Nonlinear dispersive waves in repulsive lattices.

The propagation of nonlinear waves in a lattice of repelling particles is studied theoretically and experimentally. A simple experimental setup is proposed, consisting of an array of coupled magnetic dipoles. By driving harmonically the lattice at one boundary, we excite propagating waves and demonstrate different regimes of mode conversion into higher harmonics, strongly influenced by dispersion and discreteness. The phenomenon of acoustic dilatation of the chain is also predicted and discussed. The results are compared with the theoretical predictions of the α-Fermi-Pasta-Ulam equation, describing a chain of masses connected by nonlinear quadratic springs and numerical simulations. The results can be extrapolated to other systems described by this equation.

Formation of high-order acoustic Bessel beams by spiral diffraction gratings.

The formation of high-order Bessel beams by a passive acoustic device consisting of an Archimedes' spiral diffraction grating is theoretically, numerically, and experimentally reported in this paper. These beams are propagation-invariant solutions of the Helmholtz equation and are characterized by an azimuthal variation of the phase along its annular spectrum producing an acoustic vortex in the near field. In our system, the scattering of plane acoustic waves by the spiral grating leads to the formation of the acoustic vortex with zero pressure on axis and the angular phase dislocations characterized by the spiral geometry. The order of the generated Bessel beam and, as a consequence, the size of the generated vortex can be fixed by the number of arms in the spiral diffraction grating. The obtained results allow for obtaining Bessel beams with controllable vorticity by a passive device, which has potential applications in low-cost acoustic tweezers and acoustic radiation force devices.

Extraordinary absorption of sound in porous lamella-crystals.

We present the design of a structured material supporting complete absorption of sound with a broadband response and functional for any direction of incident radiation. The structure which is fabricated out of porous lamellas is arranged into a low-density crystal and backed by a reflecting support. Experimental measurements show that strong all-angle sound absorption with almost zero reflectance takes place for a frequency range exceeding two octaves. We demonstrate that lowering the crystal filling fraction increases the wave interaction time and is responsible for the enhancement of intrinsic material dissipation, making the system more absorptive with less material.

Síndrome de Rapunzel: tratamiento laparoscópico / Rapunzel syndrome: Laparoscopic treatment

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Paediatric and adolescent traumatic gastrointestinal injuries: results of a European multicentre analysis.

AIM: Paediatric gastrointestinal injuries (GIIs) are rare, and the aim of this multicentre study was to evaluate their outcomes in a large cohort. METHODS: Hospital databases of 10 European paediatric surgical centres were reviewed for paediatric traumatic GIIs managed between 2000-2010. RESULTS: Ninety-seven patients with a median age of 9 years (0-17 years) were identified, with 72 blunt and 25 penetrating GIIs. Initial diagnostics in 90 patients led to correct diagnosis in 71%. Diagnostics were delayed in 26 patients (median 24 h). Eighty-two patients required surgery (67 laparotomy, 12 laparoscopy and three other approaches). There was a 50% conversion in the laparoscopic group. Median hospital stay was 10 days (range 1-137 days), with longer duration influenced by associated injuries (n = 41). Diagnosis <24 h was associated with significantly shorter hospital stay compared to more than 24 h (p = 0.011). In one-third of patients, morbidities were not related to a diagnostic delay or type of injury. There were five lethal outcomes, four due to associated injuries. CONCLUSION: Initial diagnostics in traumatic paediatric GIIs provide false negatives in one-third of patients. Diagnostic delay <24 h is associated with a significantly shorter hospital stay. Although laparoscopy is associated with a conversion rate of 50%, it can be used for diagnosis in suspected cases to avoid nontherapeutic laparotomy.

Bacterial biofilms and capsular contracture in patients with breast implants.

