Comparative study on the magnetic properties of Fe-substituted Co2Sn1-xFexO4 spinel oxides and its exchange bias effect.

A series of Fe-substituted Co2Sn1-xFexO4 (0 ≤ x ≤ 0.4) inverse spinel's oxides was synthesized using the solid-state reaction method. X-ray analysis reveals a single-phase cubic structure with the space group Fd3m. The transition temperature is shown to increase with a higher Fe concentration in the Co2Sn1-xFexO4 spinel oxide. The ac susceptibility at different frequencies also confirms a spin-glassy state at lower temperatures. The sample with Fe substitution (x = 0.2) exhibits a significant exchange bias effect when subjected to a constant temperature of ~10 K. The susceptibility at high temperatures, as calculated using Curie-Wise fitting, suggests that the system undergoes a shift from antiferromagnetic exchange (x < 0.2) to ferromagnetic exchange (x > 0.2).

Effect of Al substitution on the magnetization reversal and complex magnetic properties of NiCr2O4 ceramics.

A series of polycrystalline NiCr2-xAlxO4 (0.1 ≤ x ≤ 0.25) spinel ceramics have been synthesized using a sol-gel method. DC magnetization measurements are carried out at different temperatures and magnetic fields. A novel magnetization reversal has been observed in the field cooling process for the x = 0.2 sample, which can be ascribed to the competition between two magnetic sublattices due to their different temperature dependences. The magnetic interaction evolution, related to the complex magnetic properties, is revealed by exchange constants that have been estimated according to ferrimagnetic Curie-Weiss fitting and mean field theory. The fitting result confirmed the evolution of antiferromagnetic and ferromagnetic components with Al substitution, which is supported by the observations from the isothermal magnetization measurements. The positive and negative values of the magnetic moment can be utilized for storage applications based on the results of magnetic switching effect measurements.

Negative magnetization, complex magnetic ordering and applications of Cr-doped Co2TiO4.

Polycrystalline Co2Ti1-xCrxO4 (0 ≤ x ≤ 0.2) inverse spinel ceramics have been synthesized via a sol-gel technique. The dc magnetization measurement in the field-cooled mode shows that negative magnetization could be observed until x reaches 0.2. The exchange constants are calculated using the ferrimagnetic Curie-Weiss fitting and the mean-field theory. This reveals that the strength of the inter sublattice magnetic interaction presents a non-monotonic trend with the increase in Cr content and reaches the minimum at x = 0.1, giving rise to the highest compensation temperature in the x = 0.1 sample. The applicability of the x = 0.1 sample is investigated in light of two prominent magnetic effects: (i) the stable magnetic switching effect indicates the potential applications in magnetic switching and data storage and (ii) the coexistence of normal and inverse magnetocaloric effects suggests a potential application in a constant temperature bath at 54 K.

Pain and quality of life in knee osteoarthritis, chronic low back pain and fibromyalgia: a comparative cross-sectional study.

The objective of our study was to compare pain and health-related quality of life among patients with knee osteoarthritis (OA), chronic nonspecific low back pain (CNLBP) and fibromyalgia (FM). This cross-sectional study included 87 subjects, who were divided into three groups according to their diagnosis: knee OA (n=29), CNLBP (n=29) and FM (n=29), between March 2013 and March 2014. Pain intensity was measured using the Numeric Pain Rating Scale (NPRS), quality of pain using the McGill Pain Questionnaire (MPQ) and health-related quality of life using the 36-item Short-Form Health Survey (SF-36). Painful body areas were marked on a pain map. No statistically significant differences between groups were found for NPRS. Regarding MPQ, the knee OA group presented a lower pain-rating index in contrast to the CNLBP and FM groups, and no significant differences were found between the CNLBP and FM groups. A greater number of characteristic pain descriptors and painful locations were found in the FM group than in the CNLBP or knee OA groups. Regarding SF-36, the FM group presented statistically significant lower values for bodily pain in contrast to the knee OA group. Even though the global pain intensity was similar between groups, the findings suggest that the FM group presented the worst pain experience and a lower health-related quality of life than the knee OA group in terms of bodily pain. They also suggest that the pain experience was worse for the CNLBP group than for the knee OA group but health-related quality of life was similar.

