Encoding of self-initiated actions in axon terminals of the mesocortical pathway.

Significance: The initiation of goal-directed actions is a complex process involving the medial prefrontal cortex and dopaminergic inputs through the mesocortical pathway. However, it is unclear what information the mesocortical pathway conveys and how it impacts action initiation. In this study, we unveiled the indispensable role of mesocortical axon terminals in encoding the execution of movements in self-initiated actions. Aim: To investigate the role of mesocortical axon terminals in encoding the execution of movements in self-initiated actions. Approach: We designed a lever-press task in which mice internally determine the timing of the press, receiving a larger reward for longer waiting periods. Results: Our study revealed that self-initiated actions depend on dopaminergic signaling mediated by D2 receptors, whereas sensory-triggered lever-press actions do not involve D2 signaling. Microprism-mediated two-photon calcium imaging further demonstrated ramping activity in mesocortical axon terminals approximately 0.5 s before the self-initiated lever press. Remarkably, the ramping patterns remained consistent whether the mice responded to cues immediately for a smaller reward or held their response for a larger reward. Conclusions: We conclude that mesocortical dopamine axon terminals encode the timing of self-initiated actions, shedding light on a crucial aspect of the intricate neural mechanisms governing goal-directed behavior.

Aggregation-induced enhanced fluorescence emission of chiral Zn(II) complexes coordinated by Schiff-base type binaphthyl ligands.

A pair of novel chiral Zn(II) complexes coordinated by Schiff-base type ligands derived from BINOL (1,1'-bi-2-naphthol), R-/S-Zn, were synthesized. X-ray crystallography revealed the presence of two crystallographically independent complexes; one has a distorted trigonal-bipyramidal structure coordinated by two binaphthyl ligands and one disordered methanol molecule (molecule A), while the other has a distorted tetrahedral structure coordinated by two binaphthyl ligands (molecule B). Numerous CH⋯π and CH⋯O interactions were identified, contributing to the formation of a 3-dimensional rigid network structure. Both R-/S-Zn exhibited fluorescence in both CH2Cl2 solutions and powder samples, with the photoluminescence quantum yields (PLQYs) of powder samples being twice as large as those in solutions, indicating aggregation-induced enhanced emission (AIEE). The AIEE properties were attributed to the restraint of the molecular motion arising from the 3-dimensional intermolecular interactions. CD and CPL spectra were observed for R-/S-Zn in both solutions and powders. The dissymmetry factors, gabs and gCPL values, were within the order of 10-3 to 10-4 magnitudes, comparable to those reported for chiral Zn(II) complexes in previous studies.

Structure and Chiroptical Properties of Anthra[1,2-a]anthracene-1-yl Dimers as New Biaryls.

Dimers of anthra[1,2-a]anthracene-1-yl units and its mesityl derivative were synthesized by Ni(0)-mediated coupling of the corresponding chloro derivatives as new biaryls. The X-ray analysis and DFT calculations revealed that two polycyclic aromatic units with nonplanar deformations took a twisted conformation about the single bond as a chiral axis. Enantiomers of the nonsubstituted compound were resolved by chiral HPLC, and the enantiopure samples showed intense Cotton effects at 321 nm in the circular dichroism (CD) spectra and emission bands at 449 nm in the circularly polarized luminescence (CPL) spectra with dissymmetry factor of |glum| 3.6×10-3. The absolute stereochemistry of this biaryl was determined by the theoretical calculation of CD spectrum by the time-dependent DFT method. The barrier to enantiomerization was determined to be 108 kJ mol-1 at 298 K. The dynamic process proceeded via a stepwise mechanism involving the helical inversion of each aromatic unit and the rotation about the biaryl axis as analyzed by the DFT calculations.

High-Pressure Synthesis of a High-Pressure Phase of MnN Having NiAs-Type Structure.

