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The viscosity of crude oil plays a pivotal role in the exploration and development of oil fields. The predominant reliance on laboratory measurements, which are constrained by manual expertise, represents a significant limitation in terms of efficiency. Two-dimensional nuclear magnetic resonance (NMR) logging offers a number of advantages over traditional methods. It is capable of providing faster measurement rates, as well as insights into fluid properties, which can facilitate timely adjustments in oil and gas development strategies. This study focuses on the loose sandstone reservoirs with high porosity and permeability containing heavy oil in the Huabei oilfield. Two-dimensional nuclear magnetic resonance (NMR) measurements and analyses were conducted on saturated rocks with different-viscosity crude oils and varying oil saturation levels, in both natural and artificial rock samples. This study elucidates the distribution patterns of different-viscosity crude oils within the two-dimensional NMR spectra. Furthermore, the T1 and T2 peak values of the extracted oil signals were employed to establish a model correlating oil viscosity with NMR parameters. Consequently, a criterion for determining oil viscosity based on two-dimensional NMR was formulated, providing a novel approach for estimating oil viscosity. The application of this technique in the BQ well group of the Huabei oilfield region yielded an average relative error of 15% between the actual oil viscosity and the computed results. Furthermore, the consistency between the oil types and the oil discrimination chart confirms the reliability of the method. The final outcomes meet the precision requirements for practical log interpretation and demonstrate the excellent performance of two-dimensional nuclear magnetic resonance (NMR) logging in calculating oil viscosity. The findings of this study have significant implications for subsequent exploration and development endeavors in the research area's oilfields. [ABSTRACT FROM AUTHOR]

Methane catalytic combustion, a method for efficient methane utilization, features high energy efficiency and low emissions. The key to this process is the development of highly active and stable catalysts. This study involved the synthesis of a range of catalysts, including NiO/CeO2, NiO–M/CeO2, and NiO-Ba/CeO2. In order to modify the NiO/CeO2 catalysts to improve their catalytic activity, various alkaline earth metal ions were introduced, and the catalysts were characterized to evaluate the impact of different alkaline earth metal ion doping. It was found that the introduction of Ba as a dopant yielded the highest catalytic activity among the dopants tested. Based on this, the influence of the impregnation sequence, the Ba loading amount, and other factors on the catalytic activity of the NiO/CeO2 catalysts doped with Ba were investigated, and comprehensive characterization was conducted using a variety of analytical techniques, including N2 adsorption/desorption, X-ray diffraction, Fourier transform infrared, hydrogen temperature-programmed reduction, methane temperature-programmed surface reaction, and oxygen temperature-programmed oxidation. The H2–TPR characterization results suggest that Ba introduction partially enhances the reducing property of NiO/CeO2 catalysts, and improves the surface oxygen activity in the catalysts. Meanwhile, the CH4–TPSR and O2–TPO results indicate that Ba introduction also boosts the bulk-phase oxygen liquidity in the catalysts, renders the migration of bulk-phase oxygen to surface oxygen, and increases the surface oxygen number in the catalysts. These results provide evidence of the effectiveness of this catalyst in methane catalytic combustion. [ABSTRACT FROM AUTHOR]

Liquid composite molding (LCM) is a process for manufacturing fiber-reinforced resin matrix composites. The chemical rheological properties of resin in the filling stage of LCM will produce a non-isothermal flow process that includes multi-field coupling of thermal field, flow field, and chemical field. During the filling stage, the resin is injected into a closed mold pre-laid with a fiber at a certain temperature and pressure to flow continuously and undergo a curing chemical reaction. The viscosity of resin changes constantly under the influence of temperature and the curing reaction, which affects the flow of resin. The simulation of this multi-field coupling filling stage in LCM can provide an effective reference for the design of process parameters. The simulation method of the filling stage in LCM is studied in this paper. The mathematical model of the filling stage is derived based on the air–resin two-phase flow volume of the fluid model. Based on the secondary development of the ANSYS FLUENT software, the mathematical model is solved to realize the simulation. The parameters of an alkali-free glass fiber plain weave fabric are measured and the calculation model of thermosetting resin viscosity is established by designed experiments, which are applied in simulation. The filling stage experiment of LCM is designed to verify the accuracy of simulation results. Meanwhile, by comparing with the traditional simulation method, it is found that the data error obtained by the simulation method in this paper is significantly reduced. [ABSTRACT FROM AUTHOR]

