Removal of 142Pr from nuclear purity water using hydroxyapatite.

The adsorption of praseodymium using hydroxyapatite was evaluated. The hydroxyapatite (HAP) was characterized by X-ray diffraction (JCPDS 01-04-3708), scanning electron microscopy, BET specific surface area (54.2 m2/g), and point of zero charge (6.5). Adsorption kinetics and isotherms were evaluated at pH of 3 and 142Pr was determined using a gamma spectrometer. The adsorption of praseodymium was fast (1 min of contact) with an adsorption capacity of 1.68 mg/g and the data were best adjusted to the pseudo-second-order model, whereas the data of adsorption isotherm were best adjusted to the Langmuir model with a maximum adsorption capacity of 39.16 ± 0.20 mg/g. The thermodynamic parameters indicated that a physicochemical mechanism took place in the adsorption of praseodymium by HAP (adsorption enthalpy = 31.65 kJ/mol), the randomness of the system increased (adsorption entropy = 0.16 kJ/mol), and according with Gibbs free energy, the adsorption process was spontaneous at high temperature. The praseodymium in the hydroxyapatite is stable, it could not be desorbed using different solutions (ammonium sulfate, calcium chloride, sodium chloride, hydrochloric acid, and sodium hydroxide).

[Pediatric knee arthroscopy. Three-year experience at a high specialty hospital in Mexico]. / Artroscopía de rodilla pediátrica. Tres años de experiencia en un Hospital especializado en México.

INTRODUCTION: Diagnosis and management of congenital and traumatic articular ailments carry an additional problem in young people. Arthroscopy has improved treatment of these injuries, which are more frequent. OBJECTIVE: To describe the experience of arthroscopic handling in pediatric patients affected with knee disease, managed at a third level hospital in Puebla, Mexico. MATERIAL AND METHODS: Descriptive, retrospective, cross sectional study performed in patients having knee disease, admitted at Unidad Médica de Alta Especialidad Hospital de Traumatología y Ortopedia Puebla, from March first, 2015 to February 28th, 2018. Lysholm and IKDC functional scales and Tegner functional satisfaction scale were applied at zero, six and twelve months. Student's t and Wilcoxon tests were used. RESULTS: 29 young ones of five to 17 years of age became recruited, slightly more women (62.06%). The most frequently affected limb was the left one, with 55.17%. The disorders found are: discoid meniscus, harm of the anterior cruciate ligament, idiopathic inflammatory synovitis, tumor, meniscal injury, chondral damage, patellar hyperlaxity. Lysholm and IKDC registered improvement from the first semester. Tegner registered their ability to go back to previous daily occupations. On the Lysholm scale, there was improvement at six months. On the Tegner scale there was complete incorporation to their activities (previous to the presentation and surgical intervention). At six months subsequent to treatment, the IKDC evidenced improvement and recovery, and reintegration to their activities. Statistically significant differences (p 0.01) resulted, in measurements at zero, six and 12 months. CONCLUSIONS: Congenital and traumatic illnesses were found, the latter ones sports related. Arthroscopic approach registered positive functional results in these children.

INTRODUCCIÓN: El diagnóstico y manejo de numerosos trastornos articulares congénitos y traumáticos revisten un problema adicional en la población joven. La artroscopía ha mejorado el tratamiento de estas lesiones cada vez más frecuentes. OBJETIVO: Describir la experiencia de la aproximación artroscópica en enfermos pediátricos quienes presentan patología de rodilla, admitidos en un tercer nivel de atención en Puebla, México. MATERIAL Y MÉTODOS: Estudio descriptivo, retrospectivo, transversal, realizado en pacientes niños con problemas de rodilla, atendidos por artroscopía, del primero de Marzo 2015 al 28 de Febrero 2018. Se les aplicaron las escalas funcionales de Lysholm e IKDC y de satisfacción funcional de Tegner al momento de la lesión, a los seis y a los doce meses. Se utilizó t de Student y Wilcoxon. RESULTADOS: Se reclutaron 29 jóvenes de cinco a 17 años de edad con mayor porcentaje de mujeres (62.06 %). El miembro más afectado fue el izquierdo con 55.17%. Las patologías fueron: menisco discoide, traumatismo de ligamento cruzado anterior, sinovitis inflamatoria idiopática, tumoración, lesión meniscal, daño condral, hiperlaxitud rotuliana. En dichas escalas Lysholm e IKDC se halló mejoría desde el primer semestre. En la escala Tegner hubo incorporación completa a sus actividades previas al padecimiento. Se encontraron diferencias estadísticamente significativas (p 0.01) en las comparaciones de sus funciones a los cero, seis y doce meses de evolución. CONCLUSIONES: Se encontraron daños de frecuencia congénita y traumática, éstas relacionadas al deporte; a través del tratamiento artroscópico hubo resultados funcionales favorables en esa población pediátrica.

Radioactive waste treatments by using zeolites. A short review.