A novel high-pressure phase of manganese mononitride, NiAs-type MnN, was successfully synthesized through a pressure-induced phase transition from a tetragonal distorted NaCl-type MnN at pressures above approximately 55 GPa. High-pressure experiments, including starting material preparation, were conducted using a laser-heated diamond anvil cell. This result is the first example of a nitride with a structural phase transition from the distorted NaCl-type to the NiAs-type structure. Upon decompression after the phase transition to NiAs-type structure, the NiAs-type MnN underwent a structural change to the distorted NaCl-type phase, indicating the phase transition was reversible. NiAs-type MnN has a higher density and bulk modulus in comparison to the distorted NaCl-type one. The phase transition pressure of MnN is lower than that of oxides, such as FeO and MnO, which show a structural phase transition from a NaCl-type to a NiAs-type structure. It is suggested that this is due to the lattice distortion caused by antiferromagnetic ordering.

Inversion of Diaza[5]Helicenes Through an N-N Bond Breaking Pathway.

1,1',10,10'-Biphenothiazine and its S,S,S',S'-tetroxide are diaza[5]helicenes with N-N linkages. Kinetic experiments on racemization together with DFT calculations revealed that they undergo inversion through the N-N bond breaking pathway rather than the general conformational pathway. In these diaza[5]helicenes with this inversion mechanism, the reduction of electronic repulsion in the N-N bond by modification of S to SO2 at the outer position of the helix led to a significantly higher inversion barrier, 35.3 kcal/mol, compared to [5]helicene. 1,1',10,10'-Biphenothiazine S,S,S',S'-tetroxide was highly resistant to acid-mediated N-N bond breaking and racemization under acidic conditions.

Association of two variable number of tandem repeats in the monoamine oxidase A gene promoter with suicide completion: The present study and meta-analysis.

BACKGROUND: One potential cause of suicide is serotonergic dysfunction. Sex differences have been reported to modulate the effects of serotonergic polymorphisms. Monoamine oxidase A (MAOA) is an enzyme that degrades serotonin and is located on the X chromosome. A previous study indicated that the upstream (u) variable number of tandem repeat (VNTR) in the MAOA gene promoter may be associated with suicide. However, a meta-analysis showed that this polymorphism may not be related to suicide. According to a recent study, compared with the uVNTR, the distal (d)VNTR and the haplotypes of the two VNTRs modulate MAOA expression. METHODS: We examined the two VNTRs in the MAOA gene promoter in 1007 subjects who committed suicide and 844 healthy controls. We analyzed the two VNTRs using fluorescence-based polymerase chain reaction assays. We conducted a meta-analysis for the two VNTRs to update it. RESULTS: Our results demonstrated that neither the genotype-based associations nor allele/haplotype frequencies of the two VNTRs were significantly associated with suicide. In the meta-analysis, we did not indicate relationships between uVNTR and suicide nor did we identify articles analyzing dVNTR in suicide. CONCLUSION: Overall, we did not find a relationship between the two VNTRs in the MAOA promoter and suicide completion; thus, warranting further studies are required.

A double-helical S,C-bridged tetraphenyl-para-phenylenediamine and its persistent radical cation.

A structurally constrained, double-helical S,C-bridged tetraphenyl-para-phenylenediamine (TPPD) has been synthesized. The stable radical cation of the S,C-bridged TPPD was generated by chemical oxidation, and the electron spin was found to be delocalized over the entire π-conjugated framework. The excellent conformational stability of the neutral molecule facilitated the separation of its enantiomers.

Surface lattice resonance in three-dimensional plasmonic arrays fabricated via self-assembly of silica-coated gold nanoparticles.

HYPOTHESIS: Three-dimensional plasmonic nanoparticle arrays in which the nanoparticles are assembled with a certain distance apart are expected to exhibit unique optical properties attributed to surface lattice resonances because of the interactions between the nanoparticle layers. EXPERIMENTS: Multi-layered gold nanoparticle arrays were created to experimentally prove surface lattice resonances from three-dimensional arrays. Silica-coated gold nanoparticles were employed as building blocks for the array because the distance between the nanoparticles can be tuned by adjusting the thickness of the silica coating. Employing highly monodisperse building blocks enabled to fabricate both single-layered and multi-layered plasmonic arrays via a confined convective assembly method. FINDINGS: Multi-layering of monodisperse building blocks brought about some additional peaks corresponded to Bragg diffraction of gold nanoparticle periodic array and the interactions between layers in a hexagonal close-packed structure of the nanoparticles, respectively. Most importantly, the multi-layered arrays exhibited a distinctive extinction peak at the same wavelength as that observed from the single-layered array, proving the realization of surface lattice resonances from the three-dimensional plasmonic array.

