Conductance fluctuations in high mobility monolayer graphene: Nonergodicity, lack of determinism and chaotic behavior.

We have fabricated a high mobility device, composed of a monolayer graphene flake sandwiched between two sheets of hexagonal boron nitride. Conductance fluctuations as functions of a back gate voltage and magnetic field were obtained to check for ergodicity. Non-linear dynamics concepts were used to study the nature of these fluctuations. The distribution of eigenvalues was estimated from the conductance fluctuations with Gaussian kernels and it indicates that the carrier motion is chaotic at low temperatures. We argue that a two-phase dynamical fluid model best describes the transport in this system and can be used to explain the violation of the so-called ergodic hypothesis found in graphene.

Thermally Assisted Nonvolatile Memory in Monolayer MoS2 Transistors.

We demonstrate a novel form of thermally-assisted hysteresis in the transfer curves of monolayer MoS2 FETs, characterized by the appearance of a large gate-voltage window and distinct current levels that differ by a factor of ∼102. The hysteresis emerges for temperatures in excess of 400 K and, from studies in which the gate-voltage sweep parameters are varied, appears to be related to charge injection into the SiO2 gate dielectric. The thermally-assisted memory is strongly suppressed in equivalent measurements performed on bilayer transistors, suggesting that weak screening in the monolayer system plays a vital role in generating its strongly sensitive response to the charge-injection process. By exploiting the full features of the hysteretic transfer curves, programmable memory operation is demonstrated. The essential principles demonstrated here point the way to a new class of thermally assisted memories based on atomically thin two-dimensional semiconductors.

Probing weak localization in chemical vapor deposition graphene wide constriction using scanning gate microscopy.

Low-temperature scanning gate microscopy (LT-SGM) studies of graphene allow one to obtain important spatial information regarding coherent transport such as weak localization (WL) and universal conductance fluctuations. Although fascinating LT-SGM results on pristine graphene prepared by mechanical exfoliation have been reported in the literature, there appears to be a dearth of LT-SGM results on chemical vapor deposition (CVD)-grown graphene whose large scale and flexible substrate transferability make it an ideal candidate for coherent electronic applications. To this end, we have performed LT-SGM studies on CVD-grown graphene wide constriction (0.8 µm), which can be readily prepared by cost-effective optical lithography fully compatible with those in wafer foundry, in the WL regime. We find that the movable local gate can sensitively modulate the total conductance of the CVD graphene constriction possibly due to the intrinsic grain boundaries and merged domains, a great advantage for applications in coherent electronics. Moreover, such a conductance modulation by LT-SGM provides an additional, approximately magnetic-field-independent probe for studying coherent transport such as WL in graphene and spatial conductance variation.

Conduction Mechanisms in CVD-Grown Monolayer MoS2 Transistors: From Variable-Range Hopping to Velocity Saturation.

We fabricate transistors from chemical vapor deposition-grown monolayer MoS2 crystals and demonstrate excellent current saturation at large drain voltages (Vd). The low-field characteristics of these devices indicate that the electron mobility is likely limited by scattering from charged impurities. The current-voltage characteristics exhibit variable range hopping at low Vd and evidence of velocity saturation at higher Vd. This work confirms the excellent potential of MoS2 as a possible channel-replacement material and highlights the role of multiple transport phenomena in governing its transistor action.

A retrospective analysis of the risk factors for allergic reactions induced by the administration of oxaliplatin.

This study retrospectively investigated the clinical features and risk factors of allergic reactions induced by oxaliplatin administration. This study investigated the incidence of allergic reactions and analysed the background and laboratory data in patients with colorectal cancer treated with oxaliplatin-based chemotherapy at Kyushu Medical Center between April 2012 and September 2012. A total of 62 patients were included in this study. The number of patients in the allergic and non-allergic groups was 7 and 55 respectively. The incidence of allergic reactions was 11.3%. We compared the patients' characteristics and laboratory data between the two groups and found that the average dose of dexamethasone in the allergic group was significantly lower than that observed in the non-allergic group (P = 0.0111). Furthermore, the incidence of allergic reactions in the group that received prophylaxis of less than 12 mg of dexamethasone was significantly higher than that observed in the group that received more than 12 mg of dexamethasone (P = 0.0103). In conclusion, a lower dexamethasone dose is a possible risk factor for allergic reactions induced by the administration of oxaliplatin; however, given the retrospective design used in this study, further validation of this finding is warranted.

