Abstract
α
-RuCl
3
is a major candidate for the realization of the Kitaev quantum spin liquid, but its zigzag antiferromagnetic order at low temperatures indicates deviations from the Kitaev model. ...We have quantified the spin Hamiltonian of
α
-RuCl
3
by a resonant inelastic x-ray scattering study at the Ru
L
3
absorption edge. In the paramagnetic state, the quasi-elastic intensity of magnetic excitations has a broad maximum around the zone center without any local maxima at the zigzag magnetic Bragg wavevectors. This finding implies that the zigzag order is fragile and readily destabilized by competing ferromagnetic correlations. The classical ground state of the experimentally determined Hamiltonian is actually ferromagnetic. The zigzag state is stabilized by quantum fluctuations, leaving ferromagnetism – along with the Kitaev spin liquid – as energetically proximate metastable states. The three closely competing states and their collective excitations hold the key to the theoretical understanding of the unusual properties of
α
-RuCl
3
in magnetic fields.
This study investigated the effects of a static stretching (SS) program on muscle hardnesses of the gastrocnemius medialis (MG) and gastrocnemius lateralis (LG). Nineteen young men participated in ...this study. Either the right or left leg was randomly selected to conduct three bouts of 2‐min SS of the plantar flexors 6 days a week for 5 weeks in each subject (the SS group), and the other leg was assigned to a control group. Before (pretest) and after (posttest) conducting the SS program, MG and LG hardnesses were measured using shear wave ultrasound elastography. The SS program was found to decrease muscle hardnesses, but not to change the ratio of MG hardness to LG hardness. There were no significant differences between the relative changes in the MG and LG hardnesses from pretest to posttest in both the SS and control groups. Significant correlations between the muscle hardness ratios at pretest and posttest were found in both groups. The results of this study suggest that the current SS program is useful for improving muscle condition in the plantar flexors, and that its long‐term effects on the MG and LG hardnesses are of the same degree.
Amyloid plaques and neurofibrillary tangles (NFTs) in the brain are the neuropathological hallmarks of Alzheimer's disease (AD). Amyloid plaques are composed of β‐amyloid peptides (Aβ), while NFTs ...contain hyperphosphorylated tau proteins. Patients with familial AD who have mutations in the amyloid precursor protein (APP) gene have either increased production of Aβ or generate more aggregation‐prone forms of Aβ. The findings of familial AD mutations in the APP gene suggest that Aβ plays a central role in the pathophysiology of AD. Aβ42, composed of 42 amino acid residues, aggregates readily and is considered to form amyloid plaque. However, the processes of plaque formation are still not well known. It is generally thought that Aβ is secreted into the extracellular space and aggregates to form amyloid plaques. Aβ as extracellular aggregates and amyloid plaques are thought to be toxic to the surrounding neurons. The intraneuronal accumulation of Aβ has more recently been demonstrated and is reported to be involved in synaptic dysfunction, cognitive impairment, and the formation of amyloid plaques in AD. We herein provide an overview of the process of the intraneuronal accumulation of Aβ and plaque formation, and discuss its implications for the pathology, early diagnosis, and therapy of AD.
Neuromyelitis optica (NMO) is an inflammatory and necrotizing disease clinically characterized by selective involvement of the optic nerves and spinal cord. There has been a long controversy as to ...whether NMO is a variant of multiple sclerosis (MS) or a distinct disease. Recently, an NMO-specific antibody (NMO-IgG) was found in the sera from patients with NMO, and its target antigen was identified as aquaporin 4 (AQP4) water channel protein, mainly expressed in astroglial foot processes. However, the pathogenetic role of the AQP4 in NMO remains unknown. We did an immunohistopathological study on the distribution of AQP4, glial fibrillary acidic protein (GFAP), myelin basic protein (MBP), activated complement C9neo and immunoglobulins in the spinal cord lesions and medulla oblongata of NMO (n = 12), MS (n = 6), brain and spinal infarction (n = 7) and normal control (n = 8). The most striking finding was that AQP4 immunoreactivity was lost in 60 out of a total of 67 acute and chronic NMO lesions (90%), but not in MS plaques. The extensive loss of AQP4 accompanied by decreased GFAP staining was evident, especially in the active perivascular lesions, where immunoglobulins and activated complements were deposited. Interestingly, in those NMO lesions, MBP-stained myelinated fibres were relatively preserved despite the loss of AQP4 and GFAP staining. The areas surrounding the lesions in NMO had enhanced expression of AQP4 and GFAP, which reflected reactive gliosis. In contrast, AQP4 immunoreactivity was well preserved and rather strongly stained in the demyelinating MS plaques, and infarcts were also stained for AQP4 from the very acute phase of necrosis to the chronic stage of astrogliosis. In normal controls, AQP4 was diffusely expressed in the entire tissue sections, but the staining in the spinal cord was stronger in the central grey matter than in the white matter. The present study demonstrated that the immunoreactivities of AQP4 and GFAP were consistently lost from the early stage of the lesions in NMO, notably in the perivascular regions with complement and immunoglobulin deposition. These features in NMO were distinct from those of MS and infarction as well as normal controls, and suggest that astrocytic impairment associated with the loss of AQP4 and humoral immunity may be important in the pathogenesis of NMO lesions.
