Unveiling new quantum phases in the Shastry-Sutherland compound SrCu2(BO3)2 up to the saturation magnetic field

Under magnetic fields, quantum magnets often undergo exotic phase transitions with various kinds of order. The discovery of a sequence of fractional magnetization plateaus in the Shastry-Sutherland compound SrCu₂(BO₃)₂ has played a central role in the high-field research on quantum materials, but so far this system could only be probed up to half the saturation value of the magnetization. Here, we report the first experimental and theoretical investigation of this compound up to the saturation magnetic field of 140 T and beyond. Using ultrasound and magnetostriction techniques combined with extensive tensor-network calculations (iPEPS), several spin-supersolid phases are revealed between the 1/2 plateau and saturation (1/1 plateau). Quite remarkably, the sound velocity of the 1/2 plateau exhibits a drastic decrease of -50%, related to the tetragonal-to-orthorhombic instability of the checkerboard-type magnon crystal. The unveiled nature of this paradigmatic quantum system is a new milestone for exploring exotic quantum states of matter emerging in extreme conditions.

Magnetically Hidden State on the Ground Floor of the Magnetic Devil's Staircase

We investigated the low-temperature and high-field thermodynamic and ultrasonic properties of SrCu_{2}(BO_{3})_{2}, which exhibits various plateaux in its magnetization curve above 27 T, called a magnetic Devil's staircase. The results of the present study confirm that magnetic crystallization, the first step of the staircase, occurs above 27 T as a first-order transition accompanied by a sharp singularity in heat capacity C_{p} and a kink in the elastic constant. In addition, we observe a thermodynamic anomaly at lower fields around 26 T, which has not been previously detected by any magnetic probes. At low temperatures, this magnetically hidden state has a large entropy and does not exhibit Schottky-type gapped behavior, which suggests the existence of low-energy collective excitations. Based on our observations and theoretical predictions, we propose that magnetic quadrupoles form a spin-nematic state around 26 T as a hidden state on the ground floor of the magnetic Devil's staircase.

Hydride-Reduced Eu2SrFe2O6: A T-to-T' Conversion Enabling Fe2+ in Square-Planar Coordination

Low-temperature reaction of A-site-ordered layered perovskite Eu₂SrFe₂O₇ (T structure) with CaH₂ induces a shift in the Eu₂O₂ slabs to form Eu₂SrFe₂O₆ with a T' structure (I4/mmm space group) in which only the Fe cation is reduced. Contrary to the previously reported T' structures with Jahn-Teller-active d⁹ cations (Cu²⁺ and Ni⁺), stabilization of Eu₂SrFe₂O₆ with the Fe²⁺ (d⁶) cation reflects the stability of the FeO₄ square-planar unit. The stability of T'-type Eu₂SrFe₂O₆ over a T-type polymorph is confirmed by density functional theory calculations, revealing the d_z² occupancy for the T' structure. Eu₂SrFe₂O₆ has a bilayer magnetic framework with an Fe-O-Fe superexchange J_∥ and an Fe-Fe direct exchange J_⊥ (where J_∥ > J_⊥), which broadly explains the observed T_N of 390-404 K. Interestingly, the magnetic moments of Eu₂SrFe₂O₆ lie in the ab plane, in contrast to the structurally similar Sr₃Fe₂O₄Cl₂ having an out-of-plane spin alignment.

