Spin squeezing and quantum correlations

We discuss the notion of spin squeezing considering two mutually exclusive classes of spin-s states, namely, oriented and non-oriented states. Our analysis shows that the oriented states are not squeezed while non-oriented states exhibit squeezing. We also present a new scheme for construction of spin-s states using 2s spinors oriented along different axes. Taking the case of s=1, we show that the ‘non-oriented’ nature and hence squeezing arise from the intrinsic quantum correlations that exist among the spinors in the coupled state.     

Structure–Solubility Relationship of 1,4-Dioxane Complexes of Di(hydrocarbyl)magnesium

Systematic variation of the 1,4-dioxane (dx) concentration during the precipitation of sparingly soluble [MgBr₂(dx)₂] from ethereal Grignard solutions of RMgBr has allowed the structural investigation of crystallized [R₂Mg(dx)_n] (n=1, 1.5, 2, and 3), which form during this dioxane method, depending on the bulkiness of R. The numbering of the complexes explored in this study is based on the number n of dioxane molecules per magnesium atom, followed by the substituent R; an apostrophe denotes coordination polymers. The following derivatives were studied by X-ray crystal-structure determination and NMR spectroscopy: n=1: [Me₂Mg(μ-dx)]_∞ ( 1′-Me ) and [nPr₂Mg(μ-dx)]_∞ ( 1′-nPr ); n=1.5: [{iPr₂Mg(dx)}₂(μ-dx)] ( 1.5-iPr ), [{oTol₂Mg(dx)}₂(μ-dx)] ( 1.5-oTol ), and [(Me₃Si-C≡C)₂Mg(dx)_1.5]_∞ ( 1.5′-C₂SiMe₃ ); n=2: [tBu₂Mg(dx)₂] ( 2-tBu ) and [oTol₂Mg(dx)₂] ( 2-oTol ); n=3: [Ph₂Mg(dx)₃] ( 3-Ph ). In the structure types 1′ , 1.5 , and 2 , the magnesium atom exhibits the coordination number 4, whereas pentacoordinate metal atoms are observed in types 3 and 1.5′ . The structure type 2′ is realized for [(Ph-C≡C)₂Mg(dx)₂]_∞ ( 2′-C₂Ph ), [MgCl₂(dx)₂]_∞ ( 2′-Cl ), and [MgBr₂(dx)₂]_∞ ( 2′-Br ) with hexacoordinate metal atoms. The solubility of the dioxane adducts in common organic solvents strongly depends on the degree of aggregation with the solubility decreasing from molecular to strand to layer structures.     

Gaschromatographische Bestimmung des Desinfektionsmittels Glutaraldehyd in der Luft von Krankenhäusern

Zusammenfassung Zur Bestimmung von Glutaraldehyd in der Raumluft von Krankenhäusern wurde ein neues Verfahren ausgearbeitet, mit dem subppm-Mengen erfaßbar sind. Die Raumluft wird durch eine Schicht Aluminiumoxid geleitet, wobei Glutaraldehyd quantitativ adsorbiert wird. Nach Desorption des Aldehyds durch Wasser im Ultraschallbad wird die wäßrige Lösung an einer Tenax-GC-Säule chromatographiert. Die quantitative Bestimmung des Aldehyds erfolgt durch einen Flammenionisationsdetektor.

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Determination of the disinfecting agent glutaraldehyde in hospital air

Summary A new method for determination of glutaraldehyde in hospital air has been developed, by which sub-ppm quantities can be determined. Air is drawn through a layer of Alumina, by which glutaraldehyde is quantitatively adsorbed. After desorption of the aldehyde by water in an ultrasonic bath the solution is chromatographed on a Tenax-GC column. The quantitation is performed by a flame ionization detector.

     

Sleep disturbances in highly stress reactive mice: Modeling endophenotypes of major depression

Background  

Neuronal mechanisms underlying affective disorders such as major depression (MD) are still poorly understood. By selectively breeding mice for high (HR), intermediate (IR), or low (LR) reactivity of the hypothalamic-pituitary-adrenocortical (HPA) axis, we recently established a new genetic animal model of extremes in stress reactivity (SR). Studies characterizing this SR mouse model on the behavioral, endocrine, and neurobiological levels revealed several similarities with key endophenotypes observed in MD patients. HR mice were shown to have changes in rhythmicity and sleep measures such as rapid eye movement sleep (REMS) and non-REM sleep (NREMS) as well as in slow wave activity, indicative of reduced sleep efficacy and increased REMS. In the present study we were interested in how far a detailed spectral analysis of several electroencephalogram (EEG) parameters, including relevant frequency bands, could reveal further alterations of sleep architecture in this animal model. Eight adult males of each of the three breeding lines were equipped with epidural EEG and intramuscular electromyogram (EMG) electrodes. After recovery, EEG and EMG recordings were performed for two days.     

Effects of lipopolysaccharide-induced inflammation on expression of growth-associated genes by corticospinal neurons

Background  

Inflammation around cell bodies of primary sensory neurons and retinal ganglion cells enhances expression of neuronal growth-associated genes and stimulates axonal regeneration. We have asked if inflammation would have similar effects on corticospinal neurons, which normally show little response to spinal cord injury. Lipopolysaccharide (LPS) was applied onto the pial surface of the motor cortex of adult rats with or without concomitant injury of the corticospinal tract at C4. Inflammation around corticospinal tract cell bodies in the motor cortex was assessed by immunohistochemistry for OX42 (a microglia and macrophage marker). Expression of growth-associated genes c-jun, ATF3, SCG10 and GAP-43 was investigated by immunohistochemistry or in situ hybridisation.     

Three Theorems, with Computer-Aided Proofs, on Three-Dimensional Faces and Quotients of Polytopes

We prove that there is a finite list of 3-polytopes so that every rational d -polytope, d ≥ 9 , contains a three-dimensional face in the list. A similar result where ``faces' are replaced by ``quotients' is proved already for (general) 5-polytopes. We also prove that every d -polytope, d ≥ 9 , contains a three-dimensional quotient which is a simplex.