Spermatogenesis is a continuous and productive process supported by the self-renewal and differentiation of spermatogonial stem cells (SSCs), which arise from undifferentiated precursors known as ...gonocytes and are strictly controlled in a special 'niche' microenvironment in the seminiferous tubules. Sertoli cells, the only somatic cell type in the tubules, directly interact with SSCs to control their proliferation and differentiation through the secretion of specific factors. Spermatocyte meiosis is another key step of spermatogenesis, which is regulated by Sertoli cells on the luminal side of the blood-testis barrier through paracrine signaling. In this review, we mainly focus on the role of Sertoli cells in the regulation of SSC self-renewal and spermatocyte meiosis, with particular emphasis on paracrine and endocrine-mediated signaling pathways. Sertoli cell growth factors, such as glial cell line-derived neurotrophic factor (GDNF) and fibroblast growth factor 2 (FGF2), as well as Sertoli cell transcription factors, such as ETS variant 5 (ERM; also known as ETV5), nociceptin, neuregulin 1 (NRG1), and androgen receptor (AR), have been identified as the most important upstream factors that regulate SSC self-renewal and spermatocyte meiosis. Other transcription factors and signaling pathways (GDNF-RET-GFRA1 signaling, FGF2-MAP2K1 signaling, CXCL12-CXCR4 signaling, CCL9-CCR1 signaling, FSH-nociceptin/OPRL1, retinoic acid/FSH-NRG/ERBB4, and AR/RB-ARID4A/ARID4B) are also addressed.
Under investigation in this paper is a fifth-order defocusing nonlinear Schrödinger equation for the attosecond pulses in the optical fiber communication. Lax pair, one/N-fold
binary Darboux ...transformations and the limit forms of the one-fold binary Darboux transformation for such an equation are obtained. Based on one/N-fold binary Darboux transformations and the limit forms of the one-fold binary Darboux transformation, one- and N-dark soliton solutions are obtained. Soliton amplitude is not affected by the coefficients of the nonlinear-Schrödinger operator, Hirota operator, Lakshmanan-Porsezian-Daniel operator and quintic operator, but soliton velocity is linearly related to them. Overtaking interaction between the two solitons is illustrated. Parallel solitons are formed: soliton width and interval between the parallel solitons are decreased with the increasing value of each and every coefficient of the nonlinear-Schrödinger operator, Hirota operator, Lakshmanan-Porsezian-Daniel operator and quintic operator respectively. For the interactions among the three solitons, e.g. interaction among three overtaking solitons, and interaction between the parallel solitons and a single soliton are displayed. We find that the interactions between the two solitons and among the three solitons are elastic.
Plasmas are believed to be possibly the most abundant form of visible matter in the Universe. Investigation in this paper is given to a variable‐coefficient derivative nonlinear Schrödinger equation ...describing the nonlinear Alfvén waves in an inhomogeneous plasma. With respect to the left polarized Alfvén wave, the odd‐fold Darboux transformation, breather, rogue‐wave and semirational solutions are constructed on the periodic background. Conditions for the antidark/gray/black soliton solutions or periodic solutions are obtained. Period of the Akhmediev breather is independent of the dispersion coefficient. When such an equation has a constant dispersion, with the increasing value of the dispersion coefficient, quasi‐period of the Kuznetsov–Ma breather decreases, quasi‐periods of the spatio‐temporal breathers along the ξ and τ axes both decrease and range of the rogue wave along the τ axis decreases, where ξ and τ are the stretched time and space variables, respectively. When such an equation has a τ‐dependent linear dispersion, with the increasing value of |τ|, quasi‐period of the Kuznetsov–Ma breather decreases and quasi‐periods of the spatio‐temporal breathers along the ξ and τ axes both decrease. When such an equation has a constant loss/gain, linearly periodic background is exhibited. When such an equation has a τ‐dependent linear loss/gain, parabolic–periodic background is shown.
Odd‐fold Darboux transformation, breather, rogue‐wave and semirational solutions on the periodic background for a variable‐coefficient derivative nonlinear Schrödinger equation describing the nonlinear Alfvén waves in an inhomogeneous plasma are reported. With respect to the left polarized Alfvén wave, effects of the dispersion and loss/gain coefficients on those solutions are discussed respectively.
