Magnetic Compton scattering studies of magneto-dielectric Ba(Co0.85Mn0.15)O3-δ

We revealed that the Ba(Co_0.85Mn_0.15)O_3-δ ceramic samples exhibited ferromagnetic-dielectric behavior below the magnetic transition temperature of about 35 K. The origin of their magnetic ordering was expected to super-exchange coupling of Co⁴⁺(d⁵)-O^2--Mn⁴⁺(d³) with bonding angle of 180° and/or Mn⁴⁺(d³)-O^2--Mn⁴⁺(d³) with bonding angle of 90°. The magnetic spin momentum estimated by the magnetic Compton profiles (MCP) of the samples had similar temperature dependence as that determined by the temperature dependence of magnetic moment by superconducting quantum interference device, which meant that the observed magnetic moments could be ascribed to the spin moment. The shapes of the MCPs of the samples were completely same regardless of the temperature measured. This result indicates that there are no changes of the momentum space distribution of spin density between ferromagnetic and paramagnetic states. So, this magnetic transition is simply caused by a thermal fluctuation of the spin.

Metformin inhibits advanced glycation end products (AGEs)-induced growth and VEGF expression in MCF-7 breast cancer cells by suppressing AGEs receptor expression via AMP-activated protein kinase

Metformin use has been reported to decrease breast cancer incidence and mortality in diabetic patients. We have previously shown that advanced glycation end products (AGEs) and their receptor (RAGE) interaction stimulate growth and/or migration of pancreatic cancer and melanoma cells. However, effects of metformin on AGEs-RAGE axis in breast cancers remain unknown. We examined here whether and how metformin could block the AGEs-induced growth and vascular endothelial growth factor (VEGF) expression in MCF-7 breast cancer cells. Cell proliferation was measured with an electron coupling reagent WST-1 based colorimetric assay. Gene expression level was evaluated by real-time reverse-transcription polymerase chain reactions. AGEs significantly increased cell proliferation of MCF-7 cells, which was completely prevented by the treatment with 0.01 or 0.1 mM metformin or anti-RAGE antibodies. Furthermore, metformin at 0.01 mM completely suppressed the AGEs-induced upregulation of RAGE and VEGF mRNA levels in MCF-7 cells. An inhibitor of AMP-activated protein kinase, compound C significantly blocked the growth-inhibitory and RAGE and VEGF suppressing effects of metformin in AGEs-exposed MCF-7 cells. Our present study suggests that metformin could inhibit the AGEs-induced growth and VEGF expression in MCF-7 breast cancer cells by suppressing RAGE gene expression via AMP-activated protein kinase pathway. Metformin may protect against breast cancer expansion in diabetic patients by blocking the AGEs-RAGE axis.

Ankle-brachial pressure index and mini nutritional assessment in community-dwelling elderly people

BACKGROUND

A low ankle-brachial pressure index (an ABPI value <0.90) is considered predictive of cardiovascular disease, and is widely thought to increase morbidity and mortality in the elderly. However, good nutrition is beneficial both for the health and the ability to resist and recover from the disease.

OBJECTIVE

The aim of the present study was to evaluate the relationship between the ankle-brachial pressure index and the nutritional status of the elderly in a city of Kochi prefecture, Japan.

METHODS

This was a cross-sectional study in which a total of 100 elderly people, both males and females, were screened for ankle-brachial pressure index (ABPI), nutritional status (through the use of the short form of the mini nutritional assessment), activities of daily living, lifestyle, gait speed (10MWT), postural stability (OLST), and functional mobility (TUG).

RESULTS

About 67% of the participants were found to have a normal nutritional status, 27% were at risk of malnutrition, and six percent were classified as malnourished. The mean ABPI of the participants was 1.08±0.10, and three participants had an ABPI lower than 0.90. The ABPI was statistically higher in well nourished participants compared with those at risk of malnutrition or the malnourished. The mean ABPI was significantly higher in non-smokers compared with former smokers. The ABPI was found to correlate negatively with gait speed and with TUG score.

CONCLUSION

Well-nourished elderly had a higher normal ankle-brachial pressure index as compared with the malnourished elderly. This study provides supportive evidence for the necessity of adequate nutrition for elderly people.

