Magnetocaloric Effects in Metamagnetic Shape Memory Alloys

Recently, metamagnetic shape memory alloys have attracted much attention as candidates for the rare-earth free magnetic refrigerants. These materials undergo the martensitic transformation (MT) at around room temperature accompanied by a significant entropy change. The application of the magnetic field at the low-temperature martensitic phase realizes the magnetic field-induced martensitic transformation (MFIMT). Through the MFIMT, the materials show an unconventional magnetocaloric effect (MCE), which is called inverse magnetocaloric effect (IMCE). In this chapter, the direct measurement system of MCE in pulsed-high-magnetic fields is introduced. With taking the advantage of the fast field-sweep rate of pulsed field, adiabatic measurements of MCE are carried out at various temperatures. Using this technique, the IMCEs of the metamagnetic shape memory alloys NiCoMnIn and NiCoMnGa are directly measured as adiabatic temperature changes in pulsed fields. From the experimental data of MCE for NiCoMnIn, the entropy of spin system in the austenite phase is estimated through a simple mean-field model. By the combination of MCE, magnetization and specific heat measurements, the electronic, lattice and magnetic contributions to the IMCE are individually evaluated. The result for NiCoMnIn demonstrates that lattice entropy plays the dominant role for IMCE in this material

The acute effects of diazepam and sodium valproate on the human SEP (Somatosensory Evoked Potential) and EEG

The acute effects of diazepam (DZP) and sodium valproate (VPA) on somatosensory evoked potential (SEP) were studied with 16 healthy male subjects (26~43 y. o.). In the two experimental sessions on different days, DZP (0.1 mg/kg) or VP A (5 mg/kg) was orally administered for each subjects. EEGs containing SEPs evoked by electric stimuli once every 5 sec were derived from the two derivations (monopolar : C3'→A1+2, bipolar : C3'→F3') and recorded into magnetic tape, before and 30, 60, and 90 min after the administration of these drugs. Reproducing the tape, SEPs with 1024 msec of analysis time were obtained by averaging 100 responses, and EEGs were subjected to the frequency analysis. Consecutive changes of group mean SEP were studied. Individual SEPs were subjected to the component analysis, and to the statistical assessment together with EEG. The following results were obtained. 1. After the administration of DZP, amplitudes of middle and long latency compenent significantly decreased and continued from early stage. The latencies were significantly increased and recovered for the middle latency component (P3~N4), while decreased for those of long latency component (N5~) later. After administration of DZP, in EEG, the power % were significantly increased for not only drug induced β but also δ and θ, and they had significant positive correlation with the latencies of middle latency component. These results suggest that DZP has the transient inhibitory effect to brainstem reticular formation, thalamus and hypothalamus, and continuous inhibitory effect to cerebral gray matter from early stage, and might facilitate transmission in cerebral white matter through GABA neuron system. 2. After the administration of VPA, the latencies did not significantly change for latencies of middle latency component, but increased for these of long latency component (P6~). Amplitudes of middle and long latency components decreased significantly. In EEG, the power % were significantly increased for α1 and decreased for β2. These results suggest that VPA has no or weak effect to brainstem reticular formation, thalamus and hypothalamus, while it has the inhibitory effect to cerebral gray matter through GABA neuron system

