Seasonal and geographical patterns of fin whale song in the western North Atlantic Ocean

Male fin whales, Balaenoptera physalus, produce a song consisting of 20?Hz notes at regularly spaced time intervals. Previous studies identified regional differences in fin whale internote intervals (INI), but seasonal changes within populations have not been closely examined. To understand the patterns of fin whale song in the western North Atlantic, the seasonal abundance and acoustic features of fin whale song are measured from two years of archival passive acoustic recordings at two representative locations: Massachusetts Bay and New York Bight. Fin whale 20?Hz notes are detected on 99% of recorded days. In both regions, INI varies significantly throughout the year as two distinct periods: a "short-INI" season in September-January (9.6?s) and a "long-INI" season in March-May (15.1?s). February and June-August are transitional-INI months, with higher variability. Note abundance decreases with increasing INI, where note abundance is significantly lower in April-August than in September-January. Short-INI and high note abundance correspond to the fin whale reproductive season. The temporal variability of INI may be a mechanism by which fin whale individuals encode and communicate a variety of behaviorally relevant information.     

Low-threshold miniature Ce:LiCAF lasers

We present a miniature Ce:LiCAF laser with extremely low threshold used as a tunable wavelength converter for an inexpensive Nd:YVO₄ microchip laser. Untuned, the laser operates with a threshold of 200 nJ and an absolute efficiency of 31%. Using an intra-cavity prism, continuous tuning from 283 to 314 nm is observed. These sources are well suited for applications in biological and chemical detection.     

磺化水热碳催化乙酰丙酸酯化生成戊酮酸乙酯(英文)

The synthesis of carbon-based, heterogeneous sulphonic catalysts for the production of levulinate esters. Hydrothermal treatment at moderated temperatures was employed to generate highly functional carbonaceous materials, referred to as hydrothermal carbons (HTCs), from both glucose, cellulose and rye straw. The products were sulfonated to generate solid acid-catalysts. Characterisation of the as-synthesised materials as well as catalyst activity tests were performed. SEM images indicate the micrometre-sized particles present in both HTCs were largely unaffected by sulfonation, although cellulose-derived HTC displayed signs of inadequate hydrolysis. FT-IR spectroscopy and elemental analysis confirmed successful incorporation of sulphonic groups. 13C solid state NMR, in addition to TGA, elucidated the carbons’ structural composition and supported the common-ly-proposed hydrothermal carbonisation mechanism. Finally, the catalysts were tested via levulinic acid-ethanol esterification and gave high conversion and ester-selectivities ( 90%).     

Synthesis of N-alkyl-N-hydroxyamphetamines and related nitrones

The action ofm-chloroperbenzoic acid on various amphetamines and on dibenzylamine is shown to yield N-hydroxy derivatives and related nitrones.     

A method for the analysis of ginsenosides, malonyl ginsenosides, and hydrolyzed ginsenosides using high-performance liquid chromatography with ultraviolet and positive mode electrospray ionization mass spectrometric detection

A high-performance liquid chromatographic separation coupled to diode array absorbance and positive mode electrospray mass spectrometric detection has been developed for the analysis of ginsenosides, malonyl ginsenosides, and hydrolyzed ginsenosides in extracts of Asian ginseng (Panax ginseng) and American ginseng (P. quinquefolius). The method is capable of separating, identifying, and quantifying the predominant ginsenosides found in heated alcoholic extracts of Asian and American ginseng roots routinely sold as nutraceuticals. It also separates and identifies the malonyl ginsenosides often found in cold alcoholic extracts of ginseng root and has the potential to quantify these compounds if pure standards are available. Furthermore, it can separate and identify ginsenoside hydrolysis products such as those readily produced in situations mimicking gastric situations, including those used for dissolution studies (i.e., 0.1 N HCl, 37 degrees C).     

Oxidative-addition reactions of monocyclopentadienyltitanium(III) dihalides

Oxidative-addition reactions of CpTi^IIICl₂ are described, and, in particular, the reactions with compounds containing disulphide linkages.     

Spirodienones IV the synthesis of N-sulphonylcyclohexadienimines and related dienones

Oxidation of N-4-toluenesulphonylanilines bearing appropriate para substituents gives good yields of spirocyclic N-sulphonylcyclohexadienimines; these compounds may be selectively hydrolysed to the corresponding spirodienones.     

Gas chromatographic separation of optically active anti-inflammatory 2-arylpropionic acids using (+)- or (-)-amphetamine as derivatizing reagent

A method is described for the derivatization of several non-steroidal anti-inflammatory arylalkanoic acids (ibuprofen, ketoprofen, naproxen, fenoprofen, flurbiprofen, pirprofen, cicloprofen, tiaprofenic acid, etodolic acid) with optically active amphetamine. The usefulness of this reagent compared to alpha-methylbenzylamine is described. The enantiomers are separated as diastereoisomers using capillary gas chromatography with nitrogen-phosphorus detection. The procedure is readily applied to the quantification of the enantiomers in urine and plasma samples.     

Resonance Raman spectroscopy reveals new insight into the electronic structure of beta-hematin and malaria pigment

Resonance Raman spectra of beta-hematin and hemin are reported for a range of excitation wavelengths including 406, 488, 514, 568, 633, 780, 830, and 1064 nm. Dramatic enhancement of A(1g) modes (1570, 1371, 795, 677, and 344 cm(-1)), ring breathing modes (850-650 cm(-1)), and out-of-plane modes including iron-ligand modes (400-200 cm(-1)) were observed when irradiating with 780- and 830-nm laser excitation wavelengths for beta-hematin and to a lesser extent hemin. Absorbance spectra recorded during the transformation of hemin to beta-hematin showed a red-shift of the Soret and Q (0-1) bands, which has been interpreted as excitonic coupling resulting from porphyrin aggregation. A small broad electronic transition observed at 867 nm was assigned to a z-polarized charge-transfer transition d(xy) --> e(g)(pi). The extraordinary band enhancement observed when exciting with near-infrared excitation wavelengths in beta-hematin when compared to hemin is explained in terms of an aggregated enhanced Raman scattering hypothesis based on the intermolecular excitonic interactions between porphyrinic units. This study provides new insight into the electronic structure of beta-hematin and therefore hemozoin (malaria pigment). The results have important implications in the design and testing of new anti-malaria drugs that specifically interfere with hemozoin formation.