Optical fiber communication plays an important role in the modern communication. In this paper, we investigate a variable-coefficient coupled Hirota system which describes the vector optical pulses ...in an inhomogeneous optical fiber. With respect to the complex wave envelopes, we construct a Lax pair and a Darboux transformation, both different from the existing ones. Infinitely-many conservation laws are derived based on our Lax pair. We obtain the one/two-fold bright-bright soliton solutions, one/two-fold bright-dark soliton solutions and one/two-fold breather solutions via our Darboux transformation. When α(t),β(t) and δ(t) are the trigonometric functions, we present the bright-bright soliton, bright-dark soliton and breather which are all periodic along the propagation direction, where α(t),β(t) and δ(t) represent the group velocity dispersion, third-order dispersion and nonlinear terms of the self-phase modulation and cross-phase modulation. Interactions between the two bright-bright soliton, two bright-dark solitons and two breathers are presented. Bound state of the two bright-bright solitons is formed. Widths and velocities of the two bright-bright solitons do not change but their amplitudes change after their interaction via the asymptotic analysis. Periods of the bright-dark solitons decrease when the periods of the trigonometric α(t),β(t) and δ(t) decrease.
We examine the importance of multiple agents’ reputations on the market's reaction to analysts’ stock recommendation revisions (analyst revisions), individually and interactively, in the UK and ...Japanese stock markets. We find some notable variations in reputation effects between the two markets. In the UK, analyst reputation amplifies the market's reaction to analyst revisions, while in Japan, analyst reputation has no significant impact. Firm reputation diminishes (amplifies) the market's reaction to analyst revisions in the UK (Japan). Only CEO reputation generates similar effects in the UK and Japan, dampening the market's reaction to analyst revisions. We also find that reputations interact in different ways in the two markets. Specifically, firm reputation and CEO reputation tend to moderate the positive effect of analyst reputation in the UK; however, in Japan, CEO reputation tends to moderate the positive effect of firm reputation, but there is no significant interaction effect between analyst reputation and CEO/firm reputation. Our findings are explained using insights both from formal economic models and from various cultural and institutional characteristics.
Plasmas are believed to be possibly the most abundant form of visible matter in the Universe. Investigation in this paper is given to a variable-coefficient derivative nonlinear Schrödinger equation ...describing the propagation of the nonlinear Alfvén waves in an inhomogeneous plasma. Based on the existing Lax pair, with respect to the left polarized Alfvén wave, the N-fold generalized Darboux transformation, rational one/two Alfvén soliton solutions and mixed two Alfvén soliton solutions are derived, where N=1,2,3…. For those Alfvén solitons, we find that (1) the solitonic width cannot be affected by the dispersion coefficient h(τ) and the loss/gain coefficient f(τ), where τ is the stretched space variable; the solitonic amplitude grows (or decays) in the exponential rate exp−∫f(τ)dτ; the solitonic amplitude cannot be affected by h(τ); the solitonic velocity and trajectory are related to h(τ), while they cannot be affected by f(τ); (2) the rational two Alfvén solitons experience no phase shift after the interaction; (3) the modulus square of mixed two Alfvén solitons can be decomposed into two single Alfvén solitons with the ∫h(τ)dτ-dependent phase shifts; (4) the collapse of the rational one Alfvén soliton is displayed.
•Flavonoid composition of tangerine peel was analysed by LC–MS.•Anti-neuroinflammatory ability was assessed by an LPS-induced microglial system.•Tangerine peel contains abundant hesperidin, ...tangeretin and nobiletin.•Dried tangerine peel has potent anti-neuroinflammatory capacity.•Anti-neuroinflammatory ability is attributed to a collective effect of flavonoids.
