Graphene and polyethylene. A strong combination towards multifunctional nanocomposites

The key to the preparation of polymer nanocomposites with new or improved properties resides in the homogeneous dispersion of the filler and in the efficient load transfer between components through strong filler/polymer interfacial interactions. This paper reports on the preparation of a series of nanocomposites of graphene and a polyolefin using different experimental approaches, with the final goal of obtaining multifunctional materials. A high-density polyethylene (HDPE) is employed as the matrix, while unmodified and chemically modified graphene fillers are used. By selecting the correct combination as well as the adequate preparation process, the nanocomposites display optimized thermal and mechanical properties, while also conferring good gas barrier properties and significant levels of electrical conductivity

Thermoelectric power of bulk black-phosphorus

The potential of bulk black-phosphorus for thermoelectric applications has been experimentally studied. The Seebeck Coefficient (S) has been measured in the temperature range from 300 K to 385 K, finding a value of S = +335 +- 10 uV/K at room temperature (indicating a naturally occurring p-type conductivity). S increases with temperature, as expected for p-type semiconductors, which can be attributed to an increase of the charge carrier density. The electrical resistance drops up to a 40 % while heating in the studied temperature range. As a consequence, the power factor at 385 K is 2.7 times higher than that at room temperature. This work demonstrates the feasibility of black-phosphorus in thermoelectric applications, such as thermal energy scavenging, which typically require devices with high performance at temperatures above room temperature.Comment: 3 figure

Fauna de escarabajos melolóntidos (coleoptera: scarabaeoidea) en el municipio de Villaflores, Chiapas, México

A first approach to the knowledge of the Melolonthid beetles of the region Frailesca in the State of Chiapas, Mexico, is presented. Most part of the original tropical deciduous forest today is replaced by great extensions with agricultural and cattle production. Studied localities were Francisco Villa, Cuauhtémoc, El Jardín and the surrounds of Villaflores city, all from the municipality of Villaflores. Diurnal and nocturnal systematic collections of adult beetles were made in agricultural parcels during May to September, 2006, by mean of light traps, transects, and fruit traps We obtained 6,780 specimens that represent four subfamilies, eight tribes, 17 genera and 46 species. The genera with greatest number of species and individuals were Phyllophaga, Diplotaxis and Ligyrus; along with the species of the genera Cyclocephala, Anomala and Strigoderma cover 88,7% of the total abundance. An updated list of the 368 species of Melolonthidae recorded in the state of Chiapas is included.Como un primer acercamiento al conocimiento de los escarabajos melolóntidos de la región Frailesca de Chiapas, México, caracterizada por un ambiente original de bosque tropical caducifolio, en su mayor parte ahora reemplazado por grandes extensiones con producción agrícola y ganadera, se realizó la presente investigación en los ejidos de Francisco Villa, Cuauhtémoc, El Jardín y la ciudad de Villaflores, pertenecientes al municipio de Villaflores. En parcelas agrícolas se hicieron recolectas sistemáticas, diurnas y nocturnas, de escarabajos adultos durante los meses de mayo a septiembre de 2006. Se obtuvieron 6,780 ejemplares, que representan a cuatro subfamilias, ocho tribus, 17 géneros y 46 especies. Los géneros con mayor número de especies e individuos fueron Phyllophaga, Diplotaxis y Ligyrus; junto con los escarabajos de los géneros Cyclocephala, Anomala y Strigoderma cubren el 88.7 % de la abundancia total. Se incluye una lista actualizada de las 368 especies de Melolonthidae registradas en el estado de Chiapas

The effects of advanced maternal age on T- cell subsets at the maternal- fetal interface prior to term labor and in the offspring: a mouse study

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155904/1/cei13437.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155904/2/cei13437_am.pd

Hierarchical Shape Construction and Complexity for Slidable Polyominoes under Uniform External Forces

Advances in technology have given us the ability to create and manipulate robots for numerous applications at the molecular scale. At this size, fabrication tool limitations motivate the use of simple robots. The individual control of these simple objects can be infeasible. We investigate a model of robot motion planning, based on global external signals, known as the tilt model. Given a board and initial placement of polyominoes, the board may be tilted in any of the 4 cardinal directions, causing all slidable polyominoes to move maximally in the specified direction until blocked. We propose a new hierarchy of shapes and design a single configuration that is strongly universal for any w × h bounded shape within this hierarchy (it can be reconfigured to construct any w × h bounded shape in the hierarchy). This class of shapes constitutes the most general set of buildable shapes in the literature, with most previous work consisting of just the first-level of our hierarchy. We accompany this result with a O(n4 log n)-time algorithm for deciding if a given hole-free shape is a member of the hierarchy. For our second result, we resolve a long-standing open problem within the field: We show that deciding if a given position may be covered by a tile for a given initial board configuration is PSPACEcomplete, even when all movable pieces are 1 × 1 tiles with no glues. We achieve this result by a reduction from Non-deterministic Constraint Logic for a one-player unbounded game

Is it important to achieve physical activity recommendations at early stages of life to improve bone health?

