Isotropic Conduction Network and Defect Chemistry in Mg3+δ Sb2 -Based Layered Zintl Compounds with High Thermoelectric Performance.

Thermoelectric performance in the layered Zintl phase n-type Mg3+δ (Sb,Bi)2 is reported. Insertion of the excess Mg into the compounds is crucial for realizing n-type carrier transport with multivalley and isotropic character. An excellent ZT of 1.51 ± 0.06 at 716 K is achieved in the sintered polycrystals at the composition of Mg3.2 Sb1.5 Bi0.49 Te0.01 .

Locally enhanced conductivity due to the tetragonal domain structure in LaAlO3/SrTiO3 heterointerfaces.

The ability to control materials properties through interface engineering is demonstrated by the appearance of conductivity at the interface of certain insulators, most famously the {001} interface of the band insulators LaAlO3 and TiO2-terminated SrTiO3 (STO; refs 1, 2). Transport and other measurements in this system show a plethora of diverse physical phenomena. To better understand the interface conductivity, we used scanning superconducting quantum interference device microscopy to image the magnetic field locally generated by current in an interface. At low temperature, we found that the current flowed in conductive narrow paths oriented along the crystallographic axes, embedded in a less conductive background. The configuration of these paths changed on thermal cycling above the STO cubic-to-tetragonal structural transition temperature, implying that the local conductivity is strongly modified by the STO tetragonal domain structure. The interplay between substrate domains and the interface provides an additional mechanism for understanding and controlling the behaviour of heterostructures.

Measurement of the femtosecond optical absorption of LaAlO3/SrTiO3 heterostructures: evidence for an extremely slow electron relaxation at the interface.

The photocarrier relaxation dynamics of an n-type LaAlO3/SrTiO3 heterointerface is investigated using femtosecond transient absorption (TA) spectroscopy at low temperatures. In both LaAlO3/SrTiO3 heterostructures and electron-doped SrTiO3 bulk crystals, the TA spectrum shows a Drude-like free carrier absorption immediately after excitation. In addition, a broad absorption band gradually appears within 40 ps, which corresponds to the energy relaxation of photoexcited free electrons into self-trapped polaron states. We reveal that the polaron formation time is enhanced considerably at the LaAlO3/SrTiO3 heterointerface as compared to bulk crystals. Further, we discuss the interface effects on the electron relaxation dynamics in conjunction with the splitting of the t2g subbands due to the interface potential.

Scanning probe manipulation of magnetism at the LaAlO3/SrTiO3 heterointerface.

Manipulation of magnetism is a longstanding goal of research in exotic materials. In this work, we demonstrate that the small ferromagnetic patches in LaAlO(3)/SrTiO(3) heterostructures can be dramatically changed by in situ contact of a scanning probe. Our results provide a platform for manipulation of small magnets through either a strong magneto-elastic coupling or sensitivity to surface modification. The ability to locally control magnetism is particularly interesting due to the presence of superconductivity with strong spin-orbit coupling in LaAlO(3)/SrTiO(3).

Critical thickness for ferromagnetism in LaAlO3/SrTiO3 heterostructures.

In LaAlO(3)/SrTiO(3) heterointerfaces, charge carriers migrate from the LaAlO(3) to the interface in an electronic reconstruction. Magnetism has been observed in LaAlO(3)/SrTiO(3), but its relationship to the interface conductivity is unknown. Here we show that reconstruction is necessary, but not sufficient, for the formation of magnetism. Using scanning superconducting quantum interference device microscopy we find that magnetism appears only above a critical LaAlO(3) thickness, similar to the conductivity. We observe no change in ferromagnetism with gate voltage, and detect ferromagnetism in a non-conducting p-type sample. These observations indicate that the carriers at the interface do not need to be itinerant to generate magnetism. The ferromagnetism appears in isolated patches whose density varies greatly between samples. This inhomogeneity strongly suggests that disorder or local strain generates magnetism in a population of the interface carriers.

Development of a method for assessing flood vulnerability.

