Synthesis and characterization of 2-(2-benzhydrylnaphthyliminomethyl)pyridylnickel halides: formation of branched polyethylene

A series of 2-(2-benzhydrylnaphthyliminomethyl)pyridine derivatives (L1–L3) was prepared and used to synthesize the corresponding bis-ligated nickel(II) halide complexes (Ni1–Ni6) in good yield. The molecular structures of representative complexes, namely the bromide Ni3 and the chloride complex Ni6, were confirmed by single crystal X-ray diffraction, and revealed a distorted octahedral geometry at nickel. Upon activation with either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all nickel complex pre-catalysts exhibited high activities (up to 2.02 × 10⁷ g(PE) mol⁻¹(Ni) h⁻¹) towards ethylene polymerization, producing branched polyethylene of low molecular weight and narrow polydispersity. The influence of the reaction parameters and the nature of the ligands on the catalytic behavior of the title nickel complexes were investigated

(1S,4S,5S,8R)-8-Nitro­oxy-2,6-dioxa­bicyclo­[3.3.0]octan-4-yl 3,4,5-triacetoxy­benzoate

In the title compound, C19H19NO13, one of the two fused furan­ose rings adopts an envelope conformation whereas the other displays a twisted conformation. The crystal structure is stabilized by inter­molecular C—H⋯π inter­actions between a methine H atom and the triacetoxy­phenyl ring of an adjacent mol­ecule, and by weak non-classical inter­molecular C—H⋯O hydrogen bonds

Identification of alternative splicing variants of the β subunit of human Ca2+/calmodulin-dependent protein kinase II with different activities

AbstractThe β subunit of human Ca2+/calmodulin-dependent protein kinase II (β CaMKII) was identified by searching through an expressed sequence tag database and rapid amplification of cDNA 5′-ends and was assigned to chromosome 7. Reverse transcription-polymerase chain reaction and sequencing analysis identified at least five alternative splicing variants of β CaMKII (β, β6, βe, β′e, and β7) in brain and two of them (β6 and β7) were first detected in any species. When expressed in HEK 293 cells, the Ca2+/calmodulin-dependent kinase activity of β7, the shortest variant, was much lower than that of either β (the longest one) or βe (the medium one), suggesting possible regulation of β CaMKII activity by alternative splicing

The relationship between serum FSH level and ovarian response during controlled ovarian stimulation

Objectives: To evaluate whether serum follicle stimulating hormone (FSH) level during the early controlled ovarian stimulation can be used as a predictor of the ovarian response in the in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles. Material and methods: The participants of this retrospective study were chosen from Reproductive Medicine Center, Weifang People’s Hospital between January 2015 and December 2020.The participants of this study met the age of 20~43 years old, anti-Müllerian hormone (AMH) ≥ 1.2 ng/mL, antral follicle count (AFC) ≥ 5, and the data was complete and no cancellation cycle. Each participant was given GnRH agonist protocol and given a fixed dose of recombinant FSH in the first four days during the controlled ovarian stimulation (COS). According to the number of oocytes retrieved, the participants were divided into two different ovarian response groups. Serum FSH level after the fourth recombinant follicle stimulating hormone (rFSH) injection were compared during the different ovarian responders. Results: The number of participants who met both the inclusion criteria and exclusion criteria was 235. Serum sFSH levels (mean: 11.76 ± 3.10 IU/L) in the inappropriate responders was significantly higher than serum sFSH levels (mean: 10.79 ± 2.52 IU/L) in the superior responders(p = 0.029). There was a weak correlation between serum sFSH levels and the number of oocytes retrieved (r = −0.134, p = 0.041). Serum sFSH levels had significant clinical valuable (p = 0.0346) in predicting the number of oocytes retrieved. Conclusions: Serum sFSH levels may be a potential marker to predict the ovarian response during the early COS in the IVF/ICSI cycles, which can guide the adjustment of the exogenous rFSH dose