Neural mechanisms mediating association of sympathetic activity and exploration in decision-making.

The somatic marker hypothesis asserts that decision-making can be guided by feedback of bodily states to the brain. In line with this hypothesis, the present study tested whether sympathetic activity shows an association with a tonic dimension of decision-making, exploratory tendency represented by entropy in information theory, and further examined the neural mechanisms of the association. Twenty participants performed a stochastic reversal learning task that required decision-making in an unstable and uncertain situation. Regional cerebral blood flow was evaluated using (15)O-water positron emission tomography (PET), and cardiovascular indices and concentrations of catecholamine in peripheral blood were also measured, during the task. In reversal learning, increased epinephrine during the task positively correlated with larger entropy, indicating a greater tendency for exploration in decision-making. The increase of epinephrine also correlated with brain activity revealed by PET in the somatosensory cortices, anterior insula, dorsal anterior cingulate cortex, and the dorsal pons. This result is consistent with previously reported brain matrixes of representation of bodily states and interoception. In addition, activity of the anterior insula specifically correlated with entropy, suggesting possible mediation of this brain region between peripheral sympathetic arousal and exploration in decision-making. These findings shed a new light about a role of bodily states in decision-making and underlying neural mechanisms.

Morphologic analysis of mice’s pineal gland

The pineal gland or pineal body is an endocrine gland that constitutes an important part of the neuroendocrine system, due to the secretion of melatonin, a hormone responsible for the seasonal organization of several physiologic and behavioral events of an individual’s life. Experimental researches using animals such as rats, mice and rabbits are often found in the extensive specific literature but aspects related to the morphology of mice’s pineal gland are few. Concerning its small size, the present paper performed a microscopic analysis of serial median sagittal sections of the pineal gland of 13 (thirteen) Swiss mice. The pineal gland of Swissmice was found to be in the median plane below the splenium of the corpus callosus, superior and dorsal to the habenular commissure, and rostral to the rostral colliculi. The pineal gland is closely related to the third ventricle and presents itself with a characteristic tonsillar shape with a stalk. Two types of different cells were identified in the gland, that is, astrocytes and pinealocytes, spreading randomly all over the glandular tissue. Calcifications of the pineal gland were not found in any of the observed animals.

Chronic stress modulates neural and cardiovascular responses during reversal learning.

Animal studies have revealed that chronic stress shifts cognitive strategies from the flexible goal-directed action to the simple and rigid habit action. In addition, stress-induced atrophy in the prefrontal cortex and dorsomedial striatum which are involved in the goal-directed action and hypertrophy of the dorsolateral striatum which is critical for the habit action were parallel with the effects of chronic stress on behaviors. The present study tested whether these previous findings in animal studies are compatible in humans by analyzing effects of chronic stress on neural and cardiovascular responses, which are likely important for performing appropriate actions. Twenty healthy men exposed to low or high chronic job stress performed a stochastic reversal learning task, which required cognitive flexibility and the goal-directed action. Regional cerebral blood flow was evaluated during the task using (15)O-water positron emission tomography, and cardiovascular parameters such as blood pressure and heart rate were also measured. During the reversal learning task, whereas participants with low chronic job stress exhibited activity in the anterior caudate, as well as orbitofrontal cortex, ventrolateral prefrontal cortex, insula, and midbrain, which might be related to the goal-directed action, participants with high chronic job stress exhibited no activity in such brain regions. Furthermore, participants with high chronic job stress exhibited less reactivity in diastolic blood pressure, which might be mediated by anterior cingulate cortical activity. These findings, in line with previous studies, suggested that chronic job stress correlates with less activity in brain regions related to the goal-directed action, and insensitive physiological responses in humans.

Inhibitory effect of oxytocin on accelerated colonic motility induced by water-avoidance stress in rats.

