Determinación de la calidad de imágenes clínicas de proyecciones postero anterior y lateral de tórax / Determination of clinical image quality of posteroanterior and lateral chest images

RESUMEN Los estudios radiológicos son fundamentales en el diagnóstico y tratamiento de diversas patologías. Su calidad depende de múltiples variables, entre las que destacan, los parámetros de adquisición, interpretación, entre otros. Se propone una metodología estandarizada, sencilla, de fácil interpretación, permitiendo la evaluación regular de la calidad de las imágenes, dando indicios de la propiedad del trabajo en el centro de salud y poder realizar comparaciones entre centros y autores, a partir de los criterios anatómicos establecidos por la Unión Europea, definiendo el parámetro de calidad de la imagen (CI), representadas en una escala de Likert para el análisis de frecuencia, demostrando que puede ser una herramienta de utilidad para la evaluación reiterada de los centros de radiología. Evaluando 140 proyecciones postero anterior y 85 laterales de tórax, con una muestra de 225 estudios, realizados en un centro de salud, ubicado en la ciudad de Mérida, República Bolivariana de Venezuela, escogiendo estas proyecciones, ya que, representan el 32% de los estudios de radiología convencional. Permitiendo la comparación entre proyecciones y autores, obteniéndose para la proyección postero anterior un CI de 5,07 ± 1,53 criterios de los ocho establecidos, normalizado un CI de 0,62 ± 0,19; las imágenes excelentes solo representan el 22,78%. Comparado con un CI de 4,91 ± 1,17 criterios de los seis establecidos, normalizado un CI de 0,82 ± 0,19, e imágenes excelentes en un 64,71% para la proyección lateral. Se observa las notorias diferencias entre la calidad de las imágenes clínicas en hombres y mujeres para ambas proyecciones

ABSTRACT Radiological studies are essential in the diagnosis and treatment of various pathologies. Their quality depends on multiple variables, among which the acquisition and interpretation parameters, among others, stand out. A standardized methodology is proposed, simple, of easy interpretation, allowing the regular evaluation of the quality of the images, giving indications of the property of the work in the health center and being able to make comparisons between centers and authors, from the anatomical criteria established by the European Union, defining the parameter of image quality (IQ), represented on a Likert scale for frequency analysis, demonstrating that it can be a useful tool for the repeated evaluation of radiology centers. Evaluating 140 postero anterior and 85 lateral projections of the thorax, with a sample of 225 studies, performed in a health center, located in the city of Merida, Bolivarian Republic of Venezuela, taking these projections, since they represent 32% of the conventional radiology studies. Allowing the comparison between projections and authors, obtaining for the postero anterior projection an IQ of 5.07 ± 1.53 criteria of the eight established, normalized an IQ of 0.62 ± 0.19; the excellent images only represent 22.78%. Compared with an IQ of 4.91 ± 1.17 criteria of the six established, normalized IQ of 0.82 ± 0.19, and excellent images in 64.71% for the lateral projection. It is observed the notorious differences between the quality of clinical images in men and women for both projections

The Role of the Otolaryngologist in Early Recognition of Patients With ALS: A Case Report.

This case report aims to raise awareness of the possibility of amyotrophic lateral sclerosis (ALS) diagnosis in patients presenting to the Otolaryngology Department. We describe the case of a 66-year-old woman with hoarseness who was evaluated by several physicians and was referred to an ALS specialist only a year after symptom onset. Our case highlights the importance of considering motor neuron etiologies in patients with voice complaints. Early identification and referral to a specialist are critical for accurate diagnosis and prognosis and may be the key to slowing the disease's progression.

The presence of Wormian bones increases the fracture resistance of equine cranial bone.

