Stability and chemical bonding in a series of inverse sandwich actinide boride clusters (AnB) with δ bonding.

An inverse sandwich structure has been computationally predicted for uranium boride and extended to the series of actinide elements (An) from Th to Cm. The electronic structure and chemical bonding of these novel compounds have been analyzed using density functional theory and multireference wave-function based methods. We report the trends in electronic structure and bonding for AnB, and found that (d-π)π and (d-p)δ are the most important factors in the stability of AnB.

Robust Optimal Control Design for Performance Enhancement of PWM Voltage Source Inverter.

PWM (pulse-width modulation) voltage source inverters are used in a wide range of AC power systems where the output voltage must be controlled to follow a sinusoidal reference waveform. In order to achieve precision and fast-tracking control, restrictive sliding mode control (RSMC) provides a fast system state convergence time. However, the RSMC still suffers from the chattering problem, which leads to high harmonic distortion and slow response of the inverter output state.

Evaluation of ursolic acid derivatives with potential anti-Toxoplasma gondii activity.

Toxoplasma gondii is an important pathogen that causes serious public health problems. Currently, therapeutic drugs for toxoplasmosis cause serious side effects, and more effective and novel substances with relatively low toxicity are urgently needed. Ursolic acid (UA) has many properties that can be beneficial to healthcare.

Synthesis and evaluation of the HIF-1α inhibitory activities of novel ursolic acid tetrazole derivatives.

The hypoxia-inducible factor-1α (HIF-1α) pathway has been implicated in tumor angiogenesis, growth, and metastasis. Therefore, the inhibition of this pathway is an important therapeutic target for the treatment of various types of cancers. Here, we designed and synthesized 31 ursolic acid (UA) derivatives containing a tetrazole moiety and evaluated them for their potential anti-tumor activities as HIF-1α transcriptional inhibitors.

Design, synthesis, evaluation, and molecular docking of ursolic acid derivatives containing a nitrogen heterocycle as anti-inflammatory agents.

Ursolic acid derivatives containing oxadiazole, triazolone, and piperazine moieties were synthesized in an attempt to develop potent anti-inflammatory agents. Structures of the synthesized compounds were elucidated by H NMR, C NMR, and HRMS. Most of the synthesized compounds showed pronounced anti-inflammatory effects at 100 mg/kg.

Design, synthesis, and evaluation of novel ursolic acid derivatives as HIF-1α inhibitors with anticancer potential.

Hypoxia-inducible factor-1α (HIF-1α), a key mediator in tumor metastasis and angiogenesis, is associated with poor patient prognosis and has been recognized as an important cancer drug target. In this work, four novel series of ursolic acid derivatives containing oxadiazole, triazolone, and piperazine moieties were designed, synthesized, and evaluated for anti-tumor activity as HIF-1α inhibitors. The majority of the compounds showed an excellent ability to inhibit the expression of HIF-1α.

Synthesis and Positive Inotropic Activity of [1,2,4]Triazolo[4,3-a] Quinoxaline Derivatives Bearing Substituted Benzylpiperazine and Benzoylpiperazine Moieties.

In an attempt to search for more potent positive inotropic agents, two series of [1,2,4]triazolo[4,3-] quinoxaline derivatives bearing substituted benzylpiperazine and benzoylpiperazine moieties were synthesized and their positive inotropic activities evaluated by measuring left atrial stroke volume in isolated rabbit heart preparations. Several compounds showed favorable activities compared with the standard drug, milrinone. Compound was the most potent agent, with an increased stroke volume of 12.

Synthesis and biological evaluation of chalcone derivatives containing aminoguanidine or acylhydrazone moieties.

Three novel series of chalcone derivatives containing an aminoguanidine or acylhydrazone moiety were designed, synthesized and evaluated in terms of their antibacterial, antifungal and anti-inflammatory activities. Most of the synthesized compounds showed potent inhibitory activity towards various bacteria and one fungus with minimum inhibitory concentrations (MICs) ranging from 1 to 8μg/mL. Compared with our previously reported chalcone derivatives (MICs >64μg/mL), these compounds exhibited improved antibacterial activities (MICs=2μg/mL) against Gram-negative bacterial strains (Escherichia coli 1924 and 1356).

