Equation of state of a3He-4He mixture near its liquid-vapor critical point

Measurements of the pressure coefficient (P/T)_,x are reported for a ³ He- ⁴ He mixture with a mole fractionX=0.805 of ³ He in the neighborhood of the liquid-vapor critical point. These include data on 16 isochores taken over the density interval–0.50.5 and over the temperature range–0.1 t0.1, where =(– _c )/ _c andt=(T-T _c )/T _c ,with _c andT _c ,respectively, the critical density and temperature of the mixture. From the discontinuity of (P/T)_,x at the boundary between the two-phase and the one-phase regions we determine the dew-bubble curve nearT _c with better precision than was done in recentPVT experiments. From the extrapolation of data not approachingT _c closer than1 mK, (P/T)_,x along the critical isochore appears to be discontinuous atT _c ,while for the isochore / _c 0.92, (P/T)_,x is continuous across the dew curve. It is found that this latter isochore cuts the dew curve at its highest temperature. These observations are discussed in terms of general thermodynamic arguments and theoretical predictions of the asymptotic behavior. We calculate (P/T)_,x from the scaling equation of state proposed by Leung and Griffiths for ³ He- ⁴ He mixtures, using their numerical parameters. In spite of some systematic deviations, especially in the two-phase region, there is in general good agreement with experimental results. In particular, the shape of the measured dew-bubble curve and the apparent discontinuity of (P/T)_,x along the critical isochore show excellent agreement with theory.Work supported by a grant from the National Science Foundation. A report of this work has been presented at the Washington Meeting of the APS [Bull. Am. Phys. Soc. 20, 618 (1975)].     

Vorkommen und Gehalt an Aflatoxin M1 in Molkerei-Anlieferungsmilch

Zusammenfassung In der Zeit vom 4. März his 15. April 1976 wurde Molkerei-Anlieferungsmilch ab Hof auf ihren Gehalt an Aflatoxin M₁ untersucht. Von insgesamt 419 Proben aus dem Einzugsgebiet waren 79 (19%) positiv. 33% davon wiesen einen Gehalt von 0,05–0,1 g/l auf, 38% mehr als 0,1 g/l. Der höchste Wert lag bei 0,54 g/l. Andere Aflatoxine wurden nicht gefunden. Bei den Lieferanten Aflatoxin M₁-positiver Milch wurden auch Futtermittelproben (105) gezogen, wovon 45 (43%) positiv waren. 40% der positiven Proben enthielten bis zu 20 g/kg, 36% 20–50 g/kg. Die höchsten Werte wurden mit 280 bzw. 300 g/kg gefunden. Besonders betroffen waren Mischfuttermittel (Milchleistungsfutter für Rinder). Hier überschritten 47% (DLG-Standard IV) bzw. 36% (DLG-Standard III) aller untersuchten Proben den zulässigen Höchstgehalt von 20 g/kg.Es besteht ein qualitativer Zusammenhang zwischen dem Auftreten von Aflatoxin M₁ in Milch und Aflatoxin B₁ in Futtermitteln. Bei 61 erfaßten Liefe ranten positiver Milch wurde in 41 Fällen (67%) Aflatoxin B₁ im Futtermittel nachgewiesen. Eine quantitative Beziehung konnte hier nicht hergestellt werden.

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On the presence and the content of aflatoxin M₁ in milk shipped to a dairy plant

Summary Between March 4 and April 15, 1976, the aflatoxin M₁ content of milk shipped to a dairy plant was investigated. Out of 419 samples, 79 (19%) were positive. 33% of these samples showed values of 0.05–0.1 g/l, 38% of more than 0.1 g/l and the highest value was at 0.54 g/l. Other aflatoxins were not found. From samples of milk producers showing positive reactions, feed samples (n=105) were taken, 45 of which (43%) were also positive. 40% of the positive samples contained up to 20 g/kg, 36% were in the range between 20–50 g/kg and the highest values were at 280 resp. 300 g/kg, especially in mixed feed. Out of these samples, 47% (DLG Standard IV) resp. 36% (DLG Standard III) were higher than the tolerated maximum level of 20 g/kg.There is a qualitative relationship between the aflatoxin M₁ content in milk and the aflatoxin B₁ content in feed. In 61 cases where milk samples were positive, in 41 feed samples (67%) aflatoxin B₁ was detected.