Wormian (intrasutural) bones are small, irregular bones, that are found in the cranial sutures of the skull. The occurrence of Wormian bones in human skulls has been well documented but few studies have detected the presence of such bones in domestic animals. Although some research has linked the presence of Wormian bones to bone pathology, its anatomical significance in healthy individuals is not known. To the best of our knowledge, no previous study has examined the biomechanical features of Wormian bone. This study uses microCT imaging of the parietal bone region to determine the frequency of occurrence of Wormian bones in horse skulls and, through 3-point bending tests, to calculate the mechanical differences that result from the presence of such bones. In addition, bone properties such as bone mineral density (BMD) and stiffness were measured and analysed to determine the influence of Wormian bone. Our findings on 54 specimens taken from 10 horses (ages ranging from 4 to 29 years) showed that Wormian bone was present in 70% of subjects and that its occurrence was unrelated to age or sex. 3-point bend tests revealed that the stiffness normalised by cross section area (P = 0.038) was lower in samples where Wormian bone was present. An idealised Finite Element simulation confirmed that the presence of Wormian bone reduced the maximum stress and strain, as well as their distribution throughout the sample. We consequently conclude that the presence of Wormian bones, which are confined to the calvaria, increase the compliance of the bone and reduce the likelihood of skull fracture. As all skull samples were collected from a local abattoir, ethical approval was not required for this work.

Frailty and Risk of Falls in Community-Dwelling Older Adults Living in a Rural Setting. The Atahualpa Project.

BACKGROUND: Data supporting a link between frailty and risk of falls is mostly confined to individuals living in urban centers, where risk factors and lifestyles are different from that of rural settings. OBJECTIVE: To assess the association between frailty and risk of falls in older adults living in rural Ecuador. DESIGN: Population-based cross-sectional study. PARTICIPANTS: Community-dwellers aged ≥60 years living in a rural Ecuadorian village, in whom frail status and risk of falls were assessed. MEASUREMENTS: Frailty was evaluated by the Edmonton Frailty Scale (EFS) and risk of falls by the Downton Fall Risk Index (DFRI). Multivariate models were fitted to evaluate whether frailty was associated with risk of falls (dependent variable), after adjusting for demographics, alcohol intake, cardiovascular risk factors, sleep quality, symptoms of depression, and history of an overt stroke. Correlation coefficients were constructed to assess confounders modifying this association. RESULTS: A total of 324 participants (mean age: 70.5±8 years) were included. The mean EFS score was 4.4±2.5 points, with 180 (56%) participants classified as robust, 76 (23%) as pre-frail and 68 (21%) as frail. The DFRI was positive in 87 (27%) participants. In univariate analysis, the EFS score was higher among participants with a positive DFRI (p<0.001). The number of frail individuals was higher (p<0.001), while that of robust individuals was lower (p<0.001) among those with a positive DFRI. Adjusted logistic regression models showed no association between frailty and the DFRI. Correlation coefficients showed that age, high glucose levels, and history of an overt stroke tempered the association between frailty and the risk of falls found in univariate analyses. CONCLUSIONS: Frailty is not independently associated with risk of falls in older adults living in a remote rural setting. Further studies are needed to assess the impact of frailty on the risk of falls in these populations.

Calcium intake improvement after nutritional intervention in paediatric patients with osteogenesis imperfecta.

BACKGROUND: In several bone disorders, adequate calcium intake is a coadjuvant intervention to regular treatment. Osteogenesis imperfecta (OI) is a collagen disorder with a range of symptoms, ranging from fractures to minimum trauma, and it is typically treated with bisphosphonates. In the present study, we evaluate the impact of a nutritional intervention (NI) on dietary calcium intake and bone mineral density (BMD) in paediatric patients with OI. METHODS: A nonrandomised clinical trial was designed with a NI. Dietary calcium intake, anthropometry and clinical features were assessed at baseline, including anthropometry, basal metabolic rate (BMR), BMD. In addition, a food guidance form was developed and sent to patients by mail. After 12 months, clinical features of patients were reassessed and compared with the baseline data. RESULTS: Fifty-two children and adolescents were enrolled. Significant increases in total calcium intake (mg day-1 ), percentage of adequate calcium intake (%) and number of cups of milk ingested were observed after NI. We detected a positive correlation between the variation of BMD and milk consumption in patients treated with bisphosphonate. CONCLUSIONS: We observed an increase in calcium intake in patients with OI. This finding demonstrates the importance of nutrition therapy as part of a multidisciplinary treatment approach for bone health.