The efficiency of adjoint-based aerodynamic shape optimization depends critically on the solution efficiency of adjoint equations. In this letter, we employ the Proper Orthogonal Decomposition (POD) method to analyze the adjoint field samples and project them from the physical space into a low-order modal space. Subsequently, the full-order adjoint equations are reduced to low-order equations using the POD modes. Thus, we can efficiently predict the initial values for pseudo-time marching, thereby accelerating the solution of adjoint equations. Results indicate that the high-order POD modes are crucial for constructing the low-dimensional system. Moreover, this method can be seamlessly integrated with our previously established Dynamic Mode Decomposition (DMD) acceleration method to form a POD+DMD acceleration approach. Application of this approach to the flow past a National Advisory Committee for Aeronautics 0012 airfoil demonstrates a noteworthy 80.9% reduction in iteration numbers when solving the adjoint equations. Even for the airfoil located on the upper boundary of sampling space, the number of iterations is still reduced by 72.6%. Therefore, we believe that the proposed method holds significant promise for improving the efficiency of adjoint-based aerodynamic shape optimization in future research. [ABSTRACT FROM AUTHOR]

In previous research on energy harvesting from vortex-induced vibrations (VIVs), the cross section of the structure commonly utilizes basic geometric shapes like circular, ellipse, square, and semicircle. Nevertheless, exploring optimized shapes for energy harvesting from VIV remains an understudied area. To address this gap, this paper employs adjoint-based unsteady shape optimization to increase the efficiency of energy harvesting from VIV of a circular cylinder at low Reynolds numbers. The goal of the optimization is to maximize the plunge-damping derivative of a single-degree-of-freedom transversely vibrating cylinder, which represents the rate of energy injected into the structure by the flow. To facilitate this process, an efficient method to evaluate the gradient of the objective function with respect to shape parameters is provided via the proposed unsteady discrete adjoint method. Results show that, through optimization, the low-pressure region behind the cylinder is significantly enlarged and the separation points move forward, resulting in the faster development of separation vortex and reduced stability of the fluid–structure coupling system. As a consequence, the intensity of VIV as well as the corresponding power generation efficiency is remarkably enhanced, accompanied by a notable expansion in the energy harvesting region. [ABSTRACT FROM AUTHOR]

Due to the large volume change and poor conductivity, manganese oxide with high theoretical specific capacity is difficult to be widely used in the anode of lithium-ion battery. By the self-propagating sol–gel method, the nano-sized manganese oxide particles are embedded in the amorphous porous C in situ. Amorphous porous C and nano-manganese oxide particles can alleviate the volume effect of manganese oxide, and C can increase the conductivity and stability of Mn2O3/Mn3O4/C composites. Therefore, Mn2O3/Mn3O4/C composites have excellent cyclic properties: 902.9 mAh/g at 1.0 A/g after 1300 cycles; 290.5 mAh/g at 5.0 A/g after 10,000 cycles; 183.3 mAh/g at 10 A/g after 10,000 cycles. [ABSTRACT FROM AUTHOR]

