Age group characteristics of children who visited the emergency department with acute poisoning by ingestion

Purpose To investigate the age group characteristics of children who visited the emergency department with acute poisoning by ingestion. Methods We reviewed children under 19 years who visited the emergency department for acute poisoning by ingestion from 2012 to 2017. The children were divided into 3 age groups; infants (0-1 years), preschoolers (2-5 years), and schoolers (6-18 years). Clinical characteristics, intentional ingestion, involved substances (drugs, household products, artificial substances, and pesticides), decontamination and antidote therapy, and outcomes of the 3 age groups were compared. We also performed multivariable logistic regression analysis to identify factors associated with hospitalization. Results A total of 622 children with acute poisoning by ingestion were analyzed. Their annual proportions to overall pediatric emergency patients ranged from 0.3% to 0.4%. Age distribution showed bimodal peaks at 0-2 years and 15-17 years. The infants showed lower frequency of girls, intentional ingestion, ingestion of drugs, performance of decontamination and antidote therapy, and hospitalization than 2 older groups (P < 0.001). Most decontamination, antidote therapy, and hospitalization occurred in the schoolers (P < 0.001). The most frequently reported substances were household cleaning substances in the infants (18.2%), antihistamines in the preschoolers (15.8%), and analgesics in the schoolers (37.5%). The factors associated with hospitalization were intentional ingestion (adjusted odds ratio [aOR], 7.08; 95% confidence interval [CI], 2.85-17.61; P = 0.001) and schoolers (aOR, 2.33; 95% CI, 1.10-7.53; P = 0.031; compared with infants). Only 1 in-hospital mortality was found in a boy aged 2 years who ingested methomyl. Conclusion Infants may experience non-intentional ingestion, ingestion of non-pharmacologic substances (especially household cleaning substances), discharge without decontamination and antidote therapy more frequently than older children. Thus, we need age group-specific, preventive and therapeutic plans for children with acute poisoning

Enhancing Thermoelectric Performances of Bismuth Antimony Telluride via Synergistic Combination of Multiscale Structuring and Band Alignment by FeTe₂ Incorporation

It has been a difficulty to form well-distributed nano- and mesosized inclusions in a Bi₂Te₃-based matrix and thereby realizing no degradation of carrier mobility at interfaces between matrix and inclusions for high thermoelectric performances. Herein, we successfully synthesize multistructured thermoelectric Bi_0.4Sb_1.6Te₃ materials with Fe-rich nanoprecipitates and sub-micron FeTe₂ inclusions by a conventional solid-state reaction followed by melt-spinning and spark plasma sintering that could be a facile preparation method for scale-up production. This study presents a bismuth antimony telluride based thermoelectric material with a multiscale structure whose lattice thermal conductivity is drastically reduced with minimal degradation on its carrier mobility. This is possible because a carefully chosen FeTe₂ incorporated in the matrix allows its interfacial valence band with the matrix to be aligned, leading to a significantly improved p-type thermoelectric power factor. Consequently, an impressively high thermoelectric figure of merit ZT of 1.52 is achieved at 396 K for p-type Bi_0.4Sb_1.6Te₃–8 mol % FeTe₂, which is a 43% enhancement in ZT compared to the pristine Bi_0.4Sb_1.6Te₃. This work demonstrates not only the effectiveness of multiscale structuring for lowering lattice thermal conductivities, but also the importance of interfacial band alignment between matrix and inclusions for maintaining high carrier mobilities when designing high-performance thermoelectric materials

SnSe2 결함 도입으로 인한 SnSe의 고온 열전성능 증대 메커니즘

SnSe is a promising thermoelectric material due to its low toxicity, low thermal conductivity, and multiple valence band structures, which are ideal for high electronic transport properties. The multiple valence band structure has attracted many attempts to engineer the carrier concentration of the SnSe via doping, to place its fermi level at a position where the maximum number of valence bands can participate in the electronic transport. Up until now, ~5 × 1019 cm-3 was the highest carrier concentration achieved in SnSe via doping. Recently, introducing SnSe2 into SnSe was found to effectively increase the carrier concentration as high as ~6.5 × 1019 cm-3 (at 300 K) due to the generated Sn vacancies. This high carrier concentration at 300 K, combined with the reduction in lattice thermal conductivity due to SnSe2 micro-domains formed within the SnSe lattice, improved the thermoelectric performance (zT) of SnSe – xSnSe2 as high as ~2.2 at 773 K. Here, we analyzed the changes in the electronic band parameters of SnSe as a function of temperature with varying SnSe2 content using the Single Parabolic Band (SPB) model. According to the SPB model, the calculated density-of-states effective mass and the fermi level are changed with temperature in such a way that the Hall carrier concentration (nH) of the SnSe – xSnSe2 samples at 773 K coincides with the optimum nH where the theoretically maximum zT is predicted. To optimize the nH at high temperatures for the highest zT, it is essential to tune the 300 K nH and the rate of nH change with increasing temperature via doping.Aerospace Structures & Computational Mechanic