π‐Excess Aromatic σ2P Ligands: Formation of a Heterocyclic 1,2‐Diphosphine by the Addition of tBuLi and Subsequent Inverse Addition of the Product at the P=C Bonds of Two Molecules of 1‐Neopentyl‐1,3‐benzazaphosphole

The reactivity of tBuLi (pentane) toward the N‐neopentyl‐substituted π‐excess P=CH–N heterocycle 1 depends on the solvent (tetrahydrofuran, diethyl ether, hexane, and toluene) and reaction conditions. Trapping of the resulting organolithium compounds with CO₂/ClSiMe₃, ClSiMe₃, or EtI led to various products indicating CH lithiation ( 1a , b ), normal addition of tBuLi at the P=C bond (E/Z ‐2a , b ), inverse addition of the primary addition product 2_Li at the P=C bond of a second molecule 1 , affording 3‐tert‐butyl‐2,2’‐bis(1,3‐benzazaphospholines) 3 , or inverse addition of tBuLi ( 4b,c ). The formation of 3 demonstrates a novel route to asymmetric heterocyclic 1,2‐diphosphine ligands. The structure elucidation of the new compounds is based on their ³¹P and ¹³C NMR data with conclusive chemical shifts and P–C coupling constants, that of the isolated PH‐functionalized diphosphine 3 on crystal structure analysis.     

Biosynthesis of Zinc Oxide Nanoparticles from Acacia nilotica (L.) Extract to Overcome Carbapenem-Resistant Klebsiella Pneumoniae

Recently, concerns have been raised globally about antimicrobial resistance, the prevalence of which has increased significantly. Carbapenem-resistant Klebsiella pneumoniae (KPC) is considered one of the most common resistant bacteria, which has spread to ICUs in Saudi Arabia. This study was established to investigate the antibacterial activity of biosynthesized zinc oxide nanoparticles (ZnO-NPs) against KPC in vitro and in vivo. In this study, we used the aqueous extract of Acacia nilotica (L.) fruits to mediate the synthesis of ZnO-NPs. The nanoparticles produced were characterized by UV-vis spectroscopy, zetasizer and zeta potential analyses, X-ray diffraction (XRD) spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The antimicrobial activity of ZnO-NPs against KPC was determined via the well diffusion method, and determining minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), the results showed low MIC and MBC when compared with the MIC and MBC of Imipenem and Meropenem antibiotics. The results of in vitro analysis were supported by the results upon applying ZnO-NP ointment to promote wound closure of rats, which showed better wound healing than the results with imipenem ointment. The biosynthesized ZnO-NPs showed good potential for use against bacteria due to their small size, applicability, and low toxicity to human cells.     

Momordica charantia Extract Protects against Diabetes-Related Spermatogenic Dysfunction in Male Rats: Molecular and Biochemical Study

More than 90% of diabetic patients suffer from sexual dysfunction, including diminished sperm count, sperm motility, and sperm viability, and low testosterone levels. The effects of Momordica charantia (MC) were studied by estimating the blood levels of insulin, glucose, glycosylated hemoglobin (HbA1c), testosterone (TST), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) in diabetic rats treated with 250 and 500 mg/kg b.w. of the total extract. Testicular antioxidants, epididymal sperm characteristics, testicular histopathology, and lesion scoring were also investigated. Testicular mRNA expression of apoptosis-related markers such as antiapoptotic B-cell lymphoma-2 (Bcl-2) and proapoptotic Bcl-2-associated X protein (Bax) were evaluated by real-time PCR. Furthermore, caspase-3 protein expression was evaluated by immunohistochemistry. MC administration resulted in a significant reduction in blood glucose and HbA1c and marked elevation of serum levels of insulin, TST, and gonadotropins in diabetic rats. It induced a significant recovery of testicular antioxidant enzymes, improved histopathological changes of the testes, and decreased spermatogenic and Sertoli cell apoptosis. MC effectively inhibited testicular apoptosis, as evidenced by upregulation of Bcl-2 and downregulation of Bax and caspase-3. Moreover, reduction in apoptotic potential in MC-treated groups was confirmed by reduction in the Bax/Bcl-2 mRNA expression ratio.     

