Concomitant degradation of bisphenol A during ultrasonication and Fenton oxidation and production of biofertilizer from wastewater sludge

Degradation of bisphenol A (BPA), an endocrine disruptor, from wastewater sludge (WWS) has attracted great interest recently. In the present study, the effects of different pre-treatment methods, including ultrasonication (US), Fenton's oxidation (FO) and ferro-sonication (FS) was assessed in terms of increase in solubilization of WWS and simultaneous degradation of BPA. Among US, FO and FS pre-treatment, higher suspended solids (SS), volatile suspended solids (VSS), chemical oxygen demand (COD) and soluble organic carbon (SOC) solubilization (39.7%, 51.2%, 64.5% and 17.6%, respectively) was observed during a ferro-sonication pre-treatment process carried out for 180 min, resulting in higher degradation of BPA (82.7%). In addition, the effect of rheological parameters (viscosity and particle size) and zeta potential on the degradation of BPA in raw and different pre-treated sludges were also investigated. The results showed that a decrease in viscosity and particle size and an increase in zeta potential resulted in higher degradation of BPA. BPA degradation by laccases produced by Sinorhizobium meliloti in raw and pre-treated sludge was also determined. Higher activity of laccases (207.9 U L(-1)) was observed in ferro-sonicated pre-treated sludge (180 min ultrasonic time), resulting in higher removal of BPA (0.083 μg g(-1)), suggesting concomitant biological degradation of BPA.     

Local vibration assisted molecular configurations in poly(vinylidene fluoride) of ordered ferroelectric phase in N,N-dimethylformamide

Amide-based polymer liquids are important for developing biological and optical colloids or nanofluids. Functionalized properties arise from specific molecular structures. In this investigation, we report model molecular configurations of a polymer liquid, 0.3 g/L poly(vinylidene fluoride) (PVF₂) dissolved in liquid N,N-dimethylformamide (DMF), based on the characteristic IR vibration bands. Peculiarly, a ferroelectric β-PVF₂ phase reorders on a linear configuration in support with the DMF molecules, showing a characteristic band 840 cm^− 1 (CH₂ rocking and CF₂ asymmetric stretching) with the trans band at 1275 cm^− 1. Four CO stretching bands ν₁⁰, ν₁¹, ν₁², and ν₁³ of 1650, 1675, 1725, and 1760 cm^− 1 (bandwidth Δν_½ = 180 cm^− 1 in the four bands) arise in four major configurations of DMF-PVF₂ pairs (or derivatives). Only one prominent ν₁⁰ band 1660 cm^− 1 (Δν_½ = 75 cm^− 1) incurs with a shoulder ν₁¹ of 1725 cm^− 1 (Δν_½ = 25 cm^− 1) in two DMF configurations. A ferroelectric field cased in presence of β-PVF₂ leads to enhance IR absorption by as much as an order of magnitude. It leads to converging non-bonding electron density on the amide moiety.     

DIFFERENTIAL EFFECT OF ULTRAVIOLET-B RADIATION ON CERTAIN METABOLIC PROCESSES IN A CHROMATICALLY ADAPTING Nostoc

The impact of UV-B radiation on growth, pigmentation and certain physiological processes has been studied in a N2-fixing chromatically adapting cyanobacterium, Nostoc spongiaeforme. A brownish form (phycoerythrin rich) was found to be more tolerant to UV-B than the blue-green (phycocyanin rich) form of N. spongiaeforme. Continuous exposure to UV-B (5.5 W m-2) for 90 min caused complete killing of the blue-green strain whereas the brown strain showed complete loss of survival after 180 min. Pigment content was more strongly inhibited in the blue-green strain than in the brown. Nitrogenase activity was completely abolished in both strains within 35 min of UV-B treatment. Restoration of nitrogenase occurred upon transfer to fluorescent or incandescent light after a lag of 5-6 h, suggesting fresh synthesis of nitrogenase. Unlike the above processes, in vivo nitrate reductase activity was stimulated by UV-B treatment, the degree of enhancement being significantly higher in the blue-green strain. Like the effect of UV-B on nitrogenase, 14CO2 uptake was also completely abolished by UV-B treatment in both strains. Our findings suggest that UV-B may produce a deleterious effect on several metabolic activities of cyanobacteria, especially in cells lacking phycoerythrin. Strains containing phycoerythrin appear to be more tolerant to UV-B, probably because of their inherent property of adapting to a variety of light qualities.     

Relativistic R-matrix close-coupling calculations for photoionization of Ne-like Al IV

We present relativistic close-coupling photoionization calculations of Al IV using the Breit-Pauli R-matrix method to obtain photoionization cross-section of Al IV from the ground state and the lowest two J=0 (even) excited states. A multi-configuration eigenfunctions expansion of the core Al V is employed with spectroscopic configurations 2s²2p⁵, 2s2p⁶, 2s²2p⁴3s, 2s²2p⁴3p, 2s²2p⁴3d and 2s²2p⁴4s. We have included, for the first time, the lowest 68 level target states of Al V in the photoionization calculations of Al IV. Extensive configuration interaction wavefunctions are used to describe both the initial Al IV states and the final Al V states. Cross-sections are compared from three level calculations including only 2s² 2p^{5 2}P^o _3/2, _1/2 and 2s 2p^{6 2}S_1/2 levels of Al V. The present calculation using the lowest 68 target levels of Al V are presented for the first time and should provide reasonably complete database for practical application for photoionization cross-section for Al IV, where high-energy cross-sections along with near-threshold photoionization cross-section is required.     