Inhibiting microglial activation-mediated neuroinflammation has become a convincing target for the development of functional foods to treat neurodegenerative diseases. Tangerine peel (Citri reticulatae pericarpium) has potent anti-inflammatory capacity; however, its anti-neuroinflammatory capacity and the corresponding active compounds remain unclear. To this end, the composition of a tangerine peel ethanolic extract was analysed by LC–MS, and the anti-neuroinflammatory ability was evaluated using a lipopolysaccharide (LPS)-activated BV2 microglia culture system. Hesperidin is the most predominant flavonoid in tangerine peel, followed by tangeretin and nobiletin. Among the eight tested flavanone glycosides and polymethoxy flavones, only nobiletin displayed a capacity of>50% to inhibit LPS-induced proinflammatory NO, TNF-α, IL-1β and IL-6 secretion at a concentration of 100μM. At 2mg/ml, tangerine peel extract attenuated LPS-induced NO, TNF-α, IL-1β and IL-6 secretion by 90.6%, 80.2%, 66.7%, and 86.8%, respectively. Hesperidin, nobiletin, and tangeretin individually (at concentrations of 135, 40, and 60μM, respectively) in 2mg/ml tangerine peel extract were only mildly inhibitory, whereas in combination, they significantly inhibited LPS-induced proinflammatory cytokine expression at levels equal to that of 2mg/ml tangerine peel extract. Overall, tangerine peel possesses potent anti-neuroinflammatory capacity, which is attributed to the collective effect of hesperidin, nobiletin, and tangeretin.
Breast cancer (BC) is the most prevalent malignant cancer in the world, is the leading cause of cancer‐related death female. Recently, there is accumulating evidence that long noncoding RNAs ...(lncRNAs) might as an important role in the progression of BC. (epithelial‐mesenchymal transition (EMT) is considered to play a vital role in tumor cells migration and invasion. Nevertheless, the entire biological mechanisms and functions of lncRNAs in tumor migration, invasion, and EMT remain uncertain. In the present research, we observed that the expression of lncRNA AC073284.4 was downregulated in BC paclitaxel‐resistant (PR) cells (MCF‐7/PR) and tissues. Bioinformatics analysis predicted that miR‐18b‐5p was a direct target of AC073284.4, which has been validated by dual‐luciferase reporter gene assay. We further proved that AC073284.4 could directly bind to miR‐18b‐5p and relieve the suppression for dedicator of cytokinesis protein 4 (DOCK4). Furthermore, the underlying functional experiments demonstrated that AC073284.4 might sponge miR‐18b‐5p to attenuate the invasion, metastasis, and EMT of BC cell through upregulating DOCK4 expression. In summary, AC073284.4 might serve as a competing endogenous RNA (ceRNA) in BC progression via modulating miR‐18b‐5p/DOCK4 axis, which weakens EMT and migration of BC. These results suggesting that AC073284.4 might function as a potential novel diagnostic biomarker in the progression of BC.
These findings provide a novel mechanism of the AC073284.4/miR‐18‐5p/DOCK4 axis in breast cancer, especially to explore its role in invasion, metastasis, and EMT, and suggest that this pathway might be a promising molecular therapeutic target against human breast cancer.
The choice of bandwidth is crucial to the kernel density estimation (KDE) and kernel based regression. Various bandwidth selection methods for KDE and local least square regression have been ...developed in the past decade. It has been known that scale and location parameters are proportional to density functionals ∫ γ ( x ) f 2 ( x ) d x with appropriate choice of γ ( x ) and furthermore equality of scale and location tests can be transformed to comparisons of the density functionals among populations. ∫ γ ( x ) f 2 ( x ) d x can be estimated nonparametrically via kernel density functionals estimation (KDFE). However, the optimal bandwidth selection for KDFE of ∫ γ ( x ) f 2 ( x ) d x has not been examined. We propose a method to select the optimal bandwidth for the KDFE. The idea underlying this method is to search for the optimal bandwidth by minimizing the mean square error (MSE) of the KDFE. Two main practical bandwidth selection techniques for the KDFE of ∫ γ ( x ) f 2 ( x ) d x are provided: Normal scale bandwidth selection (namely, “Rule of Thumb”) and direct plug-in bandwidth selection. Simulation studies display that our proposed bandwidth selection methods are superior to existing density estimation bandwidth selection methods in estimating density functionals.
PDF