Breakup régimes and self-sustained pulsations in coaxial jets

We report on a new flow pattern transition observed in a coaxial jet configuration. Above a critical momentum ratio between the outer and the inner stream, it is found experimentally that the inner potential core breaks down into an unsteady recirculation bubble. The origin of the transition is explained and an expression for the critical velocity ratio is derived. The nature and the features of the pulsation of the bubble are discussed using an original evolution equation which relies on the interplay between the linear growth rate of the jet mixing layer disturbances and the recirculating flow induced delay of the non-linear saturation.

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Sommario In questo articolo si discute di un nuovo tipo di transizione di flusso osservata in una configurazione di getto coassiale. Si stabilisce sperimentalmente che il potenziale interno disgrega la parte interna del flusso in una ricircolazione instabile a bolla oltre un valore critico nel rapporto tra la corrente interna e quella esterna. Viene spiegata l'origine della transizione e viene derivata l'espressione della velocità critica. Sono discusse, inoltre, la natura e le caratteristiche della pulsazione della bolla, avendo a disposizione una equazione di evoluzione originale che evidenzia l'influenza reciproca tra la crescita lineare dei disturbi dello strato di mescolamento del getto ed il flusso ricircolante, che induce il ritardo della saturazione non-lineare.

     

New Cytotoxic Laurene‐, Cuparene‐, and Laurokamurene‐Type Sesquiterpenes from the Red Alga Laurencia obtusa

Three new sesquiterpene alcohols, laur‐2‐ene‐3,12‐diol ( 1 ), cuparene‐3,12‐diol ( 2 ), and 8,11‐dihydro‐1‐methoxylaurokamuren‐12‐ol ( 3 ), along with one known diterpene, kahukuen‐10‐ol ( 4 ) have been isolated from the organic extract of the red alga Laurencia obtusa. The chemical structures were elucidated on the basis of spectroscopic analysis. The cytotoxicity of the isolated compounds were evaluated against three cancer cell lines, i.e., KB, HepG2, and MCF‐7. Compound 4 exhibited a wide range of cytotoxic activity against KB, HepG2, and MCF‐7 cell lines with IC₅₀ of 0.100, 0.057, and 0.054 μm, respectively. In addition, 1 showed moderate activities towards KB and MCF‐7 cell lines with IC₅₀ values of 0.171 and 0.184 μM , respectively and 2 exhibited a moderate activity against KB cell line at a concentration of 0.213 μg/ml. On the other hand, compound 3 exhibited no cytotoxic activity against any of the three cell lines.     

Cytotoxic cembranoids from the Red Sea soft coral Sarcophyton glaucum

One new cembrane diterpene, 2R,7R,8R-dihydroxydeepoxysarcophine (1), together with three known compounds, 7alpha,8beta-dihydroxydeepoxysarcophine (2), 7beta-acetoxy-8alpha-hydroxydeepoxysarcophine (3), and sarcophine (4), have been isolated from the Red Sea soft coral Sarcophyton glaucum. Their structures were determined using 1D and 2D NMR spectroscopy. 7beta-Acetoxy-8alpha-hydroxydeepoxysarcophine (3) exhibits cytotoxic activity against HepG2, HCT-116, and HeLa cells with IC50 values of 3.6, 2.3, and 6.7 microg/mL, respectively.     

Similarity Solutions for Generalized Variable Coefficients Zakharov-Kuznetsov Equation under Some Integrability Conditions

In this paper, the symmetry method has been carried over to the generalized variable coefficients Zakharov- Kuznetsov equation. The infinitesimal symmetries and the optimal system are deduced and from this optimal system seven basic fields are determined, and for every vector field in the optimal system the admissible forms of the coefficients are found and this also leads us to transform the given equation into partial differential equations in two variables. After using some referenced transformations the mentioned partial differential equations eventually reduce to ordinary differential equations. The search for solutions to those equations has yielded many exact solutions in most cases.     

Mesenchymal Stem Cells: a Promising Therapeutic Tool for Acute Kidney Injury

Applied Biochemistry and Biotechnology - Acute kidney injury (AKI) is a rapid loss of renal function. It has high mortality rates. Still, renal replacement therapy is considered the best solution...