Recent studies have indicated that brain and gut activities are interrelated and exposure to several stressors, such as water-avoidance stress, stimulates the motor function of the gut through corticotropin-releasing factor (CRF)-signalling pathways in the brain. Central oxytocin is known to attenuate stress responses, including CRF expression in the brain. Here, we examined whether central oxytocin attenuated the acceleration of colonic motility induced by water-avoidance stress. A force transducer was attached to the distal colon of male rat, and the colonic motility and faecal pellet output were recorded while the rats were exposed to water-avoidance stress. Intracerebroventricular (i.c.v.) injections of oxytocin (5, 50 and 500 pmol) and the oxytocin receptor antagonist tocinoic acid (25 microg) were administered before exposure to water-avoidance stress, and the effect of oxytocin on colonic motor function was determined. Centrally administered oxytocin inhibited the accelerated colonic motility induced by water-avoidance stress. The effective dose ranged between 5 and 50 pmol on i.c.v. injection. Oxytocin also decreased the number of CRF-positive cells in the paraventricular nucleus and corticosterone release. The inhibitory effect of oxytocin on accelerated colonic motility was blocked by pretreatment with oxytocin receptor antagonist. Furthermore, centrally administered tocinoic acid enhanced the acceleration of colonic motility. These results suggested that endogenous central oxytocin may contribute to the regulation of colonic function and inhibit the brain CRF-signalling pathways targeting the gut, resulting in the inhibition of stress-induced colonic contractions.

[Usefulness of the thoracoscopic surgery under local anesthesia and irrigation for the patient with Bacillus cereus empyema; report of a case].

The case was 54-year-old male with some risks such as chronic heart failure, atrial fibrillation, and liver chirrhosis. He was admitted because of severe back pain and diagnosed as empyema by preoperative thoracentesis. By thoracoscopic procedures under local anesthesia, fibrinopurulent tissues were cleaned as much as possible and 3 of chest tubes were replaced. The final diagnosis was Bacillus cereus pyothorax by bacterial cultures of pleural effusion. Intrathoracic cavity was cleaned with physiological saline solution. The patient made favorable progress and recovered. Thoracoscopic surgery under local anesthesia with thoracic irrigation was so effective and safe methods to control the infection.

Controlled normothermia during ischemia is important for the induction of neuronal cell death after global ischemia in mouse.

A stable model of neuronal damage after ischemia is needed in mice to enable progression of transgenic strategies. We performed transient global ischemia induced by common carotid artery occlusions with and without maintaining normal rectal temperature (Trec) in order to determine the importance of body temperature control during ischemia. We measured brain temperature (Tb) during ischemia/reperfusion. Mice with normothermia (Trec within +/- 1 degrees C) had increased mortality and neuronal cell death in the CA1 region of hippocampus, which did not occur in hypothermic animals. If the Trec was kept within +/- 1 degrees C, the Tb decreased during ischemia. After reperfusion, Tb in the normothermia group developed hyperthermia, which reached > 40 degrees C and was > 2 degrees C higher than Trec. We suggest that tightly controlled normothermia and prevention of hypothermia (Trec) during ischemia are important factors in the development of a stable neuronal damage model in mice.

Post-challenge hyperinsulinaemia rather than hyperglycaemia is associated with the severity of coronary artery disease in patients without a previous diagnosis of diabetes mellitus.

OBJECTIVE: To ascertain the prevalence of abnormal glucose metabolism in patients with coronary artery disease (CAD) but no previous diagnosis of diabetes mellitus (DM) and to examine the relation between the severity of CAD and responses of glucose and insulin to the glucose tolerance test. METHODS AND RESULTS: Abnormalities of glucose metabolism and insulin response were analysed in 144 patients with CAD without a previous diagnosis of DM who underwent both coronary arteriography and 75 g oral glucose tolerance test. The proportions of impaired and diabetic glucose tolerance were very high (39% for impaired and 21% for diabetic glucose tolerance); only 40% had normal glucose tolerance. The parameters of glucose metabolism were not associated with the number of diseased coronary arteries or the presence of previous myocardial infarction (MI). However, the insulin concentration at 60 minutes or 120 minutes after glucose challenge, insulin area, and the ratio of insulin to glucose area were significantly higher in patients with significant coronary stenosis and with previous MI. Fasting glucose concentration and most conventional risk factors did not predict post-challenge hyperinsulinaemia. CONCLUSION: Patients with CAD without a previous diagnosis of DM had a high prevalence of abnormal glucose tolerance. Post-challenge hyperinsulinaemia was associated with the number of diseased coronary arteries and the presence of previous MI. The insulin response to the glucose challenge test requires further investigation as a potential risk factor for CAD and a potential target for intervention.

