Some properties of the k-dimensional Lyness' map

This paper is devoted to study some properties of the k-dimensional Lyness' map. Our main result presentes a rational vector field that gives a Lie symmetry for F. This vector field is used, for k less or equal to 5 to give information about the nature of the invariant sets under F. When k is odd, we also present a new (as far as we know) first integral for F^2 which allows to deduce in a very simple way several properties of the dynamical system generated by F. In particular for this case we prove that, except on a given codimension one algebraic set, none of the positive initial conditions can be a periodic point of odd period.Comment: 22 pages; 3 figure

Self-assembly of telechelic tyrosine end-capped PEO and poly(alanine) polymers in aqueous solution

The self-assembly in aqueous solution of three novel telechelic conjugates comprising a central hydrophilic polymer and short (trimeric or pentameric) tyrosine end-caps has been investigated. Two of the conjugates have a central poly(oxyethylene) (polyethylene oxide, PEO) central block with different molar masses. The other conjugate has a central poly(l-alanine) (PAla) sequence in a purely amino-acid based conjugate. All three conjugates self-assemble into β-sheet based fibrillar structures, although the fibrillar morphology revealed by cryogenic-TEM is distinct for the three polymers—in particular the Tyr5-PEO6k-Tyr5 forms a population of short straight fibrils in contrast to the more diffuse fibril aggregates observed for Tyr5-PEO2k-Tyr5 and Tyr3-PAla-Tyr3. Hydrogel formation was not observed for these samples (in contrast to prior work on related systems) up to quite high concentrations, showing that it is possible to prepare solutions of peptide–polymer-peptide conjugates with hydrophobic end-caps without conformational constraints associated with hydrogelation. The Tyr5-PEO6k-Tyr5 shows significant PEO crystallization upon drying in contrast to the Tyr5-PEO2k-Tyr5 conjugate. Our findings point to the remarkable ability of short hydrophobic peptide end groups to modulate the self-assembly properties of polymers in solution in model peptide-capped “associative polymers”. Retention of fluidity at high conjugate concentration may be valuable in potential future applications of these conjugates as bioresponsive or biocompatible materials, for example exploiting the enzyme-responsiveness of the tyrosine end-group

Molecular and Functional Characterization of the Odorant Receptor2 (OR2) in the Tiger Mosquito Aedes albopictus

In mosquitoes, the olfactory system plays a crucial role in many types of behavior, including nectar feeding, host preference selection and oviposition. Aedes albopictus, known also as the tiger mosquito, is an anthropophilic species, which in the last few years, due to its strong ecological plasticity, has spread throughout the world. Although long considered only a secondary vector of viruses, the potential of its vector capacity may constitute a threat to public health. Based on the idea that an improved understanding of the olfactory system of mosquitoes may assist in the development of control methods that interfere with their behavior, we have undertaken a study aimed at characterizing the A. albopictus Odorant Receptors. Here we report the identification, cloning and functional characterization of the AalOR2 ortholog, that represents the first candidate member of the odorant receptor (OR) family of proteins from A. albopictus. AalOR2 is expressed in the larval heads and antennae of adults. Our data indicate that A. albopictus OR2 (AalOR2) shares a high degree of identity with other mosquito OR2 orthologs characterized to date, confirming that OR2 is one of the most conserved mosquito ORs. Our data indicate that AalOR2 is narrowly tuned to indole, and inhibited by (-)-menthone. In agreement with this results, these two compounds elicit two opposite effects on the olfactory-based behavior of A. albopictus larvae, as determined through a larval behavioral assay. In summary, this work has led to the cloning and de-orphaning of the first Odorant Receptor in the tiger mosquito A. albopictus. In future control strategies this receptor may be used as a potential molecular target

Should patients with hip joint prosthesis receive antibiotic prophylaxis before dental treatment?

The safety committee of the American Academy of Orthopedic Surgeons (AAOS) recommended in 2009 that clinicians should consider antibiotic prophylaxis for all patients with total joint replacement before any invasive procedure that may cause bacteremia. This has aroused confusion and anger among dentists asking for the evidence. The present review deals with different aspects of the rationale for this recommendation giving attention to views both in favor of and against it

A dynamic regulation and scheduling scheme for real-time traffic management

Typical rate-based traffic management schemes for real-time applications attempt to allocate resources by controlling the packet delivery to the resource arbitrator (scheduler). This control is typically based only on the characteristics of the particular (tagged) traffic stream and would fail to optimally adjust to nonnominal network conditions such as overload. In this paper, a dynamic regulation and scheduling (dynamic-R&S) scheme is proposed whose regulation function is modulated by both the tagged stream's characteristics and information capturing the state of the coexisting applications as provided by the scheduler. The performance of the proposed scheme - versus an equivalent static one - is investigated under both underload and overload traffic conditions. The substantially better throughput/jitter characteristics of the dynamic-R&S scheme are established. © 2000 IEEE