Recent studies have reported wing interference patterns (WIPs), which reflect the microstructure of the wing, for small insects belonging to the Diptera and Hymenoptera orders. WIPs have been ...evaluated using RGB or multispectral images, but in contrast to these approaches, hyperspectral images allow a more detailed analysis of spectral variation, which may not be captured by RGB or multispectral images. Here, I investigated the WIPs of 12 Drosophila species using hyperspectral images. The average spectrum was calculated for each of the six compartments of the wing region and for the entire wing, including all six compartments. This information was used to evaluate sexual and interspecific differences in the WIPs of 12 Drosophila species. In addition, the possibility of species discrimination based on WIPs was explored using the random forest machine learning algorithm. The present study demonstrates significant sex and interspecific differences in WIPs for each of the six compartments of the wing regions as well as for the entire wing region. The results of the random forest machine learning algorithm suggested the possibility of species identification based on WIPs.
Hyperspectral images, which store data fromlight that is spectralized into dozens or more bands for each wavelength range, allow a more detailed analysis of spectral variation.
Here, wing interference patterns (WIPs) of 12 Drosophila species were investigated using hyperspectral images.
The present study demonstrates significant sex and interspecific differences in WIPs, and suggests the possibility of species identification based on WIPs.
Interleukin-6 (IL-6) has an important role in cancer progression, and high levels of plasma IL-6 are correlated with a poor prognosis in a variety of cancers. It has also been reported that tumour ...stromal fibroblasts are necessary for steps in cancer progression, such as angiogenesis. There have been few reports of a correlation between fibroblast actions and IL-6 levels. In this study, we examined the correlation between cancer stromal fibroblasts and IL-6 and the utility of IL-6 as a therapeutic target in human colon cancer.
The expression levels of IL-6 and VEGF of fibroblasts and cancer cell lines were evaluated using real-time PCR and ELISA. The anti-angiogenic effect of inhibiting IL-6 signalling was measured in an angiogenesis model and animal experiment.
We demonstrate that stromal fibroblasts isolated from colon cancer produced significant amounts of IL-6 and that colon cancer cells enhanced IL-6 production by stromal fibroblasts. Moreover, IL-6 enhanced VEGF production by fibroblasts, thereby inducing angiogenesis. In vivo, anti-IL6 receptor antibody targeting stromal tissue showed greater anti-tumour activity than did anti-IL6 receptor antibody targeting xenografted cancer cells.
Cancer stromal fibroblasts were an important source of IL-6 in colon cancer. IL-6 produced by activated fibroblasts induced tumour angiogenesis by stimulating adjacent stromal fibroblasts. The relationship between IL-6 and stromal fibroblasts offers new approaches to cancer therapy.
•PD is characterized by dopaminergic neurodegeneration and iron overload in the SNpc.•QSM can quantify iron deposition.•Neuromelanin imaging can quantify loss of dopaminergic neurons.•A novel ...automatic volumetric SNpc region of interest selection method was developed.•QSM and neuromelanin imaging are useful for quantifying the SNpc alterations in PD.
To quantify dopaminergic neurodegeneration and iron overload in the substantia nigra pars compacta (SNpc) to evaluate Parkinson’s disease (PD) using both quantitative susceptibility mapping (QSM) and neuromelanin imaging.
We studied 39 PD patients (PD group) and 25 healthy controls (HC group) who underwent brain MRI with QSM and neuromelanin imaging. QSM and neuromelanin values of the SNpc were obtained using a voxel-based automated region segmentation system. The signal-to-noise ratio (SNR) of the SNpc in the neuromelanin images was calculated based on the mean value for the background region. The neuromelanin value was defined as the neuromelanin volume with an SNR higher than that of the background. The significance of the intergroup differences, and according to the severity stages in the PD group was tested for each QSM and neuromelanin value. Receiver-operating characteristic (ROC) analysis for diagnosing PD was performed for QSM and neuromelanin values.
The QSM value was significantly higher in the PD group than in the HC group (P < 0.05). The neuromelanin value was significantly smaller in the PD group than in the HC group (P < 0.05). The areas under the ROC curve were 0.68 and 0.86 for QSM and neuromelanin values, respectively. Using QSM and neuromelanin imaging to classify the PD stage was difficult.
Quantifying the SNpc alterations with our region-based approach is useful for the diagnosis of PD.
ABSTRACT
The impact of the magnetic field on post-bounce supernova dynamics of non-rotating stellar cores is studied by performing 3D magnetohydrodynamics simulations with spectral neutrino ...transport. The explodability of strongly and weakly magnetized models of 20 and 27 M⊙ pre-supernova progenitors are compared. We find that although the efficiency for the conversion of the neutrino heating into turbulent energy including magnetic fields in the gain region is not significantly different between the strong and weak field models, the amplified magnetic field due to the neutrino-driven convection on large hot bubbles just behind stalled shock results in a faster and more energetic explosion in the strongly magnetized models. In addition, by comparing the difference between the 2nd- and 5th-order spatial accuracy of the simulation in the strong field model for 27 M⊙ progenitor, we also find that the higher order accuracy in space is beneficial to the explosion because it enhances the growth of neutrino-driven convection in the gain region. Based on our results of core-collapse supernova simulations for the non-rotating model, a new possibility for the origin of the magnetic field of the protoneutron star (PNS) is proposed. The magnetic field is accumulated and amplified to magnetar level, that is, $\mathcal {O}(10^{14})$ G, in the convectively stable shell near the PNS surface.
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