Phase Velocity Limit of High-Frequency Photon Density Waves

In frequency-domain photonmigration (FDPM), two factors make high modulation frequencies desirable. First, with frequencies as high as a few GHz, the phase lag versus frequency plot has sufficient curvature to yield both the scattering and absorption coefficients of the tissue under examination. Second, because of increased attenuation, highfrequency photon density waves probe smaller volumes, an asset in small volume in vivo or in vitro studies. This trend toward higher modulation frequencies has led us to reexamine the derivation of the standard diffusion equation (SDE)from the Boltzman transport equation. We find that a second-order time-derivative term, ordinarily neglected in the derivation, can be significant above 1GHzfor some biological tissue. The revised diffusion equation, including the second-order time-derivative, is often termed the PI equation. We compare the dispersion relation of the PI equation with that of the SDE. The PI phase velocity is slower than that predicted by the SDE; in fact, the SDE phase velocity is unbounded with increasing modulation frequency, while the PI phase velocity approaches c/sqrt(3) in the high frequency limit. We emphasize that the phase velocity c/sqrt(3) is attained only at modulation frequencies with periods shorter than the mean time between scatterings of a photon, a frequency regime that probes the medium beyond the applicability of diffusion theory. Finally we caution that values for optical properties deduced from FDPM data at high frequencies using the SDE can be in error by 30% or more

Desarrollo de un metodo de manufactura de injertos de polvo de hueso por moldeo

Se presentan los resultados de las pruebas de flexión, dureza (Shore A), impacto y absorción de agua realizadas a un primer modelo de mezcla biocompatible que cumpla con las cuatro propiedades mínimas que debe tener un biomaterial para ser usado como injerto óseo: osteoconducción, osteoinducción, osteogénesis y soporte estructural. Tal mezcla consiste de una matriz polimérica y un refuerzo de polvos de hueso liofilizado. Con base en los resultados obtenidos de cada prueba, se logró la inyección de piezas normalizadas útiles en implantología ósea, que muestran la viabilidad de fabricar objetos de relleno óseo a partir de mezclas de este tipo

Desarrollo de un metodo de manufactura de injertos de polvo de hueso por moldeo

Se presentan los resultados de las pruebas de flexión, dureza (Shore A), impacto y absorción de agua realizadas a un primer modelo de mezcla biocompatible que cumpla con las cuatro propiedades mínimas que debe tener un biomaterial para ser usado como injerto óseo: osteoconducción, osteoinducción, osteogénesis y soporte estructural. Tal mezcla consiste de una matriz polimérica y un refuerzo de polvos de hueso liofilizado. Con base en los resultados obtenidos de cada prueba, se logró la inyección de piezas normalizadas útiles en implantología ósea, que muestran la viabilidad de fabricar objetos de relleno óseo a partir de mezclas de este tipo

CD28null pro-atherogenic CD4 T-cells explain the link between CMV infection and an increased risk of Cardiovascular death

An increased risk of cardiovascular death in Cytomegalovirus (CMV)-infected individuals remains unexplained, although it might partly result from the fact that CMV infection is closely associated with the accumulation of CD28null T-cells, in particular CD28null CD4 T-cells. These cells can directly damage endothelium and precipitate cardiovascular events. However, the current paradigm holds that the accumulation of CD28null T-cells is a normal consequence of aging, whereas the link between these T-cell populations and CMV infection is explained by the increased prevalence of this infection in older people. Resolving whether CMV infection or aging triggers CD28null T-cell expansions is of critical importance because, unlike aging, CMV infection can be treated. Methods: We used multi-color flow-cytometry, antigen-specific activation assays, and HLA-typing to dissect the contributions of CMV infection and aging to the accumulation of CD28null CD4 and CD8 T-cells in CMV+ and CMV− individuals aged 19 to 94 years. Linear/logistic regression was used to test the effect of sex, age, CMV infection, and HLA-type on CD28null T-cell frequencies. Results: The median frequencies of CD28null CD4 T-cells and CD28null CD8 T-cells were >12-fold (p=0.000) but only approximately 2-fold higher (p=0.000), respectively, in CMV+ (n=136) compared with CMV− individuals (n=106). The effect of CMV infection on these T-cell subsets was confirmed by linear regression. Unexpectedly, aging contributed only marginally to an increase in CD28null T-cell frequencies, and only in CMV+ individuals. Interestingly, the presence of HLA-DRB1*0301 led to an approximately 9-fold reduction of the risk of having CD28null CD4 T-cell expansions (OR=0.108, p=0.003). Over 75% of CMV-reactive CD4 T-cells were CD28null. Conclusion: CMV infection and HLA type are major risk factors for CD28null CD4 T-cell-associated cardiovascular pathology. Increased numbers of CD28null CD8 T-cells are also associated with CMV infection, but to a lesser extent. Aging, however, makes only a negligible contribution to the expansion of these T-cell subsets, and only in the presence of CMV infection. Our results open up new avenues for risk assessment, prevention, and treatment

