The temperature biases of 28 CMIP5 AGCMs are evaluated over the Tibetan Plateau（TP） for the period 1979–2005. The results demonstrate that the majority of CMIP5 models underestimate annual and ...seasonal mean surface 2-m air temperatures(Tas) over the TP. In addition, the ensemble of the 28 AGCMs and half of the individual models underestimate annual mean skin temperatures（Ts） over the TP. The cold biases are larger in Tas than in Ts, and are larger over the western TP. By decomposing the Ts bias using the surface energy budget equation, we investigate the contributions to the cold surface temperature bias on the TP from various factors, including the surface albedo-induced bias, surface cloud radiative forcing, clear-sky shortwave radiation, clear-sky downward longwave radiation, surface sensible heat flux, latent heat flux,and heat storage. The results show a suite of physically interlinked processes contributing to the cold surface temperature bias.Strong negative surface albedo-induced bias associated with excessive snow cover and the surface heat fluxes are highly anticorrelated, and the cancelling out of these two terms leads to a relatively weak contribution to the cold bias. Smaller surface turbulent fluxes lead to colder lower-tropospheric temperature and lower water vapor content, which in turn cause negative clear-sky downward longwave radiation and cold bias. The results suggest that improvements in the parameterization of the area of snow cover, as well as the boundary layer, and hence surface turbulent fluxes, may help to reduce the cold bias over the TP in the models.
This paper proposes a two-axis-decoupled solar tracker based on parallel mechanism. Utilizing Grassmann line geometry, the type design of the two-axis solar tracker is investigated. Then, singularity ...is studied to obtain the workspace without singularities. By using the virtual work principle, the inverse dynamics is derived to find out the driving torque. Taking Beijing as a sample city where the solar tracker is placed, the motion trajectory of the tracker is planned to collect the maximum solar energy. The position of the mass center of the solar mirror on the platform is optimized to minimize the driving torque. The driving torque of the proposed tracker is compared with that of a conventional serial tracker, which shows that the proposed tracker can greatly reduce the driving torque and the reducers with large reduction ratio are not necessary. Thus, the complexity and power dissipation of the system can be reduced.
Micro-dimples have been applied to different mechanical components to improve friction and lubrication performances in various fields. Through-mask electrochemical micromachining (TMEMM) is a ...promising method for producing micro-dimples. In TMEMM, overcutting of micro-dimples leads to a deterioration in machining accuracy. This paper proposes a new method, sandwich-like electrochemical micromachining (SLEMM), to reduce overcutting of micro-dimples in diameter and to enhance the dimensional uniformity of micro-dimple arrays. Experimental results show that for a similar depth of 11μm, the use of SLEMM instead of TMEMM leads to a reduction in micro-dimple diameter from 124.3 to 109.0μm and a sharp increase in etch factor from 0.9 to 2.5, confirming that SLEMM should be able to enhance the machining localization and machining accuracy of micro-dimples. Arrays of 1500 micro-dimples were generated both by TMEMM and by SLEMM. For TMEMM, the micro-dimple diameter and depth increased from 120.8 and 11.0μm, respectively, near the center of the workpiece surface to 130.4 and 12.8μm, respectively, at the edge. In contrast, for SLEMM, the micro-dimple diameter and depth near the center of the workpiece surface, 109.0μm and 11.2μm, respectively, were almost the same as those at the edge. Thus, SLEMM can also improve the dimensional uniformity of micro-dimple arrays. Finally, different types of surface textures involving hexagons, ellipses, and squares can be fabricated using SLEMM.
•Simulation results show that current density distribution is more uniform on workpiece in SLEMM compared with TMEMM.•The method of SLEMM could improve the dimensional uniformity of micro-dimples, compared with TMEMM.•With this method of SLEMM, different types of surface textures can be fabricated with high machining accuracy.
The goal of this study was to explore the feasibility and accuracy of using a wearable mixed-reality holographic computer to guide external ventricular drain (EVD) insertion and thus improve on the ...accuracy of the classic freehand insertion method for EVD insertion. The authors also sought to provide a clinically applicable workflow demonstration.
Pre- and postoperative CT scanning were performed routinely by the authors for every patient who needed EVD insertion. Hologram-guided EVD placement was prospectively applied in 15 patients between August and November 2017. During surgical planning, model reconstruction and trajectory calculation for each patient were completed using preoperative CT. By wearing a Microsoft HoloLens, the neurosurgeon was able to visualize the preoperative CT-generated holograms of the surgical plan and perform EVD placement by keeping the catheter aligned with the holographic trajectory. Fifteen patients who had undergone classic freehand EVD insertion were retrospectively included as controls. The feasibility and accuracy of the hologram-guided technique were evaluated by comparing the time required, number of passes, and target deviation for hologram-guided EVD placement with those for classic freehand EVD insertion.
