Multinary diamond-like chalcogenides for promising thermoelectric application

Thermoelectric（TE）materials have been considered as a strong candidate for recovering the waste heat from industry and vehicles due to the ability to convert heat directly into electricity.Recently,multinary diamond-like chalcogenides（MDLCs）,such as Cu In Te2,Cu2Sn Se3,Cu3Sb Se4,Cu2ZnSnSe4,etc.,are eco-friendly Pb-free TE materials with relatively large Seebeck coefficient and low thermal conductivity and have aroused intensive research as a popular theme in the TE field.In this review,we summarize the TE performance and device development of MDLCs.The features of crystalline and electronic structure are first analyzed,and then the strategies that have emerged to enhance the TE figure of merits of these materials are illustrated in detail.The final part of this review describes the advance in TE device research for MDLCs.In the outlook,the challenges and future directions are also discussed to promote the further development of MDLCs TE materials.

Prognostic value of red blood cell distribution width for severe acute pancreatitis

BACKGROUND Severe acute pancreatitis(SAP)is a common condition in the intensive care unit(ICU)and has a high mortality.Early evaluation of the severity and prognosis is very important for SAP therapy.Recently,red blood cell distribution(RDW)was associated with mortality of sepsis patients and could be used as a predictor of prognosis.Similarly,RDW may be associated with the prognosis of SAP patients and be used as a prognostic indicator for SAP patients.AIM To investigate the prognostic value of RDW for SAP patients.METHODS We retrospectively enrolled SAP patients admitted to the ICU of the First Affiliated Hospital of China Medical University from June 2015 to June 2017.According to the prognosis at 90 d,SAP patients were divided into a survival group and a non-survival group.RDW was extracted from a routine blood test.Demographic parameters and RDW were recorded and compared between the two groups.The receiver operator characteristic(ROC)curve was constructed and Cox regression analysis was performed to investigate the prognostic value of RDW for SAP patients.RESULTS In this retrospective cohort study,42 SAP patients were enrolled,of whom 22 survived(survival group)and 20 died(non-survival group).The baseline parameters were comparable between the two groups.The coefficient of variation of RDW(RDW-CV),standard deviation of RDW(RDW-SD),Acute Physiology and Chronic Health Evaluation II(APACHE II)score,and Sequential Organ Failure Assessment(SOFA)score were significantly higher in the non-survival group than in the survival group(P<0.05).The RDW-CV and RDW-SD were significantly correlated with the APACHE II score and SOFA score,respectively.The areas under the ROC curves(AUCs)of RDW-CV and RDW-SD were all greater than those of the APACHE II score and SOFA score,among which,the AUC of RDW-SD was the greatest.The results demonstrated that RDW had better prognostic value for predicting the mortality of SAP patients.When the RDW-SD was greater than 45.5,the sensitivity for predicting prognosis was 77.8%and the specificity was 70.8%.Both RDW-CV and RDW-SD could be used as independent risk factors to predict the mortality of SAP patients in multivariate logistic regression analysis and univariate Cox proportional hazards regression analysis,similar to the APACHE II and SOFA scores.CONCLUSION The RDW is greater in the non-surviving SAP patients than in the surviving patients.RDW is significantly correlated with the APACHE II and SOFA scores.RDW has better prognostic value for SAP patients than the APACHE II and SOFA scores and could easily be used by clinicians for the treatment of SAP patients.

Research Progress on the Relationship between Coronary Artery Calcification and Chronic Renal Failure

Objective： Coronary artery calcification （CAC） is thought to be a controlled metabolic process that is very similar to the formation of new bone. In patients with chronic renal failure （CRF）, CAC is very common, and CAC severity correlates with the deterioration of renal lilnction. We summarized the current understanding and emerging findings of the relationship between CAC and CRF. Data Sources： All studies were identified by systematically searching PubMed, Embase, and CNKI databases for the terms ＂coronary calcification＂, ＂＇chronic renal failure＂, ＇~vascular smooth muscle cell＂, and their synonyms until September 2017. Study Selection： We examined the titles and abstracts of all studies that met our search strategy thoroughly. The full text of relevant studies was evaluated. Reference lists of retrieved articles were also scrutinized for the additional relevant studies. Results： CRF can accelerate CAC progression. CRF increases the expression of pro-inflamrnatory factors, electrolyte imbalance （e.g., of calcium, phosphorus）, parathyroid hon^none, and uremic toxins and their ability to promote calcification. These factors, through the relevant signaling pathways, trigger vascular smooth muscle cells to transtbrm into osteoblast-like cells while inhibiting the reduction of vascular calcification factors, thus inducing further CAC. Conclusions： Coronary heart disease in patients with CRF is due to multiple factors. Understanding the mechanism of CAC can help interventionists to protect the myocardium and reduce the prevalence of coronary heart disease and mortality.

Enhanced near-room-temperature thermoelectric performance in GeTe

GeTe is an excellent mid-temperature thermoelectric material with high dimensionless figure of merit(ZT)values at temperatures over 600 K.Its near-room-temperature performance is less studied due to the intrinsic high carrier concentration.Here,we successfully enhance the Seebeck coefficient of GeTe from~30 to 220μV·K^(−1) at 300 K,which is achieved by AgInSe2 alloying and Bi doping.It is demonstrated that Bi doping helps to optimize the Seebeck coefficient without deteriorating the intrinsic electrical transport properties of the matrix.A high room-temperature power factor(PF)of~11μW·cm^(−1)·K^(−2) is achieved for a wide range of Bi-doped samples.The simultaneously introduced abundant point defects cause mass and strain fluctuations,which decrease the lattice thermal conductivity(κ_(L))to a low value of 0.6 W·m^(−1)·K^(−1) at 300 K.Due to the synergetic effects of Bi doping in AgInSe2-alloyed GeTe,a high room-temperature ZT value of 0.46 is obtained together with a high ZT value of 1.1 at 523 K.