Ln Beta Research Articles

First-principles investigation of the effect of crystal structure on sulfur isotope fractionation in sulfide polymorphs

In order to study the effect of crystal structure on S isotope fractionation properties of sulfide polymorphs, the reduced partition function ratios of S-34/S-32 (10(3)ln beta(34-32)) for FeS2, CoAsS, ZnS, CdS and MnS polymorphs are calculated in the present study. Our calculations show that 10(3)ln beta(34-32) decreases in the order of pyrite > marcasite > cobaltite > alloclasite > sphalerite approximate to wurtzite > gamma-MnS > hawleyite approximate to greenockite > alabandite. The S coordination number exerts a strong influence on the equilibrium partitioning of S isotopes in these sulfides, and there exist significant S isotope fractionations between the sulfides with different S coordination numbers (CNS), such as alabandite (CNS = 6) and other sulfides (e.g., FeS2, CoAsS, ZnS and CdS polymorphs) (CNS = 4). There is a broad negative correlation between the average bond lengths of all the bonds formed by S and 10(3)ln beta(34-32) values. The compactness of atom packing plays an important role in determining S isotope fractionation properties of sulfides, and S-34 generally tends to concentrate in the phases with higher atomic packing factor (APF). The linear correlation between APF and 10(3)ln beta(34-32) can predict the change of 10(3)ln beta(34-32) with increasing pressure, but pressure has a negligible effect on S isotope fractionation factors between sulfides.

Abstract 951: Femoral Plaques Confound the Association of Circulating Oxidized Low-density Lipoprotein with Carotid Atherosclerosis in a General Population Aged 35–55 Years (Asklepios Study).

Objective. Previously reported associations of oxidized low-density lipoprotein (OxLDL) with non-invasive measures of atherosclerosis were inconsistent. Moreover oxLDL was not an independent predictor of future cardiovascular endpoints in models adjusting for lipid markers (total and HDL-cholesterol). Therefore, in the Asklepios Study cohort of 2524 asymptomatic subjects aged 35–55 years, we evaluated the multiple-adjusted association between circulating OxLDL and subclinical atherosclerosis in the carotid and femoral arteries (ultrasound based definitions). Methods and results. Participants (mean age 45 years, 51.5% females) underwent a clinical examination, ultrasound protocol for determination of intima-media thickness (IMT) and plaques (Mannheim criteria) in the left and right carotid and femoral arteries, blood analysis for OxLDL (mAb-4E6) and other risk markers. They all completed a lifestyle variables study questionnaire. OxLDL concentrations were highest in subjects with femoral plaques (n=658). In the group of subjects with carotid plaques (n=476), elevated OxLDL concentrations were related to concomitant femoral plaques detected in 54% of these subjects. Stepwise multiple regression for oxLDL comprizing classical covariates demonstrated that non-HDL-cholesterol (beta 0.41), HDL-cholesterol (beta −0.34), femoral artery plaque (beta 8.97), ln(triglycerides) (beta 4.89), and gender (beta 2.79) were significant (p < 0.05) determinants. Full models including all appropriate anthropometric, hemodynamic, biochemical, and lifestyle variables confirmed that femoral plaques are independently related to OxLDL. Similar analyses demonstrated that femoral IMT, carotid IMT, or carotid plaques were not independently associated with OxLDL. Conclusion. Circulating OxLDL is independently associated with femoral plaque and not with carotid artery wall damage.

Spreading of an Inkjet Droplet on a Solid Surface with a Controlled Contact Angle at Low Weber and Reynolds Numbers

Even though the inkjet technology has been recognized as one of the most promising technologies for electronic and bio industries, the full understanding of the dynamics of an inkjet droplet at its operating conditions is still lacking. In this study, the normal impact of water droplets on solid substrates was investigated experimentally. The size of water droplets studied here was 46 microm and was much smaller than the most of the previous studies on drop impact. The Weber number (We) and Reynolds number (Re) were 0.05-2 and 10-100, respectively, and the Ohnesorge number was fixed at 0.017. The wettability of the solid substrate was varied by adsorbing a self-assembled monolayer of octadecyltrichlorosilane followed by the exposure to UV-ozone plasma. The impact scenarios for low We impacts were found to be qualitatively different from the high to moderate We impacts. Neither the development of a thin film and lamella under the traveling sphere nor the entrapment of small bubbles was observed. The dynamics of droplet impact at the conditions studied here is found to proceed under the combined influences of inertia, surface tension, and viscosity without being dominated by one specific mechanism. The maximum spreading factor (beta), the ratio of the diameter of the wetted surface and the drop diameter before impact, was correlated well with the relationship ln beta=0.090 ln We/(fs-cos theta)+0.151 for three decades of We/(fs-cos theta), where theta is the equilibrium contact angle, and fs is the ratio between the surface areas contacting the air and the solid substrate. The result implies that the final shape of the droplet is determined by the surface phenomenon rather than fluid mechanical effects.