Giant anisotropic magnetoresistance and nonvolatile memory in canted antiferromagnet Sr2IrO4.

Antiferromagnets have been generating intense interest in the spintronics community, owing to their intrinsic appealing properties like zero stray field and ultrafast spin dynamics. While the control of antiferromagnetic (AFM) orders has been realized by various means, applicably appreciated functionalities on the readout side of AFM-based devices are urgently desired. Here, we report the remarkably enhanced anisotropic magnetoresistance (AMR) as giant as ~160% in a simple resistor structure made of AFM Sr2IrO4 without auxiliary reference layer. The underlying mechanism for the giant AMR is an indispensable combination of atomic scale giant-MR-like effect and magnetocrystalline anisotropy energy, which was not accessed earlier. Furthermore, we demonstrate the bistable nonvolatile memory states that can be switched in-situ without the inconvenient heat-assisted procedure, and robustly preserved even at zero magnetic field, due to the modified interlayer coupling by 1% Ga-doping in Sr2IrO4. These findings represent a straightforward step toward the AFM spintronic devices.

Understanding of metal-insulator transition in VO2 based on experimental and theoretical investigations of magnetic features.

The metal-insulator transition temperature Tc in VO2 is experimentally shown to be almost the same as a magnetic transition temperature Tm characterized by an abrupt decrease in susceptibility, suggesting the evidence of the same underlying origin for both transitions. The measurement of susceptibility shows that it weakly increases on cooling for temperature range of T > Tm, sharply decreases near Tm and then unusually increases on further cooling. A theoretical approach for such unusual observations in susceptibility near Tm or below is performed by modeling electrons from each two adjacent V4+ ions distributed along V-chains as a two-electron system, which indicates that the spin exchange between electrons could cause a level splitting into a singlet (S = 0) level of lower energy and a triplet (S = 1) level of higher energy. The observed abrupt decrease in susceptibility near Tm is explained to be due to that the sample enters the singlet state in which two electrons from adjacent V4+ ions are paired into dimers in spin antiparallel. By considering paramagnetic contribution of unpaired electrons created by the thermal activation from singlet to triplet levels, an expression for susceptibility is proposed to quantitatively explain the unusual temperature-dependent susceptibility observed at low temperatures. Based on the approach to magnetic features, the observed metal-insulator transition is explained to be due to a transition from high-temperature Pauli paramagnetic metallic state of V4+ions to low-temperature dimerized state of strong electronic localization.

Prognostic significance of the tumor-stroma ratio in gallbladder cancer.

In recent years, the tumor-stroma ratio (TSR) has attracted increasing attention as an independent prognostic factor for several solid tumors. However, the importance of the stromal compartment has not been investigated yet in gallbladder cancer (GBC). The objective of this study is to investigate the prognostic value of TSR in GBC and the relationship between TSR and other known prognostic parameters. A total of 51 patients who underwent operations for gallbladder carcinoma were selected for this study. TSR was determined on haematoxylin and eosin (H et E)-stained sections by two independent investigators. Stromal ratio groups were classified as stroma-poor (ratio of stroma 50%). The Mann-Whitney test, the Chi-squared test, the Kaplan-Meier method, and the Cox proportional hazards model were used to analyze the data. The median survival time for patients in the stroma-rich group was 6.00 months (95% CI, 4.47-7.54). In contrast, for the stroma-poor group, the median survival time was 17.00 months (95% CI, 3.64-30.36). The 3-year overall survival rate was 19.7% in the stroma-poor group and 7.2% in the stroma-rich group. Patients with stroma-rich tumors had a worse prognosis than those with stroma-poor tumors (log-rank P = 0.004). According to the univariate analysis, the TSR, differentiation grade, pTNM stage, and operative methods were shown to be related to overall survival (OS) with statistical significance. The hazard ratio (HR) of TSR was 2.428 (95% CI, 1.29-4.58; P = 0.006). However, the TSR did not prove to be an independent prognostic factor in the multivariate analysis. Our study demonstrated that the tumor-stroma ratio (TSR) is an important prognostic parameter for gallbladder cancer (GBC). Stroma-rich tumors were associated with poor overall survival.

