An algorithm of calculating transport parameters of thermoelectric materials using single Kane band model with Riemann integral methods.

We develop an algorithm called SKBcal to conveniently calculate within minutes the thermoelectric transport parameters such as reduced Fermi level (η), electronic thermal conductivity (κe), lattice thermal conductivity (κl), Hall factor (A), effective mass (m*), quality factor (ß) and theoretical zT within the framework of single Kane band (SKB) model. The generalized Fermi-Dirac integral for SKB model is integrated by left Riemann integral method. A concept of significant digits of relative error is involved to determine the accuracy of calculation. Furthermore, a combined program of "For" and "While" is coded to set up an iteration for refining the reduced Fermi level. To easily obtain the quality factor, we re-derive the expression into a formula related to carrier mobility. The results calculated by SKBcal are consistent with the data reported in the literatures.

Energy-Efficient Synthesis and High Thermoelectric Performance of α-Cu2-y Se1-x Tex.

The high-temperature phase of ß-Cu2 Se always appears as the major phase for the reaction carried out using chemical solution methods. Here, a procedure was developed that could fabricate a single phase of α-Cu2 Se1-x Tex (x=0.02 and 0.04) by room-temperature aqueous synthesis using NaBH4 as reducing agent followed by cold pressing and sintering at 650 °C for 6 h in a flowing gas mixture of 20 % H2 and 80 % N2 . The energy-efficient synthesis carried out at room temperature abides by the 6th principle for green chemistry with less energy consumption. The reaction mechanism was studied, and evidence was provided of α-Cu2 Se being formed via the reaction between elemental Cu and Se atoms at room temperature. The resulting materials were characterized by powder X-ray diffraction, field-emission scanning electron microscopy, thermoelectric transport measurements, and Hall measurements. Cu1.96 Se0.96 Te0.04 had the highest power factor of 11 µW cm-1 K-2 at 818 K, and Cu2 Se0.96 Te0.04 had the maximum zT≥1.4 at T≥920 K among this series of materials.

Effect of Lactobacillus rhamnosus GG immunopathologic changes in chronic mouse asthma model.

BACKGROUND: Asthma is a heterogeneous inflammatory disorder of the airway. A Th2 response usually contributes to high levels of allergen-specific IgE and eosinophilic airway inflammation. Several findings have demonstrated that neutrophils, not eosinophils, are the major inflammatory cells in chronic asthma patients with steroid-resistance. Lactobacillus rhammosus GG (LGG) exhibits anti-inflammatory properties on OVA-induced acute airway inflammation. OBJECTIVE: We hypothesized that orally administrated LGG should reduce airway remodeling in chronic experimental models. METHODS: Female Balb/c mice were sensitized with OVA. LGG was used to investigate whether oral administrations of LGG inhibited OVA-induced airway inflammation in a chronic asthma model and the different intervention times between LGG pre-treatment and post-treatment groups. BALF was analyzed with Liu's stain and ELISA assay. Lung histopathology was assayed with HE, IHC and Masson's trichrome staining. Lung tissues were assayed with PCR (T-bet, GATA3, RORrt and Foxp3). Many cytokines were detected in the serum and BALF. RESULTS: LGG significantly decreased the number of infiltrating inflammatory cells. We also found that the oral LGG group suppressed not only Th2 cytokine, but also IL-17, TNF-α and HMGB1 in the BALF levels. However, GATA3 and RORrt decreased significantly in the RNA level in the LGG groups, but the T-bet and Foxp3 increased in the RNA level. CONCLUSIONS: LGG not only had anti-inflammatory effects on OVA-induced airway inflammation, but also improved airway remodeling and collagen expression in the chronic asthma mouse model. Moreover, LGG might be an additional or supplementary therapy for allergic airway diseases.

A facile energy-saving route of fabricating thermoelectric Sb2Te3-Te nanocomposites and nanosized Te.

A facile energy-saving route is developed for fabricating Sb2Te3-Te nanocomposites and nanosized Te powders. The fabrication route not only avoids using organic chemicals, but also keeps the energy consumption to a minimum. The fabrication procedure involves two steps. Energetic precursors of nanosized powders of Sb and Te are produced at room temperature followed by hot pressing at 400°C under 70 MPa for 1 h. The resulting Sb2Te3-Te nanocomposite exhibits enhanced power factor. The dimensionless figure of merit zT value of the Sb2Te3-Te nanocomposite is 0.29 at 475 K.

Enhanced ZT of InxCo4Sb12-InSb Nanocomposites Fabricated by Hydrothermal Synthesis Combined with Solid-Vapor Reaction: A Signature of Phonon-Glass and Electron-Crystal Materials.

