Local strategies for China's carbon mitigation: An investigation of Chinese city-level CO2 emissions

This paper provides a systematic analysis that identifies the driving forces of carbon dioxide (CO2) emissions of 286 Chinese prefecture-level cities in 2012. The regression analysis confirms the economic scale and structure effects on cities' CO2 emissions in China. If China's annual economic growth continues at the rate of 7%, CO2 emissions will increase by about 6% annually. In addition, climate conditions, urbanization and public investment in R&D are identified as important driving forces to increase the CO2 emissions of Chinese cities. While an increment of the urbanization rate by 1% increases the CO2 emissions by about 0.9%; An increase in R&D investment by 1% can help reduce CO2 emissions by 0.21%. As cities in our study vary greatly based on their industry composition, development stage and geographical location, the patterns of their CO2 emissions are also variable. Our study improves the comprehensiveness and accuracy of previous carbon accounting method by distinguishing the scope 1 and scope 2 CO2 emissions and establishing a high spatial resolution dataset of CO2 emissions (CHRED). The analysis covers almost all Chinese prefectural cities and derives useful implications for China's low carbon development

A Case Study for a Worn Tool Steel in the Hot Stamping Process

A good understanding of failure mechanisms can help us improve the lifetime of the dies. This paper presents a case study investigating the wear behavior of a QRO90 die insert utilized for stamping uncoated boron-alloyed high-strength steel sheets. Topography and microstructure were characterized by means of scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), hardness measurement and X-ray photoelectron spectroscopy (XPS). Severe galling due to accumulated layers transferred from the boron-alloyed steel workpieces occurred on the die surface. Material softening was detected in the sublayer of the tool steel (up to ∼200 μm). In addition, white layers with a in a thickness of 1-2 μm were frequently observed on the surface of the round corner of the tool. The main wear mechanisms are discussed. Galling caused by surface softening and the spallation of white layers are considered to be the primary wear mechanisms for the tool

Study of defects in directed energy deposited Vanadis 4 Extra tool steel

A cold work tool steel with varied number of layers was deposited on a substrate of hot work tool steel for hard-facing by directed energy deposition technique. This study deals with the defects and microstructure in the as-cladded tool steels. Defects, including pores and cracks, were found in the deposited zone, the number of which increased with the building height or number of layers deposited. Large irregular pores were mainly located at the lower regions of the deposited layers. The formation of this type of pores was attributed to the segregation of alloy elements on the pore surface and insufficient heat input. Non-equilibrium eutectic microstructure was a characteristic feature in the regions adjacent to the pores. Cracking, on the other hand, tended to occur in the upper part of the deposited layers. Two important contributing factors were identified for cracking. The first one was the microstructural gradient, which was modified from fine cellular dendrite to columnar dendrite when moving from the bottom to the top deposited layer. Second, the deposited cold work tool steel exhibited a relatively large temperature range of solidification, as simulated by Thermocalc software, leading to high sensitivity to hot cracking

Time and temperature dependent softening of a novel maraging steel fabricated by laser metal deposition

Durability is a critical factor for hot stamping dies from an economic point of view. Refurbishing the dies by depositing new material instead of replacement is a promising method to reduce the cost. For this reason, a newly developed maraging steel (NMS) was cladded on a hot work tool steel by means of directed energy deposition. After an optimized tempering, exposures at high temperatures were carried out on the cladded NMS in order to examine the softening resistance. The microstructural evolution of the material was systematically characterized using a combination of optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and transmission electron microscopy (TEM). The precipitate in the cladded steel was identified as Laves phase. The coarsening of this phase is considered as the main reason for the thermal softening of the steel at high temperatures. The coarsening behavior was also simulated by using the revised Langer-Schwartz-Wagner (LSW) model, which was in good agreement with experimental observations. Moreover, a mathematical model of precipitate strengthening was successfully applied to evaluate the softening behavior of the steel. This model can be used to predict the hardness/strength evolution of the investigated tool steel during its high-temperature service

