Sensitivity analysis plays an important role in building energy analysis. It can be used to identify the key variables affecting building thermal performance from both energy simulation models and ...observational study. This paper is focused on the application of sensitivity analysis in the field of building performance analysis. First, the typical steps of implementation of sensitivity analysis in building analysis are described. A number of practical issues in applying sensitivity analysis are also discussed, such as the determination of input variations, the choice of building energy programs, how to reduce computational time for energy models. Second, the sensitivity analysis methods used in building performance analysis are reviewed. These methods can be categorized into local and global sensitivity analysis. The global methods can be further divided into four approaches: regression, screening-based, variance-based, and meta-model sensitivity analysis. Recent research has been concentrated on global methods because they can explore the whole input space and most of them allow the self-verification, i.e., how much variance of the model output (building energy consumption) has been explained by the method used in the analysis. Third, we discuss several important topics, which are often overlooked in the domain of building performance analysis. These topics include the application of sensitivity analysis in observational study, how to deal with correlated inputs, the computation of the variations of sensitivity index, and the software issues. Lastly, the practical guidance is given based on the advantages and disadvantaged of different sensitivity analysis methods in assessing building thermal performance. The recommendations for further research in the future are made to provide more robust analysis in assessing building energy performance.
Flexible thermoelectrics provide a different solution for developing portable and sustainable flexible power supplies. The discovery of silver sulfide–based ductile semiconductors has driven a shift ...in the potential for flexible thermoelectrics, but the lack of good p-type ductile thermoelectric materials has restricted the reality of fabricating conventional cross-plane π-shaped flexible devices. We report a series of high-performance p-type ductile thermoelectric materials based on the composition-performance phase diagram in AgCu(Se,S,Te) pseudoternary solid solutions, with high figure-of-merit values (0.45 at 300 kelvin and 0.68 at 340 kelvin) compared with other flexible thermoelectric materials. We further demonstrate thin and flexible π-shaped devices with a maximum normalized power density that reaches 30 μW cm
−2
K
−2
. This output is promising for the use of flexible thermoelectrics in wearable electronics.
A flexible power source
Thermoelectric materials can harvest heat and turn it into power. Heat sources potentially include the heat generated by humans through wearable devices and might enable self-powering systems, but the lack of ductility for most thermoelectrics poses a major problem. Yang
et al
. found a thermoelectric silver/copper–based semiconductor that also is ductile (see the Perspective by Hou and Zhu). This material allows for a thin, flexible device capable of producing power, even when adhered to a wrist. —BG
A flexible thermoelectric was developed from a silver/copper–based semiconductor that can be fashioned into a thin device.
Hetero‐shaped thermoelectric (TE) generators (TEGs) can power the sensors used in safety monitoring systems of undersea oil pipelines, but their development is greatly limited by the lack of ...materials with both good shape‐conformable ability and high TE performance. In this work, a new ductile inorganic TE material, Ag20S7Te3, with high TE performance is reported. At 300–600 K, Ag20S7Te3 crystallizes in a body‐centered cubic structure, in which S and Te atoms randomly occupy the (0, 0, 1) site. Due to the smaller generalized stacking fault energy in the (101¯)010 slip system, Ag20S7Te3 shows better ductility than Ag2S, yielding excellent shape‐conformability. The high carrier mobility and low lattice thermal conductivity observed in Ag20S7Te3 result in a maximum dimensionless figure of merit (zT) of 0.80 at 600 K, which is comparable with the best commercial Bi2Te3‐based alloys. The prototype TEG consisting of 10 Ag20S7Te3 strips displays an open‐circuit voltage of 69.2 mV and a maximum power output of 17.1 µW under the temperature difference of 70 K. This study creates a new route toward hetero‐shaped TEG.
A new ductile inorganic thermoelectric (TE) material, Ag20S7Te3, with high carrier mobility, low lattice thermal conductivity, and a maximum zT of 0.80 at 600 K is reported. The prototype hetero‐shaped TE generator consisting of 10 Ag20S7Te3 strips displays an open‐circuit voltage of 69.2 mV and a maximum power output of 17.1 μW under a temperature difference of 70 K.
The COVID-19 pandemic has swept across China and the world, causing more than 30 million infections and incalculable damage. China was seriously damaged and threatened by the disease in the first ...quarter of 2020, but finally succeeded in halting its spread in a short period. This was achieved through quick and strong measures in self-protection, mobility control, resource allocation, professional health care, and disinfection, under the organization of the government and the cooperation of all the Chinese people. The measures that were taken to prevent the spread of COVID-19 proved to be efficient in fighting the outbreak in Beijing in June 2020. This paper reviews China's experience with COVID-19, the Chinese economy's performance during the pandemic, and the government's policies to protect lives, maintain markets, and promote the economy. The data show that strong monetary and fiscal policies accelerated the country's economic recovery. These policies, including tax reductions and credit support, targeting small- and medium-size enterprises (SMEs) and industries and regions that were severely damaged, have helped to create jobs and encourage production and investment.
Objective:
Stroke is a leading cause of mortality and disability. Nicotinamide phosphoribosyltransferase (Nampt) is the rate‐limiting enzyme in mammalian nicotinamide adenine dinucleotide (NAD)+ ...biosynthesis and contributes to cell fate decisions. However, the role of Nampt in brain and stroke remains to be investigated.
Methods:
We used lentivirus‐mediated Nampt overexpression and knockdown to manipulate Nampt expression and explore the effects of Nampt in neuronal survival on ischemic stress both in vivo and in vitro. We also used adenosine monophosphate (AMP)‐activated kinase‐α2 (AMPKα2) and silent mating type information regulation 2 homolog 1 (SIRT1) knockout mice to investigate the underlying mechanisms of Nampt neuroprotection.