The crucial role of Mn spiral spin order in stabilizing the Dy-Mn exchange striction in multiferroic DyMnO3.

DyMnO3 hosts the less addressed duality of multiferroicity, owing to the Dy-Mn exchange striction and inverse Dzyaloshinskii-Moriya interaction between Mn spin pairs. Although the duality in DyMnO3 has been discussed earlier, there remains a question whether the Mn magnetic sublattice is necessarily multiferroic for generating the Dy-Mn exchange striction. In this work, we investigate the multiferroicity of Dy(Mn1-xFex)O3 (0 ≤ x ≤ 0.1) through detailed magnetic and ferroelectric characterization. It is found that Fe-doping continuously suppresses the independent Dy spin order but instead promotes the Dy-Mn(Fe) coupling. This coupling benefits the Dy-Mn(Fe) exchange striction which remarkably enhances the ferroelectric polarization at a low doping level (x ≤ 0.015), beyond which the Mn spiral spin order breaks down leading to collapse of the macroscopic polarization at x ≥ 0.05. This work discloses the crucial role of Mn spiral spin order in stabilizing the Dy-Mn exchange striction and thus highlights the duality of multiferroicity in DyMnO3.

Adeno-associated virus-mediated BMP-7 and SOX9 in vitro co-transfection of human degenerative intervertebral disc cells.

Bone morphogenetic protein-7 (BMP-7) and SOX9 are important transcription factors in chondrogenesis. In this study, we examined the biological function of the adeno-associated virus (AAV)-mediated BMP-7 and SOX9 double gene in vitro co-transfection of nucleus pulposus cells of human degenerative intervertebral disc. Human intervertebral disc nucleus pulposus cells were cultured in vitro and subcultured for 5 generations. Using rAAV-BMP-7 and rAAV-SOX9 AAV2-type AAV viruses, the cells were divided into 4 groups: blank normal, BMP-7 transfection, SOX9 transfection, and BMP-7 and SOX9 co-transfection. After 48 h, expression of type II collagen and its mRNA in nucleus pulposus cells was determined. The expression of type II collagen in BMP-7 transfection, SOX9 transfection, and co-transfection groups was up-regulated to varying degrees compared to the blank control group. The type II collagen mRNA level expression in the co-transfection group was significantly higher than in other groups (P < 0.05). AAV-mediated BMP-7 and SOX9 in vitro co-transfection can promote the synthesis of type II collagen in nucleus pulposus cells in the human degenerative intervertebral disc. Double-gene therapy has a synergistic effect in the treatment of intervertebral disc degeneration.

Postural control and balance self-efficacy in women with fibromyalgia: are there differences?