Effect of continuous low-dose intravenous diltiazem on epidural fentanyl analgesia after lower abdominal surgery.

BACKGROUND: The postoperative opioid-sparing effects of systemic L-type calcium channel blockers are controversial. We investigated whether the postoperative analgesic effect of epidural fentanyl was enhanced by i.v. infusion of diltiazem at a rate that would minimize any cardiovascular depressant effect. METHODS: After elective lower abdominal gynaecological surgery, 30 patients were randomized to receive continuous i.v. diltiazem 1 micro g kg(-1) min(-1) (diltiazem group) or the same volume of saline (control group) for 24 h. Cumulative postoperative epidural fentanyl consumption, visual analogue scale (VAS) scores and verbal rating scores (VRS) at rest and during mobilization, sedation scores, incidence of side-effects and overall patient satisfaction were assessed. RESULTS: There was no significant difference in cumulative epidural fentanyl consumption between the groups at any period. Although there were no statistically significant differences in VAS scores, VRS, sedation scores, incidence of side-effects and overall patient satisfaction, there was a trend to an increased incidence of nausea in the diltiazem group. CONCLUSIONS: Continuous i.v. infusion of diltiazem did not reduce epidural fentanyl consumption when administered at dosages having minimal haemodynamic depressant effects.

Suppression of oxidative stress after transient focal ischemia in interleukin-1 knock out mice.

Interleukin-1 (IL-1) contributes to ischemic neurodegeneration. However, the mechanisms regulating action of IL-1 are still poorly understood. In order to clarify this central issue, mice that were gene deficient both IL-1alpha and beta (IL-1 KO) and wild-type mice were subjected to 1 hour transient middle cerebral artery occlusion (tMCAO). The concentration of 8-hydroxy deoxyguanosine (8OHdG) which is considered to be a reliable oxidative DNA damage by superoxide anion, in brain and of total nitric oxide (NO) in plasma were determined by use of HPLC. Twenty-four hours after tMCAO, the ratio of 8OHdG to dG in the ipsilateral hemisphere of wild-type mice were 2.24 x 10(-3) and 4.41 x 10(-3) in the neocortex and striatum, respectively. The concentration of 8OHdG in the ipsilateral hemisphere of the wild-type mice was higher than that of the IL-1 KO mice. The concentration of total NO in the plasma of IL-1 KO mice was also lower than that of the wild-type 24 hours after tMCAO. These results strongly suggest that IL-1 is participated in generating reactive oxygen spices and it aggravates and induces the ischemic neuronal cell death.(183 words).

Expression of metabotropic glutamate receptor mRNAs in the human spinal cord: implications for selective vulnerability of spinal motor neurons in amyotrophic lateral sclerosis.

To elucidate the relevance of metabotropic glutamate receptors (mGluRs) to the selective vulnerability of motor neurons in the spinal cord in patients with amyotrophic lateral sclerosis (ALS), we investigated the distribution of mRNAs coding mGluR1-5 in the normal human spinal cord. The mRNAs for mGluR1, 4 and 5 were observed in the spinal gray matter, whereas mGluR2 mRNA was absent in the spinal cord and mGluR3 mRNA was displayed only on glial cells in the white matter. Signals for mGluR1 and mGluR5 were enriched in the dorsal horn, while mGluR4 mRNA was abundant in the ventral horn. Since agonists to group I mGluRs (mGluR 1 and 5) have been demonstrated to have neuroprotective effects on spinal motor neurons, less expression of mRNAs coding mGluR1 and mGluR5 in the ventral horn than in the dorsal horn may be implicated in the selective susceptibility of spinal motor neurons in ALS.