Environmental sustainability and eco-efficiency stand as imperative benchmarks for the upcoming era of materials. The use of sustainable plant fiber composites (PFCs) in structural components has garnered significant interest within industrial community. The durability of PFCs is an important consideration and needs to be well understood before their widespread application. Moisture/water aging, creep properties, and fatigue properties are the most critical aspects of the durability of PFCs. Currently, proposed approaches, such as fiber surface treatments, can alleviate the impact of water uptake on the mechanical properties of PFCs, but complete elimination seems impossible, thus limiting the application of PFCs in moist environments. Creep in PFCs has not received as much attention as water/moisture aging. Existing research has already found the significant creep deformation of PFCs due to the unique microstructure of plant fibers, and fortunately, strengthening fiber-matrix bonding has been reported to effectively improve creep resistance, although data remain limited. Regarding fatigue research in PFCs, most research focuses on tension-tension fatigue properties, but more attention is required on compression-related fatigue properties. PFCs have demonstrated a high endurance of one million cycles under a tension-tension fatigue load at 40% of their ultimate tensile strength (UTS), regardless of plant fiber type and textile architecture. These findings bolster confidence in the use of PFCs for structural applications, provided special measures are taken to alleviate creep and water absorption. This article outlines the current state of the research on the durability of PFCs in terms of the three critical factors mentioned above, and also discusses the associated improvement methods, with the hope that it can provide readers with a comprehensive overview of PFCs' durability and highlight areas worthy of further research. [ABSTRACT FROM AUTHOR]

The cure cycle plays a crucial role in manufacturing polymer‐matrix composite component. Unreasonable design of cure cycle can easily lead to thermal gradients during curing process, which will generate residual stress and seriously affect the quality of component. Meanwhile, the cure cycle of the three‐dimensional composite component is difficult to optimized, due to the complicated distribution of temperature and curing degree. In this paper, numerical simulation is applied to research the curing process of the polymer‐matrix composite. The change rules of temperature and curing degree are explored. An optimum design method for the cure cycle of three‐dimensional composite component is proposed. Meanwhile, numerical simulation is applied in this method to design the cure cycle by referring to the change rules of temperature and curing degree of the component, in which the internal and external thermal gradients can be balanced during the curing process. The results show that the optimized cure cycle can significantly reduce the thermal gradients for three‐dimensional composite component, which provide guidance for cure cycle design in the manufacturing of polymer‐matrix composite. [ABSTRACT FROM AUTHOR]

Objective: To observe fat tissue and the expression of adipokines in rheumatic heart valves and explore the possible role of fat tissue and adipokines in the pathology of rheumatic heart disease (RHD). Methods: In this retrospective study, a total of 29 patients who received mitral valve replacement surgery were included. The study group consisted of 25 patients with RHD while the control group consisted of 4 patients with secondary mitral insufficiency caused by coronary heart disease (CAD). The clinical data of the patients including medical history, age, body mass index (BMI), fasting blood glucose (FBG), total triglycerides (TG), total cholesterol (TC), high‐density lipoprotein‐cholesterol (HDL‐C), low‐density lipoprotein‐cholesterol (LDL‐C), apolipoprotein(a) [apo(a)], apolipoprotein(b) [apo(b)] were collected and compared. Cardiac ultrasonography was used to assess valve conditions before surgery. The removed valves were collected. The hematoxylin–eosin (HE) staining, oil‐red O staining, and Masson's trichrome staining were adopted to evaluate the histological changes in the mitral valve. Immunohistochemical (IMC) staining was performed to evaluate the expression of adiponectin, leptin, and chemerin. Results: There was no significant difference in general information and blood lipid levels between the two groups (all p >.05). Preoperative ultrasonography showed adipose tissue in the mitral valve of RHD patients. In the study group, rheumatic mitral valve samples showed thickening, adherence at the junction of the leaflets, calcification, and yellowish or fat mass by naked observation. The HE staining showed that there was calcification, inflammatory cell infiltration, fibrous tissue arranged disorder, and neovascularization. The oil‐red O staining suggested fatty infiltration. Masson's trichrome staining suggested disorderly arrangement of collagen fiber and elastic fiber in rheumatic lesions, and the lesions were dominated by collagen fiber hyperplasia and less elastic fiber hyperplasia. The results of IMC indicated that chemerin was not expressed in valves of the control group. Most of the valve samples from the study group also did not show leptin and the leptin was seen in only a few rheumatic mitral valves with vascular hyperplasia. Adiponectin was not found in the valves of the study group and the control group. Conclusion: Adipose tissue in the rheumatic mitral valve could be observed by ultrasound. The fat mass and adipokines existed in rheumatic mitral valves, the adipocytokine chemerin is involved in the progression of the pathology in RHD. [ABSTRACT FROM AUTHOR]