Effects of social isolation, re-socialization and age on cognitive and aggressive behaviors of Kunming mice and BALB/c mice.

Both Kunming (KM) mice and BALB/c mice have been widely used as rodent models to investigate stress-associated mental diseases. However, little is known about the different behaviors of KM mice and BALB/c mice after social isolation, particularly cognitive and aggressive behaviors. In this study, the behaviors of KM and BALB/c mice isolated for 2, 4 and 8 weeks and age-matched controls were evaluated using object recognition, object location and resident-intruder tests.

Synthesis and Antimicrobial Evaluation of (Z)-5-((3-phenyl-1H-pyrazol-4- yl)methylene)-2-thioxothiazolidin-4-one Derivatives.

Background: An alarming increment in pathogenic resistance to existing anti-microbial agents is a serious problem and the treatment of these bacterial infections is becoming increasingly challenging. Therefore, there is an urgent need to develop novel antimicrobial agents.

Objective: As a part of our ongoing studies toward the development of novel antibacterial agents, the synthesis and antibacterial activity of a series of (Z)-5-((3-phenyl-1H-pyrazol-4-yl)methylene)-2-thioxothiazolidin-4-one derivatives will be discussed in this study.

Design, synthesis, and negative inotropic evaluation of 4-phenyl-1H-1,2,4-triazol-5(4H)-one derivatives containing triazole or piperazine moieties.

In this study, four novel series of 4-phenyl-1H-1,2,4-triazol-5(4H)-one derivatives containing triazole or piperazine moieties were designed, synthesized, and evaluated for negative inotropic activity by measuring the left atrium stroke volume in isolated rabbit heart preparations. Almost all of the compounds showed an ability to moderate the cardiac workload by decreasing the heart rate and contractility. Among them, 7h was found to be the most potent with a change in stroke volume of -48.

Synthesis and Antibacterial Evaluation of (S,Z)-4-methyl-2-(4-oxo-5-((5-substituted phenylfuran-2-yl) methylene)-2-thioxothiazolidin-3-yl)Pentanoic Acids.

The microbial resistance has become a global hazard with the irrational use of antibiotics. Infection of drug-resistant bacteria seriously threatens human health. Currently, there is an urgent need for the development of novel antimicrobial agents with new mechanisms and lower levels of toxicity.

Bioconversion of pinoresinol into matairesinol by use of recombinant Escherichia coli.

Lignans, a class of dimeric phenylpropanoid derivative found in plants, such as whole grains and sesame and flax seeds, have anticancer activity and can act as phytoestrogens. The lignans secoisolariciresinol and matairesinol can be converted in the mammalian proximal colon into enterolactone and enterodiol, respectively, which reduce the risk of breast and colon cancer. To establish an efficient bioconversion system to generate matairesinol from pinoresinol, the genes encoding pinoresinol-lariciresinol reductase (PLR) and secoisolariciresinol dehydrogenase (SDH) were cloned from Podophyllum pleianthum Hance, an endangered herb in Taiwan, and the recombinant proteins, rPLR and rSDH, were expressed in Escherichia coli and purified.

Synthesis and antibacterial evaluation of rhodanine-based 5-aryloxy pyrazoles against selected methicillin resistant and quinolone-resistant Staphylococcus aureus (MRSA and QRSA).

With an intention to synergize the anti-bacterial activity of 5-aryloxy pyrazole and rhodanine derivatives, eight series of hybrid compounds have been synthesized and evaluated for their antibacterial activity. The majority of the synthesized compounds showed good inhibitory activity against selected methicillin resistant and quinolone-resistant Staphylococcus aureus (MRSA, QRSA) with minimum inhibitory concentration (MIC) values in the range of 1-32 μg/mL. The cytotoxicity test suggests that these compounds exhibited in vitro antibacterial activity at non-cytotoxic concentrations.