Abstract
The power spectrum of the scalar-tensor inflation with a quadratic form Ricci scalar coupling function Ω(
ϕ
) = 1 - 2
ϕ
/
ϕ
c
+ (1 +
δ
2
)(
ϕ
/
ϕ
c
)
2
can be enhanced enough to produce ...primordial black holes and generate scalar-induced gravitational waves. The masses of primordial black holes and the frequencies of scalar-induced gravitational waves are controlled by the parameter
ϕ
c
, and their amplitudes are determined by the parameter
δ
. Primordial black holes with stellar masses, planetary masses, and masses around 10
-12
M
⊙
are produced and their abundances are obtained from the peak theory. The frequencies of the corresponding scalar-induced gravitational waves are around 10
-9
Hz, 10
-6
Hz, and 10
-3
Hz, respectively. The primordial black holes with masses around 10
-12
M
⊙
can account for almost all of the dark matter, and the scalar-induced gravitational waves with frequencies around 10
-9
Hz can explain the NANOGrav 12.5 yrs signal.
Alkanes are the major constituents of natural gas and crude oil, the feedstocks for the chemical industry. The efficient and selective activation of C-H bonds can convert abundant and low-cost ...hydrocarbon feedstocks into value-added products. Due to the increasing global demand for light alkenes and their corresponding polymers as well as synthesis gas and hydrogen production, C-H bond activation of light alkanes has attracted widespread attention. A theoretical understanding of C-H bond activation in light hydrocarbons
via
density functional theory (DFT) and microkinetic modeling provides a feasible approach to gain insight into the process and guidelines for designing more efficient catalysts to promote light alkane transformation. This review describes the recent progress in computational catalysis that has addressed the C-H bond activation of light alkanes. We start with direct and oxidative C-H bond activation of methane, with emphasis placed on kinetic and mechanistic insights obtained from DFT assisted microkinetic analysis into steam and dry reforming, and the partial oxidation dependence on metal/oxide surfaces and nanoparticle size. Direct and oxidative activation of the C-H bond of ethane and propane on various metal and oxide surfaces are subsequently reviewed, including the elucidation of active sites, intriguing mechanisms, microkinetic modeling, and electronic features of the ethane and propane conversion processes with a focus on suppressing the side reaction and coke formation. The main target of this review is to give fundamental insight into C-H bond activation of light alkanes, which can provide useful guidance for the optimization of catalysts in future research.
This review describes the recent progress in computational catalysis that has addressed the C-H bond activation of light alkanes.
BODIPY-Le, a colorimetric and ratiometric fluorescent probe based on boron-dipyrromethene for selective detection sulfite ion, was investigated. Boron-dipyrromethene levulinyl ester (BODIPY-Le) is ...composed of an indole-based BODIPY dye and the levulinyl protective group, which could be easily and selectively deprotected by sulfites. As a result, the absorption and emission spectra show a dramatic red shift, and the development of a colorimetric and ratiometric fluorescent sulfite probe could be achieved. Besides, BODIPY-Le also exhibited prominent turn-on or turn-off type fluorogenic signaling toward sulfite ions once excited at 510 and 620 nm, respectively.
Drug delivery systems are generally believed to comprise drugs and excipients. A peptide–drug conjugate is a single molecule that can simultaneously play multiple roles in a drug delivery system, ...such as in vivo drug distribution, targeted release, and bioactivity functions. This molecule can be regarded as an integrated drug delivery system, so it is called a molecular drug delivery system. In the context of cancer therapy, a peptide–drug conjugate comprises a tumor-targeting peptide, a payload, and a linker. Tumor-targeting peptides specifically identify membrane receptors on tumor cells, improve drug-targeted therapeutic effects, and reduce toxic and side effects. Payloads with bioactive functions connect to tumor-targeting peptides through linkers. In this review, we explored ongoing clinical work on peptide–drug conjugates targeting various receptors. We discuss the binding mechanisms of tumor-targeting peptides and related receptors, as well as the limiting factors for peptide–drug conjugate-based molecular drug delivery systems.
A single peptide–drug conjugate molecule achieves multiple biological functions, which is proposed as a novel drug delivery system, the molecular drug delivery system.Recently, peptide–drug conjugates have been introduced as potential diagnostics and anticancer drugs in the clinic.Aminopeptidase N, integrins, the somatostatin receptor, and several other receptors are major molecular targeting receptors for current peptide–drug conjugate-based molecular drug delivery systems.Solving the problem of oral administration will greatly promote the development of peptide–drug conjugate molecular drug delivery systems.
Organic molecules are rich in carbon-hydrogen bonds; consequently, the transformation of C-H bonds to new functionalities (such as C-C, C-N, and C-O bonds) has garnered much attention by the ...synthetic chemistry community. The utility of C-H activation in organic synthesis, however, cannot be fully realized until chemists achieve stereocontrol in the modification of C-H bonds. This Review highlights recent efforts to enantioselectively functionalize C(sp
)-H bonds via transition metal catalysis, with an emphasis on key principles for both the development of chiral ligand scaffolds that can accelerate metalation of C(sp
)-H bonds and stereomodels for asymmetric metalation of prochiral C-H bonds by these catalysts.
