Selective Scatterings of Phonons and Electrons in Defective Half-Heusler Nb1- δ CoSb for the Figure of Merit zT > 1.

The recently developed defective 19-electron half-Heusler (HH) compounds, represented by Nb1- δ CoSb, possess massive intrinsic vacancies at the cation site and thus intrinsically low lattice thermal conductivity that is desirable for thermoelectric (TE) applications. Yet the TE performance of defective HHs with a maximum figure of merit (zT) <1.0 is still inferior to that of the conventional 18-electron ones. Here, a peak zT exceeding unity is obtained at 1123 K for both Nb0.7 Ta0.13 CoSb and Nb0.6 Ta0.23 CoSb, a benchmark value for defective 19-electron HHs. The improved zT results from the achievement of selective scatterings of phonons and electrons in defective Nb0.83 CoSb, using lanthanide contraction as a design factor to select alloying elements that can strongly impede the phonon propagation but weakly disturb the periodic potential. Despite the massive vacancies induced strong point defect scattering of phonons in Nb0.83 CoSb, Ta alloying is still found effective in suppressing lattice thermal conductivity while maintaining the carrier mobility almost unchanged. In comparison, V alloying significantly deteriorates the carrier transport and thus the TE performance. These results enlarge the category of high-performance HH TE materials beyond the conventional 18-electron ones and highlight the effectiveness of selective scatterings of phonons and electrons in developing TE materials even with massive vacancies.

Demonstration of valley anisotropy utilized to enhance the thermoelectric power factor.

Valley anisotropy is a favorable electronic structure feature that could be utilized for good thermoelectric performance. Here, taking advantage of the single anisotropic Fermi pocket in p-type Mg3Sb2, a feasible strategy utilizing the valley anisotropy to enhance the thermoelectric power factor is demonstrated by synergistic studies on both single crystals and textured polycrystalline samples. Compared to the heavy-band direction, a higher carrier mobility by a factor of 3 is observed along the light-band direction, while the Seebeck coefficient remains similar. Together with lower lattice thermal conductivity, an increased room-temperature zT by a factor of 3.6 is found. Moreover, the first-principles calculations of 66 isostructural Zintl phase compounds are conducted and 9 of them are screened out displaying a pz-orbital-dominated valence band, similar to Mg3Sb2. In this work, we experimentally demonstrate that valley anisotropy is an effective strategy for the enhancement of thermoelectric performance in materials with anisotropic Fermi pockets.

Differential clinical benefits of continuous blood purification treatment in critically ill patients with variable APACHE II scores.

The present study aimed to assess whether the Acute Physiology And Chronic Health Evaluation (APACHE) II score may be used to predict whether critically ill patients benefit from continuous blood purification (CBP) treatment. A total of 115 critically ill patients were retrospectively reviewed and grouped according to their baseline APACHE II scores. Each group was further divided into 2 groups based on whether they received CBP or not. At 72 h after CBP treatment, clinical indicators comprising the plasma levels of inflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-8, as well as endotoxin and procalcitonin (PCT), and severity scores (APACHE II, multiple organ dysfunction syndrome and systemic inflammatory response syndrome), were analyzed in all patients. It was observed that while CBP slightly reduced the severity scores in all patients, it significantly improved those in patients with an APACHE II score of 20-29 (P<0.05). Similarly, the plasma levels of TNF-α, IL-6, IL-8, endotoxin and PCT were significantly lower in patients receiving CBP than in those without CBP when the APACHE II score was 20-29 (P<0.05). Furthermore, CBP treatment significantly decreased the fatality rate and length of stay at the intensive care unit (ICU) for critically ill patients with an APACHE II score of 20-29 (P<0.05). In conclusion, CBP significantly decreases the inflammatory response, shortens the length of stay at the ICU and improves the prognosis for critically ill patients with an APACHE II score of 20-29 points. This observation suggests that the APACHE II score is an important clinical indicator to determine the potential benefit of CBP therapy in critically ill patients.

Association between MMP-9 -1562 C/T polymorphism and susceptibility to digestive cancers: A meta-analysis.