High-pressure synthesis and crystal structures of molybdenum nitride Mo3N5 with anisotropic compressibility by a nitrogen dimer.

A novel high-pressure molybdenum nitride phase, Mo3N5, was synthesized at above 45 GPa via a nitridation reaction of molybdenum with nitrogen under high pressure using a laser-heated diamond anvil cell. Mo3N5, having an N-N dimer and 7-coordinated Mo sites, crystallizes in an orthorhombic structure with a space group of Cmcm (No. 63) without other prototype structures. The refined lattice parameters for Mo3N5 were a = 2.86201(2) Å, b = 7.07401(6) Å, and c = 14.59687(13) Å. The DFT enthalpy calculation suggested that Mo3N5 is a high-pressure stable phase, which is also consistent with an increasing coordination number compared to ambient- and low-pressure phases. The zero-pressure bulk modulus of Mo3N5 was determined to be K0 = 328(4) GPa with K'0 = 10.1(6) by the fitting for the compression curve, which is almost consistent with the theoretical E-V curve and elastic stiffness constants. The compressibility of Mo3N5 has axial anisotropy corresponding to the N-N dimer direction in the crystal structure.

Oxidation of an Internal-Edge-Substituted [5]Helicene-Derived Phosphine Synchronously Enhances Circularly Polarized Luminescence.

Invited for the cover of this issue are the groups of Kazuteru Usui and Satoru Karasawa at Showa Pharmaceutical University, and Yoshitane Imai at Kindai University. The image depicts how a phosphine-oxide-bearing helicene exhibits markedly enhanced CPL response in the excited state compared with that of one with a corresponding phosphine. Read the full text of the article at 10.1002/chem.202202922.

Multiply Twisted Chiral Macrocycles Clamped by Tethered Binaphthyls Exhibiting High Circularly Polarized Luminescence Brightness.

Invited for the cover of this issue are Masashi Hasegawa and co-workers at Kitasto University and Kyoto Prefectural University. The image depicts the reported multiply twisted chiral macrocycles as objects in a kaleidoscope. Read the full text of the article at 10.1002/chem.202202218.

Oxidation of an Internal-Edge-Substituted [5]Helicene-Derived Phosphine Synchronously Enhances Circularly Polarized Luminescence.

Small chiral organic molecules with CD properties are in high demanded due to their potential use in promising electronic and biological applications. Herein, we reveal a system in which the oxidation of a phosphino group to the corresponding phosphine oxide on the inner rim of a helicene derivative induces a CPL response. Laterally π-extended 7,8-dihydro[5]helicenes bearing phosphine and phosphine oxide groups on their inner helical rims (i. e., the C1 position) were synthesized, and their helical structures were unambiguously determined by X-ray crystallography. The photophysical (UV/visible and emission) and chiroptical properties of these compounds were investigated in various solvents. Despite their structural similarities, phosphine oxide showed a significantly better CPL response than phosphine, with a high dissymmetry factor for emission (|glum |=(1.3-1.9)×10-3 ) that can be attributed to structural changes in the interior of the helicene helix.

Multiply Twisted Chiral Macrocycles Clamped by Tethered Binaphthyls Exhibiting High Circularly Polarized Luminescence Brightness.

Chiral macrocyclic dimers, trimers, and tetramers composed of paraphenylene and tethered binaphthyl were synthesized, and their molecular structures and chiroptical properties were investigated. X-ray analysis and theoretical calculations revealed that multiple twisted molecular structures - dimers, trimers, and tetramers - adopt figure-of-eight, Möbius triangle, and concave rectangle structures, respectively. These homologues have large ϵ values in their UV-vis absorption spectra because of the π-conjugation of the naphthalene-phenylene-naphthalene frameworks. Owing to the shape-persistent ring structure and tethering with -OCH2 CH2 O-, high fluorescence quantum yields and a relatively high dissymmetry factor gCPL in circularly polarized luminescence (CPL) spectra were achieved. This results in CPL brightness (BCPL ) of over 100, which is greater than that of the conventional organic CPL dye.