Caracterización sociodemográfica y familiar de obesos intervenidos a través de cirugía bariátrica en el Hospital Universitario de Neiva

Objective. To make a clinical and social characterization of obese people who underwent bariatric surgery at University Hospital in Neiva, between September 2011 and September 2012. Materials and Methods. A crosssectional, descriptive study was conducted at Hernando Moncaleano Perdomo University Hospital in Neiva. It was made a telephone survey and medical histories were checked for 25 patients who underwent bariatric surgery at this health center. It was considered the following variables: sex, socioeconomic status, occupation, eating habits, body mass index, characteristics of satisfaction with fitness and lifestyle before and after surgery. In order to determine family characteristics it was carried out APGAR family. Results. Most members of the sample were women whose ages were between 20 and 53. They had a stable partner, belonged to low socioeconomic stratum, had finished high school and lived in Neiva. Weight before surgery was between 93 Kg and 155 Kg, with body mass index between 36 and 59. Before surgery they didn’t feel at all satisfied with their fitness and their life. At present they feel moderately satisfied. In addition, their families are nuclear and a high percentage of them are mild dysfunctional. Conclusion. Patients have bad eating habits before surgery and it was shown family dysfunction. Objetivo. Caracterizar desde el punto de vista clínico y social a las personas obesas sometidas a cirugía bariátrica en el Hospital Universitario de Neiva en el periodo entre septiembre de 2011 y el mismo mes de 2012. Material y métodos. Se realizó un estudio descriptivo de corte trasversal en el Hospital Universitario Hernando Moncaleano Perdomo de Neiva, aplicando una encuesta telefónica y revisión de historias clínicas a 25 pacientes que fueron intervenidos a través de cirugía bariátrica en la Institución. Se estudiaron las variables: sexo, estrato socioeconómico, ocupación, hábitos alimenticios, índice de masa corporal, características de satisfacción con la condición física y vida antes y después de la cirugía, para determinar características a nivel familiar se aplicó el APGAR familiar. Resultados. En la muestra estudiada existió un predominio del sexo femenino, con edades entre 20 y 53 años, con pareja estable de estrato socioeconómico bajo, con un nivel de escolaridad hasta secundaria y viven en Neiva. El peso de las personas antes de la cirugía estaba entre 93 Kg y 155 Kg. con un índice de masa corporal entre 36 y 59. Antes de la cirugía no se sentían para nada satisfechos con su condición física y con su vida, actualmente se sienten moderadamente satisfechos. Además son familias nucleares y existe un elevado número de familias con disfuncionalidad leve. Conclusión. Los pacientes presentan malos hábitos alimenticios antes de la cirugía y se evidencio disfuncionalidad familiar

Colección de Anfibios, Museo de Historia Natural de la Universidad de Caldas, Colombia

In Colombia, amphibians are a vertebrate group with a high taxonomic richness, and an elevated representativity of species with restricted distributions. In recent years, regional collections have assisted to fill information gaps on the biogeography, intra- and interspecific variation, and systematics of the amphibians of the country. In this work we present the information of 1533 records deposited in the Amphibian Collection of the Museo de Historia Natural of the Universidad de Caldas, represented by 143 species, belonging to 49 genera and 19 families. Most of the records (n = 1194) come from the Department of Caldas, but there are records for 16 additional departments. The most representative order is Anura (n = 1487 records) followed by Caudata (n = 27 records), and Gymnophiona (n = 19 records). The collection houses 152 specimens that have been referenced in 13 national and foreign publications.En Colombia, los anfibios se posicionan como uno de los grupos vertebrados con mayor riqueza taxonómica, y una alta representatividad de especies endémicas. En los últimos años, las colecciones regionales han contribuido a llenar vacíos de información sobre la biogeografía, la variación intra e interespecífica y la sistemática de los anfibios del país. En este trabajo presentamos la información de 1533 registros depositados en la Colección de Anfibios del Museo de Historia Natural de la Universidad de Caldas, los cuales representan 143 especies distribuidas en 49 géneros y 19 familias. La mayoría de los especímenes (n = 1194) proceden del departamento de Caldas, sin embargo, se cuenta con registros (n = 339) de otros 16 departamentos del país. El orden más representado es Anura (n = 1487 registros), seguido por Caudata (n = 27 registros) y Gymnophiona (n = 19 registros). La colección alberga 152 especímenes que han sido referenciados en 13 publicaciones nacionales y extranjeras