Estimación de la huella hídrica asociada al proceso de beneficio bovino de la cadena cárnica en los frigoríficos Vijagual y Jongovito (Colombia) / Estimation of the water footprint associated with the bovine benefit process of the network of meat in the Vijagual and Jongovito meat plant (Colombia)

RESUMEN La huella hídrica es un indicador de la apropiación de los recursos de agua dulce y aporta una valiosa información sobre el impacto ambiental que ocasiona un bien o servicio. Por ello, es interesante conocer el consumo de agua y los niveles de contaminación detrás de todo proceso productivo. El objetivo de este estudio fue dar una primera aproximación a la estimación de la huella hídrica en el proceso de beneficio bovino en el Frigorífico Vijagual S.A.S. de la ciudad de Bucaramanga y en el Frigorífico Jongovito S.A de la ciudad de San Juan de Pasto. Para el cálculo de la huella hídrica azul se hizo necesario conocer el volumen de agua empleada en el proceso y el del agua que retorna a la fuente hídrica después de su tratamiento. Para el cálculo de la huella hídrica gris se tomó como indicador la carga contaminante de materia orgánica expresada en DQO, por ser el parámetro de mayor concentración. La huella hídrica verde no se determinó por no tratarse de un proceso agroforestal. Para el Frigorífico Vijagual se obtuvo como resultado una huella hídrica total de 2.583l/res, mientras que para el Frigorífico Jongovito se obtuvo una huella hídrica de 1.358 l/res. Si bien es cierto estos valores son inferiores a datos nacionales e internacionales, en términos de sostenibilidad es muy importante disminuir el consumo de agua, mejorar cada vez más los sistemas de tratamiento y realizar un esfuerzo en concienciar respecto al uso responsable del agua a sus operarios, en beneficio de las generaciones presentes y futuras.

ABSTRACT The water footprint is an indicator of the appropriation of freshwater resources that contributes a valuable information on the environmental impact caused by a good and/or service. Therefore, it is interesting to know the water consumption and the pollution behind all productive processes. The objective of this study was to give a first approximation to the accounting of the water footprint in the process of bovine benefit in the Vijagual S.A.S. meat procesing plant in Bucaramanga city and the Jongovito S.A. meat plant in San Juan de Pasto City. To calculate the blue water footprint it was necessary to know the volume of water used in the process and the water that returns to the water source after its treatment. For the calculation of the gray water footprint, the pollutant load of organic matter expressed in DQO was taken as indicator, since it is the parameter with the highest concentration. The green water footprint was not determined because it was not an agroforestry process. As a result, the Vijagual meat plant the water footprint is 2.583 l/bovine, while the Jongovito meat plant the water footprint of 1.358 l/bovine was obteined. Altough it is true that these values are lower than national and international data, in terms of sustainability, it is very important to reduce water consumption, improve treatment systems more and more, and make an effort to raise awareness about the responsible use of water by its operators, for the benefit of present and future generations.

Pyrogallol Induces Apoptosis in Human Platelets.

