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Acid fracturing is a technique to enhance productivity in carbonate formations. In this work, a thermal–hydraulic–mechanical–chemical (THMC) coupling model for acid fracture propagation is proposed based on a phase-field approach. The phase-field variable is utilized as an indicator function to distinguish the fracture and the reservoir, and to track the propagation of the fracture. The resulting system is a nonstationary, nonlinear, variational inequality system in which five different physical modules for the displacement, the phase-field, the pressure, the temperature, and the acid concentration are coupled. This multi-physical system includes numerical challenges in terms of nonlinearities, solution coupling algorithms, and computational cost. To this end, high fidelity physics-based discretizations, parallel solvers, and mesh adaptivity techniques are required. The model solves the phase-field and the displacement variables by a quasi-monolithic scheme and the other variables by a partitioned schemes, where the resulting overall algorithm is of iterative coupling type. In order to maintain the computational cost low, the adaptive mesh refinement technique in terms of a predictor-corrector method is employed. The error indicators are obtained from both the phase-field and concentration approximations. The proposed model and the computational robustness were investigated by studying fourteen cases as well as some mesh refinement studies. It is observed that the acid and thermal effect increase the fracture volume and fracture width. Moreover, the natural fractures and holes affect the acid fracture propagation direction. Highlights: thermal–hydraulic–mechanical–chemical coupling system was established for acid fracture propagation based on a phase-field method. The acid fluid equations including diffusion, transport and reaction were derived. The penalization method was introduced based on physical reality. Acid fracture problem is a kind of dynamic heterogeneous problem. The adaptive mesh refinement was extended to help researchers get smooth simulation results and save computation costs. [ABSTRACT FROM AUTHOR]

Exosomes play a crucial role in intercellular communication and can be used as biomarkers for diagnostic and therapeutic clinical applications. However, systematic studies in cancer-associated exosomal nucleic acids remain a big challenge. Here, we developed ExMdb, a comprehensive database of exosomal nucleic acid biomarkers and disease-gene associations curated from published literature and high-throughput datasets. We performed a comprehensive curation of exosome properties including 4,586 experimentally supported gene-disease associations, 13,768 diagnostic and therapeutic biomarkers, and 312,049 nucleic acid subcellular locations. To characterize expression variation of exosomal molecules and identify causal factors of complex diseases, we have also collected 164 high-throughput datasets, including bulk and single-cell RNA sequencing (scRNA-seq) data. Based on these datasets, we performed various bioinformatics and statistical analyses to support our conclusions and advance our knowledge of exosome biology. Collectively, our dataset will serve as an essential resource for investigating the regulatory mechanisms of complex diseases and improving the development of diagnostic and therapeutic biomarkers. [ABSTRACT FROM AUTHOR]

Previous studies have shown that mfat-1 transgenic mice have protective effects against some central nervous system (CNS) disorders, owing to the high docosahexaenoic acid (DHA) content enriched in their brains. However, whether this protective effect is connected to the blood–brain barrier (BBB) remains unclear. This study aims to investigate the mechanisms of the protective effect against hypoxic-ischemic brain damage (HIBD) of mfat-1 transgenic mice. mfat-1 mice not only demonstrated a significant amelioration of neurological dysfunction and neuronal damage but also partly maintained the physiological permeability of the BBB after HIBD. We initially showed this was associated with elevated major facilitator superfamily domain-containing 2a (Mfsd2a) expression on the BBB, resulting from more lysophosphatidylcholine (LPC)-DHA entering the brain. Wild-type (WT) mice showed a similar Mfsd2a expression trend after long-term feeding with an LPC-DHA-rich diet. Knockdown of Mfsd2a by siRNA intra-cerebroventricular (ICV) injection neutralized the protective effect against HIBD-induced BBB disruption in mfat-1 mice, further validating the protective function of Mfsd2a on BBB. HIBD-induced BBB high permeability was attenuated by Mfsd2a, primarily through a transcellular pathway to decrease caveolae-like vesicle-mediated transcytosis. Taken together, these findings not only reveal that mfat-1 transgenic mice have higher expression of Mfsd2a on the BBB, which partly sustains BBB permeability via vesicular transcytosis to alleviate the severity of HIBD, but also suggest that dietary intake of LPC-DHA may upregulate Mfsd2a expression as a novel therapeutic strategy for BBB dysfunction and survival in HIBD patients. [ABSTRACT FROM AUTHOR]