Functional and evolutionary analyses of the miR156 and miR529 families in land plants

Abstract\ud \ud Background\ud MicroRNAs (miRNAs) are important regulatory elements of gene expression. Similarly to coding genes, miRNA genes follow a birth and death pattern of evolution likely reflecting functional relevance and divergence. For instance, miRNA529 is evolutionarily related to miRNA156 (a highly conserved miRNA in land plants), but it is lost in Arabidopsis thaliana. Interestingly, both miRNAs target sequences overlap in some members of the SQUAMOSA promoter-binding protein like (SPL) family, raising important questions regarding the diversification of the miR156/miR529-associated regulatory network in land plants.\ud \ud \ud Results\ud In this study, through phylogenic reconstruction of miR156/529 target sequences from several taxonomic groups, we have found that specific eudicot SPLs, despite miRNA529 loss, retained the corresponding target site. Detailed molecular evolutionary analyses of miR156/miR529-target sequence showed that loss of miR529 in core eudicots, such as Arabidopsis, is correlated with a more relaxed selection of the miRNA529 specific target element, while miRNA156-specific target sequence is under stronger selection, indicating that these two target sites might be under distinct evolutionary constraints. Importantly, over-expression in Arabidopsis of MIR529 precursor from a monocot, but not from a basal eudicot, demonstrates specific miR529 regulation of AtSPL9 and AtSPL15 genes, which contain conserved responsive elements for both miR156 and miR529.\ud \ud \ud Conclusions\ud Our results suggest loss of functionality of MIR529 genes in the evolutionary history of eudicots and show that the miR529-responsive element present in some eudicot SPLs is still functional. Our data support the notion that particular miRNA156 family members might have compensated for the loss of miR529 regulation in eudicot species, which concomitantly may have favored diversification of eudicot SPLs.We thank Dr. Scott Poethig for 35S::AtMIR156a seeds; Dr. Peter Huijser for\ud spl9;spl15 seeds; Dr. Renato Vicentini for initial bioinformatic analyses and\ud helpful discussions; and Dr. Luiz Del Bem for initial phylogenetic analyses.\ud This work was supported by the State of Sao Paulo Research Foundation,\ud FAPESP, Brazil (grants no. 07/58289-5 and 12/51146-2). EGOM was a recipient\ud of a fellowship from Coordination for the Improvement of Higher Education\ud Personnel (CAPES, Brazil). GFFS (from Centro de Energia Nuclear na\ud Agricultura –CENA/USP) and EMS were recipients of a fellowship from the\ud State of Sao Paulo Research Foundation, FAPESP, Brazil

Colección de reptiles no aves (Reptilia), Museo de Historia Natural de la Universidad de Caldas, Colombia

The knowledge of reptiles in Colombia is still incomplete, although the country harbors a high diversity of this group. In recent years, regional collections have helped to fill information gaps on the biogeography, intra- and interspecific variation, and systematics of several groups. Here we present the information of 613 voucher records deposited in the Reptile Collection of the Museo de Historia Natural of the Universidad de Caldas. Most of the records (527) come from the Department of Caldas, but there are records for 15 additional departments. The best represented order is Squamata (603 records). The collection houses 108 specimens that have been referenced in 20 national and foreign publications.El conocimiento de los reptiles en Colombia es aún incompleto, aunque el país alberga una alta diversidad de este grupo. En los últimos años, las colecciones regionales han contribuido a llenar vacíos de información sobre la biogeografía, la variación intra e interespecífica y la sistemática de diversos grupos. Presentamos aquí la información de 613 registros depositados en la Colección de Reptiles del Museo de Historia Natural de la Universidad de Caldas. La mayoría de los registros (527) proceden del departamento de Caldas, pero se cuenta con registros de 15 departamentos más. El orden más representativo es Squamata (603 registros). La colección alberga 108 especímenes que han sido referenciados en 20 publicaciones nacionales y extranjeras