Over the past few decades, a growing number of studies have been conducted on the mechanisms responsible for climate change and the elaboration of future climate scenarios. More recently, studies have emerged examining the potential effects of climate change on human societies, including how variations in hydrological regimes impact water resources management. According to the Intergovernmental Panel on Climate Change's third assessment report, climate change will lead to an intensification of the hydrological cycle, resulting in greater variability in precipitation patterns and an increase in the intensity and frequency of severe storms and other extreme events. In other words, climate change will likely increase the risks of flooding in many areas. Structural and non-structural countermeasures are available to reduce flood vulnerability, but implementing new measures can be a lengthy process requiring political and financial support. In order to help guide such policy decisions, a method for assessing flood vulnerability due to climate change is proposed. In this preliminary study, multivariate analysis has been used to develop a Flood Vulnerability Index (FVI), which allows for a comparative analysis of flood vulnerability between different basins. Once fully developed, the FVI will also allow users to identify the main factors responsible for a basin's vulnerability, making it a valuable tool to assist in priority setting within decision-making processes.

Comparison of the LMA-ProSeal and LMA-Classic in children.

BACKGROUND: The LMA-ProSeal is a new laryngeal mask airway with a rear cuff and drainage tube that allows a higher seal pressure than the LMA-Classic for the same intra-cuff pressure, and it permits drainage of gastric secretions and access to the alimentary tract. The LMA-ProSeal can be used in children but it does not have a rear cuff. This study compared the LMA-ProSeal and the LMA-Classic in children for ease of insertion, airway sealing pressure and fibre-optic visualization. METHODS: Sixty ASA I-II children undergoing herniorrhaphy, orchiopexy or myringotomy were included. The patients were randomly assigned to size 2 LMA-Classic trade mark or size 2 LMA-ProSeal groups for airway management. We assessed success rates at first attempt of insertion, airway sealing pressure, fibre-optic position, success rates of gastric tube placement and postoperative blood staining of the device, tongue-lip-dental trauma and hoarseness. RESULTS: There was no statistical difference between the two groups for the success rates at first attempt of insertion, airway sealing pressure and fibre-optic position. Gastric tube insertion was successful in 90% of cases in the LMA-ProSeal group. The LMA-Classic had a higher rate of postoperative blood staining, but there was no tongue-lip-dental trauma or hoarseness in either group. CONCLUSION: We conclude that ease of insertion and airway sealing pressure are similar between the LMA-ProSeal and the LMA-Classic in children.

Inversion and isomerization of Asp-58 residue in human alphaA-crystallin from normal aged lenses and cataractous lenses.

We have previously shown that L-Asp-151 in alphaA-crystallin from the human lens is converted to the biologically uncommon D-isomer. This process was not simple racemization, but stereoinversion, accompanied by isomerization to form the beta-Asp residue, such that L-beta-Asp, D-alpha-Asp and D-beta-Asp were formed. The present study shows that Asp-58 of human alphaA-crystallin is also converted to the D-isomer to a high degree to form the same isomers with age. The D/L ratio of beta-Asp-58 in aged normal lens increased to more than 3.0, showing stereoinversion by the 60 year range, then decreased to 1.0 in the 80 year range, while the isomerization of Asp-58 increased in the 80 year range. We also measured inversion and isomerization of the same residue from cataractous and normal human lenses of the 60 year range. The D/L ratio of Asp-58 from cataractous lenses was significantly lower than that from normal lenses, while the isomerization at Asp-58 in cataractous alphaA-crystallin was significantly higher than that of normal alphaA-crystallin. These results indicate that isomerization to the beta isomer of Asp-58 in cataractous alphaA-crystallin increased more than inversion to the D-isomer, suggesting that there are changes in the native structure of alphaA-crystallin in the human cataractous lens.

Correlation between the loss of the chaperone-like activity and the oxidation, isomerization and racemization of gamma-irradiated alpha-crystallin.

Alpha-crystallin possesses a molecular chaperone-like activity that prevents proteins from aggregating; however, the mechanism of this activity is not well known. Here we have taken gamma-irradiated alpha-crystallin and studied the relationship between the decrease in chaperone-like activity and the modifications such as oxidation, isomerization and racemization of amino acids in this molecule. We found that the chaperone-like activity of alpha-crystallin decreased with increasing gamma irradiation. After 4000 Gy gamma irradiation the activity of alpha-crystallin was reduced to 40% of the level of nonirradiated, native alpha-crystallin. The circular dichroism spectrum showed that the secondary structure of the irradiated alpha-crystallin had not changed. However, its tertiary structure appeared to change following more than 1000 Gy irradiation. Sodium dodecyl sulfatepolyacrylamide gel electrophoresis also indicated that cross-linking of alpha-crystallin increased with increasing radiation doses. Irradiated and nonirradiated alpha-crystallin was subjected to trypsin digestion and peptide analysis by reverse-phase high-performance liquid chromatography and mass and sequence analysis. Depending on the radiation dose, Met-1 of alpha A-crystallin was oxidized to methionine sulfoxide. In addition, Asp-151 of alpha A-crystallin was isomerized to the beta-Asp form after irradiation, and racemization of Asp-151 decreased. Thus, the loss of the chaperone-like activity of alpha-crystallin is related to changes in its isomerization, oxidation and racemization.