Study time effects in recognition memory.

We empirically tested the assumption that study time increases recognition accuracy because the storage of information is better when study time is longer as Shiffrin and colleagues have reported, an assumption common to parallel models of recognition. In the present study with 123 subjects, we examined the effect of item strength on four measures: hit rate, false alarm rate, d', and beta, for a single-word recognition task with longer study times than those usually used in the literature. Analysis indicated significant increase for hit rate and d' and a decrease in false alarm rate, as one goes from weak to stronger study conditions, and a change in ln(beta) when study time is greater than 1 sec. These results suggest that familiarization is one, but not the only, factor underlying the strength-mirror effect.

Excitations for lattice ferromagnetic classical spin systems at high temperature: noneven single-spin distributions

We consider general d-dimensional lattice ferromagnetic spin systems with nearest neighbor interactions in the high temperature region (beta<<1). Each model is characterized by a single-site a priori spin probability distribution taken to be noneven. We state our results in terms of the parameter alpha=(<&smacr; (4)>-3<&smacr; (2)>(2)-<&smacr; (3)>(2)<&smacr; (2)>(-1))/(<&smacr; (4)>-<&smacr; (2)>(2)-<&smacr; (3)>(2)<&smacr; (2)>(-1)), where &smacr;=s-<s>, and <s(k)> denotes the kth moment of the single-site distribution. Associated with the model is a lattice quantum field theory which is known to contain a particle of mass m approximately ln beta. Assuming <&smacr;(3)> not equal0 we show that for alpha>0, beta small, there exists a bound state with mass below the two-particle threshold 2m. For alpha<0 bound states do not exist. These results are obtained using a Bethe-Salpeter (BS) equation in the ladder approximation in conjunction with a representation for the inverse of the two-point function designed to analyze the spectrum below but close to 2m.

Regulation and function of extracellular matrix intestinal epithelial restitution in vitro.

Repair of epithelial injury in the gastrointestinal tract is initially accomplished by migration of epithelial cells from the wound edge ("restitution"). To assess expression and function of the extracellular matrix (ECM) in the restitution phase after epithelial injury, in vitro studies using wounded monolayers or a rat intestinal epithelium-derived cell line (IEC-6) were undertaken. IEC-6 cells expressed fibronectin (FN) mRNA and protein in large amounts and lesser quantities of laminin-beta 1 (LN beta 1) and LN gamma 1. Collagen IV (Col IV) was weakly expressed, and LN alpha 1 was not detected. After wounding a significant decrease in FN, LN beta 1, LN gamma 1, and Col IV alpha 1 mRNA steady-state levels was observed; mean content 24 h after wounding was reduced by 75-90%. FN, LN, and Col IV proteins were also reduced. The downregulation of these ECM transcripts and proteins could be substantially prevented by transforming growth factor-beta 1, a restitution-promoting growth factor. In addition to changes of expression, the distribution of FN and LN was also altered in migrating cells after wounding, as assessed by immunofluorescence. Arg-Gly-Asp peptides that recognize the major cell attachment site on FN and antibodies recognizing the main noncollagenous domain of Col IV inhibited cell migration, but immunoneutralizing anti-LN antisera did not affect restitution. In conclusion, although paradoxically downregulated after wounding, ECM proteins, in particular FN and Col IV molecules, are able to enhance intestinal epithelial restitution.

Expression of laminins in the airways in various types of asthmatic patients: a morphometric study.