A Dynamic Regulation and Scheduling Scheme for Real-Time Traffic Management

Typical rate-based traffic management schemes for real-time applications attempt to allocate resources by controlling the packet delivery to the resource arbitrator (scheduler). This control is typically based only on the characteristics of the particular (tagged) traffic stream and would fail to optimally adjust to non-nominal network conditions such as overload. In this paper, a dynamic Regulation and Scheduling (dynamic-R&S) scheme is proposed whose regulation function is modulated by both the tagged stream's characteristics and some information capturing the state of the co-existing applications as provided by the scheduler. The performance of the proposed scheme -- as well as the equivalent static one -- is investigated under both underload and overload traffic conditions and the substantially better throughput / jitter characteristics of the dynamic-R&S scheme are established. Please send correspondence to: Prof. Ioannis Stavrakakis ECE Dept., 409 Dana Building, Northeastern Uni..

Segmental sandwich osteotomy of the posterior mandible in pre-implant surgery - A systematic review

Background: The rehabilitation of the atrophic posterior mandible with dental implants often requires bone augmentation procedures. The aim of the present study is the systematic review of the literature concerning the success rate of Segmental Sandwich Osteotomy (SSO) of the posterior mandible in pre-implant surgery. Material and Methods: Systematic review of all clinical cases and clinical studies of SSO of the posterior mandible in pre-implant surgery with a minimum follow-up of 6 months after implant loading was performed, based on specific inclusion and exclusion criteria. The search strategy involved searching the electronic databases of MEDLINE, EMBASE, COCHRANE LIBRARY, Clinical Trials (www.clinicaltrials.gov) and National Research Register (www.controlled-trials.com), supplemented by a manual search, in August 2015. In every study, the intervention characteristics and the outcome were recorded. Results: Out of the 756 initial results, only 17 articles fulfilled the predetermined inclusion and exclusion criteria. They consisted of 9 retrospective case reports or series and 8 prospective randomized clinical trials. Overall, the studies included 174 patients. In these patients, 214 SSO augmentation procedures were performed in the posterior mandible and 444 implants were placed. The follow-up period after implant loading ranged between 8 months and 5.5 years. The success rate of SSO ranged between 90% and 100%. The implant survival during the follow-up period ranged between 90.9% and 100%. Conclusions: Segmental Sandwich Osteotomy should be considered as a well documented technique for the rehabilitation of the atrophic posterior mandible, with long-term postsurgical follow-up. The success rates are very high, as well as the survival of the dental implants placed in the augmented area. © Medicina Oral S. L. C.I.F

Surgical management of primary chronic osteomyelitis of the jaws in children: A prospective analysis of five cases and review of the literature

Introduction: Primary chronic osteomyelitis (PCO) of the jaws is an uncommon non-suppurative inflammatory disease of unknown origin. Although the disease is not age-specific, only sparse cases with onset during childhood or adolescence have been reported in the literature. Purpose: This study seeks to present five cases of maxillofacial PCO in children and to evaluate the effectiveness of the applied therapeutic protocol. A review of the literature concerning diagnosis and treatment of PCO with special emphasis on surgical therapy is also performed. Patients and methods: Demographic data, clinical, radiographic and histopathologic findings, blood tests results, and the treatment protocol applied to five young patients suffering from PCO and referred to the Department of Oral and Maxillofacial Surgery at "A. & P. Kyriakou Children's Hospital" over the past 5 years are presented. Decortication and contouring of the affected bone were performed; antibiotics were administered for a short period of time and the patients remained under follow-up evaluation. Results: The posterior mandible was affected in four cases and the maxilla-zygomatic bone in one case. All patients showed remission of signs and symptoms after surgical treatment. The postsurgical clinical course was uneventful in all cases. However, recurrences have been noted, as reported in the literature. Conclusion: PCO of the jaws is a complex clinical entity, presenting both a diagnostic and therapeutic challenge, especially in young patients. Surgical treatment in conjunction with antibiotics and non-steroid anti-inflammatory drugs proved to be beneficial and to improve considerably the patients' quality of life. Nevertheless, exacerbation of the disease may appear and regular follow-up of the patients is required. © 2010 Springer-Verlag

Miniplate osteosynthesis for fractures of the edentulous mandible: a clinical study 1989-96

Our 8 years experience of treating fractures of the edentulous mandible by miniplate osteosynthesis, is discussed. Forty patients (31 men and 9 women) aged 37 to 86 Sears (mean: 6 1.6 years, SD: +/- 14.07) with 67 fracture sites were treated, The surgical approach was mainly intraoral (37 out of 40 patients) without the use of intermaxillary fixation, The postoperative clinical and radiological findings are reported and discussed. The advantages of the method are of great importance since immediate postoperative opening of the mouth is permitted, as the fractured bones are anatomically stabilized by means of titanium miniplates and screws. Our results were felt to be satisfactory, with a reoperation rate of only 3.9% (two out of 51 operated fracture sites, 16 condylar fractures,were treated conservatively). This allows us to propose intraoral miniplate osteosynthesis as a routine method of treatment in cases of edentulous mandibular fractures which are mainly seen in elderly people