BACKGROUND: It has been hypothesized that bacterial biofilms on breast implants may cause chronic inflammation leading to capsular contracture. The association between bacterial biofilms of removed implants and capsular contracture was investigated. METHODS: Breast implants explanted between 2006 and 2010 at five participating centres for plastic and reconstructive surgery were investigated by sonication. Bacterial cultures derived from sonication were correlated with patient, surgical and implant characteristics, and the degree of capsular contracture. RESULTS: The study included 121 breast implants from 84 patients, of which 119 originated from women and two from men undergoing gender reassignment. Some 50 breast prostheses were implanted for reconstruction, 48 for aesthetic reasons and 23 implants were used as temporary expander devices. The median indwelling time was 4·0 (range 0·1-32) years for permanent implants and 3 (range 1-6) months for temporary devices. Excluding nine implants with clinical signs of infection, sonication cultures were positive in 40 (45 per cent) of 89 permanent implants and in 12 (52 per cent) of 23 temporary devices. Analysis of permanent implants showed that a positive bacterial culture after sonication correlated with the degree of capsular contracture: Baker I, two of 11 implants; Baker II, two of ten; Baker III, nine of 23; and Baker IV, 27 of 45 (P < 0·001). The most frequent organisms were Propionibacterium acnes (25 implants) and coagulase-negative staphylococci (21). CONCLUSION: Sonication cultures correlated with the degree of capsular contracture, indicating the potential causative role of bacterial biofilms in the pathogenesis of capsular contracture. REGISTRATION NUMBER: NCT01138891 (http://www.clinicaltrials.gov).

Sound diffusers based on sonic crystals.

A sound diffuser is proposed based on sonic crystals, structures formed by a periodic distribution of cylindrical scatterers in a host medium, which is usually air. The diffuser is a so-called biperiodic structure, as formed by two arrays of sonic crystals with slightly different periodicities. Large diffusivity at low frequencies is achieved when the typical scale of the blocks is much larger than the periodicity of the crystals, determined by its lattice constant. An interpretation of the low frequency behavior of the diffuser is given in the homogenization limit in terms of multiple reflections and interference between the fields scattered by the different blocks. It is also shown that sonic crystal based diffusers enhance time spreading in comparison with other conventional diffusers.

Evaluación del riesgo de infecciones alimentarias en pacientes internados en un hospital pediátrico de alta complejidad y su sistema de prevención / Risk assesment of food infections in patient in a pediatric tertiary-care hospital and its prevention

The Garrahan Hospital is a tertiary-care center for pediatrics patients with complex diseases. Infections, including food-borne infections, contribute considerably to the morbidity and mortality in this population at risk. In order to prevent food-borne infections, the Foodservice Area has developed a preventive process approach system of Hazard Analysis and Critical Control Point (process approach HACCP) in food production and service. Objective: To conduct a thorough review and assessment of risk from food borne pathogens according to the pathology of patients or the therapeutic practice used, and to standardize food production and service. With the criterion "degree of safety at the time of service" preventive measures were standardized. The food was classified into four levels of process. One or more food levels are indicated according to risk, and if necessary individual adjustments are made.

El hospital Garrahan brinda asistencia a pacientes pediátricos con patologías complejas. Las infecciones, incluidas las alimentarias, contribuyen considerablemente en la morbilidad y mortalidad en esta población en riesgo. Con la finalidad de prevenir infecciones alimentarias, el Área de Alimentación desarrolla un Sistema Preventivo de Análisis de Peligros y Puntos Críticos de Control con enfoque en procesos (HACCP process approach) en la producción y servicio de alimentos. Objetivo: realizar una exhaustiva revisión y evaluación de los patógenos alimentarios de riesgo según patología o práctica terapéutica de los pacientes y estandarizar la producción y servicio de alimentos. Con el criterio "grado de inocuidad al momento del servicio" se estandarizaron las medidas preventivas. La alimentación fue clasificada en cuatro niveles de proceso. A cada grupo de población asistida, según riesgo, se le indica uno o más niveles de alimentación y se realizan los ajustes individuales necesarios.