General Formulation for the Ponderomotive Force in a Warm Two Fluid Magnetized Plasma

A general expression for the ponderomotive force in a warm, inhomogeneous, nonstationary, magnetized and collisionless two fluid plasma in the presence of electromagnetic field is obtained. We start with two fluid equations viz. continuity, momentum equations and Maxwell's equation. Expanding the physical quantities in terms of a high frequency part and a slowly varying part and averaging the quantities over one period of the high frequency, we have obtained the expression for the ponderomotive force. The results are compared with the results of earlier workers under different approximations.     

Analysis of M/M/S queues with 1-limited service

In this paper, a multiple server queue, in which each server takes a vacation after serving one customer is studied. The arrival process is Poisson, service times are exponentially distributed and the duration of a vacation follows a phase distribution of order 2. Servers returning from vacation immediately take another vacation if no customers are waiting. A matrix geometric method is used to find the steady state joint probability of number of customers in the system and busy servers, and the mean and the second moment of number of customers and mean waiting time for this model. This queuing model can be used for the analysis of different kinds of communication networks, such as multi-slotted networks, multiple token rings, multiple server polling systems and mobile communication systems.     

Dynamic Odd–Even Effect in Liquid n‐Alkanes near Their Melting Points

n‐Alkanes are the textbook examples of the odd–even effect: The difference in the periodic packing of odd‐ and even‐numbered n‐alkane solids results in odd–even variation of their melting points. However, in the liquid state, in which this packing difference is not obvious, it seems natural to assume that the odd–even effect does not exist, as supported by the monotonic dependence of the boiling points of n‐alkanes on the chain length. Herein, we report a surprising odd–even effect in the translational diffusional dynamic properties of n‐alkanes in their liquid states. To measure the dynamics of the molecules, we performed quasi‐elastic neutron scattering measurements near their melting points. We found that odd‐numbered n‐alkanes exhibit up to 30 times slower dynamics than even‐numbered n‐alkanes near their respective melting points. Our results suggest that, although n‐alkanes are the simplest hydrocarbons, their dynamic properties are extremely sensitive to the number of carbon atoms.     

Gram‐Scale Synthesis of Chiral Cyclopropane‐Containing Drugs and Drug Precursors with Engineered Myoglobin Catalysts Featuring Complementary Stereoselectivity

Engineered hemoproteins have recently emerged as promising systems for promoting asymmetric cyclopropanations, but variants featuring predictable, complementary stereoselectivity in these reactions have remained elusive. In this study, a rationally driven strategy was implemented and applied to engineer myoglobin variants capable of providing access to 1‐carboxy‐2‐aryl‐cyclopropanes with high trans‐(1R,2R) selectivity and catalytic activity. The stereoselectivity of these cyclopropanation biocatalysts complements that of trans‐(1S,2S)‐selective variants developed here and previously. In combination with whole‐cell biotransformations, these stereocomplementary biocatalysts enabled the multigram synthesis of the chiral cyclopropane core of four drugs (Tranylcypromine, Tasimelteon, Ticagrelor, and a TRPV1 inhibitor) in high yield and with excellent diastereo‐ and enantioselectivity (98–99.9% de; 96–99.9% ee). These biocatalytic strategies outperform currently available methods to produce these drugs.     

A mononuclear cobalt(II) hydroxo complex: synthesis,molecular structure,and reactivity studies

A novel Co(II) hydroxo complex Co{HB(3-^tBu-5-ⁱPrpz)₃}(OH) 4 {where HB(3-^tBu-5-ⁱPrpz)₃ = hydrotris(3-tert-butyl-5-isopropylpyrazol-l-yl)borate} has been prepared and its molecular structure has been determined by X-ray crystallography. This complex is mononuclear with distorted tetrahedral geometry. The reaction of CO₂ with Co{HB(3-^tBu-5-ⁱPrpz)₃}(OH) resulted in the formation of a μ-carbonato bridged binuclear complex [Co{HB(3-^tBu-5-ⁱPrpz)₃}]₂(CO₃) wherein the carbonate group is bound to both metal centers in an asymmetrical manner. In order to explore the role of labile metal complexes in promoting ester hydrolysis, complexes [Co{HB(3,5-ⁱPr₂pz)₃}]₂(OH)₂ and Co{HB(3-^tBu-5-ⁱPrpz)₃}(OH) have been used as catalysts in the hydrolysis of both carboxylate as well as phosphate esters. The product of 4-nitrophenylacetate hydrolysis with Co{HB(3-^tBu-5-ⁱPrpz)₃}(OH) was isolated as four coordinate Co{HB(3-^tBu-5-ⁱPrpz)₃}(OC₆H₄-4-NO₂) 6, whereas the reaction of 4-nitrophenyltrifluoroacetate with [Co{HB(3,5-ⁱPr₂pz)₃}]₂(OH)₂ resulted the formation of the six coordinate Co{HB(3,5-ⁱPr₂pz)₃}(OC₆H₄-4-NO₂)(MeCN)₂ species. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.

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