Carexduanensis (Carexsect.Rhomboidales), a new species of Cyperaceae from limestone areas of Guangxi, China.

Carexduanensis Z.C.Lu, Y.F.Lu & X.F.Jin, a new species in limestone areas of Guangxi, China, was discovered and described. The morphology showed that C.duanensis is similar to C.calcicola, but differs in having culms central, leaf blades 3-5.5 mm wide, bracts longer than spikes, utricles 4-5 mm long, shorter, and nutlets abruptly contracted into an erect beak at apex. SEM microphotographs of utricles and nutlets are provided for the new and related species, C.calcicola.

Notes on Carex (Cyperaceae) from China (IX): three new species of section Mitratae s.l.

Carexsect.Mitratae s.l. was established by Kükenthal in 1909 and can be distinguished from the closely related sections in having nutlets frequently discoid-annulate at the apex and a persistent style base. Based on field surveys and specimen examination, three new species of sect. Mitratae are described and illustrated here. Carexfatsuaniana was collected from Yunnan and differs from C.truncatigluma in having the utricles nearly glabrous, the nutlets with a ca. 0.5 mm long beak at the apex, the staminate spikes cylindrical, 5-7.5 cm long, 4-5 mm wide, and the pistillate glumes acuminate at the apex. Carexdamingshanica was collected from Guangxi and differs from C.breviscapa and C.rhynchachaenium in having 3 or 4 spikes, the lateral spikes cylindrical, the pistillate glumes, utricles and nutlets all shorter than in the other two species. Carexradicalispicula was collected from Sichuan and differs from C.truncatirostris in having the staminate spikes clavate, 1.5-2 mm wide, the pistillate glumes pale yellow-white, 3-3.2 mm long, acuminate or short-awned at the apex, and the nutlets with 3 angles shallowly constricted at the middle.

Ferrate(VI) mediated degradation of the potent cyanotoxin, cylindrospermopsin: Kinetics, products, and toxicity.

The presence of cylindrospermopsin (CYN), a potent cyanotoxin, in drinking water sources poses a tremendous risk to humans and the environment. Detailed kinetic studies herein demonstrate ferrate(VI) (FeVIO42-, Fe(VI)) mediated oxidation of CYN and the model compound 6-hydroxymethyl uracil (6-HOMU) lead to their effective degradation under neutral and alkaline solution pH. A transformation product analysis indicated oxidation of the uracil ring, which has functionality critical to the toxicity of CYN. The oxidative cleavage of the C5=C6 double bond resulted in fragmentation of the uracil ring. Amide hydrolysis is a contributing pathway leading to the fragmentation of the uracil ring. Under extended treatment, hydrolysis, and extensive oxidation lead to complete destruction of the uracil ring skeleton, resulting in the generation of a variety of products including nontoxic cylindrospermopsic acid. The ELISA biological activity of the CYN product mixtures produced during Fe(VI) treatment parallels the concentration of CYN. These results suggest the products do not possess ELISA biological activity at the concentrations produced during treatment. The Fe(VI) mediated degradation was also effective in the presence of humic acid and unaffected by the presence of common inorganic ions under our experimental conditions. The Fe(VI) remediation of CYN and uracil based toxins appears a promising drinking water treatment process.

Inhibition of Pim-2 kinase by LT-171-861 promotes DNA damage and exhibits enhanced lethal effects with PARP inhibitor in multiple myeloma.

Multiple myeloma (MM) is a malignancy of antibody-producing plasma cells with genomic instability and genetic abnormality as its two hallmarks. Therefore, DNA damage is pervasive in MM cells, which indicates irregular DNA damage response (DDR) pathway. In this study, we demonstrated that LT-171-861, a multiple kinase inhibitor, could inhibit proliferation and induce apoptosis in MM cells. LT-171-861 promoted DDR pathway and triggered DNA damage through impeding the process of homologous recombination in double strand breaks, rather than directly elevating ROS level in MM cells. Mechanism research revealed that Pim2 inhibition was responsible for LT-171-861-indcued DNA damage and cell apoptosis. LT-171-861 mainly suppressed Pim2 kinase activity and reduced the expression of its phosphorylated substrates, such as 4EBP1 and BAD. Moreover, Olaparib, a PARP inhibitor, could enhance the antitumor effect of LT-171-861 in suppressing tumor growth in MM xenografted nude mice. Taken together, our results demonstrated that LT-171-861 showed a promising therapeutic potential for MM and had an additional lethal effect with PARP inhibitors.

Fundamental study of the ultrasonic induced degradation of the popular antihistamine, diphenhydramine (DPH).

