In this paper, we study the heat engine where a charged AdS black hole surrounded by dark energy is the working substance and the mechanical work is done via the
PdV
term in the first law of black ...hole thermodynamics in the extended phase space. We first investigate the effects of a kind of dark energy (quintessence field in this paper) on the efficiency of the RN-AdS black holes as the heat engine defined as a rectangular closed path in the
P
–
V
plane. We get the exact efficiency formula and find that the quintessence field can improve the heat engine efficiency, which will increase as the field density
ρ
q
grows. At some fixed parameters, we find that a larger volume difference between the smaller black holes(
V
1
) and the bigger black holes(
V
2
) will lead to a lower efficiency, while the bigger pressure difference
P
1
-
P
4
will make the efficiency higher, but it is always smaller than 1 and will never be beyond the Carnot efficiency, which is the maximum value of the efficiency constrained by thermodynamics laws; this is consistent to the heat engine in traditional thermodynamics. After making some special choices for the thermodynamical quantities, we find that the increase of the electric charge
Q
and the normalization factor
a
can also promote the heat engine efficiency, which would infinitely approach the Carnot limit when
Q
or
a
goes to infinity.
Unprecedented advances in metal nanoparticle synthesis have paved the way for broad applications in sensing, imaging, catalysis, diagnosis, and therapy by tuning the optical properties, enhancing ...catalytic performance, and improving chemical and biological properties of metal nanoparticles. The central guiding concept for regulating the size and morphology of metal nanoparticles is identified as the precise manipulation of nucleation and subsequent growth, often known as seed‐mediated growth methods. However, since the growth process is sensitive not only to the metal seeds but also to capping agents, metal precursors, growth solution, growth/incubation time, reductants, and other influencing factors, the precise control of metal nanoparticle morphology is multifactorial. Further, multiple reaction parameters are entangled with each other, so it is necessary to clarify the mechanism by which each factor precisely regulates the morphology of metal nanoparticles. In this review, to exploit the generality and extendibility of metal nanoparticle synthesis, the mechanisms of growth influencing factors in seed‐mediated growth methods are systematically summarized. Second, a variety of critical properties and applications enabled by grown metal nanoparticles are focused upon. Finally, the current progress and offer insights on the challenges, opportunities, and future directions for the growth and applications of grown metal nanoparticles are reviewed.
The state‐of‐the‐art development in seeded growth methods from key influencing factors of growth and applications of grown metal nanoparticles are summarized in this review to highlight the achievements and help researchers understand the current investigation status of seed‐mediated methods. Furthermore, the challenges faced by seed‐mediated methods are outlined and the future directions for advancing seed‐mediated methods are outlooked.
High‐entropy alloys nanoparticles (HEANPs) are receiving extensive attention due to their broad compositional tunability and unlimited potential in bioapplication. However, developing new methods to ...prepare ultra‐small high‐entropy alloy nanoparticles (US‐HEANPs) faces severe challenges owing to their intrinsic thermodynamic instability. Furthermore, there are few reports on studying the effect of HEANPs in tumor therapy. Herein, the fabricated PtPdRuRhIr US‐HEANPs act as bifunctional nanoplatforms for the highly efficient treatment of tumors. The US‐HEANPs are engineered by the universal metal‐ligand cross‐linking strategy. This simple and scalable strategy is based on the aldol condensation of organometallics to form the target US‐HEANPs. The synthesized US‐HEANPs exhibit excellent peroxidase‐like (POD‐like) activity and can catalyze the endogenous hydrogen peroxide to produce highly toxic hydroxyl radicals. Furthermore, the US‐HEANPs possess a high photothermal conversion effect for converting 808 nm near‐infrared light into heat energy. In vivo and in vitro experiments demonstrated that under the synergistic effect of POD‐like activity and photothermal action, the US‐HEANPs can effectively ablate cancer cells and treat tumors. It is believed that this work not only provides a new perspective for the fabrication of HEANPs, but also opens the high‐entropy nanozymes research direction and their biomedical application.