Research in bone health during childhood is limited and important to prevent future diseases, particularly, osteoporosis. Bone parameters using DXA and pQCT in 295 Spanish children were evaluated and we found a benefit of meeting the World Health Organization physical activity recommendations in bone composition in childhood. Purpose To investigate the association between physical activity (PA) and bone health in a Spanish paediatric cohort, considering the influence of meeting/not meeting the current World Health Organization (WHO) PA recommendations and to elucidate if there are differences between boys and girls. Methods In a cohort of children born in the region of Aragon (Spain) in 2009, followed until the age of 7 years, bone parameters were assessed using dual-energy X-ray absorptiometry (DXA) (whole body scan) and peripheral quantitative computed tomography (pQCT) (tibia scanned at the 8% (distal) and 38% (diaphyseal) of the total tibia length) in 295 7-year-old children (154 boys) in the last evaluation performed between 2016 and 2017. PA was assessed using GT3X Actigraph accelerometers. Results Boys had significantly higher areal bone mineral density (aBMD), higher total bone mineral content (BMC) at the diaphyseal site and higher trabecular BMC and vBMD, and higher total bone area at the distal site than girls (p<0.01 for all of them). Both boys and girls complying with the WHO PA recommendations had significantly higher trabecular BMC than their inactive counterparts. Conclusions Meeting WHO PA recommendations has a beneficial effect in bone composition in childhood both in boys and in girls

Combinatorial gene therapy renders increased survival in cirrhotic rats

<p>Abstract</p> <p>Background</p> <p>Liver fibrosis ranks as the second cause of death in México's productive-age population. This pathology is characterized by acummulation of fibrillar proteins in hepatic parenchyma causing synthetic and metabolic disfunction. Remotion of excessive fibrous proteins might result in benefit for subjects increasing survival index. The goal of this work was to find whether the already known therapeutical effect of human urokinase Plasminogen Activator and human Matrix Metalloprotease 8 extends survival index in cirrhotic animals.</p> <p>Methods</p> <p>Wistar rats (80 g) underwent chronic intoxication with CCl₄: mineral oil for 8 weeks. Cirrhotic animals were injected with a combined dose of Ad-delta-huPA plus Ad-MMP8 (3 × 10¹¹and 1.5 × 10¹¹vp/Kg, respectively) or with Ad-beta-Gal (4.5 × 10¹¹) and were killed after 2, 4, 6, 8 and 10 days. Then, liver and serum were collected. An additional set of cirrhotic animals injected with combined gene therapy was also monitored for their probability of survival.</p> <p>Results</p> <p>Only the cirrhotic animals treated with therapeutical genes (Ad-delta-huPA+Ad-MMP-8) showed improvement in liver fibrosis. These results correlated with hydroxyproline determinations. A significant decrement in alpha-SMA and TGF-beta1 gene expression was also observed. Cirrhotic rats treated with Ad-delta-huPA plus Ad-MMP8 had a higher probability of survival at 60 days with respect to Ad-beta-Gal-injected animals.</p> <p>Conclusion</p> <p>A single administration of Ad-delta-huPA plus Ad-MMP-8 is efficient to induce fibrosis regression and increase survival in experimental liver fibrosis.</p

Dynamical Processing of Geophysical Signatures based on SPOT-5 Remote Sensing Imagery

An intelligent post-processing computational paradigm based on the use of dynamical filtering techniques modified to enhance the quality of reconstruction of geophysical signatures based on Spot-5 imagery is proposed. As a matter of particular study, a robust algorithm is reported for the analysis of the dynamic behavior of geophysical indexes extracted from the real-world remotely sensed scenes. The simulation results verify the efficiency of the approach as required for decision support in resources management

Alterations of antitumor and metabolic responses in L5178Y-R lymphoma-bearing mice after only 30-minute daily chronic stress exposure

Aim: In stress research, reducing times of stress induction may contribute to improving the well-being of experimental animals, especially in cancer models, already under physiological distress. To support this idea, we evaluated the effects of a short-timed stress protocol on endocrine, metabolic and immune indicators in mice bearing the L5178Y-R lymphoma. Materials and Methods: A 30-minute daily stress protocol was applied for 28 days to healthy and lymphoma-bearing BALB/c mice; body weight, plasma levels of corticosterone, norepinephrine, Th1/Th2 cytokines, insulin, and leptin, were measured. Results: We found a 12% significant decrease in body weight in non-tumor bearing mice under stress (p < 0.007). The disruption of weight evolution was accompanied by a stress induced 85% decrease in plasmatic leptin (p < 0.01) and total reduction of insulin. Tumor burden alone was associated to an increase in more than two-fold of plasmatic levels of norepinephrine (p < 0.008). Neither stress nor tumor or their combination, resulted in an elevation of systemic IL-6. IFN-γ levels were 20 times higher in lymphoma-bearing animals when compared with non-tumor bearing mice (p < 0.01); however, under stress, this response was reduced by half, indicating a suppressing effect of chronic stress on the antitumor immune response. Conclusion: A short-timed stress induction is enough to cause significant alterations in the metabolism and immunity of healthy and tumor-bearing mice, supporting the use of short-timed protocols as an efficient way to induce chronic stress that also considers concerns regarding the well-being of experimental animals in biomedical research