A class of thermoelectric materials has been synthesized with a thermoelectric figure of merit ZT (where T is temperature and Z is a function of thermopower, electrical resistivity, and thermal conductivity) near 1 at 800 kelvin. Although these materials have not been optimized, this value is comparable to the best ZT values obtained for any previously studied thermoelectric material. Calculations indicate that the optimized material should have ZT values of 1.4. These ternary semiconductors have the general formula RM4X12 (where R is lanthanum, cerium, praseodymium, neodymium, or europium; M is iron, ruthenium, or osmium; and X is phosphorus, arsenic, or antimony) and represent a new approach to creating improved thermoelectric materials. Several alloys in the composition range CeFe4-xCoxSb12 or LaFe4-xCoxSb12 (0 < x < 4) have large values of ZT.

Background In laboratory animals, exposure to most general anaesthetics leads to neurotoxicity manifested by neuronal cell death and abnormal behaviour and cognition. Some large human cohort studies have shown an association between general anaesthesia at a young age and subsequent neurodevelopmental deficits, but these studies are prone to bias. Others have found no evidence for an association. We aimed to establish whether general anaesthesia in early infancy affects neurodevelopmental outcomes. Methods In this international, assessor-masked, equivalence, randomised, controlled trial conducted at 28 hospitals in Australia, Italy, the USA, the UK, Canada, the Netherlands, and New Zealand, we recruited infants of less than 60 weeks' postmenstrual age who were born at more than 26 weeks' gestation and were undergoing inguinal herniorrhaphy, without previous exposure to general anaesthesia or risk factors for neurological injury. Patients were randomly assigned (1:1) by use of a web-based randomisation service to receive either awake-regional anaesthetic or sevoflurane-based general anaesthetic. Anaesthetists were aware of group allocation, but individuals administering the neurodevelopmental assessments were not. Parents were informed of their infants group allocation upon request, but were told to mask this information from assessors. The primary outcome measure was full-scale intelligence quotient (FSIQ) on the Wechsler Preschool and Primary Scale of Intelligence, third edition (WPPSI-III), at 5 years of age. The primary analysis was done on a per-protocol basis, adjusted for gestational age at birth and country, with multiple imputation used to account for missing data. An intention-totreat analysis was also done. A difference in means of 5 points was predefined as the clinical equivalence margin. This completed trial is registered with ANZCTR, number ACTRN12606000441516, and ClinicalTrials.gov, number NCT00756600. Findings Between Feb 9, 2007, and Jan 31, 2013, 4023 infants were screened and 722 were randomly allocated: 363 (50%) to the awake-regional anaesthesia group and 359 (50%) to the general anaesthesia group. There were 74 protocol violations in the awake-regional anaesthesia group and two in the general anaesthesia group. Primary outcome data for the per-protocol analysis were obtained from 205 children in the awake-regional anaesthesia group and 242 in the general anaesthesia group. The median duration of general anaesthesia was 54 min (IQR 41-70). The mean FSIQ score was 99•08 (SD 18•35) in the awake-regional anaesthesia group and 98•97 (19•66) in the general anaesthesia group, with a difference in means (awake-regional anaesthesia minus general anaesthesia) of 0•23 (95% CI-2•59 to 3•06), providing strong evidence of equivalence. The results of the intention-to-treat analysis were similar to those of the per-protocol analysis. Interpretation Slightly less than 1 h of general anaesthesia in early infancy does not alter neurodevelopmental outcome at age 5 years compared with awake-regional anaesthesia ...

Studies with modest numbers of patients have suggested that spinal anesthesia in infants is associated with a very infrequent incidence of complications, such as hypoxemia, bradycardia, and postoperative apnea. Although spinal anesthesia would seem to be a logical alternative to general anesthesia for many surgical procedures, it remains an underutilized technique. Since 1978, clinical data concerning all infants undergoing spinal anesthesia at the University of Vermont have been prospectively recorded. In all, 1554 patients have been studied. Anesthesia was performed by anesthesia trainees and attending anesthesiologists. The success rate for LP was 97.4%. An adequate level of spinal anesthesia was achieved in 95.4% of cases. The average time required to induce spinal anesthesia was 10 min. Oxygen hemoglobin desaturation to <90% was observed in 10 patients. Bradycardia (heart rate <100 bpm) occurred in 24 patients (1.6%). This study confirms the infrequent incidence of complications associated with spinal anesthesia in infants. Spinal anesthesia can be performed safely, efficiently, and with the expectation of a high degree of success. Spinal anesthesia should be strongly considered as an alternative to general anesthesia for lower abdominal and lower extremity surgery in infants.

No abstract

Seebeck, electrical, and thermal conductivity 'data are reported on CoSb,, and doped and undoped alloys of Co,-&,Sb, .-,Asy from-20 to 700 K. n-type semiconductors were obtained by doping with Ni, Te, or Pd, and the hole concentration in p-type samples was increased by substitution of Fe, Ru, OS, and Ge. An estimated maximum value for ZT of 0.6 (Z is the figure of merit) was found for a Te-doped (n-type) alloy at 700 K. For p-type alloys, the maximum value of ZT was found to be 0.3 at 550 K. Electrical and thermal transport data also are reported for CoAss , RhSb, , and IrSb,. Most of the samples investigated were polycrystalline, but a few measurements on CoSb, single crystals also are discussed.