a new kind of biocompatible polymers. PEG imparts non-cell adhesion while PMEA acts as an anchoring segment to prepare the polymer coating surface. The multi-block copolymers show higher stability in water than PMEA. A specific micro-sized swelling structure composed of a PEG chain is observed in the multi-block copolymer film in water. A single NIH3T3-3-4 spheroid is formed in 3 h on the surface of the multi-block copolymers with 8.4 wt% PEG. However, at a PEG content of 0.7 wt%, spheroid formed after 4 days. The adenosine triphosphate (ATP) activity of cells and the internal necrotic state of the spheroid change depending on PEG loading in the multi-block copolymers. As the formation rate of cell spheroid on low-PEG-ratio multi-block copolymers is slow, internal necrosis of cell spheroid is less likely to occur. Consequently, the cell spheroid formation rate by changing the PEG chain content in multi-block copolymers is successfully controlled. These unique surfaces are suggested to be useful for 3D cell culture., (© 2023 The Authors. Macromolecular Bioscience published by Wiley-VCH GmbH.)

Cation-uptake has been long researched as an important topic in materials science. Herein we focus on a molecular crystal composed of a charge-neutral polyoxometalate (POM) capsule [Mo VI 72 Fe III 30 O 252 (H 2 O) 102 (CH 3 CO 2 ) 15 ] 3+ encapsulating a Keggin-type phosphododecamolybdate anion [α-PMo VI 12 O 40 ] 3- . Cation-coupled electron-transfer reaction occurs by treating the molecular crystal in an aqueous solution containing CsCl and ascorbic acid as a reducing reagent. Specifically, multiple Cs + ions and electrons are captured in crown-ether-like pores {Mo VI 3 Fe III 3 O 6 }, which exist on the surface of the POM capsule, and Mo atoms, respectively. The locations of Cs + ions and electrons are revealed by single-crystal X-ray diffraction and density functional theory studies. Highly selective Cs + ion uptake is observed from an aqueous solution containing various alkali metal ions. Cs + ions can be released from the crown-ether-like pores by the addition of aqueous chlorine as an oxidizing reagent. These results show that the POM capsule functions as an unprecedented "redox-active inorganic crown ether", clearly distinguished from the non-redox-active organic counterpart., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Herein we present the first example of a vanadium-substituted δ-Keggin Al 13 -based (Al28V4) porous Ionic crystal (PIC) (Al28V4-PW9V3). Structural and theoretical studies suggested that Al28V4 may exhibit Lewis acidity, which was confirmed by acetalization reaction with Al28V4-PW9V3 as a solid catalyst and investigations with pyridine or 2,6-lutidine as basic probe molecules. A comparative study with the δ-Keggin Al13 monomer based PIC indicated that the vanadium-substitution gave rise to the Lewis acidity.

The success and continued expansion of research on metal-oxo clusters owe largely to their structural richness and wide range of functions. However, while most of them known to date are negatively charged polyoxometalates, there is only a handful of cationic ones, much less functional ones. Here, we show an all-inorganic hydroxyiodide [H 10.7 Sb 32.1 O 44 ][H 2.1 Sb 2.1 I 8 O 6 ][Sb 0.76 I 6 ] 2 ·25H 2 O ( HSbOI ), forming a face-centered cubic structure with cationic Sb 32 O 44 clusters and two types of anionic clusters in its interstitial spaces. Although it is submicrometer in size, electron diffraction tomography of HSbOI allowed the construction of the initial structural model, followed by powder Rietveld refinement to reach the final structure. The cationic cluster is characterized by the presence of acidic protons on its surface due to substantial Sb 3+ deficiencies, which enables HSbOI to serve as an excellent solid acid catalyst. These results open up a frontier for the exploration and functionalization of cationic metal-oxo clusters containing heavy main group elements.

Three isostructural porous ionic crystals (PICs) based on Keggin-type POMs with different compositions but equal negative charge ([BW 12 O 40 ] 5- (BW12), [SiW 11 NbO 40 ] 5- (SiW11Nb), and [SiW 11 TaO 40 ] 5- (SiW11Ta)) are synthesized. Experimental and theoretical characterizations of the three PICs (1&#95;BW12, 1&#95;SiW11Nb, and 1&#95;SiW11Ta) show that the substitution of Nb/Ta for W in the POMs enhances the basicity of PICs, which increases in the order of 1&#95;BW12 < 1&#95;SiW11Nb < 1&#95;SiW11Ta. These findings clearly show that the increase in basicity is due not only to the increase in negative charge of the POM molecule as is often explained, but also to the character of the substituted element itself.