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38. Mitteilung: Zur Aflatoxinbildung in Milch und Milchprodukten     

Dynamic Measurements of Thermal Transport Coefficients and Boundary Resistance. II.Model for 3He-Superfluid 4He Mixtures

This is the second of a three-part study of the ac response of liquid helium. We derive the temperature response function, T(), of a ³ He-superfluid ⁴ He mixture from the equations of superfluid hydrodynamics in the presence of two interfacial boundary resistances,R_b.Specifically, we consider the response T(), across a fluid layer of thickness,d, to an ac heat flux,Q(t) = Q_o exp(it).T() depends on the effective thermal conductivity, _eff , Griffin's diffusion coefficient, _o (i.e. the thermal diffusivity of ³ He impurities, D_iso in the low ³ He concentration limit) and the thermal boundary resistance, 2R_b. This analysis provides the basis for experiments to determine these parameters. Although past experiments to measure these properties have been carried out using dc and transient techniques, an ac technique offers significant noise reduction over these techniques. By sweeping the frequency, it is possible for an experimenter to clearly identify different components of the system response to the heat flux. For instance, if t is the slowest fluid thermal response time, conventional Kapitza boundary effects dominate at frequencies, 1. These calculations reveal an interesting analogy to the Piston Effect for near-critical classical fluids. In Part I of this work, we used normal liquid ⁴ He as a testing ground for developing models of ac heat transport. In Part III of this work, we will present results in which we apply this technique to measurements on dilute mixtures of ³ He in superfluid ⁴ He.     

Is “Delayed Onset Muscle Soreness” a False Friend? The Potential Implication of the Fascial Connective Tissue in Post-Exercise Discomfort

Strenuous and unaccustomed exercise frequently lead to what has been coined “delayed onset muscle soreness” (DOMS). As implied by this term, it has been proposed that the associated pain and stiffness stem from micro-lesions, inflammation, or metabolite accumulation within the skeletal muscle. However, recent research points towards a strong involvement of the connective tissue. First, according to anatomical studies, the deep fascia displays an intimate structural relationship with the underlying skeletal muscle and may therefore be damaged during excessive loading. Second, histological and experimental studies suggest a rich supply of algogenic nociceptors whose stimulation evokes stronger pain responses than muscle irritation. Taken together, the findings support the hypothesis that DOMS originates in the muscle-associated connective tissue rather than in the muscle itself. Sports and fitness professionals designing exercise programs should hence consider fascia-oriented methods and techniques (e.g., foam rolling, collagen supplementation) when aiming to treat or prevent DOMS.     

Coarse graining for an impeller-driven mixer system

We apply a coarse graining approach developed by Isaac Goldhirsch to data acquired from a model of an impeller-driven mixer system. The experiment uses a bidisperse system of photoelastic particles in a quasi-2D system to determine local mass and momentum densities, velocities, granular temperatures, size concentration, and pressure. Raw data consist of high speed video images obtained with polarizers (to obtain particle-scale force data) and without polarizers (to obtain particle positions). We coarse grain the experimental data using a Gaussian coarse graining function, ${\phi}$ , of variable width, w.     

The Reaction of Ozone with Bisulfide (HS−) in Aqueous Solution – Mechanistic Aspects

The ozone demand to oxidize HS^?/H₂S [pK_a(H₂S) = 6.9, k(HS^? + O₃) = 3 × 10⁹ M^?1 s^?1, k(H₂S + O₃) = 3 × 10⁴ M^?1 s^?1] to SO₄ ^2? is only 2.4 mol ozone per mol SO₄ ^2? formed, much lower than stoichiometric 4.0 mol/mol if a series of O-transfer reactions would occur. As primary step, the formation of an ozone adduct to HS^?, HSOOO^–, is suggested that decomposes into HSO^– and singlet oxygen (16%) or rearranges into peroxysulfinate ion, HS(O)OO^– (84%). Potential reactions of the above intermediates are discussed. Some of these can account for the low ozone demand.     

Sequence, genomic organization, and chromosomal location of the mouse Müllerian-inhibiting substance type II receptor gene

We have determined the sequence and structure of the mouse Müllerian-inhibiting substance (MIS) type II receptor gene. Sequence comparisons demonstrate that the mouse, rat, rabbit, and human MIS type II receptors are highly conserved. The mouse MIS type II receptor gene is encoded by 11 exons and spans approximately 9-kb. Only half of the intron/exon boundaries of its kinase domain are conserved in comparison to the kinase domain of the related activin type II receptor. Whereas the activin type II receptor gene contains large introns (> 40-kb), the largest intron of the MIS type II receptor gene is only 4.3-kb. The MIS type II receptor gene (Amhr) is closely linked to Hoxc on mouse chromosome 15. Knowledge of the sequence and genomic structure of Amhr provides important information for the genetic manipulation of the Amhr locus.