Pyrogallol is a polyphenol that generates the superoxide anion. In this study, we investigated the influence of pyrogallol on human platelets. Our data showed that exposure of platelets to pyrogallol induced numerous manifestations of apoptosis including depolarization of mitochondrial inner membrane and release of cytochrome c from the mitochondria. Pyrogallol also induced downstream extra-mitochondrial apoptotic responses, including activation of caspase-3 and phosphatidylserine exposure on the outer leaflet of the plasma membrane. Addition of glutathione significantly rescued cells from pyrogallol- induced apoptosis, as evidenced by a decrease of all markers of apoptosis. Thus, pyrogallol appears to produce depletion of intracellular glutathione content in platelets, the main non-protein antioxidant in the cells. Furthermore, inhibition of γ-glutamyl transpeptidase, an enzyme that plays the main role in the cellular supply of glutathione, reverted the glutathione (GSH) protection over platelet apoptosis. Our results indicate that pyrogallol induces apoptosis by suppressing the natural anti-oxidation in human platelets.

Prácticas de Salud Ocupacional y niveles de biomarcadores séricos en aplicadores de plaguicidas de cultivos de arroz en Natagaima-Tolima, Colombia / Occupational health practice and levels of serum biomarkers in pesticide applicators rice crops in Natagaima-Tolima, Colombia

Los pequeños agricultores de arroz del sector informal en Colombia son una población vulnerable a la intoxicación aguda y crónica por plaguicidas, especialmente porque no han sido incluidos en programas nacionales de capacitación, vigilancia y control de intoxicaciones. El objetivo de este estudio fue identificar mediante una encuesta el estado de cumplimiento de las prácticas de salud ocupacional y disposición adecuada de residuos de plaguicidas en un grupo de agricultores del municipio de Natagaima en Colombia y evaluar el nivel de biomarcadores séricos de efecto por exposición a plaguicidas en esta población. Los resultados muestran un panorama en donde prevalece una aparente percepción del riesgo por el uso de plaguicidas, pero hay una gran carencia de prácticas de salud ocupacional en la población que los manipula. El análisis de los biomarcadores séricos permitió detectar un aumento significativo en los niveles de aspartato amino transferasa, creatinina y ácido úrico y descenso de los niveles de colinesterasa sérica demostrando posibles alteraciones subclínicas de la función renal y hepática en la población estudiada (AU)

Small farmers in rice informal sector in Colombia are vulnerable to acute and chronic pesticide poisoning population, especially because they have not been included in national training programs, monitoring and poison control. The aim of this study was to identify through a survey of the state of compliance with occupational health practices and proper disposal of pesticide residues in a group of farmers in the municipality of Natagaima in Colombia and assess the level of serum biomarkers of effect exposure pesticides in this population. The results show a scenario in which prevails an apparent perception of risk by the use of pesticides, but there is a lack of practical occupational health in the population that manipulates

Root and shoot transcriptome analysis of two ecotypes of Noccaea caerulescens uncovers the role of NcNramp1 in Cd hyperaccumulation.

The Zn/Cd hyperaccumulator, Noccaea caerulescens, has been studied extensively for its ability to accumulate high levels of Zn and Cd in its leaves. Previous studies have indicated that the Zn and Cd hyperaccumulation trait exhibited by this species involves different transport and tolerance mechanisms. It has also been well documented that certain ecotypes of N. caerulescens are much better Cd hyperaccumulators than others. However, there does not seem to be much ecotypic variation for Zn hyperaccumulation in N. caerulescens. In this study we employed a comparative transcriptomics approach to look at root and shoot gene expression in Ganges and Prayon plants in response to Cd stress to identify transporter genes that were more highly expressed in either the roots or shoots of the superior Cd accumulator, Ganges. Comparison of the transcriptomes from the two ecotypes of Noccaea caerulescens identified a number of genes that encoded metal transporters that were more highly expressed in the Ganges ecotype in response to Cd stress. Characterization of one of these transporters, NcNramp1, showed that it is involved in the influx of Cd across the endodermal plasma membrane and thus may play a key role in Cd flux into the stele and root-to-shoot Cd transport. NcNramp1 may be one of the main transporters involved in Cd hyperaccumulation in N. caerulescens and copy number variation appears to be the main reason for high NcNramp1 gene expression underlying the increased Cd accumulation in the Ganges ecotype.

