Chemical modification of jute fibers for the production of green-composites

Natural fiber reinforced composites is an emerging area in polymer science. Fibers derived from annual plants are considered a potential substitute for non-renewable synthetic fibers like glass and carbon fibers. The hydrophilic nature of natural fibers affects negatively its adhesion to hydrophobic polymeric matrices. To improve the compatibility between both components a surface modification has been proposed. The aim of the study is the chemical modification of jute fibers using a fatty acid derivate (oleoyl chloride) to confer hydrophobicity and resistance to biofibers. This reaction was applied in swelling and non-swelling solvents, pyridine and dichloromethane, respectively. The formation of ester groups, resulting from the reaction of oleoyl chloride with hydroxyl group of cellulose were studied by elemental analysis (EA) and Fourier Transform infrared spectroscopy (FTIR). The characterization methods applied has proved the chemical interaction between the cellulosic material and the coupling agent. The extent of the reactions evaluated by elemental analysis was calculated using two ratios. Finally electron microscopy was applied to evaluate the surface changes of cellulose fibers after modification process.     

Are finance, management, and marketing autonomous fields of scientific research? An analysis based on journal citations

Although there is considerable consensus that Finance, Management and Marketing are ‘science’, some debate remains with regard to whether these three areas comprise autonomous, organized and settled scientific fields of research. In this paper we aim to explore this issue by analyzing the occurrence of citations in the top-ranked journals in the areas of Finance, Management, and Marketing. We put forward a modified version of the model of science as a network, proposed by Klamer and Van Dalen (J Econ Methodol 9(2):289–315, 2002), and conclude that Finance is a ‘Relatively autonomous, organized and settled field of research’, whereas Management and (to a larger extent) Marketing are relatively non-autonomous and hybrid fields of research’. Complementary analysis based on sub-discipline rankings using the recursive methodology of Liebowitz and Palmer (J Econ Lit 22:77–88, 1984) confirms the results. In conclusions we briefly discuss the pertinence of Whitley’s (The intellectual and social organization of the sciences, 1984) theory for explaining cultural differences across these sub-disciplines based on its dimensions of scholarly practices, ‘mutual dependency’ and ‘task uncertainty’.     

Prenatal exposure to mercury in a prospective mother-infant cohort study in a Mediterranean area, Valencia, Spain

BACKGROUND: Mercury (Hg) is a ubiquitous pollutant that negatively affects fetal and child neurodevelopment at accidental high-dose exposure. Some studies indicate that Mediterranean populations could be at risk of prenatal exposure to mercury through fish consumption. OBJECTIVES: To assess the prenatal exposure to total mercury (T-Hg), both inorganic and organic, in newborns by analyzing the T-Hg concentration in cord blood, and to evaluate the role of maternal fish consumption in this exposure. METHODS: In the context of a multi-center project (INMA project), a prospective birth cohort was set up in Valencia, Spain, from 2005 to 2006. A total of 253 newborns were included in this study. We compared cord blood T-Hg concentration by levels of fish intake assessed by a food frequency questionnaire completed at 28-32 weeks of gestation. Maternal covariates were obtained through a questionnaire. RESULTS: The geometric mean of T-Hg at birth was 9.9 microg/L (95% CI: 9.0, 10.8). Seventy five percent of cord blood samples were above the estimated level assumed to be without appreciable harm (5.8 microg/L). Women who consumed a portion of large oily fish, lean fish, or mixed fried fish two or more times per week had mean cord blood levels 1.6, 1.4 and 1.3 times higher, respectively, than those who rarely or never consumed fish. Other factors such as the mother's age, country of origin, smoking and season of delivery were also significantly and independently associated with cord blood T-Hg concentrations. CONCLUSIONS: Newborns from a Mediterranean area presented elevated levels of T-Hg in cord blood. Higher concentrations of T-Hg were related to maternal fish intake, particularly in the case of large oily fish species.     

Prenatal exposure to lead in Spain: cord blood levels and associated factors

Introduction and Objective

Lead is a known neurotoxic. Fetuses and infants are very vulnerable to lead exposure, since their blood-brain barrier is not completely formed. Hence, there is an importance for monitoring of blood lead levels prenatally and during early infancy. The aim of this study is to evaluate the prenatal exposure to lead and its association with maternal factors in four population based mother-child cohorts in Spain. The present research was carried out within the framework of the INMA project INfancia y Medio Ambiente (Environment and Childhood).

Methods

A total of 1462 pregnant women were recruited between 2004 and 2008. Lead was analyzed in a sample of cord blood by thermal decomposition, amalgation, and Atomic Absorption Spectrometry. Maternal sociodemographic, lifestyle and dietary factors were obtained by questionnaires during pregnancy. A multivariate logistic regression model was constructed. The dependent variable was a dichotomous lead level variable (detected vs no detected, i.e. ≥ vs < 2 μg/dL).

Results

A low percentage of cord blood samples with lead levels ≥ 2 μg/dL were found (5.9%). Geometric mean and maximum were 1.06 μg/dL and 19 μg/dL, respectively. Smoking at the beginning of pregnancy, age, social class, weight gain during pregnancy, gravidity, and place of residence were the maternal factors associated with detectable cord blood lead levels. Mother's diet does not appear to be a determining factor of lead exposure. Nevertheless, daily intake of iron and zinc may act as a protective factor against having cord blood lead levels ≥ 2 μg/dL.

Conclusion

In the different regions of Spain taking part in this study, lead levels to which newborns are exposed are low. Mobilization of lead from bones may be the main contributor to the cord blood levels.     