Understanding in situ crystallization of perovskite materials is fundamentally important for perovskite‐based materials, components, and devices. Here, in situ crystallization of perovskites in three dimensions is investigated using two‐photon excitation fluorescence microscopy with diffraction‐limited spatial resolution. By taking a perovskite precursor droplet as an example, the spatiotemporal kinetics of nanocrystal formation during crystallization is demonstrated, taking advantage of the perovskites' unique advantage of in situ synthesis from solutions. Based on the time‐lapsed 3D two‐photon excitation fluorescence imaging, the in situ formation of the "crystal crust" is observed and the results suggest a centripetal direction of the crystallization starting from the free surface of the droplet. Analysis based on fluorescence intensity further confirms the evaporation kinetics in a sessile precursor droplet. The reported results demonstrate a promising framework for utilizing two‐photon excitation fluorescence microscopy as a powerful tool to study the in situ crystallization of perovskite materials as well as more general fluorescence‐related chemical reactions in three dimensions. [ABSTRACT FROM AUTHOR]

The impact of adding H2O2 in the fuel stream on the structure of non-premixed opposed-flow NH3/O2 flames was investigated numerically using a verified computational tool and validated mechanism. The results illustrate the dual role of the added H2O2 within the fuel jet. A small amount of H2O2 within the NH3 stream acted as a fuel additive that enhanced the reaction rate via reducing the kinetic time scale. However, a novel flame structure appeared when the H2O2 mole fraction within the fuel stream increased to χ H 2 O 2 > 16%. Unlike the pure NH3/O2 flame, a premixed reaction zone was discerned on the fuel side, in which H2O2 reacts with NH3 and played the role of an oxidizer. Then, the remaining NH3 that survived premixed combustion continues reacting with O2 and forms a non-premixed flame. As a result of this structure, it was shown that the well-established conclusion of "near-equilibrium" non-premixed flame analysis in which the strain on the flame is determined by the momentum fluxes of the counter-flowing streams does not hold for the flames that were studied in this paper. It was also shown that when H2O2 acted as an oxidizer, it produced substantial amounts of HO2, which allowed for low-temperature formation of NO2 through the reaction of NO with HO2. [ABSTRACT FROM AUTHOR]

Background: Cognitive decline and neuropsychiatric symptoms (NPS) are main clinical manifestations in Alzheimer disease (AD). It is unclear whether the link between specific NPS and cognitive domains exists in AD or mild cognitive impairment (MCI). Our study aimed to examine the association between specific cognitive domain and NPS in AD and MCI, and to evaluate whether this association showed variety in different stages of cognitive impairment. Methods: A total of 458 patients diagnosed as AD or MCI were included in this study. Neuropsychological batteries were applied in the study. The association between NPS and cognitive function were evaluated by multiple linear regression, and its correlation was evaluated by Spearman correlation coefficient. Results: The prevalence of NPS increased with the severity of cognitive impairment, and there were significant differences between MCI and AD. NPS were predominantly associated with cognitive domains, including memory, language, attention, and executive function. Both regression liner analysis and correlation analysis showed delusion, hallucination, and aberrant motor behaviour (AMB) were linked to language and attention. In addition, regression liner analysis illustrated depression, anxiety, and apathy were related to learning and episodic memory. Generally, the delusion, hallucination, and AMB have the broadest impact on cognition. Conclusion: Specific NPS was predominantly associated with different cognitive domains. Symptoms of agitation, delusion and irritability indicate worse cognitive performance. Therefore, cognitive improvement should be a therapeutic strategy in managing NPS in AD. [ABSTRACT FROM AUTHOR]