Traumatismo hepático muy grave en la infancia. A propósito de dos casos con tratamiento mínimamente invasivo / Very severe hepatic trauma in childhood. the report of two cases with minimally invasive treatment

Los traumatismos hepáticos en los niños son una patología que presenta una incidencia creciente debido fundamentalmente a que cada vez los menores se ven más implicados en juegos y deportes de aventura, potencialmente peligrosos, y a los constantes accidentes de automóvil. Tradicionalmente el tratamiento es conservador, con soporte vital especializado y reposo absoluto, fundamentalmente. Ello permite en la mayoría de los casos una recuperación completa del paciente sin la agresión de la intervención quirúrgica, lo que previene, además, el daño sobreañadido de la manipulación de la víscera hepática lesionada. Presentamos dos casos clínicos de sendos niños de 6 y 4 años que sufrieron rotura traumática muy grave de hígado, intervenidos quirúrgicamente mediante técnicas mínimamente invasivas que lograron la curación completa (AU)

Liver trauma in children is a pathology that has an increasing incidence mainly due to the implications of growing children in hazardous games and sports adventure, and the frequent car accidents. There has been a shift of management in haemodynamically stable patients towards non-operative management. This allows in most cases a patient’s complete recovery without surgical aggression, preventing further damage derived from the handling of the injured liver. Here with we report two cases of a 6 and 4 year old boys who suffereda very severe traumatic rupture of the liver. They were operated through minimally invasive surgical procedures, achieving complete resolution of the serious damages (AU)

[Very severe hepatic trauma in childhood. The report of two cases with minimally invasive treatment]. / Traumatismo hepático muy grave en la infancia. A propósito de dos casos con tratamiento mínimamente invasivo.

Liver trauma in children is a pathology that has an increasing incidence mainly due to the implications of growing children in hazardous games and sports adventure, and the frequent car accidents. There has been a shift of management in haemodynamically stable patients towards non-operative management. This allows in most cases a patient's complete recovery without surgical aggression, preventing further damage derived from the handling of the injured liver. Herewith we report two cases of a 6 and 4 year old boys who suffered a very severe traumatic rupture of the liver. They were operated through minimally invasive surgical procedures, achieving complete resolution of the serious damages.

Utilización de dermis artificial en el manejo de heridas traumáticas con exposición ósea y/o tendinosa en niños / Use of artificial dermal matrix in the management of traumatic wounds with exposed bone and/or tendon in children

En los últimos años ha aumentado el uso de dermis artificial (Integra®) en niños, siendo su principal indicación la reconstrucción cutánea tras una quemadura o una extirpación de lesiones congénitas. Su uso en heridas traumáticas en niños es todavía poco frecuente, con escasas referencias en la bibliografía. Recientemente hemos utilizado dermis artificial en tres pacientes de 7, 9 y 13 años de edad, que presentaban heridas traumáticas en el miembro inferior izquierdo, el miembro inferior derecho y la región frontal, respectivamente. En todos los casos existía una importante pérdida de sustancia con exposición ósea y/o tendinosa. La dermis artificial se colocó entre los días 7 y 10 de evolución, siguiendo el protocolo habitual, tras el desbridamiento quirúrgico de las lesiones. En los tres casos la evolución ha sido satisfactoria, sin complicaciones y con unos buenos resultados estéticos y funcionales. El uso de dermis artificial en el caso de heridas traumáticas, con una importante pérdida de sustancia y exposición ósea y/o tendinosa, debe considerarse como una alternativa a los injertos de piel parcial o total, a los expansores tisulares e incluso a las transferencias de tejidos. En este tipo de heridas recomendamos la aplicación diferida de la dermis artificial (AU)

In recent years, the use of artificial dermal matrix (Integra®) in children has increased, being its main indication skin reconstruction after burn or removal of congenital lesions. Its use in traumatic wounds in children is rare, with few references in the literature. Recently, we have used artificial dermal matrix in 3 patients of 7, 9 and 13 years of age that presented traumatic wounds in left lower limb, right lower limb and frontal region respectively. In all cases there were important tissue defects with exposed bone and/or tendon. The artificial dermal matrix was applied between the 7th and 10th day of evolution, following the usual protocol, after surgical debridement of the wounds. In all 3 cases the evolution has been satisfactory, without complications and with good aesthetic and functional results. The use of artificial dermal matrix (Integra®) in cases of traumatic wounds, with important tissue subsastances and exposed bone and/or tendon, must be considered as an alternative to split or full thickness skin grafting, skin expansion and even skin flaps. We recommend in these wounds the deferred application of artificial dermal matrix (AU)