In order to obtain ultra-smooth surfaces of single-crystal silicon in ultra-precision machining, an intensive study of the deformation mechanism, mechanical properties, and the effect of oxide film under load is required. The mechanical properties of single-crystal silicon and the phase transition after nanoindentation experiments are investigated by nanoindentation and Raman spectroscopy, respectively. The results show that the pop-in event occurring in the theoretical elastic region of single-crystal silicon is caused by the stress concentration at the interface between the oxide film and the substrate. This causes the single-crystal silicon to be converted from the elastic deformation zone to the plastic deformation zone. And at this time, the elastic domain area is almost negligible, which seriously affects the machinability of single-crystal silicon for ultra-precision processing. In addition, the experimental data of single-crystal silicon under ultra-low load deviates greatly relative to the real value and fluctuates widely. However, when the nanoindentation experiment enters the fully plastic deformation zone of single-crystal silicon, the test results of its mechanical properties will be more accurate. [ABSTRACT FROM AUTHOR]

The surface quality and subsurface damage (SSD) distribution achieved with a fine-grained grinding wheel under different depth-of-cut and cutting speed is experimentally studied. The ground surface roughness (SR) is investigated via white light interferometry and expressed in terms of four typical roughness values (PV, RMS, Rz, and Ra). The SSD is characterized by the magnetorheological finishing (MRF) spot method and transmission electron microscopy. The results show that brittle-ductile surfaces and ductile-like surfaces are generated during ultra-precision grinding. Largely due to plastic flow removal, fracture defects such as fractured pits and grinding streaks on the ground surface can be mitigated. Instead, a ductile-like surface covered with grinding streaks is found. When the depth-of-cut decreases from 4 to 1 μm, the SR and SSD depth decreases from PV 1.34 μm, Ra 15.23 nm, Rz 0.94 μm, RMS 22.24 nm, and SSD 6.1 μm to PV 0.51 μm, Ra 5.07 nm, Rz 0.24 μm, RMS 6.70 nm, and SSD 1.2 μm. In addition, when the cutting speed increases from 3.9 to 23.4 m/s, the SR and SSD depth decreases from PV 1.03 μm, Ra 15.01 nm, Rz 0.82 μm, RMS 21.43 nm, and SSD 5.6 μm to PV 0.12 μm, Ra 3.17 nm, Rz 0.07 μm, RMS 4.65 nm, and SSD 0.003 μm. Moreover, the material removal mechanism under different grinding parameters is revealed by calculating undeformed chip thickness, and the mechanism of surface morphology and subsurface crack produced in brittle-ductile mode is analyzed. A linear relationship between the SR and SSD depth is in accord with the formula SSD = 0.41Ra−0.68 for brittle-ductile surfaces. [ABSTRACT FROM AUTHOR]

Efficient design and preparation of cost-effective and binder-free bifunctional electrocatalysts to accelerate the hydrogen and oxygen evolution reaction (HER and OER) are critical for overall water splitting. In this work, 3D hierarchical NiFe-LDH/FeCoS2/CFC electrodes were synthesized for the first time. The carboxyl groups derived from acid treating promote the homogeneously coated FeCoS2 on CFC, giving rise to the strongly coupled FeCoS2/CFC hybrid. The NiFe-LDH exhibited the vertical growth feature on the FeCoS2/CFC composite, which can efficiently expose the active edges sites. Due to unique structure and synergistic effect between the components, the NiFe-LDH/FeCoS2/CFC exhibits significant electrocatalytic activity and stability under alkaline environments, with overpotentials of 190 and 308 mV to achieve 10 mA cm−2 for OER and HER, respectively, providing it as a promising electrocatalyst for water splitting reaction. In addition, we deeply studied the synergistic catalytic mechanism of NiFe-LDH/FeCoS2/CFC, explaining the reasons leading to the improved catalytic performance of HER and OER. [ABSTRACT FROM AUTHOR]