Requirement of alkanes for salt tolerance of Cyanobacteria: characterization of alkane synthesis genes from salt-sensitive Synechococcus elongatus PCC7942 and salt-tolerant Aphanothece halophytica

Cyanobacteria have been attracting great interest in the research area of biofuel production. All Cyanobacteria contain C₁₅ -C₁₉ hydrocarbons, but physiological roles of hydrocarbons remain to be clarified. Recently, two universal but mutually exclusive hydrocarbon production pathways in Cyanobacteria were discovered. In this study, we constructed a deletion mutant of alkane synthesis genes in fresh water cyanobacterium Synechococcus elongates PCC 7942. The mutant was incapable to produce alkanes and exhibited normal growth phenotype at low salinity. But, the mutant became salt sensitive. Overexpression of alkane synthesis genes from halotolerant Aphanothece halophytica in Synechococcus PCC7942 restored the growth defect. The alkane synthesis gene from halotolerant cyanobacterium A. halophytica was salt induced and produced a significant amount of alkanes at high salinity. These results indicate the requirement of alkanes for salt tolerance, and the alkane synthesis genes from A. halophytica could be a promising candidate for future biofuel application.

SIGNIFICANCE AND IMPACT OF THE STUDY

Cyanobacteria have been attracting great interest in the research area of biofuel production. All Cyanobacteria contain C₁₅ -C₁₉ hydrocarbons, but physiological roles of hydrocarbons remain to be clarified. In this study, it was found that the deletion mutant of alkane synthesis genes in fresh water cyanobacterium Synechococcus elongates PCC 7942 was incapable to produce alkanes and salt sensitive. The alkane synthesis gene from halotolerant cyanobacterium Aphanothece halophytica was salt induced and produced a significant amount of alkanes at high salinity. These results demonstrate the alkane synthesis genes from A. halophytica could be a promising candidate for future biofuel application.

Inhibitory effects of mycosporine-2-glycine isolated from a halotolerant cyanobacterium on protein glycation and collagenase activity

Mycosporine-2-glycine (M2G), isolated from the halotolerant cyanobacterium Aphanothece halophytica, was purified and characterized in order to determine its utility as a cosmetic and pharmaceutical ingredient. M2G efficiently inhibited protein crosslinking. The inhibitory activity of M2G was significantly greater than that of the well-known Maillard reaction inhibitor aminoguanidine. In addition, M2G and other known mycosporine-like amino acids inhibited bacterial collagenase activity. To the best of our knowledge, this is the first report describing that M2G specifically inhibits the formation of advanced glycation end-products (AGEs), which play a critical role in ageing process and age-related diseases. These observations indicate that M2G may have potential therapeutic applications by suppressing the formation of AGEs and inhibiting excess collagenase activity.

SIGNIFICANCE AND IMPACT OF THE STUDY

Mycosporine-like amino acids (MAAs) are known as multifunctional natural compounds. The MAA mycosporine-2-glycine (M2G), isolated from the halotolerant cyanobacterium Aphanothece halophytica, has potential therapeutic applications for the prevention of skin ageing. Purified M2G was endotoxin-free. M2G had greater inhibitory activity of protein cross-linking compared with well-known inhibitor, aminoguanidine and hindered bacterial collagenase activity. The mechanisms for these inhibitory activities of M2G are discussed in this study.

Layer-by-layer manipulation of anisotropic nanoblocks: orientation-switched superlattices through orthogonal stacking of a and c directions

Nanometer-scale switching of the crystallographic orientation enables production of novel superlattices for exploration of new functions. Elaborate multilayered architectures of Mn3O4 nanocuboids were constructed by a convective self-assembly process. The nanometric cuboids were accumulated into orientation-switched superlattices on micrometric scales by controlling the a and c directions of the tetragonal crystal periodically. The orthogonal stacking of the tetragonal nanoblocks was achieved through the layer-by-layer manipulation process of two types of 2D arrays with different orientations.

Tunable mid-infrared source of light carrying orbital angular momentum in the femtosecond regime

We report on a tunable intense femtosecond mid-infrared (mid-IR) light source carrying orbital angular momentum (OAM). Our setup is based on an optical parametric amplification system with an 800 nm pump shaped with a spiral phase plate. We confirm the anisotropic OAM transfer from the pump to the idler through stimulated difference frequency generation by measuring the diffraction patterns of a triangular aperture illuminated by the signal, pump, and idler beams. The tunability of the setup is demonstrated by performing measurements at 3.0 and 3.6 μm idler wavelengths. This result provides a robust method of controlling OAM in strong field physics and designing secondary sources carrying OAM in the extreme ultraviolet spectral range through high-order harmonics generation.

