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[en] Activating transcription factor 4 (ATF4), an endoplasmic reticulum stress-inducible transcription factor, plays important roles in cancer progression and resistance to therapy. However, no report is available about its roles in endometrial cancer (EC). In this study, we found that ATF4 is commonly expressed in EC cell lines. Loss-of-function studies in two EC cell lines showed that ATF4 knockdown suppresses tumor growth of EC in vivo without influencing cell proliferation in vitro. And xenograft tumors derived from ATF4-knockdown cells had reduced M2 macrophage infiltration. In clinical specimens, ATF4-high expressing tumors indeed contained more macrophage infiltration compared to those with lower ATF4 expression. Moreover, we identified that ATF4-mediated chemokine CCL2 expression ultimately results in macrophage infiltration and tumor growth of EC. Taken together, our findings suggest that ATF4 contributes to tumor growth of EC by promoting CCL2 and subsequent recruitment of macrophage, and that ATF4/CCL2 axis might be a potential therapeutic target for EC. - Highlights: • Knockdown of ATF4 inhibits the tumor growth of EC in vivo but not in vivo. • ATF4 regulates CCL2 expression to promote macrophage infiltration in EC. • Blocking CCL2 suppresses tumor growth and macrophage infiltration in EC. • Overexpression of CCL2 restores tumor growth and macrophage infiltration in shATF4 tumor.
[en] The Chinese BeiDou navigation satellite system (BDS) is an emerging global navigation satellite system similar to the global positioning system (GPS), which provides positioning, navigation and timing services. The typical character of BDS code bias variation has received greater attention in relation to positioning and navigation in comparison with its underlying mechanism and effects on BDS carrier-phase time and frequency transfer. This study developed a code bias variation correction model. The improvements in the model correction results from nine time transfer stations were observed at two satellite frequencies (i.e. B1 and B2) and for both inclined geostationary orbit (IGSO) and medium earth orbit (MEO) satellite constellations. At frequency B1, the IGSO and the MEO variation improved by 43.64% and 46.39%, respectively. At frequency B2, the IGSO and the MEO variation improved by 52.14% and 51.08%, respectively. Raw and corrected scenarios were compared in an experiment investigating time and frequency transfer. Consequently, the impact of BDS code bias variation on time and frequency transfer was mainly concentrated on the value of the time and frequency transfer. It was not a constant value (mean time transfer value of −0.41 ns), and the corresponding amplitude is closely related to the geodetic distance of the time links. Moreover, the BDS code bias variation showed no obvious effect on the frequency stability of the time links. Therefore, the satellite-induced code bias variation is a crucial error term in practical time transfer work, which needs to be corrected to improve the accuracy of the time transfer value, particularly for a long geodetic distance time link. (paper)
[en] The carrier-phase (CP) technique, based on the global navigation satellite system (GNSS), has proved to be a useful spatial tool for remote and precise time transfer. In this study, we analysed the performance of CP time and frequency transfer with different GNSSs, using a satellite orbit and clock products collected from three analysis centres (ACs): CODE, WHU, and GFZ. From the time and frequency transfer experiments with six international time links, we concluded that the CP technique, based on different GNSSs, can all achieve a sub-nanosecond level accuracy for time and frequency transfer. Statistical analysis of the experiments shows that the global positioning system (GPS) solution can obtain the mean root mean square (RMS) of the six time links: 0.321 ns for cod (satellite products of CODE), 0.347 ns for whn (satellite products of WHU), and 0.288 ns for gbm (satellite products of GFZ). For Russian global navigation satellite system (GLONASS) solutions, the mean RMS is 0.306 ns for cod, 0.371 ns for whn, and 0.298 ns for gbm. In terms of emerging GNSSs, the Galileo can achieve a mean RMS of 0.293 ns for cod, 0.356 ns for whn, 0.295 ns for gbm, and the BeiDou navigation satellite system (BDS) can achieve a mean RMS of 0.294 ns for cod, 0.333 ns for whn, and 0.303 ns for gbm. The mean RMS is 0.288 ns for GPS, 0.298 ns for GLONASS, 0.295 ns for Galileo, and 0.303 ns for BDS. Regarding the three ACs, cod and gbm solutions show better performance than whn solutions. With respect to the frequency stability of CP technique by different GNSSs, Galileo and BDS are comparable to GPS at different averaging time intervals, while GLONASS is significantly worse than GPS. (paper)