Smart windows control indoor solar radiation by regulating the transmittance of light, which is a promising way to reduce building energy consumption. The advent of photonic crystals (PCs) has accelerated the industrialization of smart windows. The combination of static and dynamic regulation can be realized based on the photon control function of photonic band gaps, which is expected to achieve the ideal effect of light transmission and heat control. This paper reviews recent advances of electrochromic and thermochromic smart windows based on PCs. Firstly, theory, materials, performance and development of electrochromic and thermochromic smart windows based on PCs are briefly outlined. Typical structures of electrochromic and thermochromic PCs are introduced in detail, from preparation process, morphology characterization and performance analysis, which provides directions for the future development and construction of smart windows based on PCs. Finally, challenges and opportunities facing next-generation smart windows are summarized. [ABSTRACT FROM AUTHOR]

Xenotransplantation is an attractive solution to the problem of allograft shortage. However, transplants across discordant species barriers are subject to vigorous immunologic and pathobiologic hurdles, some of which might be overcome with the induction of immunologic tolerance. Several strategies have been designed to induce tolerance to a xenograft at both the central (including induction of mixed chimerism and thymic transplantation) and peripheral (including adoptive transfer of regulatory cells and blocking T cell costimulation) levels. Currently, xenograft tolerance has been well-established in rodent models, but these protocols have not yet achieved similar success in nonhuman primates. This review will discuss the major barriers that impede the establishment of immunological tolerance across xenogeneic barriers and the potential solution to these challenges, and provide a perspective on the future of the development of novel tolerance-inducing strategies. [ABSTRACT FROM AUTHOR]

Atmosphere plasma etching methods have been applied to the machining of optics. However, due to the high chemical stability and inertness of silicon carbide (SiC) ceramics, it seems difficult to improve the material removal rate (MRR) for conventional etching methods. We have found MRR will be significantly improved while arc forms between the inductively coupled plasma and SiC ceramic surface. This etching method is called arc-enhanced plasma machining (AEPM) technology. Arc-enhanced plasma (AEP) is represented as the secondary of a high-frequency transformer considering capacitive coupling in this paper. Radio frequency (RF) voltage in AEP is measured. The RF voltage of plasma is extremely high to form arc when plasma is close to the SiC ceramic surface. The measurement results of RF voltage at the metal-plasma interface show that the arc formation is related to the distance between source jet and workpiece ( D ). When D is small, a nonconductive layer of cooled argon forms over the workpiece surface, preventing arcing. Trenches are etched on SiC ceramic surface with different D , finding that the MRR is improved under the arcing action and the optimal D is obtained. [ABSTRACT FROM AUTHOR]

Ion beam figuring (IBF) technology is an effective technique for fabricating continuous phase plates (CPPs) with small feature structures. This study proposes a multi-pass IBF approach with different beam diameters based on the frequency filtering method to improve the machining accuracy and efficiency of CPPs during IBF. We present the selection principle of the frequency filtering method, which incorporates different removal functions that maximize material removal over the topographical frequencies being imprinted. Large removal functions are used early in the fabrication to figure the surface profile with low frequency. Small removal functions are used to perform final topographical correction with higher frequency and larger surface gradient. A high-precision surface can be obtained as long as the filtering frequency is suitably selected. This method maximizes the high removal efficiency of the large removal function and the high corrective capability of the small removal function. Consequently, the fast convergence of the machining accuracy and efficiency can be achieved. [ABSTRACT FROM AUTHOR]

Unlike traditional machinery manufacturing generally using simple features of workpiece as the alignment reference, optical manufacturing, which prioritizes shape tolerances of the machining surface over position tolerances between workpiece geometry features, chooses the machining surface itself as the alignment reference. Thus, the manual alignment of workpiece in optical manufacturing could be very time-consuming when the machining surface is aspheric. Workpiece localization technology is able to automate the workpiece alignment and improve its efficiency. However, there are no relevant reports about application of this technology in the field of optical manufacturing. In this work, the workpiece localization problem for aspheric surface in magnetorheological finishing (MRF) is investigated from aspects of measurement and algorithm. The probe radius error is compensated by applying the polynomial fitting method. A new localization algorithm is proposed in order to improve the computational efficiency for the localization of aspheric surface. Simulation and experiment results verify the validity of the proposed methods. The accurate and efficient workpiece localization in MRF has been achieved and applied in real application which proves its practicability. [ABSTRACT FROM AUTHOR]