This study investigated the effects of reynoutrin on the improvement of ischemic heart failure (IHF) and its possible mechanism in rats. The rat heart failure model was established by permanently ligating the left anterior descending coronary artery (LAD) and administering different doses of reynoutrin. Cardiac function, inflammatory factors releasing, oxidative stress, cardiomyocytes apoptosis, and myocardial fibrosis were evaluated. Western blotting was used to determine protein expression levels of S100 calcium-binding protein A1 (S100A1), matrix metallopeptidase 2(MMP2), MMP9, phosphorylated (p-) p65, and transforming growth factor -β1 (TGF-β1) in myocardial tissue of the left ventricle. Results showed that reynoutrin significantly improved cardiac function, suppressed the release of inflammatory factors, reduced oxidative stress, inhibited cardiomyocytes apoptosis, and attenuated myocardial fibrosis in rats with IHF. In rat myocardial tissue, permanent LAD-ligation resulted in a significant down-regulation in S100A1 expression, whereas reynoutrin significantly up-regulated S100A1 protein expression while down-regulating MMP2, MMP9, p-p65, and TGF-β1 expressions. However, when S100A1 was knocked down in myocardial tissue, the above-mentioned positive effects of reynoutrin were significantly reversed. Reynoutrin is a potential natural drug for the treatment of IHF, and its mechanism of action involves the up-regulation of S100A1 expression, thereby inhibiting expressions of MMPs and the transcriptional activity of nuclear factor kappa-B. [ABSTRACT FROM AUTHOR]

Background: To investigate the use and adherence of antidementia drugs in elderly patients with dementia from the Memory Clinic of The First Affiliated Hospital of Chongqing Medical University. Methods: Patients were recruited from the Memory Clinic of The First Affiliated Hospital of Chongqing Medical University from December 2010 to December 2018. Medical charts were reviewed, including diagnosis, dosage of antidementia medicines, neuropsychological testing scores, and the further questionnaires were conducted via face‐to‐face or telephone, included duration of treatment, types of antidementia drugs, and reasons for treatment discontinuation. Results: The data from 422 patients were analysed retrospectively for this study. Three hundred and fifteen were diagnosed with Alzheimer's disease (AD), 67 with mild cognitive impairment (MCI), and 40 with other types of dementia. From the 422 patients, 26.8% were treated with original donepezil (n = 113), 11.6% with generic donepezil (n = 49), 24.6% with memantine (n = 104), 13.3% with huperzine A (n = 56), and 23.7% with a combination of drugs (n = 100). However, 73% of patients discontinued treatment within 1 year of initiation. Patients treated for more than 36 months (37.8%) were more likely to choose combined medication, as compared with patients treated for less than 36 months. Patients with less than 9 years of education (odds ratio (OR): 2.394; 95% CI: 1.508–3.801) were more likely to discontinue treatment than patients with more than 9 years of education. Patients with elevated physical self‐maintenance scale (PSMS) scores (OR: 1.195; 95% CI: 1.086–1.316) had a high risk of discontinuation. Conclusions: Overall treatment compliance is relatively poor in memory clinics in Chongqing. Our study demonstrates that higher education may lead to better treatment adherence in dementia care. Combination therapy may increase treatment time. However, poorer PSMS scores are a significant risk factor for treatment discontinuation. [ABSTRACT FROM AUTHOR]

Presently, the mold and resin are heated to promote resin flow and shorten curing period in order to improve manufacturing efficiency of resin transfer molding (RTM). This nonisothermal manufacturing process easily generates three‐dimensional thermal gradients in the direction of resin flow and thickness of composite part. However, the existing heating systems only consider the thermal gradients along thickness direction. The thermal gradients in direction of resin flow cannot be reduced which will lead to residual stress even deformation and cracking in composite part. This article aims at reducing the three‐dimensional thermal gradients in the direction of resin flow and thickness of composite part. Based on the theory of energy and fluid flow, an optimization method of heating system design by using numerical simulation is proposed. The results show this method reduces the three‐dimensional thermal gradients effectively in composite part manufactured by RTM process. This study can provide powerful tools for heating system design to manufacture composites products in polymer industry. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48948. [ABSTRACT FROM AUTHOR]

