Split-rib reconstruction of the frontal sinus: two cases and literature review

Abstract Background: Large defects of the anterior wall of the frontal sinus require closure using either autologous or foreign material. In cases of osteomyelitis, the reconstruction must be resistant to bacterial infection. Split-rib osteoplasty can be used in different sites. Methods: Two patients with malignant sinonasal tumours underwent repeated treatment, and subsequently developed osteomyelitis of the frontal bone. After adequate therapy, a large defect of the anterior wall persisted. Reconstruction was performed using the split-rib method. The literature on this topic was reviewed. Results: Both patients' treatment were successful. No complications occurred. A PubMed search on the topic of rib reconstruction of the frontal sinus and skull was performed; 18 publications matched the inclusion criteria. From these sources, we noted that 182 reconstructions yielded good results with few complications. Conclusion: Large defects of the anterior wall of the frontal sinus can be closed successfully using autologous split-rib grafting. Aesthetic outcome is good and donor site morbidity is minima

Shear-induced reaction-limited aggregation kinetics of Brownian particles at arbitrary concentrations

The aggregation of interacting Brownian particles in sheared concentrated suspensions is an important issue in colloid and soft matter science per se. Also, it serves as a model to understand biochemical reactions occurring in vivo where both crowding and shear play an important role. We present an effective medium approach within the Smoluchowski equation with shear which allows one to calculate the encounter kinetics through a potential barrier under shear at arbitrary colloid concentrations. Experiments on a model colloidal system in simple shear flow support the validity of the model in the range considered. By generalizing Kramers' rate theory to the presence of collective hydrodynamics, our model explains the significant increase in the shear-induced reaction-limited aggregation kinetics upon increasing the colloid concentration

An investigation of standard thermodynamic quantities as determined via models of nuclear multifragmentation

Both simple and sophisticated models are frequently used in an attempt to understand how real nuclei breakup when subjected to large excitation energies, a process known as nuclear multifragmentation. Many of these models assume equilibriumthermodynamics and produce results often interpreted as evidence of a phase transition. This work examines one class of models and employs standard thermodynamical procedure to explore the possible existence and nature of a phase transition. The role of various terms, e.g. Coulomb and surface energy, is discussed.Comment: 19 two-column format pages with 24 figure

Effect of chromophore-chromophore electrostatic interactions in the NLO response of functionalized organic-inorganic sol-gel materials

In the last years, important non-linear optical results on sol-gel and polymeric materials have been reported, with values comparable to those found in crystals. These new materials contain push-pull chromophores either incorporated as guest in a high Tg polymeric matrix (doped polymers) or grafted onto the polymeric matrix. These systems present several advantages; however they require significant improvement at the molecular level - by designing optimized chromophores with very large molecular figure of merit, specific to each application targeted. Besides, it was recently stated in polymers that the chromophore-chromophore electrostatic interactions, which are dependent of chromophore concentration, have a strong effect into their non-linear optical properties. This has not been explored at all in sol-gel systems. In this work, the sol-gel route was used to prepare hybrid organic-inorganic thin films with different NLO chromophores grafted into the skeleton matrix. Combining a molecular engineering strategy for getting a larger molecular figure of merit and by controlling the intermolecular dipole-dipole interactions through both: the tuning of the push-pull chromophore concentration and the control of TEOS (Tetraethoxysilane) concentration, we have obtained a r33 coefficient around 15 pm/V at 633 nm for the classical DR1 azo-chromophore and a r33 around 50 pm/V at 831 nm for a new optimized chromophore structure.Comment: 10 pages, 11 figures, 1 tabl

