The Transverse Galvanomagnetic Properties of Dilute Bi-Sn, Bi-Te and Bi-As Alloys

The measurements were made on the transverse galvanomagnetic effects of dilute Bi-Sn, Bi-Te and Bi-As alloys at 4.2°K. These electrical properties showed remarkable differences in the concentration dependence of the impurities depending on their valencies. These galvanomagnetic effects were studied in terms of the ellipsoidal model of pure bismuth. From the Hall effect measurement on Bi-Sn alloys as a function of tin concentration, the direct energy gap between the conduction and the valence band was estimated to be about 0.029 eV

The Longitudinal Magnetoresistance of Bismuth Single Crystals in Strong Magnetic Fields

The longitudinal magnetoresistance of bismuth single crystals is studied at 289°, 77.4°and 4.2°K in magnetic fields up to 80 kilo-oersted. The size effect of resistance cannot be observed at room temperature, but is observed at temperatures of liquid nitrogen and liquid helium, and the anomalous negative magnetoresistance is found at helium temperature. Especially in the case of ρ_(z) which is obtained under the condition of the magnetic field and the electric current perpendicular to the cleavage plane of the crystal, a negative longitudinal magnetoresistance is observed

Transverse Galvanomagnetic Effect of Bismuth Single Crystal in a Strong Magnetic Field

Transverse galvanomagnetic effects of bismuth single crystal are measured in a strong magnetic field up to about 100 kilo Oersted at 4.2, 3.0 and 1.8K. And the twelve components of the galvanomagnetic tensor are obtained with respect to the magnetic field dependence. Furthermore the behaviors of the galvanomagnetic tensor components near the quantum limit of the magnetic quantization are studied, expecting that they can lend themselves to analyse the energy band structure. In a strong magnetic field, the amplitudes of the oscillatory part of the galvanomagnetic tensors are nearly temperature independent, and the behaviors of Hall effect appear to be different from the expected one from the classical theory of the two bands model

Crystallographic Anisotropy of Galvanomagnetic Effects in Antimony Single Crystals

Twelve components of the galvanomagnetic tensor in antimony single crystals are measured in a magnetic field up to 10 kilo-oersted at 4.2°and 20.4°K. The complicated results with regard to the anisotropy of the transverse magnetoresistance are understood by the tilted ellipsoidal model for Fermi surface of electron, and both of the anisotropy of the transverse magnetoresistance and the positive Hall voltage are explained on the assumption of the existence of a very light hole

Infrared Absorption and Faraday Effect in PbTe and PbSe

Free carrier absorption and Faraday effect in p-type PbSe, n- and p-type PbTe were measured in the wavelength range from 3 to 15 microns at room temperatures. The effective masses of electrons for PbTe and of holes for PbSe were deduced to be 0.11 m_0 and 0.14 m_0, respectively, and the ratios of the longitudinal to the transverse masses associated with the ellipsoidal energy surfaces were evaluated. It was concluded that four equivalent extrema exist along directions on the hole energy surface of PbSe, and this result is consistent with the similarity between the absorption characteristics of p-type PbSe and that of n-type PbTe

The de Haas-van Alphen Effect of n-Type Cd_3As_2

A study of the de Haas-van Alphen (dHvA) effect of Cd_3As_2 by the torque method is presented. One kind of the dHvA oscillations was observed in the (100) plane with fields up to 20 KG in the temperature range between 1.5 and 4.2°K. From the analysis of the dHvA oscillations, it was revealed that the Fermi surface of electrons is a revolution ellipsoid elongated along the c-(4-fold) axis. The effective mass ratio, m_〓^*/m_〓 of 0.034, 0.040 and 0.052 and the anisotropy factor m_〓^*/m_〓^* of 1.22, 1.18 and 1.13 have been obtained for the electron concentration of 2.05×10^, 2.20×10^ and 4.44×10^ cm^, respectively. These effective mass ratio and the anisotropy factor dependences on the electron concentration may suggest a non-parabolicity in the conduction band

Effect of Polyethylene Glycol Conjugated Superoxide Dismutase on Hepatic Ischemia/Reperfusion Injury in Rats