Laminins (Ln) are crucial in airway morphogenesis. Because they are able to interact with inflammatory cells, they are likely to participate in inflammation accompanied by airway structural remodeling in asthma. Taking biopsies and using immunohistochemistry and quantitative image analysis, we characterized the distribution of Ln chains alpha 1, alpha 2, and beta 2 in the bronchial mucosa of patients with seasonal (n = 17), early occupational (n = 8), and chronic asthma (n = 16) for comparison with that of normal controls (n = 8). In all asthmatic patients, both Ln chains alpha 1 and beta 2 were confined to the superficial margin of the basement membrane (BM), blood vessels, and smooth muscle. The thickness of Ln beta 2 expression in BM was significantly greater in patients with chronic (1.9 +/- 0.1 microns; P < 0.001) and occupational asthma (1.7 +/- 0.1 microns; P < 0.05) than in controls (0.4 +/- 0.3 microns). Only in patients with occupational asthma was the thickness of the Ln alpha 1 layer (2.3 +/- 0.2 microns; mean +/- SEM) significantly different from that in controls (1.4 +/- 0.5 microns; P < 0.05). There was no immunoreactivity for the Ln alpha 2 chain in controls or patients with mild asthma, but in clinically severe chronic asthma we found a discontinuous staining along the epithelial margin of the BM. Since Ln chains alpha 2 and beta 2 appear to function only during morphogenesis, increased expression of these Ln chains in adult asthma patients suggests accelerated tissue turnover in the airways, possibly as a result of airway inflammation in asthma.

Laminin chains in the basement membranes of human thymus.

In recent studies, the alpha 2 chain of laminin (Ln) has been suggested to be the only laminin alpha chain expressed in mouse and human thymus. We have now used chain-specific monoclonal antibodies and indirect immunofluorescence microscopy to study the expression of laminin chains in samples of foetal and 6-year-old human thymus. The subepithelial basement membrane of the capsule of foetal 16-to 18-week thymus presented a bright immunoreactivity for Ln alpha 1, alpha 3, beta 1, beta 3 and gamma 1 chains but not for alpha 2 chain, suggesting the expression of laminins-1 and-5. Most cortical and medullary epithelial cells, including Hassall's corpuscles, however, lacked laminin immunoreactivity. Immunoreactivity for Ln beta 2 chain was only seen in basal laminae of larger blood vessels. In thymic specimens from 6-year-old children, immunoreactivity for the laminin alpha 1, alpha 3, beta 1, beta 3 and gamma 1 chains was invariably found in subepithelial basement membrane of the capsule and that for laminin alpha 2 chain was now also distinct but more heterogeneous. Furthermore, the thymic subepithelial basement membrane of the capsule at all stages showed immunoreactivity for collagen type VII, forming the anchoring fibres in epithelial basement membranes. The subcapsular thymic epithelium also showed immunoreactivity for the BP 230 antigen and beta 4 integrin subunit, both components of hemidesmosomes. The present results show that the thymic subepithelial basement membrane of the capsule presents properties which are commonly seen in stratified and combined epithelia, and are compatible with suggestions of the antigenic similarity of thymic epithelial cells and keratinocytes.

Distribution of renal integrin receptors and their ligands in congenital nephrotic syndrome of the Finnish type.

The aim of this study was to examine the distribution of beta 1 and alpha v integrins (Ints) and some of their ligands in the kidneys of patients with congenital nephrotic syndrome of the Finnish type (CNF) and in controls using indirect immunofluorescence with monoclonal antibodies. The mesangial reactivity of Int alpha 1 and Int beta 1 subunits was more variable and an increased glomerular reactivity with Int alpha 3 and Int-alpha 6 antibodies was found in CNF kidneys than in controls. Int alpha 2 subunit was either completely missing from or found in significantly lesser amounts in CNF kidney glomeruli. The immunoreactivity for Int alpha v was more variable, fainter and also more granular in CNF samples than in control kidneys. The glomerular reactivity for Int beta 5 was more diffuse and weaker, and in sclerotic Bowman's capsules more intense in CNF kidneys than in controls. Immunoreactivity for Int beta 6 was restricted and was comparable in extent in CNF and control kidneys. Of the extracellular matrix components studied, the expression of EDAFn, EDBFn, OncFn, Ln alpha 2 chain, Ln beta 1 chain and tenascin was increased. This is also seen in several glomerular diseases with inflammation and sclerosis. Immunoreactivity for vitronectin was decreased. Several differences were found in the intensity or location of the immunostaining for the beta 1 and alpha v Ints and their ligands in CNF kidneys compared with controls, which have not been found in any other proteinuric disease. Disturbed Int expression pattern in CNF may specifically reflect the disturbance of glomerular function caused by the primary defect in this disease.