Surgical planning and hologram visualization were performed in all 15 cases in which EVD insertion involved holographic guidance. No adverse events related to the hologram-guided procedures were observed. The mean ± SD additional time before the surgical part of the procedure began was 40.20 ± 10.74 minutes. The average number of passes was 1.07 ± 0.258 in the holographic guidance group, compared with 2.33 ± 0.98 in the control group (p < 0.01). The mean target deviation was 4.34 ± 1.63 mm in the holographic guidance group and 11.26 ± 4.83 mm in the control group (p < 0.01).
This study demonstrates the use of a head-mounted mixed-reality holographic computer to successfully perform hologram-assisted bedside EVD insertion. A full set of clinically applicable workflow images is presented to show how medical imaging data can be used by the neurosurgeon to visualize patient-specific holograms that can intuitively guide hands-on operation. The authors also provide preliminary confirmation of the feasibility and accuracy of this hologram-guided EVD insertion technique.
Autophagy induction is an effective approach for OA therapy. IL-1β is one of the major inflammatory cytokines linked to OA pathological progression, and its receptor blockade interrupts OA cartilage ...destruction. The objective of this study was to decipher the link between autophagy and regulatory mechanism of IL-1β and to investigate the effect of IL-1β receptor blockade by IL-1 receptor antagonist (IL-1Ra) combined with or without an autophagy inducer (TAT-Beclin1) on extracellular matrix (ECM) in OA chondrocytes in vitro and in vivo.
IL-1β-treated rat and human OA chondrocytes were cultured in response to IL-1Ra. The expression and distribution of signal molecules regulating ECM synthesis and autophagy were investigated via western blotting, immunoprecipitation, real-time PCR, immunofluorescence, and transmission electron microscope technique. Furthermore, after intra-articular injection of IL-1Ra, TAT-Beclin1, and a combination of both in a rat OA model established by anterior cruciate ligament transection and medial meniscus resection, the morphological changes of cartilage and related signal molecule expression levels were monitored using H.E., Safranin O-Fast green, and immunohistochemistry staining.
Reduced autophagy by IL-1β contributed to ECM degradation, and blockade of IL-1β by IL-1Ra restored autophagy and attenuated ECM degradation in rat and human OA chondrocytes, as well as in a rat OA model. Akt/mTOR/ULK1, Akt/mTOR/NF-κB, and LC3B deacetylation were involved in autophagy regulated by IL-1β. Intra-articular injection of IL-1Ra combined with TAT-Beclin1 was more effective than IL-1Ra alone.
IL-1Ra restored autophagy and attenuated ECM degradation, with an implication that blocking IL-1β combined with enhancing autophagy might be a potential therapeutic strategy for OA.
Alteration of metabolic profile is one of the hallmarks of cancer cells. Statin, the inhibitors for synthesis of cholesterol, has shown anti-cancer effects on the gastric cancer cells. However, the ...functions of its target, HMGCR, in the progression of gastric cancer remain unknown. In the present study, we investigated the expression profile and the biological functions of HMGCR in gastric cancer. It was found that the expression of HMGCR was increased in gastric cancer tissues. Over-expression of HMGCR promoted the growth and migration of gastric cancer cells, while knocking down the expression of HMGCR inhibited the growth, migration and tumorigenesis of gastric cancer cells. In the further molecular mechanism study, HMGCR was shown to activate Hedgehog/Gli1 signaling and promoted the expression of Gli1 target genes. Taken together, this study demonstrated the tumor-promoting effects of HMGCR in gastric cancer and suggested HMGCR as a promising therapeutic target.
•HMGCR is overexpressed in GC samples.•HMGCR positively regulates the growth, migration and tumorigenesis of GC cells.•HMGCR activates Hedgehog signaling.
Residents’ participation in pro-environmental behaviors (PEBs) is critical for addressing environmental problems and promoting sustainable development. Place attachment (PA) may play a key role in ...motivating residents’ pro-environment behaviors, yet the mechanisms of this relationship remain ambiguous. This study integrated natural relatedness (NR) into the research to deepen understanding of its mechanism. Using data collected in Beijing ( n = 648), we found that place attachment positively and significantly influences pro-environmental behaviors through nature relatedness. Place attachment significantly affected pro-environmental behaviors. The Place attachment dimensions, including place identity (PI), natural bonding (NB), and social bonding (SB), had a significant prediction on pro-environmental behaviors. Specifically, natural bonding plays the most effective effect. However, place dependence (PD) was negatively correlated with pro-environmental behaviors. This study provides guidelines for local governments and policymakers to promote residents’ pro-environmental behaviors and improve environmental management.