PURPOSE: Matrix metalloproteinases (MMPs) play important roles in tumorigenesis. The variant in MMP-9 -1562 C/T (single nucleotide polymorphisms labeled rs3918242) has been extensively evaluated as predisposing factors to digestive cancers susceptibility. However, most of these studies only contained a small number of subjects and they showed conflicting results. Therefore, to elucidate these associations, we carried out a large-scale meta-analysis to provide this accurately comprehensive synopsis of case-control studies. METHODS: A comprehensive literature search was conducted in EMBASE, OVID, Medline, China National Knowledge Internet and Wanfang for relevant data published between Jan 2000 and Mar 2018. Overall and stratified analyses based on the cancer types, ethnicity and source of control were carried out. Odds ratios (ORs) correspondent to 95% confidence intervals (95% CIs) were calculated to evaluate the genetic correlation between the variant and digestive cancer susceptibility. Review Manager 5.2 and Stata 12.0 were used for statistical analysis. RESULTS: Twenty studies containing 3201 digestive cancer patients and 4301 matched-controls were screened out. The overall results suggested that MMP-9 -1562 C/T polymorphism increased the susceptibility to digestive cancers under homozygote and recessive models (homozygote, OR = 1.35, 95% CI 1.00-1.82, P = 0.05; recessive, OR = 1.42, 95% CI 1.07-1.88, P = 0.02). Furthermore, in the subgroup analysis based on the source of control, similar conclusions were obtained in the population-based control subgroup (homozygote, OR = 1.63, 95% CI 1.16-2.27, P = 0.004; recessive, OR = 1.67, 95% CI 1.22-2.28, P = 0.001), but not in the hospital-based control. In subgroup analyses based on cancer types and ethnicity, no association was observed. CONCLUSIONS: Our meta-analysis suggested that MMP-9 -1562 C/T polymorphism might be related to the digestive cancer susceptibility. Evidence with adequate sample size is needed.

Effect of interleukin-33 on Th1/Th2 cytokine ratio in peripheral lymphocytes in asthmatic mice.

BACKGROUND: Allergic asthma is a chronic airway inflammatory disease partly characterised by high concentration of T help 2 (Th2) cytokines in bronchoalveolar lavage fluid (BALF). There is no report on the relation of peripherally circulating blood lymphocytes and asthma. We explored the balance of Th2/Th1 cytokines in asthmatic mice. Exogenous recombinant interleukin (IL) 33 acted on murine peripheral circulating blood lymphocytes, IL-5 cytokine was selected for assessing Th2 cytokines and interferon-gamma (IFN-γ) for Th1 cytokines. METHODS: Female specific pathogen free BABL/c mice were sensitised by intraperitoneal injection of 20 µg of ovalbumin emulsified in 1 mg of aluminium hydroxide gel in a total volume of 200 µl, and challenged for 30 minutes in 7 consecutive days with an aerosol of 2 g ovalbumin in 100 ml of PBS. Then we collected BALF and isolated lymphocytes from the peripheral blood. The lymphocytes were divided into two groups: asthmatic group and normal group. Th1/Th2 cytokines was detected by enzyme-linked immunosorbent assay (ELISA) kits. RESULTS: In the asthma group, we found numerous eosinophils and lymphocytes on the glass slides. We then confirmed that the optimal concentration of IL-33 was 10 ng/ml and time of IL-33 stimulating lymphocytes was 24 hours. In the asthma group, the production of IL-5 was significantly increased over normal group after stimulation with IL-33 (P < 0.05) and the production of IFNγ was supressed from IL-33 stimulated lymphocytes (P < 0.05). CONCLUSION: IL-33 acts on lymphocytes of peripheral blood increasing secretion of Th2 cytokines and inhibiting secretion of Th1 cytokines.

Current evidence on the relationship between five polymorphisms in the matrix metalloproteinases (MMP) gene and lung cancer risk: a meta-analysis.

PURPOSE: Matrix metalloproteinase (MMP) 1, MMP2, MMP3 and MMP9 are important members of the MMP family. Recently, many studies have been carried out on the association between polymorphisms of MMP1-1607 1G/2G, MMP2-735 C/T, MMP2-1306 C/T, MMP3-1171 5A/6A and MMP9-1562 C/T and lung cancer risk. However the results of these studies remained inconclusive due to conflicting results from different case-control studies. To clarify these associations, we conducted a meta-analysis. METHODS: We conducted a comprehensive search in Medline, EMBASE, OVID and Chinese Biomedical Literature Database (date from Jan 2000 to Aug 2012). Overall and subgroup analysis by the ethnicity of study population was carried out. Odds ratio (OR) with 95% confidence interval (95%CI) was used to assess the strength of the association. RESULTS: There were 17 studies involving five polymorphic sites in four MMP genes. For MMP1-1607,increased lung cancer risk was found under dominant model (MMP1-1607 1G/2G: OR=1.14, 95%CI=1.03-1.26, P=0.01), but not in the Caucasian population. For MMP2-1306 C/T, T polymorphism decreased lung cancer risk under dominant and recessive models (dominant, OR=0.63, 95%CI=0.46-0.88, P=0.0006; recessive, OR=0.61, 95%CI=0.38-0.99, P=0.04). For MMP9-1562 C/T, TT genotype decreased this risk under the recessive model (OR=0.38, 95%CI=0.19-0.75, P=0.005), but not in the Asian population. For MMP2-735 C/T and MMP3-1171 5A/6A, there was no association between this polymorphism and lung cancer risk under the dominant and recessive models. CONCLUSIONS: MMP1-1607 1G/2G polymorphism increased lung cancer risk in Asians. It was also found that MMP2-1306 C/T polymorphism decreased lung cancer risk in Asians, while MMP9-1562 C/T polymorphism decreased lung cancer risk in Caucasians. No significant difference was found in any genotype of MMP2-735 C/T and MMP3-1171 5A/6A. Further studies with larger sample sizes should be carried out.