The immunohistochemical composition of the human corneal basement membrane.

Frozen sections of human cornea and conjunctiva were stained by immunofluorescence and immunoperoxidase methods with a panel of antibodies against various basement membrane (BM) and extracellular matrix proteins to study the composition of the human corneal BM. Laminin (Ln) immunoreactivity was detected in the BMs of the blood vessels and conjunctival, limbal, and corneal epithelia by using a polyclonal antiserum and monoclonal antibodies (MAbs) against Ln chains alpha 1, beta 1, and gamma 1, but in the cornea the reaction with MAbs against alpha 1, beta 1, and gamma 1 chains was clearly weaker than in the other BMs and in some sections totally absent. Immunoreactivity to Ln alpha 2 chain was detected only in the BM of the limbus, whereas Ln beta 2 chain was detected in the BMs of blood vessels and that of conjunctival and limbal epithelia. Ln-5 and Ln alpha 3 and beta 3 chains were seen in the BMs of the corneal, limbal, and conjunctival epithelia coaligning the integrin beta 4. Immunoreactivity for collagen type IV was lacking in the BM of the corneal epithelium, but present in the BMs of the limbal and conjunctival epithelia as well as in the vascular BM. Collagen type VII immunoreactivity was seen in the BM areas of the corneal, limbal, and conjunctival epithelia. BMs of corneal, limbal, conjunctival, and vascular epithelia expressed fibronectin (Fn), including extradomain A cellular Fn and oncofetal cellular Fn isoforms, all lacking, however, extradomain B cellular Fn. The present results give new information on the Ln chain distribution and show that the BM of the corneal epithelium differs from that of surrounding epithelia by the lack of collagen type IV.

Signal-detection analysis of recognition memory of obese subjects.

Obese and normal-weight subjects were run on a series of recognition-memory tasks with low and high meaningful CVC trigrams. Subjects received feedback or no feedback regarding the appropriateness of their answers during testing for recognition memory. A signal-detection analysis was used to examine a relatively pure index of memory (d') as compared to response-bias factors [Ln (beta)]. No significant main effect on memory of obese and control subjects was noted although a significant interaction indicated that obese subjects' memory increases over trials in a differential fashion from normal-weight individuals with poorer performance among the obese after 3 trials. Feedback facilitated memory for both groups. Analysis of response criteria [Ln (beta)] showed no significant difference between groups. Highly meaningful trigrams had a significantly lower response criterion than low meaningful trigrams and there was a significant interaction of meaningfulness by trials. An interaction of feedback by meaningfulness was also present. Advantages of using a signal-detection analysis in memory studies comparing obese and normal weight subjects are discussed. Ramifications of the present data for the internality/externality hypothesis of obesity are also discussed.

On the gauge equivalence of the equation of dynamics for uniaxial ferromagnets

The equations of dynamics for an easy-plane anisotropy uniaxial ferromagnet St-S*Sxx+ beta (S.n)S*n=0 S2=1 n=(0,0,1) beta >0 is shown to be gauge equivalent to the equation (vt+vxx-2/v/2v+2/vx/2v/( beta -4/v/2)-(vx/2) delta ln( beta -4/v)2)/ delta x=0. The formulae that relate the solutions of these equations for natural boundary conditions are derived.

Diffusion in a one-dimensional lattice with random asymmetric transition rates

The authors study one-dimensional continuous-time random walks for which the pairs (Wn+, Wn+1-) of nearest-neighbour transition rates are assumed to be independent, equally distributed random variables. The long-time asymptotic behaviour of the mean displacement, (x(t)), is determined exactly for a specific model system in which 'diodes' (u, 0) and 'two-way bonds' ( lambda v, v) occur with probabilities p and 1-p, respectively. For lambda <1-p, we find that (x(t)) approximately Tnu F( beta -1ln t), where nu =ln(1-p)/ln lambda and beta =ln lambda , and where F is a periodic function with period 1. The mean displacement thus not only increases slower than linearly in time, but exhibits superimposed, non-decaying oscillations.