Orientation-Selective Alignments of Hydroxyapatite Nanoblocks through Epitaxial Attachment in a and c Directions

Nanometric rods of hydroxyapatite (HA) were aligned in selective crystallographic directions by the alternation of adsorbing molecules. The side and end faces of HA nanorods elongated in the c direction were covered with oleic acid (OA) and tetraoctylammonium (TOA) ions, respectively. Alignment in the c direction of the OA-modified nanorods was produced through epitaxial attachment of the bare end faces in toluene because the side faces were hydrophobized with the negatively charged modifier. Another alignment-in the a direction of the TOA-modified HA nanorods-was obtained through the epitaxial attachment of the bare side faces in ethanol due to stabilization of the end faces with the positively charged modifier. Controlled alignments of the nanorods in the a and c directions were achieved through oriented attachment with the selective coverage of the c and a faces with the specific modifiers.

Orientation-selective alignments of nanoblocks in a and c directions of a tetragonal system through molecularly mediated manipulation

Selective 1D alignments of nanometric Mn₃O₄ cuboids in the a and c directions were achieved on the basis of the hydrophobic–hydrophilic interaction between a single dispersion medium and the specific crystal faces.

UV-induced epitaxial attachment of TiO2 nanocrystals in molecularly mediated 1D and 2D alignments

Molecularly mediated anatase nanocrystals were crystallographically connected via crystal bridges after UV irradiation.

Conductive polymer-mediated 2D and 3D arrays of Mn3O4 nanoblocks and mesoporous conductive polymers as their replicas

Orientation-controlled 2D and 3D microarrays of Mn3O4 nanocuboids that were mediated by a conductive polymer were fabricated by evaporation-induced self-assembly of the oxide nanoblocks and subsequent polymerization of pyrrole in the interparticle spaces. Free-standing mesoporous polypyrroles (PPy) having chain- and square-grid-like nanovoid arrays were obtained as replicas of the composite assemblies by dissolving the oxide nanoblocks. The PPy-mediated manganese oxide arrays exhibited stable electrochemical performance as an ultrathin anode of a lithium-ion secondary battery.

Formation of Monocrystalline 1D and 2D Architectures via Epitaxial Attachment: Bottom-Up Routes through Surfactant-Mediated Arrays of Oriented Nanocrystals

Monocrystalline architectures with well-defined shapes were achieved by bottom-up routes through epitaxial attachment of Mn3O4 nanocrystals. The crystallographically continuous 1D chains elongated in the a axis and 2D panels having large a or c faces were obtained by removal of the organic mediator from surfactant-mediated 1D and 2D arrays of Mn3O4 nanocrystals, respectively. Our basal approach indicates that the epitaxial attachment through the surfactant-mediated arrays is utilized for fabrication of a wide variety of micrometric architectures from nanometric crystalline units.

Formation of uniformly sized metal oxide nanocuboids in the presence of precursor grains in an apolar medium

Oriented attachment of Mn₃O₄ primary particles covered with oleic acid was found to occur in an organic medium. Faceted nanocuboids were produced through oriented attachment and subsequent crystallographic fusion.

Application of biogenic iron phosphate for lithium-ion batteries

Biogenic iron(ii) phosphate and microbially derived lithium iron phosphate spherical microparticles consisting of nanosheets produced by iron-reducing bacteria were investigated for application in lithium-ion batteries.

Direction control of oriented self-assembly for 1D, 2D, and 3D microarrays of anisotropic rectangular nanoblocks

Micrometric linear chains (1D arrays), monolayers (2D arrays), and superstructures (3D arrays) of anisotropic Mn3O4 nanocuboids were selectively produced by oriented self-assembly through evaporation of a dispersion. The 1D arrays were basically formed on a substrate via oriented self-assembly of the rectangular crystals in the ⟨100⟩ direction. The 2D and 3D microarrays were obtained by adjusting the particle concentration of the dispersion. The [001] direction of tetragonal crystal was controlled to be parallel and perpendicular to the substrate by changing the polarity of the medium.