BACKGROUND: Fibromyalgia (FM) is a rheumatic disease characterized by chronic widespread pain and symptoms such as fatigue, sleep disturbances, cognitive difficulties, and depression. Postural instability is a debilitating disorder increasingly recognized as part of FM. OBJECTIVE: To assess and compare postural control and balance self-efficacy in women with and without FM and verify the association of these variables with pain, symptom severity, and strength. DESIGN: Case-control study SETTING: Physiotherapeutic Clinical Research and Electromyography Laboratory Department of Physical Therapy, Speech Therapy, and Occupational Therapy, School of Medicine, University of Sao Paulo, Sao Paulo, Brazil. POPULATION: Case-control study of 117 women ranging from age 35 to 60 years. Of these, 67 had FM. METHODS: Posture control was assessed with the modified clinical test of sensory interaction on balance with patients in forceplates, balance self-efficacy with the Activities-specific Balance Confidence Scale, pain severity with the Visual Analog Scale, tender point pain threshold with digital algometry, symptom severity with the fibromyalgia impact questionnaire, and lower limb strength with a dynamometer. RESULTS: Individuals with FM had impaired postural control showing increased speed of oscillation of the center of gravity (P=0.004) and decreased balance self-efficacy (P<0.001). They had moderate to excellent correlations of balance self-efficacy with pain (r=0.7, P<0.01), muscle strength (r=0.52, P<0.01), and symptom severity (r=0.78, P<0.10) compared with the control group. Correlation of postural control with the same variables was weak. CONCLUSIONS: Patients with FM have impaired postural control and low balance self-efficacy that are associated with pain, muscle strength, and symptom severity. CLINICAL REHABILITATION IMPACT: Postural control and balance self-efficacy needs to be assessed in patients with FM and the treatment goals should be the improvement of postural control and balance self-efficacy.

Effectiveness of high-frequency transcutaneous electrical nerve stimulation at tender points as adjuvant therapy for patients with fibromyalgia.

BACKGROUND: Fibromyalgia is a chronic pain syndrome associated with sleep disorders, fatigue and psychological symptoms. Combinations therapies, such as electrotherapy and therapeutic exercises have been used in the clinical practice. AIM: To assess the efficacy of high-frequency transcutaneous electrical nerve stimulation (TENS) as an adjuvant therapy to aerobic and stretching exercises, for the treatment of fibromyalgia. DESIGN: Controlled clinical trial. SETTING: Unit of rehabilitation of a public hospital. POPULATION: Twenty-eight women aged 52.4±7.5 years, with fibromyalgia. METHODS: A visual analogue scale measured pain intensity; tender points pain threshold, by dolorimetry; and quality of life, by the Fibromyalgia Impact Questionnaire. All subjects participated in an eight-week program consisting of aerobic exercises, followed by static stretching of muscle chains. In TENS group, high-frequency (150 Hz) was applied on bilateral tender points of trapezium and supraspinatus. RESULTS: TENS group had a greater pain reduction (mean change score=-2.0±2.9 cm) compared to Without TENS group (-0.7±3.7 cm). There was a difference between mean change scores of each group for pain threshold (right trapezium: 0.2±1 kg/cm² in TENS group and -0.2±1.2 kg/cm² in Without TENS group). In the evaluation of clinically important changes, patients receiving TENS had relevant improvement of pain, work performance, fatigue, stiffness, anxiety and depression compared to those not receiving TENS. CONCLUSION: It has suggested that high-frequency TENS as an adjuvant therapy is effective in relieving pain, anxiety, fatigue, stiffness, and in improving ability to work of patients with fibromyalgia. CLINICAL REHABILITATION IMPACT: High-frequency TENS may be used as a short-term complementary treatment of fibromyalgia.

Aggregation between xanthan and nonyphenyloxypropyl beta-hydroxyltrimethylammonium bromide in aqueous solution: MesoDyn simulation and binding isotherm measurement.

The aggregation behavior of nonyphenyloxypropyl beta-hydroxyltrimethylammonium bromide (C9phNBr) and xanthan (XC) in aqueous solution was investigated by MesoDyn density functional simulation and binding isotherm measurement. The process of aggregate formation and the aggregate morphology are reported. The formation of aggregates includes three stages and the morphology of XC-C9phNBr aggregates is rodlike or ellipsoidal. The effects of temperature and XC concentration on the aggregation are analyzed. Results indicate that the formation of aggregates is an exothermic process, and their formation becomes more difficult and the formation rate decreases with increasing temperature. The formation of aggregates is also related to XC concentration, and it becomes much more difficult when the concentration of XC is higher than 20 vol %. The simulation results agree with binding isotherms of C9phNBr to XC obtained via the potentiometric titration method, which shows a typical cooperative binding between C9phNBr and XC.

