Ziziphus nummularia Attenuates the Malignant Phenotype of Human Pancreatic Cancer Cells: Role of ROS

Pancreatic cancer (PC) is the fourth leading cause of all cancer-related deaths. Despite major improvements in treating PC, low survival rate remains a major challenge, indicating the need for alternative approaches, including herbal medicine. Among medicinal plants is Ziziphus nummularia (family Rhamnaceae), which is a thorny shrub rich in bioactive molecules. Leaves of Ziziphus nummularia have been used to treat many pathological conditions, including cancer. However, their effects on human PC are still unknown. Here, we show that the treatment of human pancreatic ductal adenocarcinoma cells (Capan-2) with Ziziphus nummularia ethanolic extract (ZNE) (100–300 μg/mL) attenuated cell proliferation in a time- and concentration-dependent manner. Pretreatment with N-acetylcysteine, an ROS scavenger, attenuated the anti-proliferative effect of ZNE. In addition, ZNE significantly decreased the migratory and invasive capacity of Capan-2 with a concomitant downregulation of integrin α₂ and increased cell–cell aggregation. In addition, ZNE inhibited in ovo angiogenesis as well as reduced VEGF and nitric oxide levels. Furthermore, ZNE downregulated the ERK1/2 and NF-κB signaling pathways, which are known to drive tumorigenic and metastatic events. Taken together, our results suggest that ZNE can attenuate the malignant phenotype of Capan-2 by inhibiting hallmarks of PC. Our data also provide evidence for the potential anticancer effect of Ziziphus nummularia, which may represent a new resource of novel anticancer compounds, especially ones that can be utilized for the management of PC.     

On the Strong Convergence of Halpern Type Proximal Point Algorithm

The main result of this paper is to prove the strong convergence of the sequence generated by the proximal point algorithm of Halpern type to a zero of a maximal monotone operator under the suitable assumptions on the parameters and error. The results extend some of the previous results or give some different conditions for convergence of the sequence. It is also indicated that when the maximal monotone operator is the subdifferential of a convex, proper, and lower semicontinuous function, the results extend all previous results in the literature. We also prove the boundedness of the sequence generated by the algorithm with a weak coercivity condition defined in the paper and without any additional assumptions on the parameters.     

Groups with the same prime graph as the orthogonal group B n (3)

Let G be a finite group. The prime graph of G is denoted by Γ(G). It is proved in [1] that if G is a finite group such that Γ(G) = Γ(B _p (3)), where p > 3 is an odd prime, then G ? B _p (3) or C _p (3). In this paper we prove the main result that if G is a finite group such that Γ(G) = Γ(B _n (3)), where n ≥ 6, then G has a unique nonabelian composition factor isomorphic to B _n (3) or C _n (3). Also if Γ(G) = Γ(B ₄(3)), then G has a unique nonabelian composition factor isomorphic to B ₄(3), C ₄(3), or ² D ₄(3). It is proved in [2] that if p is an odd prime, then B _p (3) is recognizable by element orders. We give a corollary of our result, generalize the result of [2], and prove that B _2k+1(3) is recognizable by the set of element orders. Also the quasirecognition of B _2k (3) by the set of element orders is obtained.     

Selective oxidation of benzyl alcohols to benzaldehydes catalyzed by dioxomolybdenum Schiff base complex: synthesis,spectral characterization,crystal structure,theoretical and computational studies

Transition Metal Chemistry - A novel dioxomolybdenum Schiff base complex, MoO2L·DMF, was synthesized by treating MoO2(acac)2 with an ONO donor Schiff base ligand (H2L) derived by the...     

A novel salt bridge mechanism highlights the need for nonmobile proton conditions to promote disulfide bond cleavage in protonated peptides under low-energy collisional activation