Hiperhidrosis palmar en la infancia: simpaticolisis toracoscópica y encuesta de satisfacción / Palmar hyperhidrosis in childhood: thoracoscopic sympathectomy

Introducción. El sudor excesivo en las manos, conocido como hiperhidrosis palmar, es un problema que comienza en la infancia y que a los niños les ocasiona una afectación importante, debido al fuerte impacto negativo en su calidad de vida por el permanente rechazo por parte de sus compañeros de juego. Además, la permanente humedad delas palmas de las manos interfiere con sus actividades escolares, juegos y deportes de contacto. Material y Método. Presentamos la técnica quirúrgica, de realización fácil, simple, segura y que mejores resultados ha demostrado aportar: la simpaticolisis toracoscópica. Exponemos nuestra casuística de los últimos 5 años junto con una encuesta de satisfacción realizada a todos los pacientes. Resultados. Hemos tenido resultados excelentes en el 100% de (..) (AU)

Background. Excessive hand sweating, known as palmar hyperhidrosis, is a disabling disorder that starts during the childhood, and can have a strong negative impact on the quality of life of affected children, as they feel rejected by others due to their permanently damp hands, suffering during school activities, contact sports and daily games. Material and Methods. Thoracoscopic sympathicolysis is easy to perform and has proven to be safe, with a short operating time. A review was performed on 48 children who underwent surgical treatment of palmar hyperhidrosis and answered a follow-up questionnaire to evaluate their level of satisfaction. Results. Considering the final surgical results, the 48 patients were completely satisfied with the outcome of the operation. Significant complications or adverse effects were not detected. Conclusions. The primary palmar hyperhidrosis is a pathology that entails an important reduction in the quality of life of those who suffer it. With the results of this technique in hand, we recommend the endoscopic thoracic sympathicolysis procedure for the treatment of this pathology in paediatrics. The level of patient satisfaction was high (AU)

[Initial study of an experimental model for bladder augmentation]. / Estudio inicial de un modelo experimental para la ampliación vesical.

Since Coffey described in 1910 the Uretero-sigmoidostomy, the first auto-continent urinary derivation, many techniques have been developed and used for bladder augmentation, although none of them has been considered fully satisfactory. The availability of a product made of a bovine collagen and glycosaminoglycan base, used for regenerating dermis and oral mucosa induced us to start this study on rabbit bladder in order to verify if muscular fibers might grow in its interior. For that purpose we used 6 New Zealand rabbits, to which we implanted a fragment of artificial dermis inside the detrusor after dissecting it. We present our results after 3 and 6 weeks postoperatively.

Estudio inicial de un modelo experimental para la ampliación vesical / Initial study of an experimental model for bladder augmentation

Desde la descripción de Coffey en 1910 de la uretero-sigmoidostomía, primera derivación urinaria continente, se han utilizado multitud de técnicas para ampliar la vejiga, pero ninguna plenamente satisfactoria. La aparición de un producto compuesto por una matriz de colágeno bovino y glicosaminoglicano, utilizado en regeneración de dermis y mucosa oral, nos indujo a realizar este estudio sobre vejiga de conejo con el fin de comprobar si podrían crecer fibras musculares en su interior. Para ello utilizamos 6 conejos New Zealand, a los que tras dislacerar una porción de detrusor les implantamos un fragmento de dermis artificial. Posteriormente, se realizó estudio anatomopatológico a las tres yseis semanas, con los resultados que posteriormente se detallan (AU)

Since Coffey described in 1910 the Uretero-sigmoidostomy, the first auto-continent urinary derivation, many techniques have been developed and used for bladder augmentation, although none of them has been considered fully satisfactory. The availability of a product made of a bovine collagen and glycosaminoglycan base, used for regenerating dermis and oral mucosa induced us to start this study on rabbit bladder in order to verify if muscular fibers might grow in its interior. For that purpose we used 6 New Zealand rabbits, to which we implanted a fragment of artificial dermis inside the detrusor after dissecting it. We present our results after 3 and 6 weeks postoperatively (AU)

[Palmar hyperhidrosis in childhood: thoracoscopic sympathectomy]. / Hiperhidrosis palmar en la infancia: simpaticolisis toracoscópica y encuesta de satisfacción.