Micro-dimple arrays are widely used as surface textures in tribology to improve friction performance. Through-mask electrochemical micro-machining (TMEMM) is a popular method to generate such arrays. ...However, machining accuracy is reduced by lateral undercutting of the micro-dimples. In this paper, we present that the oxygen bubbles produced on the workpiece surface during the machining could be employed to reduce undercutting. A thick mask was introduced to prevent escape of the oxygen bubbles from the micro-dimples. Oxygen bubbles accumulating at the micro-dimple edges might protect the edges from etching, thereby reducing undercutting and improving machining accuracy. The experimental results show an undercutting of only about 3μm with a 250-μm-thick polydimethylsiloxane (PDMS) mask. In particular, there was no increase in undercutting when the applied voltage and machining time were increased. An interesting phenomenon was observed in which there was little increase in depth with increasing voltage, whereas the depth increased with longer machining time. Thus, direct or pulsed current can be used to generate different depths of micro-dimple arrays with low undercutting by simply controlling the machining time, regardless of the applied voltage.
•Oxygen bubbles were utilized to reduce the undercutting of the micro-dimples.•Bubbles at micro-dimple edges inhibited the further increase in the undercutting.•Due to the bubbles, the current has little change with the increasing voltage.•With this method, there was only 3μm undercutting in the micro-dimples.
As the number of elderly migrants in China continues to grow, it is necessary to pay closer attention to their health and health services. Some studies have confirmed that social capital plays a ...significant role in the utilization of health services. Therefore, an in-depth exploration of the relationship between social capital and the utilization of essential public health services (EPHS) by elderly migrants will not only contribute to improving their overall health but also facilitate a more balanced development of public health service system in China.
Based on the cross-sectional data from the 2017 China Migrants Dynamic Survey (CMDS), this study examined the impact of social capital on the utilization of EPHS among elderly migrants. We evaluated social capital at two distinct levels: the individual and the community, and considered two dimensions of social capital: structural social capital (SSC) and cognitive social capital (CSC). The study aimed to delve into the impact of these forms of social capital on the utilization of EPHS among elderly migrants, and whether the migration range moderates this impact by multilevel logistic regression analysis.
A total of 5,728 migrant elderly individuals were selected. The health records establishment rate and health education acceptance rate were approximately 33.0% and 58.6%, respectively. Social capital influenceed the utilization of EPHS among elderly migrants. Specifically, individual-level SSC and CSC have impacts on both the establishment of health records (OR = 1.598, 95%CI 1.366-1.869; OR = 1.705, 95%CI 1.433-2.028) and the acceptance of health education (OR = 1.345, 95%CI 1.154-1.567; OR = 2.297, 95%CI 1.906-2.768) among elderly migrants, while community-level SSC only affected the acceptance of health education (OR = 3.838, 95%CI 1.328-11.097). There were significant differences in individual-level SSC, health records, and health education among different migration range subgroups among elderly migrants. Migration range moderated the effect of social capital on the utilization of EPHS, crossing provinces could weaken the relationship between SSC and health education.
Social capital is associated with a higher utilization rate of EPHS among elderly migrants. It is necessary to encourage them to actively participate in social activities, strengthen public services and infrastructure construction in the area, and improve their sense of belonging and identity.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Precise location of intracranial lesions before surgery is important, but occasionally difficult. Modern navigation systems are very helpful, but expensive. A low-cost solution that could locate ...brain lesions and their surface projections in augmented reality would be beneficial. We used an iPhone to partially achieve this goal, and evaluated its accuracy and feasibility in a clinical neurosurgery setting.
We located brain lesions in 35 patients, and using an iPhone, we depicted the lesion's surface projection onto the skin of the head. To assess the accuracy of this method, we pasted computed tomography (CT) markers surrounding the depicted lesion boundaries on the skin onto 15 patients. CT scans were then performed with or without contrast enhancement. The deviations (D) between the CT markers and the actual lesion boundaries were measured. We found that 97.7% of the markers displayed a high accuracy level (D ≤ 5mm). In the remaining 20 patients, we compared our iPhone-based method with a frameless neuronavigation system. Four check points were chosen on the skin surrounding the depicted lesion boundaries, to assess the deviations between the two methods. The integrated offset was calculated according to the deviations at the four check points. We found that for the supratentorial lesions, the medial offset between these two methods was 2.90 mm and the maximum offset was 4.2 mm.
This low-cost, image-based, iPhone-assisted, augmented reality solution is technically feasible, and helpful for the localization of some intracranial lesions, especially shallow supratentorial intracranial lesions of moderate size.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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