Spatial learning and memory deficits after telencephalic ablation in goldfish trained in place and turn maze procedures.

The present work investigated whether the fish telencephalon is involved in spatial learning based on place strategies in a manner similar to mammalian hippocampus. Goldfish were trained in a 4-arm maze in a room with relevant spatial cues. Sham and to-be-ablated subjects were trained in each of 4 experimental procedures designed as follows: place, turn, place-turn, and control. After acquisition, complete ablations of both telencephalic hemispheres for the experimental groups were carried out. The results showed that ablation exclusively impaired performance in animals using place strategies; in these, accuracy fell to chance level during both postsurgery retraining and reversal periods. In the other groups, ablation of the telencephalon did not induce any significant deficit. These results suggest that the fish telencephalon plays a crucial role in complex place learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Holographic otoscope for nanodisplacement measurements of surfaces under dynamic excitation

We describe a novel holographic otoscope system for measuring nanodisplacements of objects subjected to dynamic excitation. Such measurements are necessary to quantify the mechanical deformation of surfaces in mechanics, acoustics, electronics, biology, and many other fields. In particular, we are interested in measuring the sound-induced motion of biological samples, such as an eardrum. Our holographic otoscope system consists of laser illumination delivery (IS), optical head (OH), and image processing computer (IP) systems. The IS delivers the object beam (OB) and the reference beam (RB) to the OH. The backscattered light coming from the object illuminated by the OB interferes with the RB at the camera sensor plane to be digitally recorded as a hologram. The hologram is processed by the IP using the Fresnel numerical reconstruction algorithm, where the focal plane can be selected freely. Our holographic otoscope system is currently deployed in a clinic, and is packaged in a custom design. It is mounted in a mechatronic positioning system to increase its maneuverability degrees to be conveniently positioned in front of the object to be measured. We present representative results highlighting the versatility of our system to measure deformations of complex elastic surfaces in the wavelength scale including a copper foil membrane and postmortem tympanic membrane. SCANNING 33: 342-352, 2011. ? 2011 Wiley Periodicals, Inc.     

Indoor and outdoor air concentrations of BTEX and determinants in a cohort of one-year old children in Valencia, Spain

BTEX is the commonly used term for a group of toxic compounds (benzene, toluene, ethyl benzene, ortho-xylene and meta- and para-xylene), some of which, most notably benzene, are known carcinogens. The aim of this study is to measure the BTEX levels both inside and outside the homes of 352 one-year old children from the Valencia cohort of the INMA study (Spain) and to analyze the determinants of these levels. Passive samplers were used to measure BTEX levels during a 15 day period and a questionnaire was administered to gather information on potentially associated factors (sociodemographics, residential conditions, and lifestyle). The average concentrations of benzene, toluene, ethyl benzene, ortho-xylene, and meta- and para-xylene were 0.9, 3.6, 0.6, 0.6, and 1.0 μg/m³, respectively. On average, the indoor levels of all the compounds were approximately 2.5 times higher than those observed outdoors. Factors associated with higher BTEX concentrations inside the home were being the child of a mother of non-Spanish origin, living in a house that had been painted within the last year, living in an apartment, and not having air conditioning. Higher outdoor concentrations of BTEX depend on the residence being situated in a more urban zone, being located within the city limits, having living in a building with more than one story, residing in an area with a greater frequency of traffic, and the season of the year in which the sample was taken. The data thus obtained provide helpful information not only for implementing measures to reduce exposure to these pollutants, but also for evaluating the relation between such exposure and possible health risks for the children in the cohort.     

Thermodynamics of hydrogen adsorption on the zeolite Ca-Y

Variable-temperature infrared spectroscopy was used for a thermodynamic study on hydrogen adsorption on the zeolite Ca-Y. Adsorption renders the H–H stretching mode infrared active, at 4078 cm⁻¹; and simultaneous measurement of IR absorbance and hydrogen equilibrium pressure, over a range of temperature, allowed standard adsorption enthalpy and entropy to be determined. They resulted to be ΔH°= −15.0(±1.0) kJ mol⁻¹ and ΔS° = −127(±10) J mol⁻¹ K⁻¹, respectively. These relatively high values of adsorption enthalpy and entropy are discussed in the broader context of corresponding data for other hydrogen adsorbents.     

Blood-group phenotypes, sulfomucins, and Helicobacter pylori in Barrett's esophagus

Barrett's esophagus, morphologically analogous to gastric intestinal metaplasia, often precedes the development of esophageal adenocarcinoma. In the stomach, expression of sulfomucins and aberrant Lewis(a) (Le[a]) antigen is an excellent predictor of premalignant progression, and Helicobacter pylori infection is a crucial determinant for the development of atrophy, metaplasia, and adenocarcinoma. In the esophagus, the significance of sulfomucin expression is controversial, the aberrant expression of Le(a) has not been explored, and the role of H pylori in the evolution of preneoplastic conditions is unknown. We investigated in 155 patients referred for endoscopy the association of Barrett's esophagus with expression of sulfomucins, Lewis, secretor, and ABO phenotypes, and H pylori infection. We report a subtype of intestinal metaplasia, present in all patients with esophageal adenocarcinoma, similar to gastric intestinal metaplasia of colonic type (type III or incomplete), that expresses sulfomucins and aberrant Le(a) in goblet and columnar cells. Lewis(a+b-), nonsecretor and blood group A phenotypes, were all positively associated with esophageal adenocarcinoma, suggesting a genetic susceptibility. H pylori infection was detected in 75% of patients with esophageal adenocarcinoma.