[Analysis of difficult tracheal intubation in patients with first and second brachial arch syndrome].

We experienced 87 anesthetic managements of 26 patients with first and second brachial arch syndrome in the past 20 years. We analyzed retrospectively the occurrence of difficulty in tracheal intubation with these patients. The incidence of difficult intubation was as high as 39.5% of the cases. Furthermore it was quite difficult to place endotracheal tube, especially in younger children undergoing oral procedure. We examined the correlation among classification of mandibular hypoplasia (Pruzansky classification), the fusion of cervical spines and the degrees of difficulty in intubation for 16 patients who had had radiographs of skull, but we found no correlation among them. But in all the 3 patients with the fusion of cervical spines, intubation was difficult. Therefore, we must perform radiographic assessment of the fusion of the cervical spine.

Influence of head and neck position on cuff position and oropharyngeal sealing pressure with the laryngeal mask airway in children.

We studied how head and neck position affect the cuff position and oropharyngeal sealing pressures of the laryngeal mask airways (LMAs) in children. We studied 39 non-paralyzed healthy children aged 1.5-8.0 yr, weighing 10.3-27.0 kg, managed with size 2 or 2.5 LMAs during elective surgery. Head and neck movements did not adversely affect airway patency in 97% of patients. One child developed apparent airway obstruction with head and neck flexion, which was relieved in the neutral position. Oropharyngeal sealing pressure was significantly greater during neck flexion compared with the neutral position (P<0.02). Fibreoptic examination revealed that the epiglottis covered a larger area of the LMA aperture during neck flexion, compared with the neutral position (P<0.02).

Comparison of d-aspartic acid contents in alpha A-crystallin from normal and age-matched cataractous human lenses.

We have previously shown that biologically uncommon d-beta-aspartic acids (Asp) were localized with very high contents at Asp-151 and Asp-58 of alpha A-crystallin from aged human lenses. The amounts increased with age, and we have proposed the mechanism of this reaction. In the present study, in order to elucidate the possible relationship between the formation of d-beta-aspartic acids in alpha A-crystallin and cataract formation, we measured the d/l ratio of beta-Asp-151 of alpha A-crystallin from both cataractous and age-matched normal human lenses. alpha A-crystallin from total proteins of cataractous and age-matched normal lenses was prepared, followed by tryptic digestion and quantification of d/l ratios for tryptic fragments containing the alpha- and beta-aspartate forms of Asp-151 residues. The results demonstrate that the d/l ratio of beta-Asp-151 of alpha A-crystallin from normal lenses is not statistically significant from that of alpha A-crystallin from cataractous lenses, suggesting that formation of this biologically uncommon amino acid may not play a role in human cataractogenesis.

Anaesthetic management of children with congenital insensitivity to pain with anhidrosis.

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare sensory neuropathy, which affects patients' pain sensation and thermoregulation. There are several issues to consider when planning anaesthesia for those with this congenital disorder. Over a 20-year period, six patients with CIPA underwent 20 surgical procedures under general anaesthesia in our institution. We analysed our experience with these patients retrospectively. We conclude that patients with CIPA are able to undergo surgical procedures under general anaesthesia without major problems.

Formation of four isomers at the asp-151 residue of aged human alphaA-crystallin by natural aging.

Although proteins are generally composed entirely of l-amino acids, we have previously shown that Asp-151 in alphaA-crystallin from aged human lens is converted to the biologically uncommon d-isomer to a high degree. The formation of d-isomer was not simple racemization, but stereoinvertion. The reaction was also accompanied with isomerization to form beta-Asp (isoaspartate) residue simultaneously; therefore, four isomers of Asp-151, normal l-alpha-Asp and biologically uncommon l-beta-Asp, d-alpha-Asp, and d-beta-Asp, are formed in alphaA-crystallins. In the present study, we measured the ratio of the four isomers of Asp-151 in alphaA-crystallins obtained from total lens proteins of human lenses of newborn and 30-, 60-, and 80-year-olds. The isomers increased with age, and the total amount of three isomers was more than that of normal l-alpha-Asp in the alphaA-crystallin of the human lenses of the 80-year-olds. These drastic changes started at birth, with about 45% of normal l-alpha-Asp lost by 30 years. These modifications of the Asp residue likely affect the three-dimensional packing array of the lens proteins.