Diphenhydramine (DPH) the active ingredient in Benadryl, has been detected in streams, rivers and other surface water sources. As a bioactive compound, DPH impacts human health even at low concentrations. Ultrasonic irradiation at 640 kHz leads to the rapid degradation of DPH in aqueous solution. Radical scavenging experiments and detailed product studies indicate the DPH degradation involves direct pyrolysis and degradation reactions mediated by the hydroxyl radicals produced during cavitation. The degradation can be modeled by pseudo-first order kinetics yielding rate constants k of 0.210, 0.130, 0.082, 0.050, 0.035, 0.023 min-1 at the initial concentrations of 2.8, 5.2, 13.9, 27.0, 61.0, 160.0 µmol L-1, respectively. The degradation process follows the Langmuir-Hinshelwood (heterogeneous) model with a partition coefficient, KL-H = 0.06 µmol·L-1and reactivity constant kr = 1.96 µmol min-1·L-1. A competition kinetic study conducted employing the hydroxyl radical trap, coumarin, illustrates that DPH was degraded primarily by hydroxyl radical mediated processes. Computational studies employing Gaussian 09 basis set provide fundamental insight into the partitioning of the reaction pathways and the degradation mechanisms. The study demonstrates the ultrasonic degradation of DPH is rapid, follows simple kinetic expressions and is accurately modeled using computational methods.

Oxidative remediation of 4-methylcyclohexanemethanol (MCHM) and propylene glycol phenyl ether (PPh). Evidence of contaminant repair reaction pathways.

A large spill of 4-methylcyclohexanemethanol (MCHM) and propylene glycol phenyl ether (PPh) into the Elk River near Charleston, West Virginia on January 9, 2014 led to serious water contamination and public concerns about appropriate remediation. To assess the feasibility of advanced oxidation processes (AOPs) for remediation of waters contaminated with these compounds, we induced hydroxyl radical (HO˙) reactions using time-resolved and steady-state radiolysis methods. Detailed product analyses showed initial HO˙ attack was at the benzene ring of PPh, and occurred through H-atom abstraction reactions for MCHM. Pulse radiolysis and steady state radiolysis experiments conducted using pure compound solutions, mixtures of the compounds and real water solvents allowed us to obtain mechanistic insights of hydroxyl radical attack and establish the fate of the compounds using AOP remediation technologies. These results demonstrate that hydroxyl radical induced oxidization of PPh can lead to "repair-type" reactions, which regenerates this contaminant. The study further highlights the importance of such counterproductive reactions for the quantitative estimate of the required amount of oxidant in any large-scale treatment approaches.

9.80-W and 0.54-mJ actively Q-switched Nd:YAG/Nd:YVO4 hybrid gain intracavity Raman laser at 1176 nm.

Here we propose an efficient diode-end-pumped actively Q-switched 1176-nm Nd:YAG/Nd:YVO4 hybrid gain intracavity Raman laser. By virtue of the construction of a coaxial double crystal, the laser not only can operate efficiently at low pulse repetition frequencies (PRFs), thereby realizing relatively high-energy and high-peak-power pulsed output, but also is capable of generating a high average output power at high PRFs. A maximum pulse energy of 0.54 mJ for the 1176-nm Stokes light is achieved at the PRF of 10 kHz, and the maximum average output power up to 9.80 W is obtained at the PRF of 100 kHz, while the incident pump power is 42.0 W.

Efficient 914-nm Nd:YVO4 laser under double-end polarized pumping.

We report herein the enhancement of output power and optical efficiency of a quasi-three-level Nd:YVO4 laser through a double-end polarized pumping scheme, which improves the usually insufficient pump absorption of the short laser gain medium with low doping concentration, and meanwhile alleviates the influence of thermal effect. 17.7 W laser output at 914 nm is obtained under the launched 808-nm pump of 53.0 W, corresponding to an optical efficiency of 33.4%.

Photochemical Transformation of Aminoglycoside Antibiotics in Simulated Natural Waters.

Aminoglycoside antibiotics are widely used in human therapy and veterinary medicine. We report herein a detailed study on the natural-organic-matter- (NOM-) photosensitized degradation of aminoglycosides in aqueous media under simulated solar irradiation. It appears that the direct reaction of the excited states of NOM ((3)NOM*) with aminoglycosides is minor. The contributions of reactive oxygen species (ROSs) in the bulk solutions are also unimportant, as determined by an assessment based on steady-state concentrations and bimolecular reaction rate constants in a homogeneous reaction model. The inhibition of the photodegradation by isopropamide is rationalized through competitive sorption with aminoglycosides on the NOM surface, whereas the addition of isopropanol negligibly affects degradation because it quenches HO(•) in the bulk solution but not HO(•) localized on the NOM surface where aminoglycosides reside. Therefore, a sorption-enhanced phototransformation mechanism is proposed. The sorption of aminoglycosides on NOM follows a dual-mode model involving Langmuir and linear isotherms. The steady-state concentration of HO(•) on the surface of NOM was calculated as 10(-14) M, 2 orders of magnitude higher than that in the bulk solution. This fundamental information is important in the assessment of the fate and transport of aminoglycosides in aqueous environments.

5.2-W high-repetition-rate eye-safe laser at 1525 nm generated by Nd:YVO4₋YVO4stimulated Raman conversion.