Caveolins/caveolae protect adipocytes from fatty acid-mediated lipotoxicity

Mice and humans lacking functional caveolae are dyslipidemic and have reduced fat stores and smaller fat cells. To test the role of caveolins/caveolae in maintaining lipid stores and adipocyte integrity, we compared lipolysis in caveolin-1 (Cav1)-null fat cells to that in cells reconstituted for caveolae by caveolin-1 re-expression. We find that the Cav1-null cells have a modestly enhanced rate of lipolysis and reduced cellular integrity compared with reconstituted cells as determined by the release of lipid metabolites and lactic dehydrogenase, respectively, into the media. There are no apparent differences in the levels of lipolytic enzymes or hormonally stimulated phosphorylation events in the two cell lines. In addition, acute fasting, which dramatically raises circulating fatty acid levels in vivo, causes a significant upregulation of caveolar protein constituents. These results are consistent with the hypothesis that caveolae protect fat cells from the lipotoxic effects of elevated levels fatty acids, which are weak detergents at physiological pH, by virtue of the property of caveolae to form detergentresistant membrane domains

Efficient and scalable prediction of stochastic reaction–diffusion processes using graph neural networks

The dynamics of locally interacting particles that are distributed in space give rise to a multitude of complex behaviours. However the simulation of reaction–diffusion processes which model such systems is highly computationally expensive, the cost increasing rapidly with the size of space. Here, we devise a graph neural network based approach that uses cheap Monte Carlo simulations of reaction–diffusion processes in a small space to cast predictions of the dynamics of the same processes in a much larger and complex space, including spaces modelled by networks with heterogeneous topology. By applying the method to two biological examples, we show that it leads to accurate results in a small fraction of the computation time of standard stochastic simulation methods. The scalability and accuracy of the method suggest it is a promising approach for studying reaction–diffusion processes in complex spatial domains such as those modelling biochemical reactions, population evolution and epidemic spreading

Effect of reduced energy density of close-up diets on metabolites, lipolysis and gluconeogenesis in Holstein cows

Objective An experiment was conducted to determine the effect of reduced energy density of close-up diets on metabolites, lipolysis and gluconeogenesis in cows during the transition period. Methods Thirty-nine Holstein dry cows were blocked and assigned randomly to three groups, fed a high energy density diet (HD, 1.62 Mcal of net energy for lactation [NEL]/kg dry matter [DM]), a medium energy density diet (MD, 1.47 Mcal NEL/kg DM), or a low energy density diet (LD, 1.30 Mcal NEL/kg DM) prepartum; they were fed the same lactation diet to 28 days in milk (DIM). All the cows were housed in a free-stall barn and fed ad libitum. Results The reduced energy density diets decreased the blood insulin concentration and increased nonesterified fatty acids (NEFA) concentration in the prepartum period (p0.05). The dietary energy density had no effect on mRNA abundance of insulin receptors, leptin and peroxisome proliferator-activated receptor-γ in adipose tissue, and phosphoenolpyruvate carboxykinase, carnitine palmitoyltransferase-1 and peroxisome proliferator-activated receptor-α in liver during the transition period (p>0.05). The HD cows had higher mRNA abundance of hormone-sensitive lipase at 3 DIM compared with the MD cows and LD cows (p = 0.001). The mRNA abundance of hepatic pyruvate carboxykinase at 3 DIM tended to be increased by the reduced energy density of the close-up diets (p = 0.08). Conclusion The reduced energy density diet prepartum was effective in controlling adipose tissue mobilization and improving the capacity of hepatic gluconeogenesis postpartum

Quantifying how post-transcriptional noise and gene copy number variation bias transcriptional parameter inference from mRNA distributions