Extrapyramidal motor symptoms versus striatal infarction volume after focal ischemia in mongolian gerbils.

Few behavioral tests are available to evaluate extrapyramidal dysfunctions after focal cerebral ischemia in rodents, although extrapyramidal motor dysfunctions are often observed clinically in patients with cerebral infarction. We evaluated the methamphetamine (MP)-induced rotation test for the detection and quantification of extrapyramidal motor dysfunction induced by striatal infarction in gerbils after focal cerebral ischemia. Mongolian gerbils (n=79) underwent the left common carotid artery occlusion (CCAO) for 10, 15, or 20 min. Spontaneous and MP-induced rotation tests were repeated postischemia, and the results compared with the extent of ischemic tissue injury. The density of dopaminergic neurons immunostained with a tyrosine hydroxylase antibody in the substantia nigra pars compacta (SNpc) also was measured. Histological examination revealed selective neuronal death of the hippocampal cornu ammonis 1 (CA1) sector in 10-min CCAO animals, infarction confined to the striatum and hippocampal neuronal death in 15-min CCAO animals, and widespread hemispheric infarction in 20-min CCAO animals. Dopaminergic neurons in the SNpc were preserved in 10- and 15-min CCAO animals but were significantly reduced in 20-min CCAO animals. In MP-induced rotation tests, 15-min CCAO animals showed biased rotation ipsilateral to the lesioned side. Biased rotation persisted 4 weeks postischemia, and the number of rotations significantly correlated with the regional infarction volume of the striatum. Twenty-minute CCAO animals showed biased rotation contralateral to the lesioned side; rotation number was not correlated with the infarction volume. Our results show that biased rotation behavior is a sensitive parameter of the extent of striatal injury after focal cerebral ischemia provided the lesion is not extended to the ipsilateral cortex. MP-induced rotation in rodents probably coordinates with the extrapyramidal motor dysfunction after striatal infarction in patients with vascular Parkinsonism.

High-level expression of Amsacta moorei entomopoxvirus spheroidin depends on sequences within the gene.

Spheroidin (SPH) is the most highly expressed gene of the entomopoxvirus isolated from Amsacta moorei (AmEPV). The level of expression of poxvirus genes is believed to be governed in large part by the promoter. Poxvirus promoters generally consist of approximately 40 bp which frequently terminate at the 3' end with a translation initiating TAAATG sequence. We have examined the requirements for high levels of SPH gene expression by constructing AmEPV recombinants containing either the SPH promoter or the late vertebrate poxvirus promoter derived from the cowpox virus A-type inclusion (ATI) gene. In addition, we have examined SPH promoter derivatives which extend beyond the 3' TAAATG to include 2 or 20 bp of the 5' coding sequence of the SPH gene. Examination of insect cells infected with these AmEPV ATI-lacZ or SPH-lacZ recombinants suggests that ATI-lacZ expression begins 12 h before and is essentially complete prior to any SPH-lacZ expression, allowing functional distinction between the ATI and SPH promoters and implying that different factors regulate the two promoters within the insect environment. SPH promoter-regulated expression is significantly enhanced within infected insect cells by including the additional 20 bp of the N-terminal SPH coding sequences as part of the promoter. However, when any of the SPH promoter constructs, including those containing the downstream sequences, were inserted into vaccinia virus, only very low levels of beta-galactosidase expression were observed. These results imply that downstream coding sequences within the SPH gene enhance SPH gene expression only within the insect environment.

[The antihepatoma effect of lyophilized aclacinomycin A polyisobutylcyanoacrylate nanoparticles in vitro and in vivo].