Notes on the Third Law of Thermodynamics.I

We analyze some aspects of the third law of thermodynamics. We first review both the entropic version (N) and the unattainability version (U) and the relation occurring between them. Then, we heuristically interpret (N) as a continuity boundary condition for thermodynamics at the boundary T=0 of the thermodynamic domain. On a rigorous mathematical footing, we discuss the third law both in Carath\'eodory's approach and in Gibbs' one. Carath\'eodory's approach is fundamental in order to understand the nature of the surface T=0. In fact, in this approach, under suitable mathematical conditions, T=0 appears as a leaf of the foliation of the thermodynamic manifold associated with the non-singular integrable Pfaffian form $\delta Q_{rev}$. Being a leaf, it cannot intersect any other leaf $S=$ const. of the foliation. We show that (N) is equivalent to the requirement that T=0 is a leaf. In Gibbs' approach, the peculiar nature of T=0 appears to be less evident because the existence of the entropy is a postulate; nevertheless, it is still possible to conclude that the lowest value of the entropy has to belong to the boundary of the convex set where the function is defined.Comment: 29 pages, 2 figures; RevTex fil

The liquid to vapor phase transition in excited nuclei

For many years it has been speculated that excited nuclei would undergo a liquid to vapor phase transition. For even longer, it has been known that clusterization in a vapor carries direct information on the liquid- vapor equilibrium according to Fisher's droplet model. Now the thermal component of the 8 GeV/c pion + 197Au multifragmentation data of the ISiS Collaboration is shown to follow the scaling predicted by Fisher's model, thus providing the strongest evidence yet of the liquid to vapor phase transition.Comment: four pages, four figures, first two in color (corrected typo in Ref. [26], corrected error in Fig. 4

Potential of Diagnostic Microbiology for Treatment and Prognosis of Dental Caries and Periodontal Diseases

Most evidence suggests that only a finite number of bacteria are responsible for dental caries and periodontal diseases. This knowledge led to the development of microbial tests which can identify suspected pathogens. Current evaluation of the diagnostic power of microbial tests has shown that they have a low sensitivity and a low prognostic value. Despite these shortcomings, there are valid indications for microbiological-based diagnosis. Salivary microbial tests for the detection of mutans streptococci and lactobacilli may be useful, for example, in young children, oligosialic patients, and orthodontic patients. These tests can be used to monitor the success of chemopreventive measures or compliance with dietary recommendations. Microbial diagnosis may also be valuable in the treatment of early-onset periodontitis or in subjects who respond poorly to periodontal therapy. The use of microbial tests to monitor the efficacy of chemotherapy or mechanical treatment is of particular interest.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68094/2/10.1177_10454411960070030401.pd

The postulates of gravitational thermodynamics

The general principles and logical structure of a thermodynamic formalism that incorporates strongly self-gravitating systems are presented. This framework generalizes and simplifies the formulation of thermodynamics developed by Callen. The definition of extensive variables, the homogeneity properties of intensive parameters, and the fundamental problem of gravitational thermodynamics are discussed in detail. In particular, extensive parameters include quasilocal quantities and are naturally incorporated into a set of basic general postulates for thermodynamics. These include additivity of entropies (Massieu functions) and the generalized second law. Fundamental equations are no longer homogeneous first-order functions of their extensive variables. It is shown that the postulates lead to a formal resolution of the fundamental problem despite non-additivity of extensive parameters and thermodynamic potentials. Therefore, all the results of (gravitational) thermodynamics are an outgrowth of these postulates. The origin and nature of the differences with ordinary thermodynamics are analyzed. Consequences of the formalism include the (spatially) inhomogeneous character of thermodynamic equilibrium states, a reformulation of the Euler equation, and the absence of a Gibbs-Duhem relation.Comment: 28 pages, Revtex, no figures. An important sentence and several minor corrections included. To appear in Physical Review

Ninth and Tenth Order Virial Coefficients for Hard Spheres in D Dimensions

We evaluate the virial coefficients B_k for k<=10 for hard spheres in dimensions D=2,...,8. Virial coefficients with k even are found to be negative when D>=5. This provides strong evidence that the leading singularity for the virial series lies away from the positive real axis when D>=5. Further analysis provides evidence that negative virial coefficients will be seen for some k>10 for D=4, and there is a distinct possibility that negative virial coefficients will also eventually occur for D=3.Comment: 33 pages, 12 figure