Abstract
There is a growing awareness of the impact of women in science, technology, engineering, and mathematics (STEM) or STEM-related fields and the influence of marriage on women’s retention in ...those fields. This study examines the relationship between the continued employment of married women with STEM or STEM-related majors in relevant occupations and their spouses having the same field of occupation/major, as well as the difference in this association when considering the presence of children. This study analyzed a sample comprising 147,467 married college-educated women aged 25–55 years. The analysis was restricted to women with a STEM or STEM-related major and a spouse who was college-educated and employed. All the data were drawn from the 2015–2019 waves of data released by the American Community Survey (ACS). The results reveal that spousal occupational similarity is positively associated with married women’s retention in STEM and STEM-related (healthcare) occupations. Moreover, the presence of children is a moderator variable in the relationship between women’s employment in STEM or STEM-related occupations and their spouses’ having STEM or STEM-related occupations. This study aims to provide information for research on spousal homogamy, women’s career development, and women with STEM or STEM-related majors and their families.
In this paper, we solve two problems concerning the ideally conjunctive join-semilattices. First, we show that
L
/
R
1
(
Id
L
)
|
L
is ideally conjunctive for all join-semilattices
L
. Then we ...characterize those ideally conjunctive join-semilattices
L
such that
coz
a
is compact for all
a
∈
L
.
Moreover, we give the definition of conjunctive posets and prove that the category of ideally conjunctive join-semilattices and join homomorphisms is reflective in the category of conjunctive posets and weakly ideal-continuous maps. As a corollary, we obtain the free ideally conjunctive join-semilattices over conjunctive posets.
In this paper, we introduce the concepts of generalized continuous posets and present topological dualities for them. Moreover, we show that the category of generalized continuous posets and ...continuous morphisms is dually equivalent to the category of F-spaces and F-morphisms. In particular, some special cases are obtained, such as the topological representations for posets, domains, continuous lattices and join-semilattices.
This review provides a critical overview of current developments on nanoelectronic biochemical sensors based on graphene. Composed of a single layer of conjugated carbon atoms, graphene has ...outstanding high carrier mobility and low intrinsic electrical noise, but a chemically inert surface. Surface functionalization is therefore crucial to unravel graphene sensitivity and selectivity for the detection of targeted analytes. To achieve optimal performance of graphene transistors for biochemical sensing, the tuning of the graphene surface properties via surface functionalization and passivation is highlighted, as well as the tuning of its electrical operation by utilizing multifrequency ambipolar configuration and a high frequency measurement scheme to overcome the Debye screening to achieve low noise and highly sensitive detection. Potential applications and prospectives of ultrasensitive graphene electronic biochemical sensors ranging from environmental monitoring and food safety, healthcare and medical diagnosis, to life science research, are presented as well.
This review provides a critical overview of the chemical functionalization, operation, and application of graphene‐based field‐effect transistor devices that are both sensitive and selective, with a particular focus on ultrasensitive biochemical detection enabled by the unique electronic properties of graphene.
Hair follicle stem cells (HFSCs) are among the most widely available resources and most frequently approved model systems used for studying adult stem cells. HFSCs are particularly useful because of ...their self-renewal and differentiation properties. Additionally, the cyclic growth of hair follicles is driven by HFSCs. There are high expectations for the use of HFSCs as favourable systems for studying the molecular mechanisms that contribute to HFSC identification and can be applied to hair loss therapy, such as the activation or regeneration of hair follicles, and to the generation of hair using a tissue-engineering strategy. A variety of molecules are involved in the networks that critically regulate the fate of HFSCs, such as factors in hair follicle growth and development (in the Wnt pathway, Sonic hedgehog pathway, Notch pathway, and BMP pathway), and that suppress apoptotic cues (the apoptosis pathway). Here, we review the life cycle, biomarkers and functions of HFSCs, concluding with a summary of the signalling pathways involved in HFSC fate for promoting better understanding of the pathophysiological changes in the HFSC niche. Importantly, we highlight the potential mechanisms underlying the therapeutic targets involved in pathways associated with the treatment of hair loss and other disorders of skin and hair, including alopecia, skin cancer, skin inflammation, and skin wound healing. Keywords: Hair follicle stem cells (HFSCs), Signalling, Wnt, Shh, Notch, BMP, Apoptosis
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•Boron-doped polymeric carbon nitride co-modified with carbon-ring and carboxyl was synthesized via a thermal polymerization.•The boron doping, carbon-ring and carboxyl modification ...boosted photocatalytic overall water-splitting.•The photocatalytic overall water-splitting underwent a stepwise 2e−/2e− pathway.
The photocatalytic overall water-splitting to generation hydrogen and oxygen over polymeric carbon nitrides is highly crucial in green energy usages and industry applications. To promote the separation efficiency of photoinduced charge carriers and adjust the band structure of polymeric carbon nitrides (PCNs), boron doped PCN modified with carbon-ring (CR) and carbonyl was synthesized via a polymerization of melamine with boric acid and benzoic acid. The combination of doped boron atom into the heptazine structure by displacing a carbon atom with the introduction of CR conjugated to the carbon atom in heptazine unit regulated the band structure, electronic structure, and delocalized the distribution of electrons, leading to improved separation and transfer of charge carriers photoinduced. Moreover, experimental results combined with density functional theory (DFT) calculations proved that the introduced polar groups, carboxyl, facilitated the adsorption of water molecules and promoted the photocatalytic hydrogen evolution. Importantly, the CR in-situ formed promoted the photocatalytic dioxygen evolution. The combined effect of doped boron, CR modification and carboxyl group endowed the improved the photocatalytic overall water-splitting activity. This work provides an avenue for the synthesis of metal-free photocatalysts with improved overall water-splitting activity via the combination of heterogeneous atom doping and construction of delocalized π-conjugated structures and polar group modification.