High pressure synthesis and the valence state of vanadium ions for the novel transition metal pernitride, CuAl2-type VN2.

A novel transition metal pernitride, CuAl2-type VN2, has been synthesized at a pressure above 73.3 GPa. The bulk modulus has been determined to be K0 = 347(12) GPa. By hard X-ray absorption spectrum measurements of VN2, the valence state of transition metal ions in pernitrides has been for the first time experimentally reported.

Reprint of: Automated geometric aberration correction for large-angle illumination STEM.

Depth resolution in scanning transmission electron microscopy (STEM) is physically limited by the illumination angle. In recent notable progress on aberration correction technology, the illumination angle is significantly improved to be larger than 60 milliradians, which is 2 or 3 times larger than those in the previous generation. However, for three-dimensional depth sectioning with the large illumination angles, it is prerequisite to ultimately minimize lower orders of aberrations such as 2- and 3-fold astigmatisms and axial coma. Here, we demonstrate a live aberration correction using atomic-resolution STEM images rather than Ronchigram images. The present method could save the required time for aberration correction, and moreover, it is possible to build up a fully automated program. We demonstrate the method should be useful not only for axial depth sectioning but also phase imaging in STEM including differential phase-contrast imaging.

Pressure-Tunable Crystal Structure and Magnetic Transition Temperature of the Nowotny Chimney-Ladder CrGeγ Phase.

A Nowotny chimney-ladder (NCL) chromium germanide (CrGeγ) with varying compositions has been synthesized under high pressure. Crystal structure parameters of the NCL CrGeγ have been calculated by Le Bail refinement based on the superspace group. The refined γ of CrGeγ increases with the synthesis pressure, indicating an increasing Ge content. The NCL CrGeγ phases are ferromagnetic at T = 2 K regardless of their composition, and the magnetic transition temperature (TC) increases when the γ becomes higher. It is noteworthy that CrGe1.763 and CrGe1.774 synthesized at P = 10 and 14 GPa have magnetic transition temperatures of T = 295 and 333 K above room temperature, respectively. Surprisingly, the magnetic transition temperature has changed by ΔTC = 270 K, although the γ values of the raw material and the sample synthesized at P = 14 GPa differ by only Δγ = 0.05, corresponding to an atomic concentration of 0.62 atom %. The synthesis pressure acts as an essential parameter in tuning the composition of the NCL phase. Accordingly, the high-pressure synthesis may significantly control several physical characteristics of NCL phases by utilizing compositional and structural modulation.

Helical Oligophenylene Linked with [2.2]Paracyclophane: Stereogenic π-Conjugated Dye for Highly Emissive Chiroptical Properties.

A stereogenic π-system based on dimer (2) and trimer (3) of [2.2]paracyclophane (PC) and biphenyl was prepared and its structural, photophysical, and chiroptical properties were investigated. X-ray analysis revealed that the quaterphenyl moieties in 2 adopt a double helical structure anchoring [2.2]PC from both sides. Furthermore, 3 forms a isosceles triangle structure with a large chiral cavity. A homodesmotic reaction using DFT calculations revealed that 2 has a larger strain energy than 3 owing to its highly twisted phenylene linkers. Electronic and circular dichroic (CD) spectra were recorded in CH2 Cl2 solution. The spectra of both 2 and 3 are similar, and their longest absorption band accompanying a remarkable Cotton effect is attributed to the transition from HOMO to LUMO, which is delocalized to the quaterphenyl moiety. These compounds exhibit fairly high fluorescence quantum yields (ϕ=0.70-0.83) and moderate dissymmetry factor (|gCPL |=1.6×10-3 ) in circularly polarized luminescence (CPL).

Crystal and Electronic Structure of U7Te12-Type Tungsten Nitride Synthesized under High Pressure.

