Application of ultrasound in bone surgery: two case reports

The present study describes some of the applications of ultrasound in bone surgery, based on the presentation of two clinical cases. The Piezosurgery® ultrasound device was used (Tecnología Mectron Medical, Carasco, Italy). In one case the instrument was used to harvest a chin bone graft for placement in a bone defect at level 1.2, while in the other case a bony window osteotomy was made in the external wall of the maxillary sinus, in the context of a sinus membrane lift procedure. The Piezosurgery® device produces specific ultrasound frequency modulation (25-29 kHz), and has been designed to secure increased precision in application to bone surgery. This instrument produces selective sectioning of the mineralized bone structures, and causes less intra- and postoperative bleeding. One of the advantages of the Piezosurgery® device is that it can be used for maxillary sinus lift procedures in dental implant placement. In this context it considerably lessens the risk of sinus mucosa laceration by preparing the bony window in the external wall of the upper maxilla, and can be used to complete the lifting maneuver. The use of ultrasound in application to hard tissues can be regarded as a slow technique compared with the conventional rotary instruments, since it requires special surgical skill and involves a certain learning curve.

Surgical reconstruction of TMJ

Certain situations and pathological processes that arise with temporomandibular joint destruction can only be resolved with surgical reconstructive procedures in order to attempt a functional and anatomical rehabilitation of this joint. Many of these situations can be surgically treated with the patient's own autologous tissues. However, in some patients reconstruction is complex and the use of autologous tissues is unadvisable whereas reconstruction utilizing alloplastic materials may be an appropriate alternative. The following report describes 4 clinical cases in which autologous grafts or Christensen joint prosthesis are employed in temporomandibular joint reconstruction

Eliciting and fostering learners' metacognitive knowledge about language learning in self-directed learning programs: a review of data collection methods and procedures

Són molts els estudis que avui en dia incideixen en la necessitat d’oferir un suport metodològic i psicològic als aprenents que treballen de manera autònoma. L’objectiu d’aquest suport és ajudar-los a desenvolupar les destreses que necessiten per dirigir el seu aprenentatge així com una actitud positiva i una major conscienciació envers aquest aprenentatge. En definitiva, aquests dos tipus de preparació es consideren essencials per ajudar els aprenents a esdevenir més autònoms i més eficients en el seu propi aprenentatge. Malgrat això, si bé és freqüent trobar estudis que exemplifiquen aplicacions del suport metodològic dins els seus programes, principalment en la formació d’estratègies o ajudant els aprenents a desenvolupar un pla de treball, aquest no és el cas quan es tracta de la seva preparació psicològica. Amb rares excepcions, trobem estudis que documentin com s’incideix en les actituds i en les creences dels aprenents, també coneguts com a coneixement metacognitiu (CM), en programes que fomenten l’autonomia en l’aprenentatge. Els objectius d’aquest treball son dos: a) oferir una revisió d’estudis que han utilitzat diferents mitjans per incidir en el CM dels aprenents i b) descriure les febleses i avantatges dels procediments i instruments que utilitzen, tal com han estat valorats en estudis de recerca, ja que ens permetrà establir criteris objectius sobre com i quan utilitzar-los en programes que fomentin l’aprenentatge autodirigit.

The role of central bank operating procedures in an economy with productive government spending

The choice of either the rate of monetary growth or the nominal interest rate as the instrument controlled by monetary authorities has both positive and normative implications for economic performance. We reexamine some of the issues related to the choice of the monetary policy instrument in a dynamic general equilibrium model exhibiting endogenous growth in which a fraction of productive government spending is financed by means of issuing currency. When we evaluate the performance of the two monetary instruments attending to the fluctuations of endogenous variables, we find that the inflation rate is less volatile under nominal interest rate targeting. Concerning the fluctuations of consumption and of the growth rate, both monetary policy instruments lead to statistically equivalent volatilities. Finally, we show that none of these two targeting procedures displays unambiguously higher welfare levels.

Fair procedures. Evidence from games involving lotteries

Procedural fairness plays a prominent role in the social discourse concerning the marketplace in particular, and social institutions in general. Random procedures are a simple case, and they have found application in several important social allocation decisions. We investigate random procedures in the laboratory. We find that an unbiased random procedure is an acceptable substitute for an unbiased allocation: similar patterns of acceptance and rejection result when either is inserted as a feasible proposal in a sequential battle-of-the-sexes. We also find that unbiasedness, known to be a crucial characteristic of allocation fairness, is important to procedural fairness: in the context of a random offer game, a biased outcome is more readily accepted when chosen by an unbiased random draw than by one that is biased. Procedural fairness is conceptually different than allocation fairness or attribution-based behavior, and none of the current models of fairness and reciprocity captures our results. Post hoc extension of one of these models (ERC) suggests that a deeper understanding of procedural fairness requires further investigation of competing fairness norms.

Welfare comparisons: sequential procedures for heterogenous populations

Some analysts use sequential dominance criteria, and others use equivalence scales in combination with non-sequential dominance tests, to make welfare comparisons of oint distributions of income and needs. In this paper we present a new sequential procedure hich copes with situations in which sequential dominance fails. We also demonstrate that there commendations deriving from the sequential approach are valid for distributions of equivalent income whatever equivalence scale the analyst might adopt. Thus the paper marries together the sequential and equivalizing approaches, seen as alternatives in much previous literature. All results are specified in forms which allow for demographic differences in the populations being compared.

Perioperative stress in dogs underwent elective surgery: evaluation of the antioxidant activity

Projecte de recerca elaborat a partir d’una estada al Department of Biological Science a la University of Lincoln, a la Gran Bretanya, entre octubre i desembre del 2006. L'objectiu del present assaig va ser desciure les respostes antioxidants d'estrès en gossos sotmesos a cirurgia electiva, en condicions de pràctica clínica normals, durant les fases de preoperatori i postoperatori.Setze gossos van ser sotmesos a orquiectomia o ovariohisterectomia electives, utilitzant un protocol quirúrgic estàndard. Durant les fases preoperatoria i postoperatoria, cada animal va ser confinat a la Unitat de Cures Intensives, temps durant el qual es va estudiar la seva resposta antioxidant. Els valors obtinguts a diferents temps van ser comparats amb el valor basal, que s'havia obtingut del mateix animal estant aquest en el seu ambient habitual. No es van detectar variacions significants causades per l'estrès perioperatori. Els valors màxims es van observar durant la fase preoperatoria, just després que l'animal fós confinat a la Unitat de Cures Intensives, moment en el que l'estrès percebut era degut a les amenaces psicològiques de una àrea restringida i de la manipulació per persones desonegudes. L'abscència de variacions significants podrien ser degudes al sistema i el temps d'emmagatzement de les mostres. En humana s'han descrit les alteracions en l'activitat dels antioxidants sèrics després d'un mes d'emmagatzematent. Per definir l'estabilitat, després de la recollida de mostres, de l'activitat dels antioxidants en sèrum de gos és necessari realitzar més estudis.