Positron emission tomography (PET) image reconstruction from low‐count projection data and physical effects is challenging because the inverse problem is ill‐posed and the resultant image is usually noisy. Recently, generative adversarial networks (GANs) have also shown their superior performance in many computer vision tasks and attracted growing interests in medical imaging. In this work, the authors proposed a novel model [deep residual generative adversarial network (DRGAN)] based on GANs for the reduction of streaking artefacts and the improvement of PET image quality. An innovative feature of the proposed method is that the authors trained a generator to produce 'residual PET map' (RPM) for image representation, rather than generate PET images directly. DRGAN used two discriminators (critics) to enforce anatomically realistic PET images and RPM. To better boost the contextual information, the authors designed residual dense connections followed with pixel shuffle operations (RDPS blocks) that encourage feature reuse and prevent losing resolution. Both simulation data and real clinical PET data are used to evaluate the proposed method. Compared with other state‐of‐the‐art methods, the quantification results show that DRGAN can achieve better performance in bias–variance trade‐off and provide comparable image quality. Their results were rigorously evaluated by one radiologist at the Shanxi Cancer Hospital. [ABSTRACT FROM AUTHOR]

Trauma, organ transplantation, and thromboembolism are the main causes of lung ischemia-reperfusion injury (LIRI), and new therapies and drugs are urgent to relieve LIRI. In preliminary experiment, authors found that kaempferol could improve LIRI in rats, and the current study further explored its possible mechanism. The model of rat LIRI was established and appropriate research methods were implemented. Results shown that kaempferol could significantly improve LIRI, inhibit release of inflammatory factors including interleukin (IL) 6 and tumor necrosis factor (TNF) α in bronchoalveolar lavage fluid, and reduce oxidative stress reaction. Western blotting was used to detect protein expression levels and found that kaempferol could up-regulate the protein expressions of phosphorylated (p-) p65 and p65, and down-regulate the protein expression of sirtuin (SIRT) 1. Immunofluorescence was used to localize the expression of high mobility group box (HMGB) 1 and found its higher expression in outside of nucleus. However, the above effects of kaempferol on LIRI markedly attenuated by EX 527, a selective inhibitor of SIRT 1. Taken together, we first reported the protective effect of kaempferol on rat LIRI and confirmed that kaempferol's antiinflammation and antioxidative stress involving the SIRT1/HMGB1/NF-κB axis. [ABSTRACT FROM AUTHOR]

Among the various types of lung nodules, ground glass nodules (GGNs) are difficult to segment accurately due to complex morphological characteristics. Moreover, GGNs are associated with a higher malignancy probability. Three-dimensional (3D) segmentation and reconstruction techniques can help physicians intuitively elucidate the relationship between lung nodules and their surrounding tissues. We propose an improved supervoxel 3D region growing approach based on positron emission tomography/computed tomography (PET/CT) multimodal data for the segmentation and reconstruction of GGNs. First, the seed point is automatically located with PET information and a 3D mask is generated. Then, a fuzzy connectivity (FC) map is generated based on the 3D mask, and an improved supervoxel 3D region growing is utilized on a fuzzy connectivity map under the constraints of the 3D mask. Finally, 3D GGNs segmentation and reconstruction results are obtained. Qualitative and quantitative comparisons between our proposed method and other region growing methods shows great superiority of our proposed method, with the Jaccard similarity coefficient between our proposed method and physician manual segmentation reaching 95.61%; the average processing time is 16.38 s. Experimental results show that our proposed supervoxel-based 3D region growing method is very promising for assisting physicians in diagnosis. [ABSTRACT FROM AUTHOR]