Resultados quirúrgicos a largo plazo en pacientes con epilepsia fármaco-resistente del lóbulo temporal sin anormalidades histológicas / Long-term surgical outcomes in patients with drug-resistant temporal lobe epilepsy and no histological abnormalities

Introducción: Los reportes de los resultados quirúrgicos en los pacientes con epilepsia fármaco-resistente del lóbulo temporal sin anormalidades histológicas son escasos. Métodos: Fueron revisados retrospectivamente los datos de los pacientes con epilepsia del lóbulo temporal tratados con lobectomía temporal anterior con amígdalo-hipocampectomía que no presentaban alteraciones en los estudios histopatológicos. Fueron analizadas las variables: edad, género, edad al inicio de las crisis epilépticas, edad al momento de la cirugía, tiempo de evolución de la epilepsia desde el diagnóstico hasta la fecha de la cirugía, periodo de seguimiento y clasificación según la escala de Engel. Resultados: De una base de datos de 256 lobectomías temporales, fueron identificados 21 pacientes que cumplieron los criterios de inclusión. El promedio de edad a la cual se realizó el diagnóstico de epilepsia fue 8,3 años, al momento de la cirugía fue 28,6 años y de tiempo transcurrido desde el diagnóstico hasta la cirugía fue 20,2 años. Tras un seguimiento promedio de 6,5 años, el 90,5% obtuvo resultados favorables (clases i y ii ) y el 42,9% estaba libre de crisis (clase i A). Tras el análisis comparativo de las variables estudiadas, solo existieron diferencias estadísticamente significativas en la edad de inicio de las crisis, siendo inferior en los pacientes que obtuvieron resultados favorables. Conclusión: Aunque en la gran mayoría de los pacientes los resultados quirúrgicos a largo plazo fueron favorables, la proporción de pacientes libres de crisis es inferior a la de los pacientes con epilepsia lesional y comparables con lo reportado previamente en la literatura (AU)

Introduction: Reports on surgical outcomes in patients with drug-resistant temporal lobe epilepsy without histological abnormalities are scarce. Methods: Retrospective review of data from patients with drug-resistant temporal lobe epilepsy and no histopathological alterations who underwent anterior mesial temporal lobectomy. We analysed the following variables: age, sex, age at seizure onset, age at surgery, time elapsed between diagnosis and the date of the surgery, follow-up time, and classification according to the Engel rating scale. Results: From a database of 256 temporal lobectomies, 21 were identified as meeting the inclusion criteria. The average age upon diagnosis of epilepsy was 8.3 years and average age at time of surgery was 28.6 years. The mean time elapsed between diagnosis and surgery was 20.2 years. After a mean follow-up of 6.5 years, 90.5% of the patients showed favourable outcomes (classes i and ii ) and 42.9% were seizure-free (class IA). Comparative analysis of the variables revealed that average age at seizure onset was the only statistically significant difference between groups, with age at onset being lower in patients with favourable outcomes. Conclusion: Although long-term surgical outcomes were favourable for a large majority of patients, the percentage of seizure-free patients is lower than in patients with lesional epilepsy and comparable to that previously reported in the literature (AU)

Long-term surgical outcomes in patients with drug-resistant temporal lobe epilepsy and no histological abnormalities.

