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[Display omitted] • Serum FGF23 levels increased with gestational age in normal pregnant women. • Preeclampsia group had lower FGF23 levels than control group in the third trimester. • FGF23 promoted cell migration, invasion and tube formation abilities in vitro. • FGF23 stimulated placental VEGF-A expression via ERK1/2-EGR-1 pathway. • This study provides a potential mechanism involved in progression of preeclampsia. This study aimed to investigate the expression of fibroblast growth factor 23 (FGF23) in pregnant women with preeclampsia and elucidate its role in promoting placental angiogenesis through the ERK1/2-EGR-1 signaling pathway. Serum FGF23 levels were measured by ELISA in healthy pregnant women and patients with preeclampsia during the first, second, and third trimesters of pregnancy. Wound healing, Transwell, and tube formation assays were performed to investigate the effects of FGF23 on cell migration, invasion and tube formation. The expression of vascular endothelial growth factor A (VEGF-A) and its upstream signaling molecules, p-ERK, and EGR-1, in placental tissues was detected by RT-qPCR and western blotting. Additionally, the effect of FGF23 on VEGF-A, p-ERK, and EGR-1 expression was further explored in vitro. Serum FGF23 levels increased with gestational age. During the third trimester, the control group exhibited a more pronounced increase in FGF23 levels than the preeclampsia group. Administering exogenous FGF23 promoted trophoblast cell migration, invasion and enhanced tube formation in vascular endothelial cells. The expression levels of VEGF-A, p-ERK, and EGR-1 in the placental tissues were significantly lower in the preeclampsia group than in the control group. In vitro experiments confirmed that FGF23 up-regulated VEGF-A expression through the p-ERK/EGR-1 signaling pathway. The serum level of FGF23 decreased in pregnant women with preeclampsia, inhibiting the ERK1/2-EGR-1 pathway and resulting in decreased expression of VEGF-A, thereby inhibiting placental angiogenesis. This could be a potential mechanism involved in the progression of preeclampsia. [ABSTRACT FROM AUTHOR]

The research on orthogonal Steiner systems S (t , k , v) was initiated in 1968. For (t , k) ∈ { (2 , 3) , (3 , 4) } , this corresponds to orthogonal Steiner triple systems (STSs) and Steiner quadruple systems (SQSs), respectively. The existence problem of a pair of orthogonal STSs or SQSs was settled completely thirty years ago. However, for Steiner systems with t ≥ 3 and k ≥ 5 , only two small examples of orthogonal pairs were known to exist before this work. An infinite family of orthogonal Steiner systems S (3 , 5 , v) is constructed in this paper. In particular, the existence of a pair of orthogonal Steiner systems S (3 , 5 , 4 m + 1) is established for any even m ≥ 2 ; additionally a pair of orthogonal G-designs G ( 4 m + 1 5 , 5 , 5 , 3) is displayed for any odd m ≥ 3. The construction is based on the Steiner systems admitting 3-transitive automorphism groups supported by elementary symmetric polynomials. Moreover, 50 mutually orthogonal Steiner systems S (5 , 8 , 24) are shown to exist. [ABSTRACT FROM AUTHOR]

This paper concentrates on mutually disjoint 2-chromatic Steiner quadruple systems of order v (briefly by SQS(v)s), meaning that the SQS(v)s are mutually disjoint and they are mutually 2-chromatic having the same two color classes. Following Phelps and Rosa's work, we study maximum sets of mutually disjoint 2-chromatic SQS(v)s by applying direct constructions for suitable collections of triple representatives of V q by utilizing automorphism groups of affine transformations in the finite fields F q for prime powers q. Our main result presents many new maximum sets of mutually disjoint 2-chromatic SQS(v)s. We also improve the lower bounds on the number of mutually disjoint SQS(v)s as a by-product. [ABSTRACT FROM AUTHOR]

Abstract: The problem of the existence of large sets of Kirkman triple systems (LKTS) is one of the most celebrated open problems in design theory. Only a few sparsely distributed infinite classes have been determined, although LKTS have been investigated by many authors. The purpose of this paper is to survey constructions and results on LKTS and related designs. A systematic account of this work is provided. Most of the known constructions are unified and generalized; the approaches to LKTS are enriched; a couple of new constructions for related designs are also displayed. In particular, a new existence class of LKTS is demonstrated and some new results of overlarge sets of Kirkman triple systems are also produced. [Copyright &y& Elsevier]

Hollow polyethylene spheres were achieved from solution-based ɑ-diimine nickel catalyst system with morphological controllable one-step synthesis. • Homogenous ɑ- diimine nickel complexes often produce bulk viscous polyethylene. • Spherical hollow polyethylene produced by coordination dispersion polymerization. • Tri-nuclear nickel complex show high activity for ethylene polymerization. In this paper, ɑ-diimine nickel catalyst without immobilization was successfully used for one-step synthesis of spherical hollow polyethylene particles at mild condition (1.0 MPa, 25 °C) by conducting coordination dispersion polymerization. It was found 2-methyl-2-pentanol (MP) played a key role in the formation of the unusual hollow particular morphology. By varying the addition amount of MP, changing the bulky groups of alkyl aluminum, and adjusting the concentration of nickel catalyst, the particle size was finely tuned. A plausible mechanism was proposed to interpret the formation of these polyethylene hollow particles. [ABSTRACT FROM AUTHOR]

An (n , k) - Sperner partition system is a collection of partitions of some n -set, each into k nonempty classes, such that no class of any partition is a subset of a class of any other. The maximum number of partitions in an (n , k) -Sperner partition system is denoted SP (n , k). In this paper we introduce a new construction for Sperner partition systems and use it to asymptotically determine SP (n , k) in many cases as n k becomes large. We also give a slightly improved upper bound for SP (n , k) and exhibit an infinite family of parameter sets (n , k) for which this bound is tight. [ABSTRACT FROM AUTHOR]