Magnetization of SrCu2(BO3)2 in ultrahigh magnetic fields up to 118 T

The magnetization process of the orthogonal-dimer antiferromagnet SrCu2(BO3)2 is investigated in high magnetic fields of up to 118 T. A 1/2 plateau is clearly observed in the field range 84 to 108 T in addition to 1/8, 1/4, and 1/3 plateaus at lower fields. Using a combination of state-of-the-art numerical simulations, the main features of the high-field magnetization, a 1/2 plateau of width 24 T, a 1/3 plateau of width 34 T, and no 2/5 plateau, are shown to agree quantitatively with the Shastry-Sutherland model if the ratio of inter- to intradimer exchange interactions J'/J=0.63. It is further predicted that the intermediate phase between the 1/3 and 1/2 plateaus is not uniform but consists of a 1/3 supersolid followed by a 2/5 supersolid and possibly a domain-wall phase, with a reentrance into the 1/3 supersolid above the 1/2 plateau.

High CC chemokine receptor 7 expression improves postoperative prognosis of lung adenocarcinoma patients

BACKGROUND

Chemokines and chemokine receptors not only have significant roles in cancer metastasis and tumorigenesis but also act as antitumour agents. The interaction between the Crk-like adaptor protein (CrkL), which is encoded by the CRKL gene, and non-receptor tyrosine kinase c-ABL is reported to transform many cells into malignant cells. We examined the effects of CC chemokine receptor 7 (CCR7), CCR7 ligands and CrkL and c-ABL in lung adenocarcinoma.

METHODS

One hundred and twenty patients with lung adenocarcinoma were included in this historical cohort analysis. We examined CCR7 and CCR7 ligands and CrkL and c-ABL mRNA expressions in surgically resected lung adenocarcinoma specimens and evaluated their contribution to prognosis, and the relationship with epidermal growth factor receptor (EGFR) and TP53 mutations.

RESULTS

High CCR7 mRNA expressions indicated better prognoses than those of the groups with low CCR7 mRNA expressions (P=0.007, HR=2.00, 95% CI of ratio: 1.22 -3.31). In lung adenocarcinoma, CrkL and c-ABL mRNAs were related to CCR7 mRNA expression (P<0.0001). CrkL and c-ABL mRNA expressions were influenced by EGFR mutations. A high expression of CCL19 was a good prognostic factor of lung adenocarcinoma.

CONCLUSION

We propose that CCR7 and CCL19 are clinically good prognostic factors and that CCR7 is strongly related to CrkL and c-ABL kinase mRNA expression in lung adenocarcinoma.

Incomplete devil's staircase in the magnetization curve of SrCu2(BO3)2

We report on NMR and torque measurements on the frustrated quasi-two-dimensional spin-dimer system SrCu(2)(BO(3))(2) in magnetic fields up to 34 T that reveal a sequence of magnetization plateaus at 1/8, 2/15, 1/6, and 1/4 of the saturation and two incommensurate phases below and above the 1/6 plateau. The magnetic structures determined by NMR involve a stripe order of triplets in all plateaus, suggesting that the incommensurate phases originate from proliferation of domain walls. We propose that the magnetization process of SrCu(2)(BO(3))(2) is best described as an incomplete devil's staircase.