Radionuclides in the environment is an important issue, many techniques have been developed for the removal of radionuclides from the environment. One of those techniques is the adsorption and natural and synthesized materials have been used to remove different radionuclides from water. The adsorbents used for removal of radionuclides should have high retention capacity and they should be resistant to radiation. One of the natural materials used is the zeolites due to its high ion exchange capacities, adsorption efficiency, resistance to radiation and abundance. The present review describes the advances made on radioactive waste treatments using zeolites as adsorbents, the elements: cesium, strontium, cobalt, molybdenum, uranium, plutonium, americium, samarium, and europium were selected according to their nuclear importance and their presence in the environment. Firstly, a brief description of the zeolites is given and then a review on the separation of these radionuclides from water by using zeolites is presented.

[Analysis to determine optimal age for surgical management of equinus foot in patients with childhood cerebral palsy]. / Análisis para determinar la edad óptima para el manejo quirúrgico del pie equino en pacientes con parálisis cerebral infantil.

INTRODUCTION: Childhood cerebral palsy, a non-progressive brain injury, occurs before, during or after delivery, with variable neurological damage from mild to disabling. The deformity in equine is treated conservatively at an early age, but when is surgical management indicated? OBJECTIVE: Our goal was to determine the optimal age for surgical management of the equine foot in CCP patients. MATERIAL AND METHODS: Retrospective study, in patients diagnosed with CCP (all types), treated surgically with open or percutaneous Achilles tendon elongation, assessed with external consultation notes, in patients aged 1-16 years, and average follow-up of 6 years, evaluating progress with relapse of deformity and gait with plantigrade support. RESULTS: 55 patients, 74 equinus feet (29 in girls, 45 in boys) were analyzed with surgical treatment. Those treated before six years old presented relapses, with vulnerable period in 4-6 years. Monoplegia presented 100% relapses, and triplegia presented 0%. Open surgery presented 50% recurrence and percutaneous technique only 19%. CONCLUSION: In our institution, the optimal age is suggested in 6-12 years. Percutaneous technique over the open, should be preferred, and greater attention should be paid to monitoring monoplexy.

INTRODUCCIÓN: La parálisis cerebral infantil es una lesión cerebral no progresiva que ocurre antes, durante o después del parto y provoca daño neurológico variable que oscila de leve hasta discapacitante. La deformidad en el pie equino se trata conservadoramente en edades tempranas, pero ¿cuándo está indicado el manejo quirúrgico? OBJETIVO: Determinar la edad óptima para el manejo quirúrgico del pie equino en pacientes con PCI. MATERIAL Y MÉTODOS: Estudio retrospectivo realizado en pacientes con diagnóstico de PCI (todos los tipos), tratados quirúrgicamente con alargamiento del tendón de Aquiles abierto o percutáneo y valorados con notas de la consulta externa; los pacientes tuvieron de 1-16 años y un seguimiento promedio de seis años, valorándose la marcha con recidiva de deformidad y la marcha plantígrada. RESULTADOS: Se analizaron 55 pacientes, 74 con pie equino (29 niñas y 45 niños); de éstos, presentaron más recidivas los operados antes de los seis años de edad, con un período vulnerable entre los cuatro y seis años. La monoplejía registró 100% de recidivas, mientras que la triplejía 0%. La cirugía abierta se asoció con recurrencia en 50% y la cirugía percutánea sólo en 19%. CONCLUSIONES: En nuestra institución, se sugiere que la edad óptima de la cirugía esté entre los 6-12 años. Es preferible la técnica percutánea sobre la abierta, debiendo poner mayor atención en el seguimiento de la monoplejía.

Análisis para determinar la edad óptima para el manejo quirúrgico del pie equino en pacientes con parálisis cerebral infantil / Analysis to determine optimal age for surgical management of equinus foot in patients with childhood cerebral palsy

Resumen: Introducción: La parálisis cerebral infantil es una lesión cerebral no progresiva que ocurre antes, durante o después del parto y provoca daño neurológico variable que oscila de leve hasta discapacitante. La deformidad en el pie equino se trata conservadoramente en edades tempranas, pero ¿cuándo está indicado el manejo quirúrgico? Objetivo: Determinar la edad óptima para el manejo quirúrgico del pie equino en pacientes con PCI. Material y métodos: Estudio retrospectivo realizado en pacientes con diagnóstico de PCI (todos los tipos), tratados quirúrgicamente con alargamiento del tendón de Aquiles abierto o percutáneo y valorados con notas de la consulta externa; los pacientes tuvieron de 1-16 años y un seguimiento promedio de seis años, valorándose la marcha con recidiva de deformidad y la marcha plantígrada. Resultados: Se analizaron 55 pacientes, 74 con pie equino (29 niñas y 45 niños); de éstos, presentaron más recidivas los operados antes de los seis años de edad, con un período vulnerable entre los cuatro y seis años. La monoplejía registró 100% de recidivas, mientras que la triplejía 0%. La cirugía abierta se asoció con recurrencia en 50% y la cirugía percutánea sólo en 19%. Conclusiones: En nuestra institución, se sugiere que la edad óptima de la cirugía esté entre los 6-12 años. Es preferible la técnica percutánea sobre la abierta, debiendo poner mayor atención en el seguimiento de la monoplejía.

