Morphological and genetic evidence for early Holocene cattle management in northeastern China.

The domestication of cattle is generally accepted to have taken place in two independent centres: around 10,500 years ago in the Near East, giving rise to modern taurine cattle, and two millennia later in southern Asia, giving rise to zebu cattle. Here we provide firmly dated morphological and genetic evidence for early Holocene management of taurine cattle in northeastern China. We describe conjoining mandibles from this region that show evidence of oral stereotypy, dated to the early Holocene by two independent ¹4C dates. Using Illumina high-throughput sequencing coupled with DNA hybridization capture, we characterize 15,406 bp of the mitogenome with on average 16.7-fold coverage. Phylogenetic analyses reveal a hitherto unknown mitochondrial haplogroup that falls outside the known taurine diversity. Our data suggest that the first attempts to manage cattle in northern China predate the introduction of domestic cattle that gave rise to the current stock by several thousand years.

An improved hollow fiber solvent-stir bar microextraction for the preconcentration of anabolic steroids in biological matrix with determination by gas chromatography-mass spectrometry.

In this paper, a convenient and self-assembled hollow fiber solvent-stir bar microextraction (HF-SSBME) device was developed, which could stir by itself. In the extraction process, the proposed device made the solvent "bar" not floating at the sample solution and exposing to air while organic solvents outside hollow fiber always wrapped with donor phase solvent, which reduced the vaporization of organic solvents. This design could improve the precisions and recoveries of experiments. For evaluating the device, seven anabolic steroids (prasterone, 5α-androstane-3α, 17ß-diol, methandriol, 19-norandrostenediol, androstenediol, methyltestosterone and methandienone) were used as model analytes and extraction conditions such as type and volume of organic solvents, agitation speed, extraction time, extraction temperature and salt addition were studied in detail. Under the optimum conditions (15 µL toluene, 40 °C, stirring at 750 rpm for 30 min with 1.5 g sodium chloride addition in 20.0 mL donor phase), the linear ranges of anabolic steroids were 0.25-200 ng mL(-1) with gas chromatography-mass spectrometry. The limits of detection were lower than 0.10 ng mL(-1). The recoveries and precisions in spiked urine and hair samples were between 73.97-93.56% and 2.18-4.47% (n=5). HF-SSBME method combined the intrinsical merits of hollow fiber with the superiority of the proposed self-stirring device which can be developed to two-phase, three-phase and in situ derivatization modes with wide prospect of application. Besides, the pedestal of this proposed device can be converted to fix stir bar in stir bar sorptive extraction (SBSE) method.

Novel multifunctional acceptor phase additive of water-miscible ionic liquid in hollow-fiber protected liquid phase microextraction.

In this paper, water-miscible ionic liquid (IL) such as 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) is introduced for the first time as a novel multifunctional acceptor phase additive in hollow-fiber protected liquid phase microextraction (HF-LPME). For investigating the performances of [BMIM]Cl, it was respectively mixed with NaOH, HCl and deionized water. And their extraction performance was preliminary evaluated with alkaline compounds (clenbuterol, metoprolol, carteolol and propranolol), acidic compounds (diethylstilbestrol, hexestrol, phenol and bisphenol A) and neutral compounds (acenaphthylene, fluorene and fluoranthene). Furthermore, a complete extraction and determination method using IL-three phase HF-LPME and liquid chromatography was established for polycyclic aromatic hydrocarbons (PAHs) in river water. The extraction conditions, such as concentration of IL, extraction temperature, extraction time, stirring speed, ionic strength and the addition of methanol were studied in detail. Under the optimum conditions, the linear ranges of acenaphthylene, fluorene and fluoranthene were 1-100, 1-200 and 1-200 ng mL(-1), respectively. Limit of detections (LODs) were lower than 0.25 ng mL(-1). The recoveries of PAHs in three kinds of spiked real water are between 90.97 and 109.7% and the precisions are in the range of 2.53-7.01%. Since water-miscible ionic liquids had various forms, similar extraction capabilities to organic solvents and could be conveniently adjusted by acid, alkaline and buffer, this proposed method should have great potentiality in sample preparation of HF-LPME.

Analysis of beta-agonists and beta-blockers in urine using hollow fibre-protected liquid-phase microextraction with in situ derivatization followed by gas chromatography/mass spectrometry.

A method using hollow fibre-protected liquid-phase microextraction (HF-LPME) with in situ derivatization followed by gas chromatography/mass spectrometry (GC/MS) was established for the analysis of beta-agonists and beta-blockers in urine. Because it can simultaneously extract and derivatize compounds of interest by methylbenzol and N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA) in HF-LPME, the approach overcomes the drawbacks of considerable time-consuming and tedious operation, meanwhile improves enrichment multiple. The optimized conditions were extraction for 20 min at 35 degrees C with 5.0 microL of mixed extraction solvent (methylbenzol/MSTFA=1:1, v/v) with stirring speed of 925 rpm in 5.0 mL sample under pH 12.0 and 14% (w/v) NaCl. The method provided very wide linear ranges (0.25-400 ng mL(-1)) and low detection limits in the range of 0.08-0.10 ng mL(-1) for clenbuterol, metoprolol and propranolol while enrichment factors reached up to 256. The analytes could be determined in spiked urine by the method with high extraction efficacy (93.79-109.04% recoveries) and precision (<9.70% RSD). It has a satisfactory result for metoprolol in practical human urine samples for a single-dose administration of 50 mg after 36 h. The proposed method only needs few microliters of organic solvent and derivatizing agent; the operation is simple, convenient and rapid for the trace analysis of beta-agonists and beta-blockers in biological fluids; it can be readily generalized for high sample throughput. So, it is hopeful that the study will facilitate the monitoring of beta-agonists and beta-blockers in the competition sports.

A method by homemade OH/TSO-PMHS fibre solid-phase microextraction coupling with gas chromatography-mass spectrometry for analysis of antiestrogens in biological matrices.

A kind of homemade solid-phase microextraction fibre coupled with gas chromatography-mass spectrometry (GC-MS) was developed for trace analysis of antiestrogens (tamoxifen, cis- and trans-clomiphene) in biological matrices. In this method, derivatization was unnecessary and sample solution could be injected directly after very simple deproteinization operation. The conditions of influencing adsorption of the solid-phase microextraction (SPME) fibre and desorption of the analytes were investigated in details. Matrix effects were studied in different background. Under optimum conditions, the proposed method was further validated by spiking analytes into rabbit liver solutions. Linear ranges of tamoxifen, cis- and trans-clomiphene were 0.02-2.56, 0.08-2.56 and 0.16-2.56 ng mL(-1), respectively. The limits of quantitation were in the range of 0.02-0.16 ng mL(-1). The intra-day accuracy was ranged 96.2-106.2% and precision were in the range of 5.1-8.7%. The extraction recoveries of the antiestrogens in rabbit liver solution were between 73.8% and 113.1%, and R.S.D.s were from 3.6% to 14.1%. The results show that the homemade sol-gel coating is suitable for determination of trace antiestrogens in complex matrices. The proposed approach was proved to be rapid, simple, easy, sensitive and reproducible for trace analysis of antiestrogens in biological matrices.