[en] Interface states influence the operation of nanocrystal (NC) solar cell carrier transport, recombination and energetic mechanisms. In a typical CdTe NC solar cell with a normal structure of a ITO/p-CdTe NCs/n-acceptor (or without)/Al configuration, the contact between the ITO and CdTe is a non-ohm contact due to a different work function (for an ITO, the value is ∼4.7 eV, while for CdTe NCs, the value is ∼5.3 eV), which results in an energetic barrier at the ITO/CdTe interface and decreases the performance of the NC solar cells. This work investigates how interface materials (including Au, MoOx and C60) affect the performance of NC solar cells. It is found that devices with interface materials have shown higher Voc than those without interface materials. For the case in which we used Au as an interface, we obtained a high open-circuit voltage of 0.65 V, coupled with a high fill factor (62%); this resulted in a higher energy conversion efficiency (ECE) of 5.3%, which showed a 30% increase in the ECE compared with those without the interlayer. The capacitance measurements indicate that the increased Voc in the case in which Au was used as the interface is likely due to good ohm contact between the Au’s and the CdTe NCs’ thin film, which decreases the energetic barrier at the ITO/CdTe interface. (paper)
[en] Highlights: • Three parameters are used to evaluate the startup performance. • The startup is faster and overshoot is larger when the distribution is more uneven. • Heating on one evaporator with same Q with the other makes transition time longer. • Heating on one evaporator with same Q with the other makes the overshoot smaller. • Transition time is about twice as much as peak time when peak time exists. - Abstract: Loop thermosyphon with multiple evaporators is a promising device in multi-source heat transfer. The startup performance is very important for its thermal control ability. In this paper, the effect of heating power distribution on the startup of a loop thermosyphon with dual evaporators is investigated experimentally. The startup time and stationarity under different power distributions are analyzed utilizing three parameters: peak time, transition time and temperature (pressure) overshoot. The results show that the startup process is faster and the overshoot of pressure and temperature is larger when the distribution is more uneven; Heating on one evaporator with the same heating power with the other evaporator makes the startup process longer while it makes the overshoot smaller or even disappear; The transition time is approximately twice as much as the peak time when the peak time exists.
[en] Wave energy is one of the most promising renewable energy for power generation. This research develops a novel power take-off methodology to surmount the problems associated with mooring, seawater corrosion and access for maintenance in conventional WEC (wave energy converters) with direct-driven linear generators. Its prototype consists of two bodies, the floating body acting as a buoy to extract the wave energy, while the inner body undergoes a forced oscillation, whose relative motion generates the electronic power. Its feasibility is investigated theoretically by coupling the dynamics of the wave, the floating and the inner bodies and the electromagnetic characteristics of the linear generator. As a result, the generator can induce a highly sinusoidal voltage. Furthermore, the performance of the system is investigated in detail under different conditions. The results show that, a resonance has been achieved in the case with the spring constant of 12,633 N/m, with a maximum power capture ratio of 57%. The performance of the system is shown to be sensitive to the load resistance, the wave height, and the spring constant. - Highlights: • A fully floating wave energy converter utilizing the relative motion is proposed. • The generator is fixed in an enclosed cavity without contact with the seawater. • A coupled dynamic and electromagnetic theoretically model has been established. • The linear generator in the WEC can induce a nearly sinusoidal voltage. • A resonance has been achieved in the WEC with a maximum power capture ratio of 57%.
[en] Highlights: • An unsteady analytical model for predicting the infiltration flow rate is developed. • The proposed model is validated by two independent experiments. • The prediction errors of infiltration air volume are distributed between ±10%. • The feasibility of applying the model to practical applications is analyzed. - Abstract: Infiltration through the doorway, which accounts for a very large part of total cooling load, has been highlighted in the previous studies on energy consumption of cold stores. Usually, the prediction of the infiltration flow rate is based on steady models and CFD simulations. However, the steady models are not very accurate for predictions of dynamic flow rates and the CFD transient simulations are time consuming. In this paper, the infiltration flow inside the door is described by the time-dependent differential equations of motion and continuity. An unsteady analytical model is developed by using these equations based on two independent infiltration procedures. Meanwhile, an equation to calculate the effective length of the infiltration is introduced to the proposed model to help improving prediction accuracy. The transient variables in this model are velocity, density and time. And these equations yield an ODE system, which can be numerically solved by using the Matlab software to get the dynamic infiltration flow rates. This model is validated by two independent experiments: infiltration with small and large door opening sizes respectively. The prediction errors are between ±10% for infiltration air volume and ±12% for infiltration flow rate. The performance of this model is also compared with the steady models. It is concluded that the proposed model has a better accuracy than the steady models in the strong transient occasions (with large door opening sizes). And this model is simpler than the CFD simulations on the calculations of the dynamic infiltration flow rates.