The ultra‐small PtPdRuRhIr high‐entropy alloy nanoparticles (US‐HEANPs) are fabricated by the universal metal‐ligand cross‐linking strategy. This strategy takes advantage of simplicity, scalability, and genericity. The developed US‐HEANPs exhibit excellent peroxidase‐like activity and possess a high photothermal conversion effect. Under the synergistic effects of peroxidase‐like activity and photothermal action, the US‐HEANPs can effectively ablate cancer cells and treat tumors.
Machine-assisted pathological recognition has been focused on supervised learning (SL) that suffers from a significant annotation bottleneck. We propose a semi-supervised learning (SSL) method based ...on the mean teacher architecture using 13,111 whole slide images of colorectal cancer from 8803 subjects from 13 independent centers. SSL (~3150 labeled, ~40,950 unlabeled; ~6300 labeled, ~37,800 unlabeled patches) performs significantly better than the SL. No significant difference is found between SSL (~6300 labeled, ~37,800 unlabeled) and SL (~44,100 labeled) at patch-level diagnoses (area under the curve (AUC): 0.980 ± 0.014 vs. 0.987 ± 0.008, P value = 0.134) and patient-level diagnoses (AUC: 0.974 ± 0.013 vs. 0.980 ± 0.010, P value = 0.117), which is close to human pathologists (average AUC: 0.969). The evaluation on 15,000 lung and 294,912 lymph node images also confirm SSL can achieve similar performance as that of SL with massive annotations. SSL dramatically reduces the annotations, which has great potential to effectively build expert-level pathological artificial intelligence platforms in practice.
Holographic striped superconductor Ling, Yi; Wu, Meng-He
The journal of high energy physics,
03/2021, Letnik:
2021, Številka:
3
Journal Article
Recenzirano
Odprti dostop
A
bstract
We construct a holographic model describing the striped superconductor (SSC), which is characterized by the presence of pair density waves (PDW). We explicitly demonstrate that the SSC ...phase is implemented as the intertwined phase of charge density waves (CDW) order and uniform superconducting (SC) order. The interplay of PDW order, CDW order as well as the uniform SC order in SSC phase is studied. It is found that the PDW order is prominent when both CDW order and uniform SC order are balanced. The critical temperature of CDW becomes higher in the presence of the uniform SC order, but its charge density amplitude is suppressed. On the other hand, the SC order is not sensitive to the presence of CDW order. We also demonstrate that among all the possible solutions, the black hole in SSC phase has the lowest free energy and thus is thermodynamically favored.
Epstein‐Barr virus (EBV) was the first tumor virus discovered in humans and can cause various types of tumors. Molecular classification suggests that EBV‐associated gastric cancer (EBVaGC) is a ...unique subtype of gastric cancer.EBV was also the first virus found to encode its own microRNAs. However, the functions of many miRNAs remain unknown. This study investigated the roles and targets of miR‐BART2‐5p (BART2‐5p) and miR‐BART11‐5p (BART11‐5p) in EBVaGC. The expression of RB and p21 in EBVaGC and EBV negative GC (EBVnGC) cells was evaluated by western blotting. Expression of BART2‐5p and BART11‐5p in EBVaGC cells was evaluated by droplet digital PCR. The effects of BART2‐5p or BART11‐5p and their potential mechanisms were further investigated using cell counting kit‐8, colony formation assay, flow cytometry analysis, and transwell assay. BART2‐5p and BART11‐5p were abundantly expressed and RB and p21 were downregulated in EBVaGC cells. BART2‐5p regulates RB and p21 expression by directly targeting them. BART11‐5p regulates RB expression by directly targeting RB. Both BART2‐5p and BART11‐5p promoted proliferation and migration of gastric cancer cells, while inhibiting apoptosis and promoting S‐phase arrest of the cell cycle. Thus, BART2‐5p and BART11‐5p play important roles in promoting proliferation and migration, and inhibiting apoptosis in EBVaGC by targeting RB and p21, thus providing new potential therapeutic targets for EBVaGC.