Abstract: Introduction: Childhood cerebral palsy, a non-progressive brain injury, occurs before, during or after delivery, with variable neurological damage from mild to disabling. The deformity in equine is treated conservatively at an early age, but when is surgical management indicated? Objective: Our goal was to determine the optimal age for surgical management of the equine foot in CCP patients. Material and methods: Retrospective study, in patients diagnosed with CCP (all types), treated surgically with open or percutaneous Achilles tendon elongation, assessed with external consultation notes, in patients aged 1-16 years, and average follow-up of 6 years, evaluating progress with relapse of deformity and gait with plantigrade support. Results: 55 patients, 74 equinus feet (29 in girls, 45 in boys) were analyzed with surgical treatment. Those treated before six years old presented relapses, with vulnerable period in 4-6 years. Monoplegia presented 100% relapses, and triplegia presented 0%. Open surgery presented 50% recurrence and percutaneous technique only 19%. Conclusion: In our institution, the optimal age is suggested in 6-12 years. Percutaneous technique over the open, should be preferred, and greater attention should be paid to monitoring monoplexy.

Sorption behavior of fluoride ions from aqueous solutions by hydroxyapatite.

The effects of pH, contact time, fluoride-ion concentration, and the dose of sorbent on the sorption of fluoride ions by hydroxyapatite were studied. Equilibrium was reached in 16 h of contact time and the maximum sorption of fluoride ions was in the pH(eq) range between 5 and 7.3. The highest efficiency in the sorption system was determined by using 0.01 g of hydroxyapatite and 25 mL of solution. The pseudo-second order model described the kinetic sorption processes, and the Freundlich model, the sorption isotherm process. These results indicated that the mechanism was chemisorption on a heterogeneous material. Fluoride ions were partially desorbed using an alkaline solution.

Determination of formation constants of hydroxo and carbonate complexes of Pr(3+) in 2 M NaCl at 303 K.

The hydrolysis of praseodymium III in 2 M sodium chloride at 303 K was studied. Two methods were used: pH titration followed by a computational refinement and solvent extraction in the presence of a competitive ligand. The hydrolysis constants obtained by pH titration were: logbeta(1,H)=-7.68+/-0.07, logbeta(1,2H)=-15.10+/-0.03, and beta(1,3H)=-23.80+/-0.04. The stability constants of praseodymium carbonate complexes were determined by pH titration as well and were: logbeta(1,CO(2-)(3))=5.94+/-0.08 and logbeta(1,2CO(2-)(3))=11.15+/-0.15. Praseodymium carbonate species were taken into consideration for calculating the first hydrolysis constants by the solvent extraction method and the value obtained was: logbeta(1,H)=-7.69+/-0.27. The values for logbeta(1,H) attained by both methods are the same. The species-distribution diagram was obtained from the stability constants of praseodymium carbonate complexes and hydrolysis products in the conditions of the present work.

Sodium and chlorine concentrations in mixed saliva of healthy and cystic fibrosis children.

Sodium and chlorine concentrations in mixed saliva were simultaneously measured by neutron activation analysis in nine normal children and in nine patients with cystic fibrosis. Sodium levels showed a significant difference (P < 0.01) between patients and control. The concentration of chlorine was similar in both the control and the cystic fibrosis groups.

Selenium levels in the serum of workers at a rubber tire repair shop.

Selenium analysis by neutron activation was performed on serum samples taken from 20 workers at a rubber tire repair shop and from a control group of 18 healthy persons. The mean values were: 148 +/- 56 (70-296) and 100 +/- 18 (70-127) micrograms/L for the tire workers and the control groups, respectively. The difference between mean values was significant (p < 0.01). A high correlation (r = 0.82) was obtained between selenium level and seniority for those values higher than the control group range. None of the shop workers showed evidence of selenosis.

Rotavirus. I. Hemagglutination and complement fixation inhibitor antibodies in individuals of Mexico city.

Hemagglutination inhibiting antibodies were studied in 1,278 sera of individuals of different ages in Mexico City representative of four different socioeconomic levels. It was found that 1,261 (98.7 per cent) had antibodies against the Nebraska strain (calf rotavirus). An unusual finding was that more than 95 per cent of children from one to four years of age, had antibodies. For this reason five year old children were studied utilizing two viral strains as antigens in hemagglutination inhibition tests. It was found that in 918 sera, 821 (89.4 per cent) had antibodies against SA-11 samples (monkey rotavirus); percentage increased from 87.2 per cent in neonates to 97.5 percent in children from four to five years of age. A similar phenomenon was observed when Nebraska strain hemagglutinin was utilized. Also complement fixation antibodies against SA-11 strain in 583 sera were studied finding that 260 (44.6 per cent) had antibodies. Utilization of this technique showed that seropositivity percentage decreased from 47.6 per cent in the neonate group to 14.5 per cent in the one ot three month old children increasing progressively until reaching 65.1 per cent in children three to four years of age. These results show that rotavirus infection takes place at early ages, as has been confirmed by other authors that have used electron microscopy techniques, RNA electrophoresis, etc., regardless of the presence of transplacental antibodies.