Results:
Nampt inhibition by a highly‐specific Nampt inhibitor, FK866, aggravated brain infarction in experimentally cerebral ischemia rats, whereas Nampt overexpression in local brain and Nampt enzymatic product nicotinamide mononucleotide (NMN) reduced ischemia‐induced cerebral injuries. Nampt overexpression and knockdown regulated neuron survival via the AMPK pathway. Neuroprotection of Nampt was abolished in AMPKα2−/− neurons. In neurons, Nampt positively modulated NAD+ levels and thereby controlled SIRT1 activity. SIRT1 coprecipitated with serine/threonine kinase 11 (LKB1), an upstream kinase of AMPK, and promoted LKB1 deacetylation in neurons. Nampt‐induced LKB1 deacetylation and AMPK activation disappeared in SIRT1−/− neurons. In contrast, Ca2+/calmodulin‐dependent protein kinase kinase‐β (CaMKK‐β), another upstream kinase of AMPK, was not involved in the neuroprotection of Nampt. More important, Nampt overexpression‐induced neuroprotection was abolished in SIRT1+/− and AMPKα2−/− mice.
Interpretation:
Our findings reveal that Nampt protects against ischemic stroke through rescuing neurons from death via the SIRT1‐dependent AMPK pathway and indicate that Nampt is a new therapeutic target for stroke. Ann Neurol 2011.
Platinum‐based atomically ordered alloys (i.e., intermetallic compounds) have distinct advantages over disordered solid solution counterparts in boosting the cathodic oxygen‐reduction reaction (ORR) ...in proton‐exchange‐membrane fuel cells. Nevertheless, the pivotal role of ordering degree of intermetallic catalysts in promoting ORR performance has been ignored heavily so far, probably owing to the lack of synthetic routes for controlling the ordering degree, especially for preparing highly ordered intermetallic catalysts. Herein, a family of intermetallic PtFe catalysts with similar particle size of 3–4 nm but varied ordering degree in a wide range of 10–70% are prepared. After constructing the PtFe/Pt core/shell structure with around 3 Pt‐layer skin, a positive correlation between the ordering degree of the intermetallic catalysts and their ORR activity and durability is identified. Notably, the highly ordered PtFe/Pt catalyst exhibits a high mass activity of 0.92 A mgPt−1 at 0.9 ViR‐corrected as cathode catalyst in H2–O2 fuel cell, with only 24% loss after accelerated durability tests. The ordering degree‐dependent performance can be ascribed to the compressive strain effect induced by the intermetallic PtFe core with smaller lattice parameters, and the more thermodynamically stable intermetallic structure compared to disordered alloys.
A strong and positive correlation between the ordering degree of the PtFe/Pt catalysts with their oxygen reduction reaction activity and durability is identified, which can be ascribed to the compressive strain effects and the more thermodynamically stable intermetallic structures compared to disordered alloys.
Esophageal cancer (ECa) remains a major cause of mortality across the globe. The expression of EIF3J-AS1 is altered in a plethora of tumors, but its role in ECa development and progression are ...undefined. Here, we show that EIF3J-AS1 is up-regulated in ECa and that its expression correlates with advanced TNM stage (P = 0.014), invasion depth (P = 0.001), positive lymph node metastasis (P < 0.001) and poor survival (OS: P = 0.0059; DFS: P = 0.0037) in ECa. Functional experiments showed that knockdown EIF3J-AS1 inhibited ECa growth and metastasis through in vitro and in vivo experiments. Regarding the mechanism, EIF3J-AS1/miR-373-3p/AKT1 established the ceRNA network involved in the modulation of cell progression of ECa cells. Overall, EIF3J-AS1 may exhibit an oncogenic function in ECa via acting as a sponge for miR-373-3p to up-regulate AKT1 mRNA level, and may serve as a potential therapeutic target and a prognostic biomarker for ECa patients.
Abstract
Geometric and topological properties of protein structures, including surface pockets, interior cavities and cross channels, are of fundamental importance for proteins to carry out their ...functions. Computed Atlas of Surface Topography of proteins (CASTp) is a web server that provides online services for locating, delineating and measuring these geometric and topological properties of protein structures. It has been widely used since its inception in 2003. In this article, we present the latest version of the web server, CASTp 3.0. CASTp 3.0 continues to provide reliable and comprehensive identifications and quantifications of protein topography. In addition, it now provides: (i) imprints of the negative volumes of pockets, cavities and channels, (ii) topographic features of biological assemblies in the Protein Data Bank, (iii) improved visualization of protein structures and pockets, and (iv) more intuitive structural and annotated information, including information of secondary structure, functional sites, variant sites and other annotations of protein residues. The CASTp 3.0 web server is freely accessible at http://sts.bioe.uic.edu/castp/.
High-performance liquid-like thermoelectrics have attracted global renewed attention since the paradigm of ‘phonon-liquid electron-crystal’ was proposed in 2012. As one of the most typical ...liquid-like thermoelectric materials, Cu2Se-based compounds have been widely studied and their thermoelectric figure of merits have continuously increased up to >2.0. Herein, a comprehensive overview is presented on the recent progress and future challenges for Cu2Se-based thermoelectric materials. First, the basic properties of Cu2Se, such as the complex crystal structures, unique liquid-like behavior, and anomalous critical phenomenon during phase transition are presented. Next, some common synthesis recipes are concisely outlined and the impact on the thermoelectric properties is intercompared. The effective strategies for improving the thermoelectric performance are then summarized, with some typical studies highlighted. Furthermore, the utmost concerned stability issues, in particular Cu ion migration, are discussed followed by the latest progress on Cu2Se-based thermoelectric devices. Finally, the challenges and outlook toward further development of Cu2Se-based materials, devices, and applications are provided.
PDF
