Enhancement of thermoelectric properties of SrTiO3/LaNb–SrTiO3 composite by different doping levels

Strontium titanate（STO）is an n-type oxide thermoelectric material,which has shown great prospects in recent years.The doping of La and Nb into STO can improve its power factor,whereas its thermal conductivity is still very high.Thus,in order to obtain a high thermoelectric figure-of-merit z T,it is very important to reduce its thermal conductivity.In this paper,using a combination of a hydrothermal method and a high-efficiency sintering method,we succeed in preparing a composite of pure STO and La Nb-doped STO,which simultaneously realizes lower thermal conductivity and higherSeebeck coefficient,therefore,the thermoelectric properties of STO are significantly improved.In the SrTiO3/La Nb–SrTiO3 bulk samples,the lowest thermal conductivity is 2.57 W·m^-1·K^-1 and the highest z T is 0.35 at 1000 K for the STO/La（10）Nb（20）–STO sample.

Compound heterozygous p.L483P and p.S310G mutations in GBA1 cause type 1 adult Gaucher disease:A case report

BACKGROUND Gaucher disease(GD)is caused by a GBA1 gene mutation that leads to decreased acidβ-glucosidase activity[glucocerebrosidase(GCase)].This study aimed to identify and characterise compound heterozygous mutations in GBA1 in a patient with type 1 GD.CASE SUMMARY Here,we report a rare adult-onset type 1 GD in a 46-year-old female patient with clinical manifestations of giant spleen,thrombocytopenia,and bone pain,diagnosed by enzymatic and genetic testing.Enzymology and whole exome sequencing revealed heterozygous missense mutations in exon 10 c.1448T>C(p.L483P)and exon 7 c.928A>G(p.S310G)of GBA1.The latter was first reported in patients with GD.Structural modelling showed that p.S310G and p.L483P were distant from the GCase active site.The p.S310G mutation in domain 1 may decrease stability between theα2 andα3 helices of GBA1.The p.L483P mutation in domain 2 reduced the van der Waals force of the side chain and disrupted the C-terminalβ-sheet.The patient was treated with imiglucerase replacement therapy,and her condition was stable.CONCLUSION The p.L483P/p.S310G novel compound heterozygous mutation underlies type 1 GD and likely affects GCase protein function.This is the first description of p.S310G being associated with mild type 1 GD in the context of a coinherited p.L483P mutation.

Thermoelectric enhancement in triple-doped strontium titanate with multi-scale microstructure

Strontium titanate(SrTiO_(3))is a thermoelectric material with large Seebeck coefficient that has potential applications in high-temperature power generators.To simultaneously achieve a low thermal conductivity and high electrical conductivity,polycrystalline SrTiO_(3)with a multi-scale architecture was designed by the co-doping with lanthanum,cerium,and niobium.High-quality nano-powders were synthesized via a hydrothermal method.Nano-inclusions and a nano/micro-sized second phase precipitated during sintering to form mosaic crystal-like and epitaxial-like structures,which decreased the thermal conductivity.Substituting trivalent Ce and/or La with divalent Sr and substituting pentavalent Nb with tetravalent Ti enhanced the electrical conductivity without decreasing the Seebeck coefficient.By optimizing the dopant type and ratio,a low thermal conductivity of 2.77 W·m^(-1)·K^(-1)and high PF of 1.1 mW·m^(-1)·K^(-2)at 1000 K were obtained in the sample co-doped with 5-mol%La,5-mol%Ce,and 5-mol%Nb,which induced a large ZT of 0.38 at 1000 K.

Pencil painting like preparation for flexible thermoelectric material of high-performance p-type Na_(1.4)Co_(2)O_(4) and novel n-type NaxCo_(2)O_(4)

Flexible thermoelectric materials are presented with potential applications in electronic devices and energy conversion due to their convenient preparation,good flexibility,and various forms.However,as ductility is rarely observed in inorganic semiconductors and ceramic insulators,reports on applications of inorganic oxide materials in flexible thermoelectric materials are sparse.Here,we report a new method for the synthesis of a flexible Na_(1.4)Co_(2)O_(4) thermoelectric material based on Na_(1.4)Co_(2)O_(4) bulk materials,which are prepared by a self-flux method and painted on print paper.Seebeck coefficient and power factor of the obtained thermoelectric material are 78-102 μVK^(-1) and 159e223 mWm^-(1)K^(-2),respectively,in a temperature range of 303-522 K,which are superior to those values of other conductive polymers and their compounds.More interestingly,the n-type Na_(1.4)Co_(2)O_(4) flexible material is obtained in the painting process at higher pressure with Seebeck coefficients of109 to183 μVK^(-1) in a temperature range of 303-522 K.The convenient preparation method of these novel flexible thermoelectric materials may be expanded to the synthesis of other flexible thermoelectric materials,which will be the focus of future work.