Atmosphere plasma etching methods have been demonstrated efficient in the etching of fused silica or ULE. However, because of the high chemical stability of silicon carbide (SiC), the conventional plasma etching methods seem incapable of obtaining a high material removal rate (MRR). We have found that MRR will be significantly improved while the electric spark appears between the plasma and the SiC surface. As a result, a new plasma source is designed to generate stable arc at the surface. Due to the generation of arc, the MRR of 0.35 mm/min is obtained, about 10 times as high as the conventional method. In this paper, the removal characteristics and the thermal effect of this method are presented. MRR and the surface temperature are investigated in dependence on plasma parameters: RF power, travel speed of plasma source, SF gas flow and O gas flow. Due to the negligible thermal effect, the surface figuring can be achieved using the conventional dwell time method. The shape error of a flat SiC surface is corrected, verifying the figuring capability and the effectiveness of this method. [ABSTRACT FROM AUTHOR]

According to forming principle of line contact spherical generating by cup-shaped wheel, the sources of grinding error were analyzed, and a new method for error analysis and compensation was proposed in this paper. In a certain grinding condition, the grinding error caused by the pose errors between wheel and workpiece was simulated, the corresponding curve fitting of grinding error was carried out, and an appropriate parametric model was established. If the actual grinding error is known, the model can identify the corresponding pose error as well as compensate the grinding error. The simulation and experiment processes of compensation validate the efficient and workability of parametric model, and improve the grinding precision. [ABSTRACT FROM AUTHOR]

n-3 Polyunsaturated fatty acids ( n-3 PUFAs) contribute to preventing many types of diseases, including cancer; however, a high n-6 polyunsaturated fatty acids ( n-6 PUFAs) intake in modern diets has the opposite effect. Previously, we developed a transgenic mouse model that expresses a gene, fat-1, encoding an n-3 fatty acid desaturase, which converts n-6 PUFAs to n-3 PUFAs in vivo. MicroRNAs (miRNAs) in serum are stable, reproducible, and consistent among individuals of the same species and serve as potential biomarkers for the detection of cancers and other diseases. Employing illumina sequencing, we analyzed all the serum miRNAs in wild-type and m fat-1 transgenic mice. Using quantitative real-time PCR (RT-qPCR), we identified 12 miRNAs that were highly expressed in m fat-1 mice. Pathway analysis of targets regulated by these miRNAs revealed a significant number of genes involved in the development of cancer, including phosphatidylinositol 3-kinase (PI3K), mitogen-activated protein kinases (MAPK), and mammalian target of rapamycin (mTOR), which suggested a relationship between n-3 PUFAs and cancer prevention. [ABSTRACT FROM AUTHOR]

When fabricating optical cantilever parts with single-point diamond turning (SPDT) technique, chatter phenomenon happens and degenerates the surface quality. This paper studies the chatter phenomenon and proposes a scheme to solve the problem. A kind of viscoelastic material is presented as the auxiliary supporter under the vibration location of optical cantilever parts to suppress chatter. Mirror surfaces can be generated and surface shape can be maintained after uninstalling the supporter because of the special features of viscoelastic material which acts like solid to enhance the rigidity of the cantilevers when cutting forces act on it and acts like liquid to avoid distortion of the surface shape during setting and unsetting the supporter. The effect of the viscoelastic material is discussed by virtue of finite element simulation on the basis of elasticity theory. Cutting experiments are carried out and the cutting forces as well as the surface quality with and without viscoelastic supporter are compared. The results show that chatter is suppressed effectively by using viscoelastic supporter, and surface roughness average (Ra) of around 5 nm is obtained on the whole surface with no obvious distortion on machined surface shape. [ABSTRACT FROM AUTHOR]