Superroxide anion radical (02-) has been suggested as a causative factor of ischemia/reperfusion injury to the liver. Superxide dismutase (SOD)is a specific scavenger for 02, but its elimination half life in the blood is about five min. Polyethylene glycol conjugated SOD (PEG-SOD) has a chracteristics of long half life (14hr) in the circulating blood and low immunogenicity. In the present study, we compared the effect of PEG-SOD to conventional SOD in protecting the ischemia/reperfusion injury to the liver. In rats with an occluded inflow against 70% of the liver for 30min followed by 30min reperfusion, elevations of serum aspartate aminotransferase and alanine aminotransferase,and lipid peroxide concentrations in the liver were not significantly inhibited by intravenous administration of PEG-SOD, compared to those treated with conventional SOD. These results indicate that sustained presence of radical scavenger activity in the circulating blood has no more beneficial effects on hepatic ischemia/reperfusion injury than its temporary presence when reperfusion begins

Cricotracheostomy for patients with severe COVID-19: A case control study

BackgroundTracheostomy is an important procedure for the treatment of severe coronavirus disease-2019 (COVID-19). Older age and obesity have been reported to be associated with the risk of severe COVID-19 and prolonged intubation, and anticoagulants are often administered in patients with severe COVID-19; these factors are also related to a higher risk of tracheostomy. Cricotracheostomy, a modified procedure for opening the airway through intentional partial cricoid cartilage resection, was recently reported to be useful in cases with low-lying larynx, obesity, stiff neck, and bleeding tendency. Here, we investigated the usefulness and safety of cricotracheostomy for severe COVID-19 patients.Materials and methodsFifteen patients with severe COVID-19 who underwent cricotracheostomy between January 2021 and April 2022 with a follow-up period of ≥ 14 days were included in this study. Forty patients with respiratory failure not related to COVID-19 who underwent traditional tracheostomy between January 2015 and April 2022 comprised the control group. Data were collected from medical records and comprised age, sex, body mass index, interval from intubation to tracheostomy, use of anticoagulants, complications of tracheostomy, and decannulation.ResultsAge, sex, and days from intubation to tracheostomy were not significantly different between the COVID-19/cricotracheostomy and control/traditional tracheostomy groups. Body mass index was significantly higher in the COVID-19 group than that in the control group (P = 0.02). The rate of use of anticoagulants was significantly higher in the COVID-19 group compared with the control group (P < 0.01). Peri-operative bleeding, subcutaneous emphysema, and stomal infection rates were not different between the groups, while stomal granulation was significantly less in the COVID-19 group (P = 0.04).ConclusionsThese results suggest that cricotracheostomy is a safe procedure in patients with severe COVID-19

Survey of understanding and awareness of fertility preservation in pediatric patients: Is conversation about fertility preservation unpleasant for pediatric patients?

ObjectiveTo verify understanding and awareness of fertility preservation (FP) in pediatric patients undergoing FP treatments.MethodsA questionnaire survey was conducted before and after explanation of fertility issues and FP treatments for patients 6–17 years old who visited or were hospitalized for the purpose of ovarian tissue cryopreservation (OTC) or oocyte cryopreservation (OC), or sperm cryopreservation between October 2018 and April 2022. This study was approved by the institutional review board at St. Marianna University School of Medicine (No. 4123, UMIN000046125).ResultParticipants in the study comprised 36 children (34 girls, 2 boys). Overall mean age was 13.3 ± 3.0 years. The underlying diseases were diverse, with leukemia in 14 patients (38.9%), brain tumor in 4 patients (11.1%). The questionnaire survey before the explanation showed that 19 patients (52.8%) wanted to have children in the future, but 15 (41.7%) were unsure of future wishes to raise children. And most children expressed some degree of understanding of the treatment being planned for the underlying disease (34, 94.4%). Similarly, most children understood that the treatment would affect their fertility (33, 91.7%). When asked if they would like to hear a story about how to become a mother or father after FP which including information of FP, half answered “Don’t mind” (18, 50.0%). After being provided with information about FP treatment, all participants answered that they understood the adverse effects on fertility of treatments for the underlying disease. Regarding FP treatment, 32 children (88.9%) expressed understanding for FP and 26 (72.2%) wished to receive FP. “Fear” and “Pain” and “Costs” were frequently cited as concerns about FP. Following explanations, 33 children (91.7%) answered “Happy I heard the story” and no children answered, “Wish I hadn’t heard the story”. Finally, 28 of the 34 girls (82.4%) underwent OTC and one girl underwent OC.DiscussionThe fact that all patients responded positively to the explanations of FP treatment is very informative. This is considered largely attributable to the patients themselves being involved in the decision-making process for FP.ConclusionsExplanations of FP for children appear valid if age-appropriate explanations are provided