A rapid route of synthesizing pristine Co4Sb12 at relatively low temperature was previously developed. However, filling the voids using the same procedure is not successful. We develop a new route to fabricate In-filled cobalt skutterudites with InSb nanoinclusions InxCo4Sb12-(InSb)y via solid-vapor reaction between hydrothermally synthesized Co4Sb12 powder and the indium chunk. The nanocomposites are characterized using powder X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and inductively coupled plasma mass spectrometry (ICP-MS). With the success of partial filling of In into the voids and InSb nanoinclusions, the power factor of the InxCo4Sb12-(InSb)y nanocomposites is significantly enhanced, and the thermal conductivity is lowered as compared with the pristine Co4Sb12. As a result, ZT with its highest value of 1.0 is attained for the hierarchical structured In0.04Co4Sb12-(InSb)0.05 nanocomposite at 575 K. The attained ZT value is among the highest ever reported value at T ≤ 575 K for In-filled cobalt skutterudites.

An Initial Attack of Urinary Stone Disease Is Associated with an Increased Risk of Developing New-Onset Irritable Bowel Syndrome: Nationwide Population-Based Study.

BACKGROUND: The neurotransmitter pathways in irritable bowel syndrome (IBS) and urinary stone attacks are both related to serotonin, and each disease may be influenced by viscero-visceral hyperalgesia. However, the relationship between urinary tract stone disease and IBS has never been addressed. We aimed to investigate the risk of suffering new-onset IBS after an initial urinary stone attack using a nationwide database. METHODS: A study group enrolled a total of 13,254 patients who were diagnosed with an initial urinary stone attack; a comparison group recruited 39,762 matched non-urinary stone participants during 2003 and 2007. We followed each patient for 3 years to determine new-onset IBS. We also used Cox proportional hazards models to analyze the risk of IBS between the study and comparison groups after modified by demographics, residence, patient characteristics and personal histories. RESULTS: The occurrence rates of IBS were 3.3% (n = 440) and 2.6% (n = 1,034) respectively in the study and comparison groups. A covariate-adjusted hazard ratio (HR) of IBS in the study group that was 1.28 times greater (HR = 1.29, 95% CI, 1.15-1.44) than that in the comparison group was showed in the stratified Cox proportional analysis. The adjusted HRs of IBS did not decrease after considering demographics and past histories. The majority of IBS (30.5%) occurred within the first 6 months after the stone attack. CONCLUSION: Patients with an initial urinary stone attack are at increased risk of developing new-onset IBS. The HRs of IBS did not decrease even after adjusting for patient demographics and past histories. Most importantly, 30.5% of IBS occurred within the first 6 months after the urinary stone attack.

Optimization and Analysis of Thermoelectric Properties of Unfilled Co(1-x-y)Ni(x)Fe(y)Sb3 Synthesized via a Rapid Hydrothermal Procedure.

A series of nanostructured co-doped Co(1-x-y)Ni(x)Fe(y)Sb3 were fabricated using a rapid hydrothermal method at 170 °C for a duration of 12 h, followed by evacuated-and-encapsulated heating at 580 °C for a short period of 5 h. The resulting samples were characterized using powder X-ray diffraction, field emission scanning electron microscopy, bulk density, electronic and thermal transport measurements. The power factor of Co(1-x-y)Ni(x)Fe(y)Sb3 is significantly enhanced in the high-temperature region due to significant enhancement of the electrical conductivity and absolute value of thermopower. The latter arises from the onset of bipolar effect being shifted to higher temperatures as compared with the non-doped CoSb3. The room temperature thermal conductivity falls in the range between 1.22 and 1.67 W m(-1) K(-1) for Co(1-x-y)Ni(x)Fe(y)Sb3. The thermal conductivity of both the (x,y) = (0.14,10) and (0.14,12) samples is measured up to 600 K and found to decrease with increasing temperature. The thermal conductivity of the (0.14,10) sample goes down to ∼1.02 W m(-1) K(-1). As a result, zT = 0.68 is attained at 600 K. The lattice thermal conductivity is analyzed to gain insight into the contribution of various scattering processes that suppress the heat transfer through the phonons in Co(1-x-y)Ni(x)Fe(y)Sb3. The effect of the simultaneous presence of Co, Ni, and Fe elements on the electronic structure and transport properties of Co(1-x-y)Ni(x)Fe(y)Sb3 is described using the quantum mechanical tunneling theory of electron transmission among the potential barriers.