SmCo film with perpendicular magnetic anisotropy is a promising candidate ultrahigh-density magnetic recording medium due to its huge magnetocrystalline anisotropy. This paper investigates the effect of Cu substitution for Co on the magnetic properties and microstructure of SmCo film by simulations and experiments. The simulation results based on first-principles theory show that Cu substitution for Co in SmCo can reduce the total exchange- correlation constant and increase the coercivity of SmCo film. Sm(Co,Cu)/Cu/TiW film samples with different Cu doping were fabricated on quartz glass substrates by radiofrequency (RF) magnetron sputtering, and the dependence of the coercivity of the Sm(Co,Cu) film on the Cu doping and annealing conditions was studied. The experimental results demonstrate that Cu doping can decrease the grain size and increase the coercivity of SmCo film. By optimizing the sputtering and annealing conditions, perpendicular coercivity of 3796 Oe was obtained in Sm(CoCu) film. [ABSTRACT FROM AUTHOR]

n-3 Polyunsaturated fatty acids (n-3 PUFA) are important for human health. Alternative resources of n-3 PUAFs created by transgenic domestic animals would be an economic approach. In this study, we generated a mfat-1 transgenic cattle expressed a Caenorhabditis elegans gene, mfat-1, encoding an n-3 fatty acid desaturase. Fatty acids analysis of tissue and milk showed that all of the examined n-3 PUAFs were greatly increased and simultaneously the n-6 PUAFs decreased in the transgenic cow. A significantly reduction of n-6/n-3 ratios ( P < 0.05) in both tissue and milk were observed. [ABSTRACT FROM AUTHOR]

In order to restrain the mid-spatial frequency error in magnetorheological finishing (MRF) process, a novel part-random path is designed based on the theory of maximum entropy method (MEM). Using KDMRF-1000F polishing machine, one flat work piece (98 mm in diameter) is polished. The mid-spatial frequency error in the region using part-random path is much lower than that by using common raster path. After one MRF iteration (7.46 min), peak-to-valley (PV) is 0.062 wave (1 wave =632.8 nm), root-mean-square (RMS) is 0.010 wave and no obvious mid-spatial frequency error is found. The result shows that the part-random path is a novel path, which results in a high form accuracy and low mid-spatial frequency error in MRF process. [ABSTRACT FROM AUTHOR]

Mid-high spatial frequency errors are often induced on optical surfaces polished by computer-controlled optical surfacing (CCOS) processes. In order to efficiently remove these errors, which would degrade the performances of optical systems, the ability of a CCOS process to correct the errors have been investigated based on the convolution integral model in view of the availability of material removal. To quantify the ability, some conceptions, such as figure correcting ability and material removal availability (MRA), have been proposed. The research result reveals that the MRA of the CCOS process to correct a single spatial frequency error is determined by its tool removal function (TRF), and it equals the normalized amplitude spectrum of the Fourier transform of its TRF. Finally, three sine surfaces were etched using ion beam figuring (IBF), which is a typical CCOS process. The experimental results have verified the theoretical analysis. The employed method and the conclusions of this work provide a useful mathematical basis to analyze and optimize CCOS processes. [ABSTRACT FROM AUTHOR]

Galactose-α1,3-galactose (α1,3Gal) is the major xenoantigen causing hyperacute rejection in pig-to-human xenotransplantation. Disruption of the gene encoding pig (α1,3-galactosyltransferase (α1,3GT) by homologous recombination is a means to completely remove the α1,3Gal epitopes from xenografts. Here we report the disruption of one allele of the pig α1,3GT gene in both male and female porcine primary fetal fibroblasts. Targeting was confirmed in 17 colonies by Southern blot analysis, and 7 of them were used for nuclear transfer. Using cells from one colony, we produced six cloned female piglets, of which five were of normal weight and apparently healthy. Southern blot analysis confirmed that these five piglets contain one disrupted pig α1,3GT allele. [ABSTRACT FROM AUTHOR]

Reports on the successful cloning of pigs. Discussion of the cloning process for animals such as sheep and goats which involves the transplant of diploid donor nuclei into enucleated MII oocytes; Results of the nuclear transfer process on pigs which was unsuccessful; Details of a successful pig cloning which involved a two-stage nuclear transfer procedure.