Fatal obstructive lung disease after haploidentical sibling cord blood transplantation.

We report the case of a patient with fatal obstructive lung disease after an HLA-haploidentical sibling cord blood transplant (CBT), with severe acute GVHD. A 2-year-old girl developed expiratory air trapping gradually with acute and chronic GVHD after CBT for the treatment of ALL. Anti-CMV and immunosuppressive therapy were ineffective, and the patient died of progressive respiratory acidosis. Necropsy of the lung revealed severe bronchiolitis obliterans with cytomegalic inclusion cells in the granulation tissues of the bronchiolitis. Thus, immunologic and GVHD problems can occur even in CBT.

Slow induction with sevoflurane was associated with complete atrioventricular block in a child with hypertension, renal dysfunction, and impaired cardiac conduction.

We describe the appearance of complete atrioventricular block (CAVB) with sevoflurane and nitrous oxide during the slow induction in a ten-year-old male patient with hypertension, renal dysfunction, and impaired cardiac conduction. Sinus rhythm was restored following the washout of the anaesthetic gas. And CAVB recurred after the subcutaneous injection of lignocaine. The present report shows that sevoflurane should be treated with care like other inhalational anaesthetics as regards the effect on cardiac conduction.

Asphyxiating thoracic dystrophy: surgical correction and 2-year follow-up in a girl.

A 15-month-old girl under mechanical ventilation with asphyxiating thoracic dystrophy underwent surgical thoracic expansion according to the procedure of Todd et al. (1986). Now aged 4 years, she is free from respiratory distress, is of normal intelligence, and leads an active life.

[Evaluation of cross circulation in conjoined twins].

This report describes the evaluation of cross circulation in conjoined twins. Female thoracoomphalopagus conjoined twins were delivered by cesarean section after 37 week's gestation. CT, MRI and echography were performed. A partial communication of pericardium and sternum, and a union of the liver were found. For the preoperative evaluation of cross circulation, a bolus of indigo carmine was injected, and the pigment appeared in the urine of the other twin. RI angiography showed that radionuclides in one twin were similar to those in the other after 5-10 minutes. During the operation, an injected bolus of SCC to one twin was not effective for the other twin. Inhaled isoflurane in one twin did not appear in the expired gas of the other twin. After the intentional hemorrhage for 3 minutes from one twin, the hemoglobin concentration of one of the twin was the same as that of the other. This demonstrates that acute hemorrhage from one twin seems to result in a significant and rapid decrease of hemoglobin in both babies equally. However, intravenous infusion of drugs to one of the twins requires a relatively long time to take effect in the other baby. We must be careful in anesthetic management of the surgical separation of conjoined twins.

[Effect of induction methods of pediatric anesthesia on serum myoglobin].

Two hundred and twenty nine children from infancy to middle teens divided into six groups were studied to determine the effect of induction methods of pediatric general anesthesia on serum myoglobin. After the slow induction with nitrous oxide-oxygen-halothane (GOF), the serum myoglobin increased significantly to 1774.7 +/- 4285.8 ng.ml-1 (mean +/- SD) by iv administration of succinylcholine 1 mg.kg-1. This significant increase of serum myoglobin was reduced by pretreatment with d-tubocurarine (dTc) 0.05 mg.kg-1 before administration of succinylcholine. However, it was not reduced by pretreatment with thiopental 3 mg.kg-1. After the rapid induction with thiopental 5 mg.kg-1 and succinylcholine 1 mg.kg-1, the serum myoglobin increased slightly to 387.6 +/- 596.5 ng.ml-1. But this increase in serum myoglobin was stopped by pretreatment with dTc 0.05 mg.kg-1 before the rapid induction. Serum myoglobin was not changed without succinylcholine after the slow induction with GOF. In each group, there was no relation with serum myoglobin and ages or fasciculation. Serum myoglobin was more influenced by the induction methods of pediatric general anesthesia than by ages.