Observation of self-binding in monolayer 3He

We report clear experimental signatures of the theoretically unexpected gas-liquid transition in the first three monolayer systems of (3)He adsorbed on graphite. The transition is inferred from the linear density dependence of the gamma coefficient of the heat capacity measured in the degenerate region (2≤T≤80 mK) below a critical liquid density (ρ(c0)). Surprisingly, the measured ρ(c0) values (0.6-0.9 nm(-2)) are nearly the same for all these layers in spite of their quite different environments. We conclude that the ground state of (3)He in strictly two dimensions is not a dilute quantum gas but a self-bound quantum liquid with the lowest density ever found.

Metformin inhibits advanced glycation end products (AGEs)-induced renal tubular cell injury by suppressing reactive oxygen species generation via reducing receptor for AGEs (RAGE) expression

Advanced glycation end products (AGEs) and their receptor (RAGE) play a role in tubulointerstitial damage in diabetic nephropathy. Recently, metformin has been shown to ameliorate tubular injury both in cell culture and diabetic animal model. However, effects of metformin on AGEs-induced tubular cell apoptosis and damage remain unknown. We examined here whether and how metformin could block the AGEs-RAGE-elicited tubular cell injury in vitro. Gene expression level was evaluated by real-time reverse-transcription polymerase chain reactions. Reactive oxygen species (ROS) generation was measured with dihydroethidium staining. Apoptosis was evaluated by DNA fragmentation and annexin V expression level. AGEs upregulated RAGE mRNA levels and subsequently increased ROS generation and intercellular adhesion molecule-1, monocyte chemoattractant protein-1 and transforming growth factor-β gene expression in human renal proximal tubular cells, all of which were significantly blocked by the treatment of 0.01 and 0.1 mM metformin. Compound C, an inhibitor of AMP-activated protein kinase significantly blocked the effects of metformin on RAGE gene expression and ROS generation in AGEs-exposed tubular cells. Furthermore, metformin dose-dependently inhibited the AGEs-induced apoptotic cell death of tubular cells; 1 mM metformin completely suppressed the pro-apoptotic effects of AGEs in 2 different assay systems. Our present study suggests that metformin could inhibit the AGEs-induced apoptosis and inflammatory and fibrotic reactions in tubular cells probably by reducing ROS generation via suppression of RAGE expression through AMP-activated protein kinase activation. Metformin may protect against tubular cell injury in diabetic nephropathy by blocking the AGEs-RAGE-ROS axis.

Glucose-dependent insulinotropic polypeptide (GIP) inhibits signaling pathways of advanced glycation end products (AGEs) in endothelial cells via its antioxidative properties

Glucose-dependent insulinotropic polypeptide (GIP) is one of the incretins, a gut hormone secreted from K cells in the intestine in response to food intake. It could be a potential therapeutic target for the treatment of patients with type 2 diabetes. However, effects of GIP on vascular injury remain unknown. Since interaction of advanced glycation end products (AGEs) with their receptor RAGE has been shown to play a crucial role in vascular damage in diabetes, this study investigated whether and how GIP blocked the deleterious effects of AGEs on human umbilical vein endothelial cells (HUVECs). GIP receptor was expressed in HUVECs. GIP, an analogue of cyclic AMP or inhibitors of NADPH oxidase inhibited the AGE-induced reactive oxygen species (ROS) generation in HUVECs. Furthermore, GIP reduced both RAGE mRNA and protein levels in HUVECs. GLP-1 also blocked the AGE-induced increase in mRNA levels of vascular cell adhesion molecule-1 (VCAM-1) and plasminogen activator inhibitor-1 in HUVECs. In addition, an antioxidant N-acetylcysteine mimicked the effects of GIP on RAGE and VCAM-1 gene expression in HUVECs. Our present study suggests that GIP could block the signal pathways of AGEs in HUVECs by reducing ROS generation and subsequent RAGE expression probably via GIP receptor-cyclic AMP axis.

