Effect of familial hypophosphatemic rickets on dental development: a controlled, longitudinal study

Familial or X-linked hypophosphatemic rickets (XLHR) is the most common type of rickets in developed countries today. While the dental manifestations of rickets are well reported, there is little information regarding its relationship to dental development and other dental anomalies. This investigation studied the rate of dental development and associated dental anomalies in 19 XLHR subjects compared with 38 race-, age-, and sex-matched control children. The results showed that in both XLHR and control children, no significant differences existed in dental age compared with the respective chronological age, indicating that rickets did not affect the rate of dental development. Longitudinal growth curves of seven XLHR and matched control children substantiated that relationships of dental to chronological ages were comparable in both groups. Male XLHR subjects showed significantly increased tendency for dental taurodontism with mean Crown-Body (CB):Root (R) ratio of 1.1 compared with 1.0 in females and 0.8 in controls (P < 0.02). Male XLHR children also showed significantly increased prevalence (50%) of ectopic permanent canines compared with control children (8%, P < 0.01).     

Sum and difference of two squared correlated Nakagami variates in connection with the McKay distribution

General formulas for the probability density function of the sum and the difference of two correlated, not necessarily identically distributed, squared Nakagami variates (or equivalently, gamma variates) are derived. These expressions are shown to be in the form of the McKay "Bessel function" distributions. In addition, formulas for the moments of these distributions, in terms of the Gauss hypergeometric function, are provided. An application of these new results relevant to the calculation of outage probability in the presence of self-interference is discussed.     

Die Methode der Finiten Prismen bei anisotropen Materialeigenschaften

The Finite Prism Method is a semi-analytical solution technique for structural elements with prismatic geometry. In this case the basic equations of the theory of elasticity will be transformed and the variables can be separated. Statements on the effectiveness of the Finite Prism Method for isotropic materials already exist. An extension to anisotropic materials is possible, but restrictions for the constitutive behaviour are given by the limitations of the method. The application areas of the proposed theory are demonstrated by exemplary numerical tests.     

A Reduced-Basis Element Method

Reduced basis methods are particularly attractive to use in order to diminish the number of degrees of freedom associated with the approximation of a set of partial differential equations. The main idea is to construct ad hoc basis functions with a large information content. In this note, we propose to develop and analyze reduced basis methods for simulating hierarchical flow systems, which is of relevance for studying flows in a network of pipes, an example being a set of arteries or veins. We propose to decompose the geometry into generic parts (e.g., pipes and bifurcations), and to contruct a reduced basis for these generic parts by considering representative geometric snapshots. The global system is constructed by gluing the individual basis solutions together via Lagrange multipliers.     

Promoting Bacillus cereus spore germination for subsequent inactivation by mild heat treatment

Sublethal heat treatment may activate dormant spores and thereby potentiate the conversion of spores to vegetative cells. As the germinated spore is known to possess lower heat resistance than its dormant counterpart, it has been postulated that double heat treatment, i.e., spore heat activation followed by germination and then by heat inactivation, can be used to control spores in foods. Production of refrigerated processed foods of extended durability often includes more than one heat treatment of the food components. This work simulates conventional heat treatment procedures and evaluates double heat treatment as a method to improve spore control in model food matrixes of meat broth and cream sauce. Bacillus cereus NVH 1230-88 spores were supplemented in food model matrixes and heat activated at 70°C and then heat inactivated at 80 or 90°C. The samples were held at 29 to 30°C for 1 h between primary and secondary heat treatments, to allow spore germination. Nutrients naturally present in the food matrixes, e.g., amino acids and inosine, could act as germinants that induce germination. The levels of germinants could be too low to produce effective germination within 1 h. Following primary heat treatment, some samples were therefore supplemented with a combination of L-alanine and inosine, a germinant mixture known to be effective for B. cereus spores. In both matrixes, a combination of double heat treatment (heat activation, germination, and inactivation) and addition of germinants gave a reduction in spore counts equivalent to or greater than that obtained with a single heat treatment for 12 min at 90°C. Addition of germinants was essential to induce effective germination in cream sauce during 1 h at 29 to 30°C, and germinants were therefore a crucial supplement to obtain an effect of double heat treatment in this matrix. These data will be valuable when setting up temperature-time-germinant combinations for an optimized spore reduction in mild-heat-treated foods.     

Laboratory Measurements and a Theoretical Analysis of the TCT Fading Channel Radio System

This paper documents the laboratory and theoretical performance of a pilot-aided digital radio system. The technique considered transmits a midband pilot tone to improve the receiver data detection performance in a multipath fading channel and is referred to as the tone calibrated technique (TCT). We report on the performance of a 860 MHz prototype system carrying 2.4 kbit/s data under Rician fading conditions. Both experimental and analytical results show that the error floor experienced with nonpilot-aided transmission methods is effectively removed by the TCT scheme, resulting in significant performance gains at high signal-to-noise ratio (SNR) values. The paper also examines the TCT system performance under typical operating conditions and presents a new analysis of the TCT theoretical error probability.     

Evolutionary link between glycogen phosphorylase and a DNA modifying enzyme

We report here an unexpected similarity in three-dimensional structure between glucosyltransferases involved in very different biochemical pathways, with interesting evolutionary and functional implications. One is the DNA modifying enzyme beta-glucosyltransferase from bacteriophage T4, alias UDP-glucose:5-hydroxymethyl-cytosine beta-glucosyltransferase. The other is the metabolic enzyme glycogen phosphorylase, alias 1.4-alpha-D-glucan:orthophosphate alpha-glucosyltransferase. Structural alignment revealed that the entire structure of beta-glucosyltransferase is topographically equivalent to the catalytic core of the much larger glycogen phosphorylase. The match includes two domains in similar relative orientation and connecting helices, with a positional root-mean-square deviation of only 3.4 A for 256 C alpha atoms. An interdomain rotation seen in the R- to T-state transition of glycogen phosphorylase is similar to that observed in beta-glucosyltransferase on substrate binding. Although not a single functional residue is identical, there are striking similarities in the spatial arrangement and in the chemical nature of the substrates. The functional analogies are (beta-glucosyltransferase-glycogen phosphorylase): ribose ring of UDP-pyridoxal ring of pyridoxal phosphate co-enzyme; phosphates of UDP-phosphate of co-enzyme and reactive orthophosphate; glucose unit transferred to DNA-terminal glucose unit extracted from glycogen. We anticipate the discovery of additional structurally conserved members of the emerging glucosyltransferase superfamily derived from a common ancient evolutionary ancestor of the two enzymes.