Background Context: The posterior cervical approach is a very popular surgical procedure. Because of the slope-shaped laminae, a suitable landmark for laminectomy, laminoplasty, and pedicle screw placement does not exist., Purpose: We investigated the association between the nutrient foramen and spinal canal, and the safety of bone gutter placement using nutrient foramina for safe and effective spinal surgery., Study Design: Observational SETTING: University Hospital PATIENT SAMPLES: Two hundred and sixty-six consecutive patients treated for cervical pathologies in our university hospital between January 2005 and December 2019., Outcome Measures: We identified the location of nutrient foramina and their anatomical association with the spinal canal using preoperative three-dimensional CT scanning., Methods: We studied the distance between each foramen and the spinal canal, and the angle of the nutrient foramen at each vertebral level., Results: The nutrient foramina were always located outside the spinal canal, with an average distance of +3.06±1.74 mm. The lower the spinal level, the closer the nutrient foramen to the spinal canal., Conclusions: The nutrient foramen can be considered a reliable landmark when using the posterior cervical approach., Competing Interests: Declarations of competing interests The authors report no conflicts of interest in this work and are responsible for the content and writing of this article., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Considerable efforts have been devoted to developing oxygen evolution reaction (OER) catalysts based on transition metal oxides. Polyoxometalates (POMs) can be regarded as model compounds of transition metal oxides, and cobalt-containing POMs (Co-POMs) have received significant interest as candidates. Nanocomposites based on Co-POMs have been reported to show high OER activities due to synergistic effects among the components; however, the role of each component is unclear due to its complex structure. Herein, we utilize porous ionic crystals (PICs) based on Co-POMs, which enable a composition-structure-function relationship to be established to understand the origin of the synergistic catalysis. Specifically, a Keggin-type POM [α-CoW 12 O 40 ] 6- and a Cr complex [Cr 3 O(OOCCH 2 CN) 6 (H 2 O) 3 ] + are implemented as PIC building blocks for the OER under nonbasic conditions. The potentially OER-active but highly soluble [α-CoW 12 O 40 ] 6- was successfully anchored in the crystalline PIC matrix via Coulomb interactions and hydrogen bonding induced by polar cyano groups of the Cr complex. The PIC exhibits efficient and sustained OER catalytic activity, while each building block is inactive. The Tafel slope of the linear sweep voltammetry curve and the relatively large kinetic isotope effect value suggest that elementary steps closely related to the OER rate involve single-electron and proton transfer reactions. Electrochemical and spectroscopic studies clearly show that the synergistic catalysis originates from the charge transfer from the Cr complex to [α-CoW 12 O 40 ] 6- ; the increased electron density of [α-CoW 12 O 40 ] 6- may increase its basicity and accelerate proton abstraction as well as enhance electron transfer to stabilize the reaction intermediates adsorbed on [α-CoW 12 O 40 ] 6- .

Polyoxometalates (POMs) are oxide cluster anions composed of high-valence early transition metals and are widely used as catalysts. Yet base catalysis of POMs remains an ongoing challenge; group V (V, Nb, and Ta) elements form more negatively charged POMs than group VI (Mo and W) elements, and in particular, polyoxoniobates and polyoxotantalates are known to show strong basicity in solution due to the highly negative surface oxygen atoms. Herein, we report for the first time porous ionic crystals (PICs) comprising Nb or Ta. The PICs are composed of Dawson-type Nb/W or Ta/W mixed-addenda POMs with oxo-centered trinuclear Cr III carboxylates and potassium ions as counter cations to control the crystal structure. Among the PICs, those with Nb or Ta tri-substituted POMs exhibit the highest yield (78-82%) and selectivity (99%) towards the Knoevenagel condensation of benzaldehyde and ethyl cyanoacetate (353 K, 6 h), which is a typical base-catalyzed reaction, as reusable solid catalysts, and they can also catalyze the reaction of other active methylene compounds. A detailed investigation into the crystal structures together with DFT calculations and in situ IR spectroscopy with methanol as a basic probe molecule shows that the exposure of [Nb 3 O 13 ] or [Ta 3 O 13 ] units with highly negative surface oxygen atoms to the pore surface of PICs is crucial to the catalytic performance. These findings based on the composition-structure-function relationships show that Nb- and Ta-containing PICs can serve as platforms for rational designing of heterogeneous base catalysts.