Ferromagnetically coupled Shastry-Sutherland quantum spin singlets in (CuCl)LaNb₂O₇

A thorough crystal structure determination at very low temperature of (CuCl)LaNb₂O₇, originally proposed as a spin-1/2 square-lattice antiferromagnet, is reported thanks to the use of single-crystal x-ray diffraction and powder neutron diffraction. State-of-the-art calculations (maximum entropy method) reveal that (CuCl)LaNb₂O₇ is orthorhombic with Pbam symmetry. First-principles calculations demonstrate that the dominant magnetic interactions are antiferromagnetic between fourth nearest neighbors with a Cu-Cl-Cl-Cu exchange path, which lead to the formation of spin singlets. The two strongest interactions between the singlets are ferromagnetic, which makes (CuCl)LaNb₂O₇ the first system of ferromagnetically coupled Shastry-Sutherland quantum spin singlets.

Galanin-like peptide: a key player in the homeostatic regulation of feeding and energy metabolism?

The hypothalamus has a critical role in the regulation of feeding behavior, energy metabolism and reproduction. Galanin-like peptide (GALP), a novel 60 amino-acid peptide with a nonamidated C-terminus, was first discovered in porcine hypothalamus. GALP is mainly produced in the hypothalamic arcuate nucleus and is involved in the regulation of feeding behavior and energy metabolism, with GALP-containing neurons forming networks with several feeding-regulating peptide-containing neurons. The effects of GALP on food intake and body weight are complex. In rats, the central effect of GALP is to first stimulate and then reduce food intake, whereas in mice, GALP has an anorectic function. Furthermore, GALP regulates plasma luteinizing hormone levels through activation of gonadotropin-releasing hormone-producing neurons, suggesting that it is also involved in the reproductive system. This review summarizes the research on these topics and discusses current evidence regarding the function of GALP, particularly in relation to feeding and energy metabolism. We also discuss the effects of GALP activity on food intake, body weight and locomotor activity after intranasal infusion, a clinically viable mode of delivery.

NMR evidence for the persistence of a spin superlattice beyond the 1/8 magnetization plateau in SrCu2(BO3)_{2}

We present 11B NMR studies of the 2D frustrated dimer spin system SrCu2(BO3)_{2} in the field range 27-31 T covering the upper phase boundary of the 1/8 magnetization plateau, identified at 28.4 T. Our data provide a clear evidence that above 28.4 T the spin superlattice of the 1/8 plateau is modified but does not melt even though the magnetization increases. Although this is precisely what is expected for a supersolid phase, the microscopic nature of this new phase is much more complex. We discuss the field-temperature phase diagram on the basis of our NMR data.

[Evaluation of the product-specific standard input function for the IMP-ARG method]

To confirm the previous reports demonstrating the difference in the octanol extraction fractions between the currently available two N-isopropyl-4-iodoamphetamine (123I) products (IMP(A) and IMP(B)), we newly developed the standard input function for IMP(B) in 19 healthy volunteers and compared it with the established standard input function, which has been originally generated with IMP(A). The octanol extraction fractions of IMP(B) were stable from 5 minutes to 16 minutes post injection and significantly higher than those of IMP(A). The mCBFs calculated with IMP(B) by using the established standard input function for IMP(A) tended to be higher than those with the combination of IMP(A) and the established standard input function though the difference was not significant. When measured with IMP(B) combined with the correspondent standard input function, mCBFs were identical to those calculated with IMP(A) with the established standard input function, suggesting that the appropriate standard input function should be used according to the product used.

[Metastatic lung tumor from uterine leiomyosarcoma]