Glypican-1 (GPC-1) has been recognized as biomarker of pancreatic cancer. Quantification of GPC-1 level is also pivotal to breast cancer and prostate cancer’s patients. We hereby report the first biosensor for GPC-1 detection. Instead of using crosslinking technique and surface immobilization of antibody, we applied a novel method for biosensor fabrication, using S-Acetylmercaptosuccinic anhydride (SAMSA) to modify the Anti-GPC-1 producing a thiol-linked Anti-GPC-1. The thiol-linked Anti-GPC-1 was then directly formed a single-layer antibody layer on the gold biosensor, minimizing the biosensor preparation steps significantly. Time of Flight Secondary Ions Mass Spectroscopy (TOF-SIMS) characterization verified the thiol-linked antibody layer and demonstrated a unique perspective for surface protein characterization. Differential pulse voltammetry (DPV) was applied to quantify GPC-1 antigen in undiluted human serum with a concentration range of 5,000 pg/µL to 100 pg/µL. The performance of this newly designed biosensor was also compared with modified self-assembled monolayer system fabricated biosensor, demonstrating the high-sensitivity and high-reproducibility of the SAMSA modified antibody based biosensor. This simple fabrication method can also expand to detection of other biomolecules. The simplified operation process shows great potential in clinical application development. [ABSTRACT FROM AUTHOR]

This corrects the article DOI: 10.1038/srep46146 [ABSTRACT FROM AUTHOR]

Epidemiologic studies showed the correlation between the deficiency of omega-3 polyunsaturated fatty acids (n-3 PUFAs) and the progression of chronic kidney diseases (CKD), however, the role and mechanisms for n-3 PUFAs in protecting against kidney fibrosis remain obscure. In this study, NRK-49F cells, a rat kidney interstitial fibroblast cell line, were stimulated with TGFβ1. A Caenorhabditis elegans fat-1 transgenic mouse model in which n-3 PUFAs are endogenously produced from n-6 PUFAs owing to the expression of n-3 fatty acid desaturase were deployed. Docosahexaenoic acid (DHA), one member of n-3 PUFAs family, could suppress TGFβ1-induced fibroblast activation at a dose and time dependent manner. Additionally, DHA could largely inhibit TGFβ1-stimulated Akt but not S6 or Smad3 phosphorylation at a time dependent manner. To decipher the role for n-3 PUFAs in protecting against kidney fibrosis, fat-1 transgenic mice were operated with unilateral ureter obstruction (UUO). Compared to the wild types, fat-1 transgenics developed much less kidney fibrosis and inflammatory cell accumulation accompanied by less p-Akt (Ser473), p-Akt (Thr308), p-S6 and p-Smad3 in kidney tissues at day 7 after UUO. Thus, n-3 PUFAs can attenuate fibroblast activation and kidney fibrosis, which may be associated with the inhibition of mTORC2 signaling. [ABSTRACT FROM AUTHOR]

Intramuscular fat (IMF) content has been generally recognized as a desirable trait in pork meat because of its positive effect on eating quality. An effective approach to enhance IMF content in pork is the generation of transgenic pigs. In this study, we used somatic cell nuclear transfer (SCNT) to generate cloned pigs exhibiting ectopic expression of phosphoenolpyruvate carboxykinase (PEPCK-C) driven by an α-skeletal-actin gene promoter, which was specifically expressed in skeletal muscle. Using qRT-PCR and Western blot analysis, we demonstrated that PEPCK-C was functionally expressed and had a significant effect on total fatty acid content in the skeletal muscle of the transgenic pigs, while the n-6/n-3 polyunsaturated fatty acid (PUFA) ratio showed no difference between transgenic and control pigs. Thus, genetically engineered PEPCK-Cmus pigs may be an effective solution for the production of IMF-enriched pork. [ABSTRACT FROM AUTHOR]

Meat products are generally low in omega-3 (n-3) fatty acids, which are beneficial to human health. We describe the generation of cloned pigs that express a humanized Caenorhabditis elegans gene, fat-1, encoding an n-3 fatty acid desaturase. The hfat-1 transgenic pigs produce high levels of n-3 fatty acids from n-6 analogs, and their tissues have a significantly reduced ratio of n-6/n-3 fatty acids (P < 0.001). [ABSTRACT FROM AUTHOR]