Existence of Positive Solution for BVP of Nonlinear Fractional Differential Equation

We consider the following boundary value problem of nonlinear fractional differential equation: (CD0+αu)(t)=f(t,u(t)),  t∈[0,1],  u(0)=0,   u′(0)+u′′(0)=0,  u′(1)+u′′(1)=0, where α∈(2,3] is a real number,  CD0+α denotes the standard Caputo fractional derivative, and f:[0,1]×[0,+∞)→[0,+∞) is continuous. By using the well-known Guo-Krasnoselskii fixed point theorem, we obtain the existence of at least one positive solution for the above problem

Dissecting the roles of DR4, DR5 and c-FLIP in the regulation of Geranylgeranyltransferase I inhibition-mediated augmentation of TRAIL-induced apoptosis

<p>Abstract</p> <p>Background</p> <p>Geranylgeranyltransferase I (GGTase I) has emerged as a cancer therapeutic target. Accordingly, small molecules that inhibit GGTase I have been developed and exhibit encouraging anticancer activity in preclinical studies. However, their underlying anticancer mechanisms remain unclear. Here we have demonstrated a novel mechanism by which GGTase I inhibition modulates apoptosis.</p> <p>Results</p> <p>The GGTase I inhibitor GGTI-298 induced apoptosis and augmented tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in human lung cancer cells. GGTI-298 induced DR4 and DR5 expression and reduced c-FLIP levels. Enforced c-FLIP expression or DR5 knockdown attenuated apoptosis induced by GGTI-298 and TRAIL combination. Surprisingly, DR4 knockdown sensitized cancer cells to GGTI298/TRAIL-induced apoptosis. The combination of GGTI-298 and TRAIL was more effective than each single agent in decreasing the levels of IκBα and p-Akt, implying that GGTI298/TRAIL activates NF-κB and inhibits Akt. Interestingly, knockdown of DR5, but not DR4, prevented GGTI298/TRAIL-induced IκBα and p-Akt reduction, suggesting that DR5 mediates reduction of IκBα and p-Akt induced by GGTI298/TRAIL. In contrast, DR4 knockdown further facilitated GGTI298/TRAIL-induced p-Akt reduction.</p> <p>Conclusions</p> <p>Both DR5 induction and c-FLIP downregulation contribute to GGTI-298-mediated augmentation of TRAIL-induced apoptosis. Moreover, DR4 appears to play an opposite role to DR5 in regulation of GGTI/TRAIL-induced apoptotic signaling.</p

2-(1-(2-Benzhydrylnaphthylimino)ethyl)pyridylnickel halides: Synthesis, characterization, and ethylene polymerization behavior

A series of 2-(1-(2-benzhydrylnaphthylimino)ethyl)pyridine derivatives (L1–L3) was synthesized and fully characterized. The organic compounds acted as bi-dentate ligands on reacting with nickel halides to afford two kinds of nickel complexes, either mononuclear bis-ligated L₂NiBr₂ (Ni1–Ni3) or chloro-bridged dinuclear L₂Ni₂Cl₄ (Ni4–Ni6) complexes. The nickel complexes were fully characterized, and the single crystal X-ray diffraction revealed for Ni2, a distorted square pyramidal geometry at nickel comprising four nitrogens of two ligands and one bromide; whereas for Ni4, a centrosymmetric dimer possessing a distorted octahedral geometry at nickel was formed by two nitrogens of one ligand, two bridging chlorides and one terminal chloride along with oxygen from methanol (solvent). When activated with diethylaluminium chloride (Et₂AlCl), all nickel complexes performed with high activities (up to 1.22 × 10⁷ g (PE) mol⁻¹(Ni) h⁻¹) towards ethylene polymerization; the obtained polyethylene possessed high branching, low molecular weight and narrow polydispersity, suggestive of a single-site active species. The effect of the polymerization parameters, including the nature of the ligands/halides on the catalytic performance is discussed