We herein present 2 cases of metastatic lung tumor derived from uterine leiomyosarcoma. In the case 1, a 59-year-old woman was admitted to our hospital to examine abnormal shadow detected on chest X-ray. She had undergone hysterectomy and oophorectomy for uterine leiomyosarcoma 19 months previously. A round 3 cm mass in the right lung (S10) was seen on chest X-ray and computed tomography (CT). No other distant metastases or local recurrence were found, and the right lower lobectomy was perfomed under the clinical diagnosis of metastatic lung tumor. Postoperative pathologic examination revealed the tumor as a metastatic leiomyosarcoma. The patient recovered uneventfully, and there have been no signs of recurrence for 26 months after the pulmonary resection. In the case 2, a 58-year-old woman, who had undergone hysterectomy and oophorectomy for uterine leiomyosarcoma 7 months previously, was admitted to our hospital for further examination of pulmonary tumors on chest X-ray. Two tumors were recognized in the left lung (S8 and S10) on chest X-ray and CT. No other distant metastases or local recurrence were found, and the left lower lobectomy was performed under the clinical diagnosis of metastatic lung tumors. Pathological examinations revealed smooth muscle cells with nuclear pleomorphism and high mitotic indices. The tumors proved to be lung metastases derived from uterine leiomyosarcoma. Postoperative course was uneventful. However, brain metastasis was found 1 month after the pulmonary resection, and she underwent resection of brain metastasis. Two months after the brain metastasectomy, local recurrence of the brain tumor developed and re-resection followed by stereotactic radiotherapy was performed. Furthermore, intrapelvic recurrence was found 4 months after the pulmonary resection. Exploratory laparotomy revealed the tumor was unresectable, and she received 4 courses of chemotherapy (paclitaxel and carboplatin). For metastatic lung tumor from uterine leiomyosarcoma, surgery has been considered the best choice. However, for patients with uterine leiomyosarcoma who cannot be treated surgically because of multiple metastatic tumors or poor surgical risk chemotherapy (paclitaxel and carboplatin) or stereotactic radiotherapy can be strategies.

Left temporal perfusion associated with suspiciousness score on the Brief Psychiatric Rating Scale in schizophrenia

We evaluated the relationship between regional cerebral blood flow (rCBF) and clinical symptoms in patients with schizophrenia. Single photon emission computed tomography with N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) was used to study 29 patients with schizophrenia. Clinical symptoms were assessed using the Brief Psychiatric Rating Scale (BPRS). We examined the correlation between rCBF and each BPRS item score using Statistical Parametric Mapping software. Corrected P-values < 0.05 were considered as statistically significant. The suspiciousness score on the BPRS was positively correlated with rCBF in the left inferior temporal gyrus. There was no significant correlation between rCBF and any other items of the BPRS. There was no significant correlation between rCBF and chlorpromazine-equivalent dosage. This analysis permits the quantitative assessment of the severity of persecutory delusions in relation to left temporal perfusion in patients with schizophrenia.

Bcl-2 is a key regulator for the retinoic acid-induced apoptotic cell death in neuroblastoma

Retinoic acid (RA) has been shown to induce neuronal differentiation and/or apoptosis, and is widely used as a chemotherapeutic agent for treating the patients with neuroblastoma. However, the therapeutic effect of RA is still limited. To unveil the molecular mechanism(s) inducing differentiation and apoptosis in neuroblastoma cells, we compared CHP134 and NB-39-nu cell lines, in which all-trans-RA (ATRA) induces apoptosis, with LA-N-5 and RTBM1 cell lines, in which it induces neuronal differentiation. Here, we found that Bcl-2 was strongly downregulated in CHP134 and NB-39-nu cells, whereas it was abundantly expressed in LA-N-5 and RTBM1 cells. ATRA-mediated apoptosis in CHP134 and NB-39-nu cells was associated with a significant activation of caspase-9 and caspase-3 as well as cytoplasmic release of cytochrome c from mitochondria in a p53-independent manner. Enforced expression of Bcl-2 significantly inhibited ATRA-mediated apoptosis in CHP134 cells. In addition, treatment of RTBM1 cells with a Bcl-2 inhibitor, HA14-1, enhanced apoptotic response induced by ATRA. Of note, two out of 10 sporadic neuroblastomas expressed bcl-2 at undetectable levels and underwent cell death in response to ATRA in primary cultures. Thus, our present results suggest that overexpression of Bcl-2 is one of the key mechanisms to give neuroblastoma cells the resistance against ATRA-mediated apoptosis. This may provide a new therapeutic strategy against the ATRA-resistant and aggressive neuroblastomas by combining treatment with ATRA and a Bcl-2 inhibitor.