The gas-phase fragmentation mechanisms of small models for peptides containing intermolecular disulfide links have been studied using a combination of tandem mass spectrometry experiments, isotopic labeling, structural labeling, accurate mass measurements of product ions, and theoretical calculations (at the MP2/6-311 + G(2d,p)//B3LYP/3-21G(d) level of theory). Cystine and its C-terminal derivatives were observed to fragment via a range of pathways, including loss of neutral molecules, amide bond cleavage, and S-S and C-S bond cleavages. Various mechanisms were considered to rationalize S-S and C-S bond cleavage processes, including charge directed neighboring group processes and nonmobile proton salt bridge mechanism. Three low-energy fragmentation pathways were identified from theoretical calculations on cystine N-methyl amide: (1) S-S bond cleavage dominated by a neighboring group process involving the C-terminal amide N to form either a protonated cysteine derivative or protonated sulfenyl amide product ion (44.3 kcal mol(-1)); (2) C-S bond cleavage via a salt bridge mechanism, involving abstraction of the alpha-hydrogen by the N-terminal amino group to form a protonated thiocysteine derivative (35.0 kcal mol(-1)); and (3) C-S bond cleavage via a Grob-like fragmentation process in which the nucleophilic N-terminal amino group forms a protonated dithiazolidine (57.9 kcal mol(-1)). Interestingly, C-S bond cleavage by neighboring group processes have high activation barriers (63.1 kcal mol(-1)) and are thus not expected to be accessible during low-energy CID experiments. In comparison to the energetics of simple amide bond cleavage, these S-S and C-S bond cleavage reactions are higher in energy, which helps rationalize why bond cleavage processes involving the disulfide bond are rarely observed for low-energy CID of peptides with mobile proton(s) containing intermolecular disulfide bonds. On the other hand, the absence of a mobile proton appears to "switch on" disulfide bond cleavage reactions, which can be rationalized by the salt bridge mechanism. This potentially has important ramifications in explaining the prevalence of disulfide bond cleavage in singly protonated peptides under MALDI conditions.     

Syntheses and characterization of mixed-chelate copper(II) complexes containing different counter ions; spectroscopic studies on solvatochromic properties

Solvatochromic mixed-chelate copper(II) complexes, [Cu(Cl-acac)(diamine)]X (where Cl-acac = 3-chloroacetylacetonate ion, diamine = N,N′-dimethyl,N′-benzyl-1,2-diaminoethane and X = B(Ph)₄⁻, PF₆⁻, BF₄⁻ and ClO₄⁻), have been prepared. The complexes were characterized on the basis of elemental analysis, molar conductance, UV-Vis and IR spectroscopies. Single crystals of [Cu(Cl-acac)(diamine)(H₂O)]PF₆, complex 2, were also characterized by X-ray diffraction. The influence of the solvent polarity and counter ions on the ν_max values of the d-d bands of the complexes have been investigated by means of visible spectroscopy. All the complexes demonstrated negative solvatochromism. A multi-parametric equation has been utilized to explain the solvent effect on the d-d transition of the complexes using SPSS/PC software. The stepwise multiple linear regression (SMLR) method demonstrated that the donor power of the solvent plays the most important role in the solvatochromism of the compounds. The relative donor power of the anions X was determined by visible spectra in the solvent dichloromethane.     

Stripping voltammetric determination of Cd(II) based on multiwalled carbon nanotube functionalized with 1-(2-pyridylazo)-2-naphthol

The present work has focused on the modification of multiwalled carbon nanotube with a ligand,l-（2-pyridylazo）-2-naphthol, and its potential application for the development of a new,simple and selective modified glassy carbon electrode for stripping voltammetric determination of Cd（Ⅱ）.The analytical curve for Cd（Ⅱ） ions covered the linear range varying from 0.8 up to 220.4μgL^-1.The limit of detection was found to be 0.1μgL^-1,while the relative standard deviation（RSD） at 50.0μgL^-1 was 1.8%（n=5）.This modified electrode was successfully applied for determination of Cd（Ⅱ） in some water samples.     

Application of a Carbon‐Paste Electrode Modified with 2,7‐Bis(ferrocenyl ethyl)fluoren‐9‐one and Carbon Nanotubes for Voltammetric Determination of Levodopa in the Presence of Uric Acid and Folic Acid

A carbon‐paste electrode modified with 2,7‐bis(ferrocenyl ethyl)fluoren‐9‐one and carbon nanotubes was used for the sensitive voltammetric determination of levodopa (LD). The electrochemical response characteristics of the modified electrode toward LD, uric acid (UA) and folic acid (FA) were investigated. The results showed an efficient catalytic activity of the electrode for the electrooxidation of LD, which leads to lowering its overpotential by more than 320 mV. The modified electrode exhibits an efficient electron mediating behavior together with well‐separated oxidation peaks for LD, UA and FA. Also, the modified electrode was used for determination of LD in some real samples.     

Anodic Stripping Voltammetric Determination of Iron(II) at a Carbon Paste Electrode Modified with Dithiodianiline (DTDA) and Gold Nanoparticles (GNP)

A differential pulse anodic stripping voltammetric procedure was developed for the determination of trace amounts of iron(II) in the presence of iron(III) at a carbon paste electrode (CPE) modified with dithiodianiline and gold nanoparticle. At the pH working of 3.0, a wide concentration range from 0.1 nM to 100 nM was observed with the detection limit of 0.05 nM. The relative standard deviation for a solution containing 50 nM of iron(II) was found to be 3.11 % (n=9). Possible interferences from the coexisting ions were also investigated. The validity of the method and applicability of the sensor were successfully tested by determining of iron(II) in lentil, wheat seed and barley seed samples.