We perform a comprehensive study of the dark energy equation of state (EoS) utilizing the model-independent Gaussian processes (GP). Using a combination of the Union 2.1 data set, the 30 newly added ...H(z) cosmic chronometer data points and Planck’s shift parameter, we modify the usual GaPP code and provide a tighter constraint on the dark energy EoS than the previous literature about GP reconstructions. Subsequently, we take the “controlling variable method ” to investigate directly the effects of the variable matter density parameter Ωm0, variable cosmic curvature Ωk0, and variable Hubble constant H0 on the dark energy EoS. We find that too small or large Ωm0, Ωk0, and H0 are all disfavored by our GP reconstructions based on current cosmological observations. Subsequently, we find that variables Ωm0 and Ωk0 affect the reconstructions of the dark energy EoS but hardly affect the reconstructions of the normalized comoving distance D(z) and its derivatives D′(z) and D′′(z). However, variable H0 affects the reconstructions of the dark energy EoS by affecting obviously those of D(z), D′(z), and D′′(z). Furthermore, we find that the results of our reconstructions support substantially the recent local measurement of H0 reported by Riess et al.
This paper presents data-driven optimization study of a periodic beam with multiple acoustic black holes (ABH) for better dynamic performance. The vibration and sound radiation of the structure are ...analyzed by the spectral element method (SEM). A data-driven multi-objective optimization method is proposed to investigate the design problems for minimizing the structural weight and maximizing the sound transmission loss. Several cases are presented to demonstrate the accuracy of the SEM compared with the finite element method, and the multi-objective optimal designs of the ABH beam. Numerical results indicate that the data-driven method can significantly improve the computational efficiency. Pareto solutions provide a variety of design options and reveal the mechanisms about band gaps of the periodic beam.
The spectrin-based membrane skeleton is a ubiquitous membrane-associated two-dimensional cytoskeleton underneath the lipid membrane of metazoan cells. Mutations of skeleton proteins impair the ...mechanical strength and functions of the membrane, leading to several different types of human diseases. Here, we report the cryo-EM structures of the native spectrin-actin junctional complex (from porcine erythrocytes), which is a specialized short F-actin acting as the central organizational unit of the membrane skeleton. While an α-/β-adducin hetero-tetramer binds to the barbed end of F-actin as a flexible cap, tropomodulin and SH3BGRL2 together create an absolute cap at the pointed end. The junctional complex is strengthened by ring-like structures of dematin in the middle actin layers and by patterned periodic interactions with tropomyosin over its entire length. This work serves as a structural framework for understanding the assembly and dynamics of membrane skeleton and offers insights into mechanisms of various ubiquitous F-actin-binding factors in other F-actin systems.
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•Cryo-EM structures of intact spectrin-actin junctional complex from erythrocytes•Structural basis of the stability and plasticity of membrane skeleton is explained•Molecular roles of SH3BGRL2, dematin, adducin, and tropomyosin are revealed•Several actin and spectrin-binding motifs of these skeleton factors are identified
Structures of the native spectrin-actin junctional complex in red blood cells reveal the organization and interactions of proteins in the complex, suggesting their regulatory role in the assembly and dynamics of the erythrocyte membrane skeleton.
A highly hydrophobic and oleophilic chitin sponge was synthesized, for the first time, via a freeze-dried method and then by using a thermal chemical vapor deposition of methyltrichlorosilane (MTCS) ...at different relative humidity. Fourier-transform infrared, energy-dispersive X-ray spectra, and scanning electron microscopy confirmed that the silanization occurred on the pore wall surface of the chitin sponge. The MTCS-coated chitin sponge had interconnected open-cell structures with the average pore size from 20 to 50 μm, and the MTCS nanofilaments immobilized on the chitin matrix, leading to the high hydrophobicity, as a result of the existence of a solid/air composite rough surface. Cyclic compression test indicated that the hydrophobic chitin sponges exhibited excellent elasticity and high mechanical durability. The sponges could efficiently collect organics both on the surface and bottom from the water with the highest 58 times of their own weight absorption capacities through the combination of the particular wettability and great porosity. Furthermore, the biodegradation kinetics of the chitin sponge forecasted that the chitin could be completely biodegraded within 32 days by the microorganisms in the soil. This work provided a new pathway to prepare the chitin-based materials for highly effective removal of oil from water, showing potential application in the pollutant remediation field.
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