BACKGROUND: Excessive hand sweating, known as palmar hyperhidrosis, is a disabling disorder that starts during the childhood, and can have a strong negative impact on the quality of life of affected children, as they feel rejected by others due to their permanently damp hands, suffering during school activities, contact sports and daily games. MATERIAL AND METHODS: Thoracoscopic sympathicolysis is easy to perform and has proven to be safe, with a short operating time. A review was performed on 48 children who underwent surgical treatment of palmar hyperhidrosis and answered a follow-up questionnaire to evaluate their level of satisfaction. RESULTS: Considering the final surgical results, the 48 patients were completely satisfied with the outcome of the operation. Significant complications or adverse effects were not detected. CONCLUSIONS: The primary palmar hyperhidrosis is a pathology that entails an important reduction in the quality of life of those who suffer it. With the results of this technique in hand, we recommend the endoscopic thoracic sympathicolysis procedure for the treatment of this pathology in paediatrics. The level of patient satisfaction was high.

Nuestra experiencia con el hidro-desbridamiento en lesiones cutáneas variadas. Adelanto técnico e innovador en cirugía pediátrica / Our experience with hydro-debridement in varied skin lesions. Technical and innovating advance in pediatric surgery

Presentamos nuestra experiencia en el uso de la hidro-dermoabrasión con desbridamiento de tejidos necróticos en lesiones cutáneas en niños. El sistema de hidrocirugía funciona mediante un chorro de suerosalino estéril con presión elevada y aspiración simultanea controlable según las condiciones de la lesión. Hemos utilizado este sistema en 15 pacientes con patología diversa (quemaduras, heridas graves traumáticas y necrosis cutánea), logrando su resolución en más corto período de tiempo. Este método constituye una herramienta innovadora en el manejo de los pacientes con lesiones cutáneas agudas y crónicas que requieren curas periódicas Presentamos nuestra experiencia en el uso de la hidro-dermoabrasión con desbridamiento de tejidos necróticos en lesiones cutáneas en niños. El sistema de hidrocirugía funciona mediante un chorro de suero salino estéril con presión elevada y aspiración simultanea controlable según las condiciones de la lesión. Hemos utilizado este sistema en 15 pacientes con patología diversa (quemaduras, heridas graves traumáticas y necrosis cutánea), logrando su resolución en más corto período de tiempo. Este método constituye una herramienta innovadora en el manejo de los pacientes con lesiones cutáneas agudas y crónicas que requieren curas periódicas (AU)

We present our experience in the use of Hydrosurgery with debridement of necrotic tissues from skin wounds in children. The Hydrosurgery system uses a high velocity stream of sterile saline solution, which can be controlled according to the state of thelesion. We have used this system in 15 patients suffering from a wide range of pathologies (burns, severe traumatic wounds, skin necrosis etc),achieving its complete resolution in shorter period of time. This method is an innovative technique in the management of patients with acute o r chronic skin lesions that require periodic procedure (AU)

[Our experience with hydro-debridement in varied skin lesions. Technical and innovating advance in pediatric surgery]. / Nuestra experiencia con el hidro-desbridamiento en lesiones cutáneas variadas. Adelanto técnico e innovador en cirugía pediátrica.

We present our experience in the use of Hydrosurgery with debridement of necrotic tissues from skin wounds in children. The Hydrosurgery system uses a high velocity stream of sterile saline solution, which can be controlled according to the state of the lesion. We have used this system in 15 patients suffering from a wide range of pathologies (burns, severe traumatic wounds, skin necrosis etc), achieving its complete resolution in shorter period of time. This method is an innovative technique in the management of patients with acute o r chronic skin lesions that require periodic procedures.

[Prospective study comparing the incidence of wound infection following appendectomy for acute appendicitis in children: conventional treatment versus using reabsorbable antibacterial suture or gentamicin-impregnated collagen fleeces]. / Estudio comparativo de la incidencia de abscesos de pared abdominal en niños intervenidos quirúrgicamente por apendicitis aguda: tratamiento convencional vs con suturas recubiertas de antiséptico o con apósitos impregnados de antibiótico.

