Assessment of the N-nitrosopiperidine formation risk from piperine and piperidine contained in spices used as meat product additives

The N-nitrosopiperidine (NPIP) formation in blends of spices and nitrite curing salt was investigated in relation with the piperine and piperidine contents in spices. Firstly, two analytical methods were developed. Piperine was extracted with dichloromethane by means of accelerated solvent extraction (ASE) and determined by high-performance liquid chromatography (HPLC)–diode array detector (λ = 343 nm). A selective hydroextraction of piperidine using ASE and its quantification by HPLC–ELSD was applied. Both methods were sufficiently sensitive and accurate (limit of detection, limit of quantification, and recovery: 0.28, 0.84 μg, and 98.9 ± 2.6 % for piperine, and 5.76, 17.45 μg, and 95.9 ± 2.9 % for piperidine, respectively). Secondly, both compounds were quantified in commercial samples (black and white pepper, paprika, chili pepper, allspice, and nutmeg). The maximum amount of piperine (21.12 mg g^?1) was found in pepper, while the other spices contained only traces. Piperidine was detected mainly in the pepper samples, whereby the highest concentration was found in the white pepper extract (11.42 mg g^?1). Thirdly, during the storage of spices blended with nitrite curing salt, the NPIP content was determined, using a gas chromatograph coupled with a thermal energy analyzer. Against our expectations, no NPIP formation was observed in the curing mixture which contained white pepper extract. This result remains in contrast with the white pepper mixture, in which the NPIP content significantly increased from not detected to 9.80 ± 0.41 ng g^?1 after the 2 months storage period. In conclusion, high amounts of piperine or piperidine in spices do not systematically result in the formation of NPIP, when blended with nitrite curing salt .     

Affinity capillary electrophoresis

The application of affinity capillary electrophoresis (ACE) to the study of molecular interactions is reviewed. ACE appears to be a sensitive, versatile and convenient tool to obtain reliable data on binding constants and stoichiometries of interacting systems using the Hummel-Dreyer method and variants thereof. A powerful feature is the possibility to analyze simultaneously the affinity of a large number of compounds for the same ligand, making it a promising tool for the screening of large combinatorial libraries.     

Communal reproductive success in rats (Rattus norvegicus): Effects of group composition and prior social experience.

Compared the reproductive success and maternal behavior of sibling pairs of female Long-Evans rats (Rattus norvegicus) housed together from birth (familiar) to that of pairs of unrelated females housed apart during development (unfamiliar). Sires either remained in the colonies through weaning of their pups or were removed before parturition. Familiar animals reared more pups to weaning, were more likely to share in caring for pups, and were less likely to exhibit infanticide than were unfamiliar ones. The presence of males in cages with pups had no direct effect on the reproductive success of females, but female pairs housed with males spent less time than female pairs housed alone caring for pups together in a combined nest. Conflicting evidence for communal rearing in populations of wild rats may reflect differences in the genetic relatedness or early social experience of female rats. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Survey of total and respirable suspended particulate matter in an iron foundry. Comparison of stationary sampling and personal monitoring

In the workshop of an iron foundry total and respirable suspended particulate matter was collected. The performances of (1) filtration systems with 47 mm membrane filters, (2) Andersen cascade impactors, and (3) personal total or respirable monitoring, were compared at a position away from intense sources of particulate debris.Using 15 stationary samplers a survey was made of the particulate levels in the workshop, over a period of 2 weeks. Very large concentration gradients and concentration variations as a function of time were measured for total suspended particulate matter.In the three major source areas, i.e. the pouring department, the core-making department and the shake-out department, special studies were performed to compare stationary and personal monitoring.In the immediate vicinity of intense point sources of coarse particles, such as core-making or shake-out, stationary sampling cannot be used to estimate the personal exposure to total suspended particulates. For respirable particles, however, one or two well-situated stationary size-selective samplers can provide a good estimate of the personal exposure as measured with a personal respirable monitor. The differences found are in the order of 10–20%.     

Fine-structured aluminium products with controllable texture by selective laser melting of pre-alloyed AlSi10Mg powder

This study shows that AlSi10Mg parts with an extremely fine microstructure and a controllable texture can be obtained through selective laser melting (SLM). Selective laser melting creates complex functional products by selectively melting powder particles of a powder bed layer after layer using a high-energy laser beam. The high-energy density applied to the material and the additive character of the process result in a unique material structure. To investigate this material structure, cube-shaped SLM parts were made using different scanning strategies and investigated by microscopy, X-ray diffraction and electron backscattered diffraction. The experimental results show that the high thermal gradients occurring during SLM lead to a very fine microstructure with submicron-sized cells. Consequently, the AlSi10Mg SLM products have a high hardness of 127 ± 3 Hv0.5 even without the application of a precipitation hardening treatment. Furthermore, due to the unique solidification conditions and the additive character of the process, a morphological and crystallographic texture is present in the SLM parts. Thanks to the knowledge gathered in this paper on how this texture is formed and how it depends on the process parameters, this texture can be controlled. A strong fibrous 〈1 0 0〉 texture can be altered into a weak cube texture along the building and scanning directions when a rotation of 90° of the scanning vectors within or between the layers is applied.     