INTRODUCTION: Reports on surgical outcomes in patients with drug-resistant temporal lobe epilepsy without histological abnormalities are scarce. METHODS: Retrospective review of data from patients with drug-resistant temporal lobe epilepsy and no histopathological alterations who underwent anterior mesial temporal lobectomy. We analysed the following variables: age, sex, age at seizure onset, age at surgery, time elapsed between diagnosis and the date of the surgery, follow-up time, and classification according to the Engel rating scale. RESULTS: From a database of 256 temporal lobectomies, 21 were identified as meeting the inclusion criteria. The average age upon diagnosis of epilepsy was 8.3 years and average age at time of surgery was 28.6 years. The mean time elapsed between diagnosis and surgery was 20.2 years. After a mean follow-up of 6.5 years, 90.5% of the patients showed favourable outcomes (classes i and ii) and 42.9% were seizure-free (class IA). Comparative analysis of the variables revealed that average age at seizure onset was the only statistically significant difference between groups, with age at onset being lower in patients with favourable outcomes. CONCLUSION: Although long-term surgical outcomes were favourable for a large majority of patients, the percentage of seizure-free patients is lower than in patients with lesional epilepsy and comparable to that previously reported in the literature.

Aporte calórico y macronutrimental de los menús infantiles de la comida rápida y convencional / Caloric and macronutrient contribution of the children's menu of fast and conventional food

The caloric and macronutrient contribution of the children's menu in fast food restaurants and conventional restaurants was analyzed, according to mealtimes and recommended intakes for children between 4 and 8 years old in a city in the Northeastern of Mexico with the highest childhood obesity rate in the world. This is an observational, descriptive and transversal study. The sampling was by convenience and directed when typical cases of children's menus were selected from 152 restaurants. The range of carbohydrates contribution of the children's menu varied from 53.8% to 97.9% of the recommendation; in any case the protein contribution was less than 82.2%. With regard to fats, contribution ranges were from 63% to 165.3%. These contributions increase considerably when they are analyzed by mealtimes: from 97.8% to 373.4%. In conclusion, fast food and conventional restaurants offer unhealthy meals in big portions to child population.

Se analizó el aporte calórico y de macronutrientes de me-nús infantiles en restaurantes de comida rápida y restaurantes convencionales según tiempos de comidas e ingesta recomendada para niños de 4 a 8 años en una ciudad del noreste mexicano que presenta una prevalencia de obesidad infantil de las más altas del mundo. Es un estudio observacional, descriptivo y transversal. El muestreo fue por conveniencia y dirigido al ser seleccionados casos típicos de menús infantiles de cadenas de restaurantes de mayor presencia (152 establecimientos). Los resultados muestran que el rango de aporte de hidratos de carbono varió del 53,8% a 97,9% de la recomendación; el aporte de proteína no fue menor al 82,2%; el aporte de lípidos fue de 63.0% a 165,3%. Estos aportes aumentan considerablemente al analizarlos por tiempos de comida: de 97,8% a 373,4%. Se concluye que tanto los restaurantes de comida rápida como los restaurantes convencionales ofrecen a la población infantil alimentos y porciones poco saludables.

Rickettsia felis in cat fleas, Ctenocephalides felis parasitizing opossums, San Bernardino County, California.

Los Angeles and Orange Counties are known endemic areas for murine typhus in California; however, no recent reports of flea-borne rickettsioses are known from adjacent San Bernardino County. Sixty-five opossums (Didelphis virginiana) were trapped in the suburban residential and industrial zones of the southwestern part of San Bernardino County in 2007. Sixty out of 65 opossums were infested with fleas, primarily cat fleas, Ctenocephalides felis (Bouché, 1835). The flea minimum infection rate with Rickettsia felis was 13.3% in pooled samples and the prevalence was 23.7% in single fleas, with two gltA genotypes detected. In spite of historic records of murine typhus in this area, no evidence for circulation of R. typhi in fleas was found during the present study. Factors contributing to the absence of R. typhi in these cat fleas in contrast to its presence in cat fleas from Orange and Los Angeles Counties are unknown and need to be investigated further in San Bernardino County.

Elevated expression of TcHMA3 plays a key role in the extreme Cd tolerance in a Cd-hyperaccumulating ecotype of Thlaspi caerulescens.