The speed of gravitational waves provides us a new tool to test alternative theories of gravity. The constraint on the speed of gravitational waves from GW170817 and GRB170817A is used to test some ...classes of Horndeski theory. In particular, we consider the coupling of a scalar field to Einstein tensor and the coupling of the Gauss–Bonnet term to a scalar field. The coupling strength of the Gauss–Bonnet coupling is constrained to be in the order of
10
-
15
. In the Horndeski theory we show that in order for this theory to satisfy the stringent constraint on the speed of GWs the mass scale
M
introduced in the non-minimally derivative coupling is constrained to be in the range
10
15
GeV
≫
M
≳
2
×
10
-
35
GeV taking also under consideration the early times upper bound for the mass scale
M
. The large mass ranges require no fine-tuning because the effect of non-minimally derivative coupling is negligible at late times.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Optical characteristics of luminescent materials, including emission color (wavelength), lifetime, and excitation mode, play crucial roles in data communication and information security. Conventional ...luminescent materials generally display unicolor, unitemporal, and unimodal (occasionally bimodal) emission, resulting in low‐level readout and decoding. The development of multicolor, multitemporal, and multimodal luminescence in a single material has long been considered to be a significant challenge. In this study, for the first time, the superior integration of colorful (red–orange–yellow–green), bitemporal (fluorescent and delayed), and four‐modal (thermo‐/mechano‐motivated and upconverted/downshifted) emissions in a particular piezoelectric particle via optical multiplexing of dual‐lanthanide dopants is demonstrated. The as‐prepared versatile NaNbO3:Pr3+,Er3+ luminescent microparticles shown are particularly suitable for embedding into polymer films to achieve waterproof, flexible/wearable and highly stretchable features, and synchronously to provide multidimensional codes that can be visually read‐out using simple and commonly available tools (including the LED of a smartphone, pen writing, cooling–heating stimuli, and ultraviolet/near‐infrared lamps). These findings offer unique insight for designing highly integrated stimuli‐responsive luminophors and smart devices toward a wide variety of applications, particularly advanced anticounterfeiting technology.
Thermo‐mechano‐opto‐responsive bitemporal (fluorescent and delayed) colorful (red–orange–yellow–green) luminescence is designed and achieved through optical multiplexing of dual‐lanthanides of Pr3+ and Er3+ in NaNbO3 piezoelectric microparticles. The smart materials are well‐embedded into polymer elastomers to show waterproof, flexible/wearable and highly‐stretchable features, and provide multidimensional codes that enable visual readout using commonly available tools (e.g., smartphone flashlight, pen writing, and cooling‐heating stimuli).
Visually readable codes play a crucial role in anticounterfeiting measures. However, current coding approaches do not enable time‐dependent codes to be visually read, adjusted, and differentiated in ...bright and dark fields. Here, using a combined strategy of piezoelectric lattice selection, oxygen vacancy engineering, and activator doping, a lanthanide ion‐doped titanate is developed that integrates mechano‐, thermo‐, and photo‐responsive color change (>18 h for bright field), persistent luminescence (>6 h for dark field), and stimulus‐triggered multimodal luminescence. The feasibility of optical encoding, visual displaying, and stimulus‐responsive encrypting of time‐dependent, dual‐field information by using the developed material is demonstrated. In particular, the differentiated display of dual‐field modes is achieved by combining mechanostimulated abolition of only the persistent luminescence and thermo‐ and photostimulated reversal of both the color change and persistent luminescence. The results provide new insights for designing advanced materials and encryption technologies for photonic displays, information security, and intelligent anticounterfeiting.
The encoding, displaying, and encrypting of information in bright and dark fields are demonstrated via a newly designed versatile material that integrates bright‐field color change, dark‐field persistent luminescence, and stimuli‐responsive multiluminescence. Differential encryption of the dual‐field patterns is creatively modulated by combining the mechanostimulated loss of only the dark‐field patterns and thermo‐ and photostimulated dual abolition of the dual‐field patterns.
Abstract
We show that the NANOGrav signal can come from the Higgs
field with a noncanonical kinetic term in terms of the scalar
induced gravitational waves. The scalar induced gravitational waves
...generated in our model are also detectable by space-based
gravitational wave observatories. Primordial black holes with
stellar masses that can explain LIGO-Virgo events are also produced.
Therefore, the NANOGrav signal and the BHs in LIGO-Virgo events may
both originate from the Higgs field.
Fibronectin 1 (FN1) is involved in cell adhesion and migration processes including embryogenesis, wound healing, blood coagulation, host defense, metastasis, and implicated in various biochemical ...processes. However, its effects on the development and progression of human cancer, especially colorectal cancer (CRC), are unclear. To evaluate the relationship between the expression of FN1 and the histopathologic parameters of patients with CRC or the proliferation, migration, and invasion of colorectal cancer cell lines, we screened FN1 as a new candidate gene which promotes development of CRC, in an independent dataset (The Human Protein Atlas website). Here, we reported that FN1 was elevated in CRC tissues compared with normal colon tissues. Further, FN1 expression level was correlated with age, lymph vascular invasion, and survival rate. Knockdown of FN1 in two CRC cell lines, LOVO, and SW1116, significantly inhibited cell proliferation, migration and invasion, and induced cell apoptosis. Western blot analysis showed that down‐regulation of FN1 significantly decreased the expression of Bcl‐2, MMP‐9, Twist, and increased the expression of Bax, Caspase‐3, and E‐cadherin in LOVO and SW1116 cells. Then, we found that the protein ITGA5 was identified as a binding partner of FN1 and ITGA5 overexpression reversed FN1‐induced tumorigenesis of CRC in vitro. Taken together, FN1 suppressed apoptosis and promoted viability, invasion, and migration in CRC through interacting with ITGA5. FN1 may be a prognostic factor and potential target for CRC treatment.
FN1 may act as an oncogene in CRC via suppressing apoptosis and promoting invasion and migration in CRC carcinogenesis. FN1 may be a prognostic factor and potential target for CRC treatment.
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