HLPおよびDZPのVEPおよび脳波への急性効果

The acute effects of haloperidol (HLP) and diazepam (DZP) on the Visual Evoked Potential (VEP) and EEG were studied with 16 healthy male subjects (26~43 y.o.). In the two experimental session for each subject, HLP (0.02 mg/kg) were intra-venously and DZP (0.1 mg/kg) were per-orally administered. EEGs and VEPs were recorded through the two derivations (2 ch : O1→A1+2, 5 ch : O1→Cz), with 1024 msec of analysis time, averaging 100 responses. In the experimental session, EEGs and VEPs were recorded before and 15, 30, and 45 min after administration of HLP, before and 30,60, and 90 min after DZP. Consecutive change of group mean VEP were studied. Individual VEPs were subjected to the component analysis, and to the statistical assessment together with EEG. The following results were obtained. 1. After the administration of HLP, the latencies of short, middle and long latency component significantly increased, and the peak-to-peak amplitude N 1-P 2, P 5-N 5 and N 5-P 6 significantly decreased. The largest peak-to-peak amplitude P 4-N 7 significantly increased. In EEG, δ and θ-power% increased, and α2-power% decreased significantly. Significant positive correlation was found between δ, θ-power% of EEG and VEP latencies, and significant negative correlations was found between α2-power% and VEP latencies. These findings indicate the inhibitory effect of HLP all over the visual system through dopaminergic neuron system. The largest peak-to-peak amplitude (P 4-N 7) increased significantly synchronizing with increased θ waves. 2. After the administration of DZP, the latencies of short and middle latency component, P 3 and P 5, increased, P 2 latency decreased significantly. The peak-to-peak amplitude P 3-N 3, N 3-P 4, P 5-N 5, and N 5-P 6 decreased, N 2-P 3 amplitude increased significantly. In EEG, β1-power% increased, and α2-power% decreased significantly. Significant negative correlation was found between δ, θ-power% of EEG and VEP amplitudes, and positive correlations between α2-power% and VEP amplitudes. These findings indicate the inhibitory effect of DZP mainly on lateral geniculate body, optic radiation, and up to the visual cortex making BZD-receptor and GABA-receptor complex. Some exciting effect of DZP before the lateral geniculate body was suggested

An application of wavelet analysis to the human cerebral evoked potential

Adopting Wavelet analysis for the analysis of the waveform of EP (Evoked Potential), it was intended to confirm possibility of the subjective diagnosis for schizophrenia, epilepsy and healthy subject. 1. Each waveform of EPs (SEP, VEP and AEP) of 100 healthy male subjects (25.4±3.1 y.o.), 100 male schizophrenics (31.6± 10.4 y.o.) and 99 male epileptics (35.9± 13.1 y.o.) were subjected to the Wavelet analysis and the multiresolution analysis. As a result, the difference of Wavelet values among these subject groups were verified significantly. The Wavelet values was defined as the square means of each wavelet coefficients at each scale of multiresolution analysis. 2. The waveform of EPs of each subject were discriminated by use of discriminant method derived from Wavelet Function, in order to judge to which subject group the subject belongs, according to the wavelet values. Analyzing the waveform of EP, between 15~600msec of latency, the highest value of sensitivity, 89%, 87% and 88% was obtained for normal subject, schizophrenics and epileptics, respectively. As the conclusion, the possibility of the subjective diagnosis for schizophrenia, epilepsy, and normal subjects, by Wavelet analysis of EP waveform, were verified possible

Variation in Dehydration Tolerance, ABA Sensitivity and Related Gene Expression Patterns in D-Genome Progenitor and Synthetic Hexaploid Wheat Lines

The wild wheat Aegilops tauschii Coss. has extensive natural variation available for breeding of common wheat. Drought stress tolerance is closely related to abscisic acid (ABA) sensitivity. In this study, 17 synthetic hexaploid wheat lines, produced by crossing the tetraploid wheat cultivar Langdon with 17 accessions of Ae. tauschii, were used for comparative analysis of natural variation in drought tolerance and ABA sensitivity. Ae. tauschii showed wide natural variation, with weak association between the traits. Drought-sensitive accessions of Ae. tauschii exhibited significantly less ABA sensitivity. D-genome variations observed at the diploid genome level were not necessarily reflected in synthetic wheats. However, synthetic wheats derived from the parental Ae. tauschii accessions with high drought tolerance were significantly more tolerant to drought stress than those from drought-sensitive accessions. Moreover, synthetic wheats with high drought tolerance showed significantly higher ABA sensitivity than drought-sensitive synthetic lines. In the hexaploid genetic background, therefore, weak association of ABA sensitivity with drought tolerance was observed. To study differences in gene expression patterns between stress-tolerant and -sensitive lines, levels of two Cor/Lea and three transcription factor gene transcripts were compared. The more tolerant accession of Ae. tauschii tended to accumulate more abundant transcripts of the examined genes than the sensitive accession under stress conditions. The expression patterns in the synthetic wheats seemed to be additive for parental lines exposed to drought and ABA treatments. However, the transcript levels of transcription factor genes in the synthetic wheats did not necessarily correspond to the postulated levels based on expression in parental lines. Allopolyploidization altered the expression levels of the stress-responsive genes in synthetic wheats