Dipole orientation differs between high frequency oscillations and N20m current sources in human somatosensory evoked magnetic fields to median nerve stimulation.

The dipole orientation of equivalent current source for the high frequency oscillations (HFOs) above 300 Hz and that for the underlying N20m were compared. Somatic magnetic fields were recorded over the left hand somatosensory area to right median nerve stimulation at the wrist with a wide-bandpass (0.1-2000 Hz). The HFOs and underlying N20m were extracted by digital filtering of 300-900 Hz and 1-300 Hz, respectively. We found that the orientation of the HFOs and underlying N20m current sources differs and that the HFO source orientation shows a more divergent pattern than the N20m. These results suggest that the somatosensory HFOs are not generated from the pyramidal cell population in area 3b which produces the underlying N20m and that they may reflect activities of the non-pyramidal neuron population.

[A case of acute sensory neuropathy associated with cytomegalovirus infection].

We report a non-compromised patient with acute sensory neuropathy (ASN) developed following cytomegalovirus (CMV) hepatitis. A 67-year-old man admitted to a hospital because of acute hepatic dysfunction accompanying fever and skin eruption. One month later, when hepatic function normalized, numbness and clumsiness started acutely first in the right upper limb next to all the extremities. He found difficulty in walking in a couple of weeks. One month after the commencement of neurological illness, he was referred to us. On examination, he had sensory limb ataxia. His gait was wide-based, and Romberg sign was positive. Position sense was severely diminished in the extremities. Skin sensation was also attenuated distally, while no motor weakness was noted. Tendon reflexes were almost absent. Nerve conduction studies revealed absent sensory potentials in all but the left median nerve, in which amplitude was 5.5 microV with sensory conduction velocity of 40.7 m/s. Motor conduction studies, on the other hand, appeared normal except for a slight focal delay in the right ulnar nerve across the elbow. Mild increase in F-wave latencies was noted. A sural nerve specimen taken two months after the neurological onset showed a marked decrease in myelinated fiber density and active fiber degenerations accompanying axonal sproutings. Sjögren syndrome and paraneoplastic neuropathy were excluded serologically and by comprehensive imaging techniques. Although IgM anti-CMV antibody was not detected, serum IgG anti-CMV antibody was positive and significantly increased during the neurological illness. The intrathecal antibody synthesis of IgG anti-CMV antibody was suggested by a low serum/cerebrospinal fluid (CSF) antibody ratio and a high CSF IgG index. From these observations, it was strongly suggested that acute hepatitis and subsequent ASN were associated with CMV infection in this patient. Although some cases with post-infectious ASN have been previously reported, this is the first report of ASN preceded by CMV infection.

Fluoxetine reduces L-DOPA-derived extracellular DA in the 6-OHDA-lesioned rat striatum.

We investigated the effect of fluoxetine, a selective serotonin reuptake inhibitor (SSRI), on L-DOPA-derived extracellular dopamine (DA) levels in the striatum of rats with nigrostriatal dopaminergic denervation using in vivo microdialysis. Treatment with fluoxetine (10 mg/kg, i.p.) induced a 41% reduction in the cumulative amount of extracellular DA during 300 min following L-DOPA administration (50 mg/kg, i.p.; p < 0.01). This effect was antagonized by pretreatment with WAY-100635, a potent 5-HT1A antagonist, indicating that this effect of fluoxetine is due to its indirect 5-HT1A agonistic property. These results suggest that SSRIs may impair motor functions in patients with Parkinson's disease by reducing efflux of exogenous L-DOPA-derived DA.

[Recurrence of bullous pemphigoid after surgery: report of a case].

We report a 38-year-old woman with myoma uteri and bullous pemphigoid controlled by oral prednisolone (7.5 mg.day-1). She underwent transabdominal hysterectomy under epidural anesthesia using mepivacaine supplemented with intravenous midazolam and butorphanol, without untoward event. On the postoperative day 2, recurrence of bullous pemphigoid was noted. The skin lesion of pemphigoid was improved after increasing the prednisolone dose up to 60 mg a day.