MFM and PEEM observation of micrometre-sized magnetic dot arrays fabricated by ion-microbeam irradiation in FeRh thin films

FeRh thin films were irradiated with a 10 MeV iodine ion microbeam to produce micrometre-scale ferromagnetic microstructures by modifying the local magnetic character from antiferromagnetism to ferromagnetism using ion-microbeam irradiation. Two-dimensional magnetic dot arrays of dimensions ∼2 µm × 4 µm as well as 10 µm × 10 µm were successfully produced on the FeRh surface, which was confirmed by magnetic force microscopy (MFM). The results of photoemission electron microscopy (PEEM) combined with X-ray magnetic circular dichroism reveal that the easy axis of the magnetization of the ion-beam-irradiated ferromagnetism in the FeRh thin films lies in the film planes along the <001> direction of the MgO substrates.

Ferromagnetism in hydrogenated graphene nanopore arrays

Theoretically, the so-called zigzag edge of graphenes provides localized electrons due to the presence of flat energy bands near the Fermi level. Spin interaction makes the localized spins strongly polarized, yielding ferromagnetism. However, in most experimental studies, ferromagnetism has been observed in uncontrollable and complicated carbon-based systems. Here, we fabricate graphenes with honeycomblike arrays of hexagonal nanopores, which have a large ensemble of hydrogen-terminated and low-defect pore edges that are prepared by a nonlithographic method (nanoporous alumina templates). We observe large-magnitude ferromagnetism derived from electron spins localizing at the zigzag nanopore edges. This promises to be a realization of graphene magnets and novel spintronic devices.

A novel stress monitoring method through stress-induced respiratory alterations: non-contact measurement of respiratory V(T)/T(I) alterations induced by stressful sound using a 10 GHz microwave radar

We have developed a non-contact stress monitoring system which measures respiratory V(T)/T(I) (tidal volume/inspiration time) alterations using a 10 GHz microwave radar. The measurable distance of the system is 50 cm, which is 10 times longer than our previously developed stress monitoring system which measures heart rate variability using a 24-GHz microwave-radar. The study was conducted with eight subjects (23 ± 1 years old) to evaluate the efficacy of the system. An audio stimulus at 95 dB sound pressure level was presented to the subjects following a silent period of 120 seconds. During the silent period, V(T)/T(I) averaged 826 ± 384 ml s(-1), while it increased significantly (p < 0.05) with an average of 1227 ± 704?ml s(-1) during audio stimulus low frequency component (LF)/high frequency component (HF), which reflects sympatho-vagal valance, showed a peak during audio stimuli. This paper aims to study the efficacy of the non-contact stress monitoring system for its future applications in many fields including health and safety.

Sitagliptin augments protective effects of GLP-1 against advanced glycation end product receptor axis in endothelial cells

Sitagliptin is a stable inhibitor of dipeptidyl peptidase-IV, a responsible enzyme that mainly inactivates glucagon-like peptide-1 (GLP-1), and now one of the widely used agents for the treatment of diabetes. However, effects of sitagliptin on vascular injury are largely unknown. Since advanced glycation end products (AGEs) and their receptor (RAGE) axis contribute to vascular damage in diabetes, we investigated here whether sitagliptin inhibits the AGE-RAGE-induced endothelial cell damage in vitro. Although effects of 10 pM GLP-1 or 0.5 μM sitagliptin monotherapy on RAGE gene and protein expression were modest, combination therapy completely blocked the AGE-induced increase in RAGE mRNA and protein levels in human umbilical vein endothelial cells (HUVEC). AGEs induced reactive oxygen species (ROS) generation and reduced endothelial nitric oxide synthase (eNOS) mRNA level in HUVEC, both of which were also completely blocked by the treatment with 10 pM GLP-1 and 0.5 μM sitagliptin, but not with GLP-1 or sitagliptin monotherapy. Further, anti-RAGE antibody restored the decrease in eNOS mRNA level in AGE-exposed HUVEC. The present study suggests that sitagliptin augments the effects of GLP-1 on eNOS mRNA level in AGE-exposed HUVEC by suppressing RAGE expression and subsequent ROS generation. Sitagliptin may work as a vasoprotecitve agent in diabetes by blocking the AGE-RAGE axis.