Tungsten nitride continues to drive fundamental interests because of its potential as a functional compound, which combines features such as high hardness together with thermal, chemical, and wear resistance. Here, we report a novel tungsten nitride phase synthesized from MoC-type WN0.6 and molecular nitrogen after laser irradiation at P = 70 GPa in a diamond anvil cell. This novel phase is quenchable at ambient pressure and determined to be U7Te12-type tungsten nitride and crystallizes in the hexagonal space group (P6) having lattice parameters of a = 8.2398(3) Å, c = 2.94948(14) Å, and V = 173.423(13) Å3. Tungsten atoms are coordinated to eight and nine nitrogen atoms, higher than previously reported tungsten nitrides. The bulk modulus is determined to be K0 = 312 (5) GPa (K0' = 4.0 fixed), and DFT calculations predict that U7Te12-type W7N12 has a metallic nature.

Single cell plasticity and population coding stability in auditory thalamus upon associative learning.

Cortical and limbic brain areas are regarded as centres for learning. However, how thalamic sensory relays participate in plasticity upon associative learning, yet support stable long-term sensory coding remains unknown. Using a miniature microscope imaging approach, we monitor the activity of populations of auditory thalamus (medial geniculate body) neurons in freely moving mice upon fear conditioning. We find that single cells exhibit mixed selectivity and heterogeneous plasticity patterns to auditory and aversive stimuli upon learning, which is conserved in amygdala-projecting medial geniculate body neurons. Activity in auditory thalamus to amygdala-projecting neurons stabilizes single cell plasticity in the total medial geniculate body population and is necessary for fear memory consolidation. In contrast to individual cells, population level encoding of auditory stimuli remained stable across days. Our data identifies auditory thalamus as a site for complex neuronal plasticity in fear learning upstream of the amygdala that is in an ideal position to drive plasticity in cortical and limbic brain areas. These findings suggest that medial geniculate body's role goes beyond a sole relay function by balancing experience-dependent, diverse single cell plasticity with consistent ensemble level representations of the sensory environment to support stable auditory perception with minimal affective bias.

Phase relations and thermoelasticity of magnesium silicide at high pressure and temperature.

Within the exploration of sustainable and functional materials, narrow bandgap magnesium silicide semiconductors have gained growing interest. Intriguingly, squeezing silicides to extreme pressures and exposing them to non-ambient temperatures proves fruitful to study the structural behavior, tune the electronic structure, or discover novel phases. Herein, structural changes and thermoelastic characteristics of magnesium silicides were probed with synchrotron x-ray diffraction techniques using the laser-heated diamond anvil cell and large volume press at high pressure and temperature and temperature-dependent synchrotron powder diffraction. Probing the ambient phase of Mg2Si (anti-CaF2-type Mg2Si, space group: Fm3¯m) at static pressures of giga-Pascals possibly unveiled the transformation to metastable orthorhombic anti-PbCl2-type Mg2Si (Pnma). Interestingly, heating under pressures introduced the decomposition of Mg2Si to hexagonal Mg9Si5 (P63) and minor Mg. Using equations of state (EoS), which relate pressure to volume, the bulk moduli of anti-CaF2-type Mg2Si, anti-PbCl2-type Mg2Si, and Mg9Si5 were determined to be B0 = 47(2) GPa, B0 ≈ 72(5) GPa, and B0 = 58(3) GPa, respectively. Employing a high-temperature EoS to the P-V-T data of anti-CaF2-type Mg2Si provided its thermoelastic parameters: BT0 = 46(3) GPa, B'T0 = 6.1(8), and (∂BT0/∂T)P = -0.013(4) GPa K-1. At atmospheric pressure, anti-CaF2-type Mg2Si kept stable at T = 133-723 K, whereas Mg9Si5 transformed to anti-CaF2-type Mg2Si and Si above T ≥ 530 K. This temperature stability may indicate the potential of Mg9Si5 as a mid-temperature thermoelectric material, as suggested from previous first-principles calculations. Within this realm, thermal models were applied, yielding thermal expansion coefficients of both silicides together with estimations of their Grüneisen parameter and Debye temperature.