Long Noncoding RNA UCA1 Overexpression Is Associated with Poor Prognosis in Digestive System Malignancies: A Meta-analysis

Long noncoding RNA(IncRNA)urothelial carcinoma associated 1(UCA1)has been reported to be highly expressed in many kinds of cancers.This meta-analysis summarized its potential prognostic value in digestive system malignancies.A meta-analysis was performed through a comprehensive search in PubMed,EMBASE,the Cochrane Library,Web of Science and Chinese National Knowledge Infrastructure(CNKI)for suitable articles on the prognostic impact of UCA1 in digestive system malignancies from inception to June 27,2019.Pooled hazard ratios(HRs)with 95% confidence interval(95%CI)were calculated to summarize the effect.Sixteen studies were included in the study,with a total of 1504 patients.A significant association was observed between UCA1 abundance and poor overall survival(OS),and shorter disease-free survival(DFS)for patients with digestive system malignancies,with pooled HR of 2.07(95%CI:1.74-2.47),and of 2.50(95%CI:1.62-3.86).Subgroup analysis and sensitivity analysis suggested the reliability of our findings.It is suggested that UCA1 abundance may serve as a reliable predictive factor for poor prognosis in patients with digestive system malignancies.

Improved electrical transport properties and optimized thermoelectric figure of merit in lithium-doped copper sulfides

Copper sulfide Cu2S is a p-type semiconducting compound that has attracted great attentions in the thermoelectric （TE） community most recently. Considering the intrinsic ultralow lattice thermal conductivity, the enhancement of TE performance in CuzS should be achieved through improving its electrical transport properties. To achieve this goal, lithium element was doped into CuzS in this study. A series of Cu2_xLixS samples with different Li contents （x = 0, 0.005, 0.010, 0.050, and 0.100） was synthesized by the melting-annealing method. When x 〈 0.05, the Cuz_xLixS samples are stable and pure phases, having the same monoclinic structure with the pristine Cu2S at room temperature. The electrical conductivities in the Cu2_xLixS samples are greatly improved with the Li-doping content increasing due to the enhanced carrier concentrations. Meanwhile, doping Li into CuzS increases the ionic activation energy and lessens the influence of mobile Cu ions on the heat-carrying phonons. Thus, the thermal conductivities of the Li-doped Cu2S samples increase. A maximal figure of merit （zT） of 0.84 at 900 K is obtained in Cul.99Lio.018, about 133% improvement as compared with that in Cu2S matrix.

Design and discovery of materials guided by theory and computation

Computational materials science and engineering has emerged as an interdisciplinary subfield spanning materials science and engineering,condensed matter physics,chemistry,mechanics and engineering in general.Modern materials research often requires a close integration of computation and experiments in order to fundamentally understand the materials structures and properties and their relation to synthesis and processing.A number of computational methods and tools at different spatiotemporal scales are now well established,ranging from electronic structure calculations based on density functional theory,1,2 atomic molecular dynamics3,4 and Monte Carlo techniques,5 phase-field method6–9 to continuum macroscopic approaches.Over the last few years,computational materials activities have been steadily moving from technique development and purely computational studies of materials towards discovering and designing new materials guided by computation,machine learning and data mining or by a closely tied combination of computational predictions and experimental validation.This movement is being further accelerated by the recent initiatives by various government agencies in the United States,Europe,China and other countries to pursue the materials genome initiative,10 integrated computational materials engineering11–13 as well as the‘Big Data’initiative.

Improving thermoelectric properties of ZrPtSn-based half-Heusler compound by Sb doping

Bipolar diffusion appeared at high temperature leads to the performance deterioration of thermoelectric(TE) materials, and TE materials with large band gaps have high intrinsic excitation temperature, which is important for high-temperature application. Previous calculation has revealed that ZrPtSn half-Heusler has a large band gap(~1.0 eV) among various half-Heusler compounds,which may be a good candidate for thermoelectric generators at high temperature. In this study, the structure and TE properties of Zr PtSn_(1-x)Sb_(x) half-Heusler compounds were studied by optimization of carrier concentration through Sb doping. With 8% Sb substitution at Sn sites, the enhanced power factor of 23 μ W·cm^(-1)·K^(-2) at 850 K and figure of merit(zT) value of 0.5 at 1000 K were reported in n-type ZrPtSn compounds. Further, the effect of Ni alloying in ZrPt_(1-y)Ni_(y)Sn_(0.92)Sb_(0.08) compounds were also investigated. With the strong point defect scattering for phonons,the lattice thermal conductivity is decreased by~40% at room temperature compared with that of unalloyed compounds. However, due to the depressed carrier mobility, the final zT does not show much superiority with ZrPtSn_(0.92)Sb_(0.08) sample.

Anion-site-modulated thermoelectric properties in Ge2Sb2Te5-based compounds

The amalgamation of multi-subjects often elicits novel materials,new concepts and unexpected applications.Recently,Ge2 Sb2 Te5,as the most established phasechange material,has been found to exhibit decent thermoelectric performance in its stable,hexagonal phase.The challenge for higher figure of merit(zT) values lies in reducing the hole carrier concentration and enhancing the Seebeck coefficient,which,however,can be hardly realized by conventional doping.Here in this work,we report that the electrical properties of Ge2 Sb2 Te5 can be readily optimized by anion-site modulation.Specifically,Se/S substitution for Te induces stronger and more ionic bonding,lowering the hole density.Furthermore,an increase in electronic density of state is introduced by Se substitution,contributing to a large increase in Seebeck coefficient.Combined with the reduced thermal conductivity,maximum zT values above 0.7 at 800 K have been achieved in Se/S-alloyed materials,which is ~30% higher than that in the pristine Ge2Sb2 Te5.