The acute effects of antidepressants on the human VEP and EEG

The acute effects of clomipramine hydrochloride (CMI), tricyclic antidepressant, were studied and compared with those of mianserin hydrochloride (MSR), tetracyclic antidepressant, by visual evoked potential (VEP), with each 16 and 12 healthy male subjects, respectively. In the two experimental session on different days, CMI (0.5mg/kg) or MSR (0.3mg/kg) were orally administered for each subject. EEGs containing VEPs evoked by flash stimuli once every 5sec were derived from the two derivations (2ch : O1→ A1 + 2, 5ch : O1→Cz) and recorded into magnetic tape. Reproducing the tape, VEPs before and 120min after the administration of each drug, with 1024msec of analysis time, were obtained by averaging 100 responses, and EEGs were subjected to the frequency analysis. The changes of the waveform of group mean VEP were studied and compared between these drugs. Individual VEPs were subjected to the component analysis, and to the statistical assessment together with EEG. The following, statistically significant, results were obtained. 1. After the administration of CMI, both latencies and peak-to-peak amplitudes of VEP did not significantly change. In EEG, the power% of α1 frequency band increased. These findings indicate that few effect of CMI on the visual system. 2. After the administration of MSR, latencies of short latency components (P3 and N3) significantly increased and peak-to-peak amplitudes of short latency components (P3-N3 and N3-P4) significantly decreased in VEP. In EEG, the power% of δ and θ frequency band increased, and that of α2 and β2 decreased. These findings indicate the inhibitory effect of MSR mainly on the lateral geniculate body and the optic radiation in the visual system. 3. From these results, it was considered that CMI has less effect on depression with anxiety or irritability than MSR

The acute effects of antidepressant on the human SEP (Somatosensory Evoked Potential) and EEG

The acute effects of clomipramine hydrochloride (CMI) and mianserin hydrochloride (MSR) on somatosensory evoked potential (SEP) were studied with each 12 and 16 healthy male subjects, respectively. In the two experimental sessions, CMI (0.5mg/kg) or MSR (0.3mg/ kg) was orally administered for each subject. EEGs containing SEPs evoked by electric stimuli, once every 5 sec, were derived from the two derivations (monopolar : C3'→A1+2, bipolar : C3'→F3'), and recorded into magnetic tape. Reproducing the tape, SEPs before and 120 min after the administration of these drugs, with 1024 msec of analysis time, were obtained by averaging 100 responses, and EEGs were subjected to the frequency analysis. The changes of the waveform of group mean SEP were studied. Individual SEPs were subjected to the component analysis, and to the statistical assessment together with EEG. The following, statistically significant (P<0.01, P<0.05), results were obtained. 1. After the administration of CMI, the latencies were significantly decreased for the early middle latency component (P2 and N2), and significantly increased for the long latency component (monopolar : P6~, bipolar : P7~). While those of late middle latency component (P4~P5) did not change significantly. The amplitudes of middle latency component (P3 and P4) increased significantly. In EEG, the power % were significantly increased for α1. In conclusion, stimulatory properties of CMI was verified by SEP. 2. After the administration of MSR, the latencies were significantly increased for the almost all middle and long latency component. The amplitudes of middle and long latency components (N4, P5 and P6) decreased significantly. In EEG, the power % were significantly increased for δ and θ, and significantly decreased for α2 and β2. In conclusion, sedative properties of MSR was verified by SEP