This paper reports the results of experiments on the antihepatoma effects of live targeted drug delivery system--lyophilized aclacinomycin A polyisobutylcyanoacrylate nanoparticle (ACM-IBC-NP) in vitro and in vivo. The median inhibition concentration were found to be 0.28 micrograms.ml-1 and 0.34 micrograms.ml-1 of lyophilized ACM-IBC-NP and ACM respectively in vitro. The inhibition ratio of colony formation were found to be 99% and 88% of lyophilized ACM-IBC-NP and ACM respectively in vitro. The antihepatoma activity was shown to be significantly concentration dependent. The results showed that lyophilized ACM-IBC-NP and ACM possess strong cytotoxicity on human hepatoma cell 7703, and the cytotoxicity was not significantly different between lyophilized ACM-IBC-NP and ACM in vitro. The model of orthotopic transplantation of human hepatoma in nude mice were used for evaluation of the activity of lyophilized ACM-IBC-NP against hepatoma. The tumor inhibition rate were found to be 86.84% for lyophilized ACM-IBC-NP and 46.69% for ACM. The cell proliferative activity of hepatoma were found to be 20.83% by lyophilized ACM-IBC-NP and 72.50% by ACM. All the results indicate that lyophilized ACM-IBC-NP and ACM have clinical application potential and the antihepatoma activity of lyophilized ACM-IBC-NP was obviously higher than that of ACM.

[Distribution, content and action site of leucine-enkephalin in pulmonary artery wall of rat and rabbit].

Using immunohistochemical method to investigate the distribution of peptidergic fibers in the pulmonary artery wall of SD rat, L-enkephalin immunoreactive (L-ENK ir) fibers were easily demonstrated. The contents of L-ENK in pulmonary artery of rat and rabbit measured by radioimmunoassay were respectively 439.18 +/- 30.52 and 29.9 +/- 1.4 (pg/mg of wct tissue). Contraction of superfused strips of pulmonary artery of rabbit could be evoked by parameter I electric field stimulation. The response was blocked by alpha-receptor antagonist phentolamine. Alpha 2-receptor antagonist Yohimbine enhanced the response in small doses (0.06-0.12 mumol/L), while inhibited in large (3.2 mumol/L). The contraction could also be enhanced when the artery strips were preincubated with naloxone. After the alpha-receptors were blocked with phentolamine, stronger contraction could still be evoked by parameter II electric field stimulation and the response was not affected by naloxone. L-ENK had no effect on the contraction evoked by exogenous NE. The present experiments demonstrate that enkephalin presented in the pulmonary artery wall are released by electric field stimulation. Enkephalin may reduce the release of NE from sympathetic nerve endings via opioid receptors and inhibit the contraction response.

[Effects of diazepam on the rat open field behavior and high K+ induced release of monoamine neurotransmitters from brain slices].

Acute i. p injection of diazepam (3 mg/kg) significantly decreased the open field behaviors (locomotion and rearing) of rats. However, when diazepam (3 mg/kg) was given ip daily for 15 consecutive days, no depressive effect on the open field behaviors was observed. After the open field observation, rats were immediately decapitated and brain slices of cortex, hippocampus, amygdala and brain stem were stimulated by high K+ (65 mmol/L) to cause the release of noradrenaline (NA), dopamine (DA) and serotonin (5-HT). Diazepam (9 mumol/Ls) significantly depressed the release of monoamine neurotransmitters caused by high K+, which were antagonized by Ro 15-1788 (5 mumol/L) in vitro. Acute administration of diazepam (ip 3 mg/kg) also significantly depressed the release of monoamine neurotransmitters caused by high K+ from all regions observed. However, hippocampus showed tolerance to the depressive effects of diazepam on the releases of NA and DA, and amygdala only on the release of DA, caused by high K+, when given ip chronically (3 mg/kg, 15 d). Our results suggest that the depressive effect of benzodiazepines on the release caused by anxiogenic factors of catecholamine in the hippocampus, front cortex and amygdala regions may be one of the mechanisms of sedative and anxiolytic actions of benzodiazepines.