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•Acrylate-modified hydrochar with excellent adsorption properties was prepared easily.•The removal amounts of Pb(II) and methylene blue exceed 291.96 and 1014.96 mg/g.•Acrylate plays ...a key role in the adsorption process.•The acrylate content was more influential on adsorption than specific surface area.•The structure of hydrochar significantly affects its functional modification.
Hydrochars are promising sorbents for wastewater treatment. Herein, two acrylate-modified hydrochars (AMHC1 and AMHC2) were obtained by grafting acrylic acid on the surface of two hydrochars (MHC1 and MHC2 hydrothermally carbonized in water and acidic medium respectively) with free radical polymerization. Characterizations show that MHC2 is more prone to free radical polymerization than MHC1 does, and has higher carboxylate content after modification. The adsorption amounts of AMHC2 over methylene blue (MB) and Pb(II) are much higher than those of AMHC1. Pseudo-second-order kinetic and Langmuir isotherm equations well fit the Pb(II) and MB sorption data of AMHC2. The Pb(II) adsorptive mechanism is mainly inner-surface complexation accompanied by ion exchange and cation-π interaction. MB adsorption involves ion exchange, electrostatic interaction, H-bonding and π-π interaction. Hence, the one-step modification method of free radical polymerization under alkaline condition has great potential for preparing carboxylate-modified hydrochars to adsorb cationic pollutants.
Ligand receptor interactions instruct axon guidance during development. How dendrites are guided to specific targets is less understood. The
PVD sensory neuron innervates muscle-skin interface with ...its elaborate dendritic branches. Here, we found that LECT-2, the ortholog of leukocyte cell-derived chemotaxin-2 (LECT2), is secreted from the muscles and required for muscle innervation by PVD. Mosaic analyses showed that LECT-2 acted locally to guide the growth of terminal branches. Ectopic expression of LECT-2 from seam cells is sufficient to redirect the PVD dendrites onto seam cells. LECT-2 functions in a multi-protein receptor-ligand complex that also contains two transmembrane ligands on the skin, SAX-7/L1CAM and MNR-1, and the neuronal transmembrane receptor DMA-1. LECT-2 greatly enhances the binding between SAX-7, MNR-1 and DMA-1. The activation of DMA-1 strictly requires all three ligands, which establishes a combinatorial code to precisely target and pattern dendritic arbors.
•Using DFT calculations to explore the internal interactions in ESP system at molecular level.•Chemical agglomeration models is put forward by SEM.•Experimental data and calculated data are ...consistent with particle agglomeration.
Fine particles are significantly harmful to the human body and the atmospheric environment. However, the electrostatic precipitator (ESP) removal efficiency for PM2.5 is low, therefore chemical agglomeration technology, which uses various chemical agents to induce particle agglomeration, improving the efficiency of ESP seems to be a promising pretreatment technology. In the present contribution a combination of experimental and DFT calculations has been used to study this technique. We used water, pectin and sodium alginate solutions as agglomeration agents. Experimental results showed that sodium alginate solutions is most effective, the particle diameter increased from 0.1 μm to 1 μm and the ESP removal efficiency of number concentration increased above 20% with chemical agglomeration technology. In theoretical studies we simulated various molecular clusters consisting of water, pectin and sodium alginate in combination with simple model silica particles (TOS) by using DFT calculations to explore the internal interactions in ESP system at molecular level. In our results, water, pectin and sodium alginate interacted with TOS by hydrogen bond, with interaction energy of 4.0 kcal/mol, 6.7 kcal/mol and 7.4 kcal/mol, respectively. Finally, according to the experimental and theoretical results, the chemical agglomeration models were put forward.
The Markov method is a common reliability assessment method. It is often used to describe the dynamic characteristics of a system, such as its repairability, fault sequence and multiple degradation ...states. However, the “curse of dimensionality”, which refers to the exponential growth of the system state space with the increase in system complexity, presents a challenge to reliability assessments for complex systems based on the Markov method. In response to this challenge, a novel reliability assessment method for complex systems based on non-homogeneous Markov processes is proposed. This method entails the decomposition of a complex system into multilevel subsystems, each with a relatively small state space, in accordance with the system function. The homogeneous Markov model or the non-homogeneous Markov model is established for each subsystem/system from bottom to top. In order to utilize the outcomes of the lower-level subsystem models as inputs to the upper-level subsystem model, an algorithm is proposed for converting the unavailability curve of a subsystem into its corresponding 2×2 dynamic state transition probability matrix (STPM). The STPM is then employed as an input to the upper-level system’s non-homogeneous Markov model. A case study is presented using the reliability assessment of the Reactor Protection System (RPS) based on the proposed method, which is then compared with the models based on the other two contrast methods. This comparison verifies the effectiveness and accuracy of the proposed method.
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