Transcriptional rates are often estimated by fitting the distribution of mature mRNA numbers measured using smFISH (single molecule fluorescence in situ hybridization) with the distribution predicted by the telegraph model of gene expression, which defines two promoter states of activity and inactivity. However, fluctuations in mature mRNA numbers are strongly affected by processes downstream of transcription. In addition, the telegraph model assumes one gene copy but in experiments, cells may have two gene copies as cells replicate their genome during the cell cycle. While it is often presumed that post-transcriptional noise and gene copy number variation affect transcriptional parameter estimation, the size of the error introduced remains unclear. To address this issue, here we measure both mature and nascent mRNA distributions of GAL10 in yeast cells using smFISH and classify each cell according to its cell cycle phase. We infer transcriptional parameters from mature and nascent mRNA distributions, with and without accounting for cell cycle phase and compare the results to live-cell transcription measurements of the same gene. We find that: (i) correcting for cell cycle dynamics decreases the promoter switching rates and the initiation rate, and increases the fraction of time spent in the active state, as well as the burst size; (ii) additional correction for post-transcriptional noise leads to further increases in the burst size and to a large reduction in the errors in parameter estimation. Furthermore, we outline how to correctly adjust for measurement noise in smFISH due to uncertainty in transcription site localisation when introns cannot be labelled. Simulations with parameters estimated from nascent smFISH data, which is corrected for cell cycle phases and measurement noise, leads to autocorrelation functions that agree with those obtained from live-cell imaging

Higher fraction of inspired oxygen during anesthesia increase the risk of postoperative pulmonary complications in patients undergoing non-cardiothoracic surgery: a retrospective cohort study

ObjectiveThe ideal intra-operative inspired oxygen concentration remains controversial. We aimed to investigate the association between the intraoperative fraction of inspired oxygen (FiO2) and the incidence of postoperative pulmonary complications (PPCs) in patients undergoing non-cardiothoracic surgery.MethodsThis was a retrospective cohort study of elderly patients who underwent non-cardiothoracic surgery between April 2020 and January 2022. According to intraoperative FiO2, patients were divided into low (≤60%) and high (>60%) FiO2 groups. The primary outcome was the incidence of a composite of pulmonary complications (PPCs) within the first seven postoperative days. Propensity score matching (PSM) and inverse probability treatment weighting (IPTW) were conducted to adjust for baseline characteristic differences between the two groups. Multivariate logistic regression analysis was used to calculate the odds ratios (OR) for FiO2 and PPCs.ResultsAmong the 3,515 included patients with a median age of 70 years (interquartile range: 68–74), 492 (14%) experienced PPCs within the first 7 postoperative days. Elevated FiO2 was associated with an increased risk of PPCs in all the logistic regression models. The OR of the FiO2 > 60% group was 1.252 (95%CI, 1.015–1.551, P = 0.038) in the univariate analysis. In the multivariate logistic regression models, the ORs of the FiO2 > 60% group were 1.259 (Model 2), 1.314 (Model 3), and 1.32 (model 4). A balanced covariate distribution between the two groups was created using PSM or IPTW. The correlation between elevated FiO2 and an increased risk of PPCs remained statistically significant with PSM analysis (OR, 1.393; 95% CI, 1.077–1.804; P = 0.012) and IPTW analysis (OR, 1.266; 95% CI, 1.086–1.476; P = 0.003).ConclusionHigh intraoperative FiO2 (>60%) was associated with the postoperative occurrence of pulmonary complications, independent of predefined risk factors, in elderly non-cardiothoracic surgery patients. High intraoperative FiO2 should be applied cautiously in surgical patients vulnerable to PPCs

Joint Channel and Power Assignment for Underwater Cognitive Acoustic Networks on Marine Mammal-Friendly

When marine animals and underwater acoustic sensor networks (UASNs) share spectrum resources, problems such as serious harm caused to marine animals by underwater acoustic systems and scarcity of underwater spectrum resources are encountered. To address these issues, a mammal-friendly underwater acoustic sensor network channel power allocation algorithm is proposed. Firstly, marine animals are treated as authorized users and sensor nodes as unauthorized users. Considering the interference level of sensor nodes on authorized users, this approach improves network service quality and achieves a mammal-friendly underwater communication mechanism. Secondly, to maximize the utility of unauthorized users, the algorithm incorporates a network interference level and node remaining energy into a game-theoretical framework. Using channel allocation and power control, a game model is constructed with a unique Nash equilibrium point. Finally, through simulation, it can be found that the proposed algorithm can obtain a stable optimal power value, and with the increase of network load, the system capacity of the proposed algorithm is significantly improved than that of the traditional cognitive radio technology and the common spectrum allocation algorithm, and the transmitted power of nodes can be controlled according to the size of the residual energy, so as to comprehensively improve the overall performance of the network