Cadmium (Cd) is a highly toxic heavy metal for plants, but several unique Cd-hyperaccumulating plant species are able to accumulate this metal to extraordinary concentrations in the aboveground tissues without showing any toxic symptoms. However, the molecular mechanisms underlying this hypertolerance to Cd are poorly understood. Here we have isolated and functionally characterized an allelic gene, TcHMA3 (heavy metal ATPase 3) from two ecotypes (Ganges and Prayon) of Thlaspi caerulescens contrasting in Cd accumulation and tolerance. The TcHMA3 alleles from the higher (Ganges) and lower Cd-accumulating ecotype (Prayon) share 97.8% identity, and encode a P(1B)-type ATPase. There were no differences in the expression pattern, cell-specificity of protein localization and transport substrate-specificity of TcHMA3 between the two ecotypes. Both alleles were characterized by constitutive expression in the shoot and root, a tonoplast localization of the protein in all leaf cells and specific transport activity for Cd. The only difference between the two ecotypes was the expression level of TcHMA3: Ganges showed a sevenfold higher expression than Prayon, partly caused by a higher copy number. Furthermore, the expression level and localization of TcHMA3 were different from AtHMA3 expression in Arabidopsis. Overexpression of TcHMA3 in Arabidopsis significantly enhanced tolerance to Cd and slightly increased tolerance to Zn, but did not change Co or Pb tolerance. These results indicate that TcHMA3 is a tonoplast-localized transporter highly specific for Cd, which is responsible for sequestration of Cd into the leaf vacuoles, and that a higher expression of this gene is required for Cd hypertolerance in the Cd-hyperaccumulating ecotype of T. caerulescens.

Envelope molecular-orbital theory of extended systems. I. Electronic states of organic quasilinear nanoheterostructures.

A conceptually appealing and computationally economical course-grained molecular-orbital (MO) theory for extended quasilinear molecular heterostructures is presented. The formalism, which is based on a straightforward adaptation, by including explicitly the vacuum, of the envelope-function approximation widely employed in solid-state physics leads to a mapping of the three-dimensional single-particle eigenvalue equations into simple one-dimensional hole and electron Schrödinger-like equations with piecewise-constant effective potentials and masses. The eigenfunctions of these equations are envelope MO's in which the short-wavelength oscillations present in the full MO's, associated with the atomistic details of the molecular potential, are smoothed out automatically. The approach is illustrated by calculating the envelope MO's of high-lying occupied and low-lying virtual π states in prototypical nanometric heterostructures constituted by oligomers of polyacetylene and polydiacetylene. Comparison with atomistic electronic-structure calculations reveals that the envelope-MO energies agree very well with the energies of the π MO's and that the envelope MO's describe precisely the long-wavelength variations of the π MO's. This envelope MO theory, which is generalizable to extended systems of any dimensionality, is seen to provide a useful tool for the qualitative interpretation and quantitative prediction of the single-particle quantum states in mesoscopic molecular structures and the design of nanometric molecular devices with tailored energy levels and wavefunctions.

Manipulating and imaging the shape of an electronic wave function by magnetotunneling spectroscopy.

We measure the current due to electrons tunneling through the ground state of hydrogenic Si donors placed in a GaAs quantum well in the presence of a magnetic field tilted at an angle to the plane of the well. The component of B parallel to the direction of current compresses the donor wave function. By measuring the current as a function of the perpendicular component of B, we probe how the magnetocompression affects the spatial form of the wave function and observe directly the transition from Coulombic to magnetic confinement at high fields.

Green liquor dregs effect on Kraft mill secondary sludge composting.

Increased Kraft pulp mill production generates increased solid wastes. In response, composting has emerged as an interesting alternative for disposal of these solid wastes. A central composite factor design was used to investigate the influence of incubation conditions (dregs addition and operation time) on chemical and biological parameters, determining the best in-vessel conditions in order to develop a correct composting design. Dregs helped reduce the pH drop that occurs at the beginning of the process. Biological activities presented high values during the active phase, followed by a decrease with stable final values along with N-NH(4)(+) and N-NO(3)(-) trend, which were indicative of mature compost. Dregs addition had not significant effect on the biological activities during composting of Kraft mill sludge. However, moderate amounts of dregs (between 5% and 8%) at operation time of 60-70 days would be the best compromise.