We report herein an efficient eye-safe Raman laser, which is based upon Nd:YVO4₋YVO4 and in-band pumped by a wavelength-locked laser diode array at 878.6 nm. By virtue of mitigated thermal load and improved pump absorption, a maximum average output power of 5.2 W at 1525 nm is obtained under the incident pump power of 30.6 W with the pulse repetition frequency of 140 kHz, corresponding to an optical efficiency of 17.0%.

Reductive and oxidative degradation of iopamidol, iodinated X-ray contrast media, by Fe(III)-oxalate under UV and visible light treatment.

Iopamidol, widely employed as iodinated X-ray contrast media (ICM), is readily degraded in a Fe(III)-oxalate photochemical system under UV (350 nm) and visible light (450 nm) irradiation. The degradation is nicely modeled by pseudo first order kinetics. The rates of hydroxyl radical (OH) production for Fe(III)-oxalate/H2O2/UV (350 nm) and Fe(III)-oxalate/H2O2/visible (450 nm) systems were 1.19 ± 0.12 and 0.30 ± 0.01 µM/min, respectively. The steady-state concentration of hydroxyl radical (OH) for the Fe(III)-oxalate/H2O2/UV (350 nm) conditions was 10.88 ± 1.13 × 10(-14) M and 2.7 ± 0.1 × 10(-14) M for the Fe(III)-oxalate/H2O2/visible (450 nm). The rate of superoxide anion radical (O2(-)) production under Fe(III)-oxalate/H2O2/UV (350 nm) was 0.19 ± 0.02 µM/min with a steady-state concentration of 5.43 ± 0.473 × 10(-10) M. Detailed product studies using liquid chromatography coupled to Q-TOF/MS demonstrate both reduction (multiple dehalogenations) and oxidation (aromatic ring and side chains) contribute to the degradation pathways. The reduction processes appear to be initiated by the carbon dioxide anion radical (CO2(-)) while oxidation processes are consistent with OH initiated reaction pathways. Unlike most advanced oxidation processes the Fe(III)-oxalate/H2O2/photochemical system can initiate to both reductive and oxidative degradation processes. The observed reductive dehalogenation is an attractive remediation strategy for halogenated organic compounds as the process can dramatically reduce the formation of the problematic disinfection by-products often associated with oxidative treatment processes.

A review on cylindrospermopsin: the global occurrence, detection, toxicity and degradation of a potent cyanotoxin.

Cylindrospermopsin is an important cyanobacterial toxin found in water bodies worldwide. The ever-increasing and global occurrence of massive and prolonged blooms of cylindrospermopsin-producing cyanobacteria poses a potential threat to both human and ecosystem health. Its toxicity is associated with metabolic activation and may involve mechanisms that adversely affect a wide variety of targets in an organism. Cylindrospermopsin has been shown to be cytotoxic, dermatotoxic, genotoxic, hepatotoxic in vivo, developmentally toxic, and may be carcinogenic. Human exposure may occur through drinking water, during recreational activities and by consuming foods in which the toxin may have bioaccumulated. Drinking water shortages of sufficient quality coupled with growing human pressures and climate variability and change necessitate an integrated and sustainable water management program. This review presents an overview of the importance of cylindrospermopsin, its detection, toxicity, worldwide distribution, and lastly, its chemical and biological degradation and removal by natural processes and drinking water treatment processes.

Sevoflurane-induced oxidative stress and cellular injury in human peripheral polymorphonuclear neutrophils.

Sevoflurane is an inhalation anesthetic used for general anesthesia. Several studies have demonstrated that reactive oxygen species (ROS) exist in cardioprotection when preconditioned with sevoflurane. Moreover, sevoflurane can also directly trigger the formation of peroxynitrite. Up to now, information pertinent to the effect of sevoflurane on cellular injuries in human polymorphonuclear neutrophils (PMN) is scant. In this study, we demonstrated that sevoflurane significantly increases intracellular H2O2 and/or peroxide, superoxide, and nitric oxide (NO) in PMN within 1h treatment. Intensification of intracellular glutathione (GSH) depletion in PMN has been demonstrated with the presence of sevoflurane. Inhibition of sevoflurane-mediated intracellular H2O2 and/or peroxide in PMN by catalase, mannitol, dexamethasone, N-acetylcysteine (NAC) and trolox, but not superoxide dismutase (SOD) pretreatment, was observed. Among them, catalase has the best effect scavenging intracellular H2O2 and/or peroxide, suggesting that H2O2 is the major ROS during sevoflurane treatment. Two apoptotic critical factors-lowering of the mitochondrial transmembrane potential (DeltaPsim) and activation of caspase 3/7-were significantly increased after 1h of sevoflurane treatment. Apoptosis of PMN were determined by comet assay and flow cytometric analysis of annexin V-FITV protein binding to the cell surface. Exposure of PMN to sevoflurane markedly increased apoptosis in a dose-dependent manner. In summary, these results are important for demonstrating the oxidative stress and cellular injury on sevoflurane-treated human PMN.