Postappendectomy wound infection is frequent in the pediatric age. It causes them important discomfort. We have conducted a prospective clinical study to evaluate this incidence under different surgical management. The subjects were children undergoing appendectomy for acute appendicitis. The patients belonging to the Control Group were operated, by standard surgical technique, along the first 9 months of the study period (n: 58). The Study Group was constituted by 101 children operated during the 9 consecutives months, identical on the basis of demographics and operations undergone, except for the use of, in an alleatory manner, sutures with antiseptic impregnation (Vicryl Plus, Ethicon Johnson & Johnson Medical), to close the incisi6n in children included in Study Sub-Group A, or gentamycin-containing collagen sponge (Collatamp EG, Aculia Fombona, S.A.; Schering-Plough, S.A.), placed within the muscles before wound closure, in the children belonging to the Study Sub-Group B. We have analyzed in the two Groups the incidence of postoperative wound infection and the mean Hospital stay. The use of sutures with antiseptic impregnation and/or gentamycin-containing collagen sponge, significantly reduced the wound infection rates in the children operated on for appendicectomy included in the Study Group, compared with the ones in the Control Group, therefore contributing to decrease the Hospital length of stay.

Estudio comparativo de la incidencia de abscesos de pared abdominal en niños intervenidos quirúrgicamente por apendicitis aguda: tratamiento convencional vs con suturas recubiertas de antiséptico o con apósitos impregnados de antibiótico / Prospective study comparing the incidence of wound infection following appendectomy for acute appendicitis in children: conventional treatment versus using reabsorbable antibacterial suture or gentamicin impregnated collagen fleeces

La infección de la herida, tras la apendicectomía en la infancia, esun problema frecuente y que produce trastornos muy molestos. Revisamos prospectivamente a los niños operados por apendicitis aguda, con técnicas quirúrgicas convencionales, durante un período consecutivo de 9 meses (Grupo Control: 58 pacientes), y a los niños intervenidos durante los 9 meses siguientes, bajo las mismas circunstancias quirúrgicas excepto utilizar, de manera aleatoria, sutura recubierta de antiséptico (Vicryl Plus®, Ethicon Johnson & Johnson Medical), para el cierre de la pared abdominal en un Subgrupo o esponja de colágeno impregnada en gentamicina (Collatamp EG®, Acuña Fombona, S.A.;Schering-Plough, S.A.), introducida entre la musculatura de la incisión, en el otro Subgrupo (Grupo Estudio: 101 pacientes).Estudiamos en los dos grupos, fundamentalmente, la incidencia de abscesos de pared y la estancia media hospitalaria. La introducción de suturas recubiertas de antiséptico y/o esponja de colágeno impregnada en gentamicina, en el cierre de la herida quirúrgica postapendicectomía, ha contribuido a reducir de manera estadísticamente significativa la incidencia de abscesos de pared y de la estancia media hospitalaria de los niños incluidos en el Grupo Estudio, con respecto a los pertenecientes al Grupo Control (AU)

Postappendectomy wound infection is frequent in the pediatric age. It causes them important discomfort. We have conducted a prospective clinical study to evaluate this incidence under different surgical management. The subjects were children undergoing appendectomy for acute appendicitis. The patients belonging to the Control Group were operated, by standard surgical technique, along the first 9 months of the study period (n: 58).The Study Group was constituted by 101 children operated during the 9 consecutive months, identical on the basis of demographics and operations undergone, except for the use of, in an aleatory manner, sutures with antiseptic impregnation (Vicryl Plus®, Ethicon Johnson& Johnson Medical), to close the incision in children included in Study Sub-Group A, or gentamycin-containing collagen sponge (CollatampEG®, Acuña Fombona, S.A.; Schering-Plough, S.A.), placed within the muscles before wound closure,. In the children belonging to the Study Sub-Group B. We have analyzed in the two Groups the incidence of postoperative wound infection and the mean Hospital stay. The use of sutures with antiseptic impregnation and/or gentamycin containing collagen sponge, significantly reduced the wound infection rates in the children operated on for appendectomy included in the Study Group, compared with the ones in the Control Group, therefore contributing to decrease the Hospital length of stay (AU)