A randomized controlled trial on the efficacy and safety of a food ingredient, collagen hydrolysate, for improving joint comfort.

INTRODUCTION: Current options to promote joint comfort are limited to medicines that can reduce pain but can also have adverse effects. Collagen, a major component of joint cartilage, is found in the diet, particularly in meat. Its hydrolysed form, collagen hydrolysate (CH), is well absorbed. CH may stimulate the joint matrix cells to synthesize collagen, so helping to maintain the structure of the joint and potentially to aid joint comfort. METHODS: In a randomized, double-blind, controlled multicentre trial, 250 subjects with primary osteoarthritis of the knee were given 10 g CH daily for 6 months. RESULTS: There was a significant improvement in knee joint comfort as assessed by visual analogue scales to assess pain and the Womac pain subscale. Subjects with the greatest joint deterioration, and with least intake of meat protein in their habitual diets, benefited most. CONCLUSION: CH is safe and effective and warrants further consideration as a food ingredient.

Cadmium sorption, influx, and efflux at the mesophyll layer of leaves from ecotypes of the Zn/Cd hyperaccumulator Thlaspi caerulescens.

Differential sorption and transport characteristics of the leaf mesophyll layer of the Prayon and Ganges ecotypes of the hyperaccumulator Thlaspi caerulescens were examined. (109)Cd influx and efflux experiments were conducted with leaf sections, and X-ray absorption near edge structure (XANES) data were collected from leaves as a general comparison of in vivo cadmium (Cd) coordination. There were modest differences in cell wall sorption of Cd between ecotypes. There were obvious differences in time- and concentration-dependent Cd influx, including a greater V(MAX) for Prayon but a lower K(M) for Ganges for concentration-dependent Cd uptake and a notably greater Cd uptake by Ganges leaf sections at 1000 microm Cd. Leaf sections of Prayon had a greater Cd efflux than Ganges. The XANES spectra from the two ecotypes suggested differences in Cd coordination. The fundamental differences observed between the two ecotypes may reflect differential activity and/or expression of plasma membrane and tonoplast transporters. More detailed study of these transporters and the in vivo coordination of Cd are needed to determine the contribution of these processes to metal homeostasis and tolerance.

Efficient removal of hexavalent chromium by a tolerant Streptomyces sp. affected by the toxic effect of metal exposure.

AIMS: To isolate and analyse chromium-resistant micro-organisms suitable for bioremediation. METHODS AND RESULTS: Strain CG252, with a minimal inhibitory concentration of 500 microg ml(-1), was isolated from contaminated soils and identified as a Streptomyces sp. by 16S rDNA sequence analysis. Assays carried out at various Cr(VI) concentrations indicated that chromium removal was more efficient at lower concentrations and that this activity resulted in accumulation of Cr(III). Atomic adsorption analysis indicated that the chromium removed was not associated with cell mass and activity assays showed that the capacity to reduce Cr(VI) was most probably due to a soluble cytosolic enzyme. Cells grown as biofilms showed enhanced removal of Cr(VI) with respect to planktonic cells, while analysis of growth and colony morphology indicated that Cr(VI) had a toxic effect on this strain. CONCLUSIONS: Streptomyces sp. CG252 tolerated heavy metals and elevated levels of chromium, despite its negative effect on growth and development, and was efficient at removing Cr(VI) by promoting reduction to Cr(III). SIGNIFICANCE AND IMPACT OF THE STUDY: Strain CG252's capacity to tolerate heavy metals and to reduce Cr(VI) to the less toxic Cr(III), especially when forming biofilms, makes it a promising candidate for detoxification of sites containing this heavy metal.