Design and analysis of the W7-X divertor scraper element

Thehigh heat-flux divertor of the Wendelstein 7-X large stellarator experiment consists of 10 divertor units which are designed to carry a steady-state heat flux of 10 MW/m². However, the edge elements of this divertor are limited to only 5 MW/m², and may be overloaded in certain plasma scenarios. It is proposed to reduce this heat by placing an additional “scraper element” in each of the ten divertor locations. It will be constructed using carbon fiber composite (CFC) monoblock technology. The design of the monoblocks and the path of the cooling tubes must be optimized in order to survive the significant steady-state heat loads, provide adequate coverage for the existing divertor, be located within sub-millimeter accuracy, and take into account the boundaries to other in vessel components, all at a minimum cost. Computational fluid dynamics modeling has been performed to examine the thermal transfer through the monoblock swirl tube channels for the design of the monoblock orientation. An iterative physics modeling and computer aided design process is being performed to optimize the placement of the scraper element within the severe spatial restrictions.     

Elemental composition and source investigation of particulates suspended in the air of an iron foundry

In the workshop of an iron foundry suspended particulate matter was daily collected with stationary filtration systems, Andersen cascade impactors and personal samplers. During a two-week period, with a network of sixteen stationary samplers and personal samplers carried by three workers active in the different departments of the workshop, a survey was made of the levels. Some samples were also taken of the major emission sources in the foundry. All samples were analysed by instrumental neutron activation analysis. Data were obtained for 21 elements in all samples, while 15 additional elements could only be detected in the large majority of the samples. For visualisation and interpretation of the data computer programs for contour plotting, classification and clustering of the elements and the samples were applied. The size distribution, the air concentration profile delineation and the element clusters indicated the presence of three main groups of elements. The La-group, consisting of lithophilic elements such as Na, K, Mg, Ca, Sc, La, Ce and Eu and associated with large particles, is primarily generated by the pouring, shake-out and moulding process. The Fe-group, with elements such as V, Cr, Mn, Fe, Co, Zn, As, Sb and Ba, originates primarily during fettling and shake-out. A few of these, Mn, Zn, As and Sb, are largely associated with fine particles. The elements Br and Cl, which are produced from burning pitch, are nearly evenly distributed throughout the room. The results allow estimates of the impact of the major emission sources on the entire workroom, and of some localized sources in their immediate vicinity. Suggestions for representative sampling locations and indicator elements are obtained from the results.     

Effect of the manufacturing conditions on the structure and performance of thin-film composite membranes

A systematic investigation of the influence of the manufacturing conditions on the structure and performance of thin-film composite (TFC) membranes is presented for polyamide (PA) supported by poly(ether sulfone) (PES). The TFC membranes were composed of an ultrathin PA layer synthesized by interfacial polymerization on top of a porous PES support layer formed by immersion precipitation. For the PES support layer, the role of the wetting pretreatment, initial casting film thickness, and relative air humidity were studied. Assuming a strong correlation between the thermodynamics and the hydrodynamics of the casting process, we derived new insights from scanning electron microscopy images and the experimental data. In view of optimization of the flux through the membranes, a wetting pretreatment should be avoided. Important polymer savings were obtained without a loss of performance through a decrease in the casting thickness in combination with the use of a very smooth support. Last but not least, a high air humidity during casting was found to inhibit the formation of a dense, defect-free skin layer. For the PA layer, the interfacial polymerization method, the drying method, and the curing time were studied. The clamping of the membrane in a frame with one side in contact with the piperazine (PIP) solution and the other side to the air yielded the highest membrane flux and rejection with the lowest use of PIP and trimesoylchloride solution. Because of the absence of a uniform PIP solution layer for some drying methods, nodular PA structures could be observed in the macrovoids of the underlying PES layer because of hexane intrusion; this resulted in a dramatic decrease in the flux. Moreover, the omission of the drying step did not result in a significant loss of performance and enhanced the ease of operation. Finally, a curing time of 8 min was found to be optimal. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Potential of yeast antagonists on invitro biodegradation of ochratoxin A

Six antagonistic yeast strains were screened initially for their ability to degrade Ochratoxin A (OTA) in liquid medium amended with OTA (7.5 μg ml^?1) and different concentrations of yeast cells at 30 °C. Highest OTA degradation was observed when the yeast cell concentration used at 1 × 10⁸ cells/ml ranging from 7.8 to 84%. Out of six yeast strains, three strains [Metschnikowia pulcherrima (MACH1), Pichia guilliemonodii (M8) and Rhodococcus erythropolis (AR14)] were selected for further studies. In preliminary studies yeast strains were evaluated for their ability to degrade OTA at different temperature regimes (10, 15, 20, 25, 30 and 35 °C) and found that 30 °C was the optimum temperature for yeast growth and highest OTA degradation ranging from 10.4 to 83.5%. These three strains were further evaluated to test their potential on OTA degradation using different concentrations of OTA (5 and 10 μg ml^?1) only at 30 °C. Three strains showed more or less same results with that of 7.5 μg ml^?1 concentration ranging from 7.5 to 81%. The three yeast antagonists were further tested to confirm either degradation or cell wall adsorption of OTA at different time intervals. Among the strains, MACH1 effectively degraded the OTA (>80%) at 30 °C after 15 days incubation compared to other strains tested and few amounts of OTA adsorption was observed in the yeast cell wall. LC–MS studies revealed that no by-product like α-OT or Phenylalanine was found during the degradation process. Therefore, further studies are needed to understand the mechanism of action of these yeast strains during OTA degradation.