Influence of Sonication on the Molecular Characteristics of Carbopol® and Its Rheological Behavior in Microgels.

In this work, the effect of sonication on the molecular characteristics of polyacrylic acid (Carbopol® Ultrez 10), as well as on its rheological behavior in aqueous dispersions and microgels, was analyzed for the first time by rheometry, weight-average molecular weight (Mw) measurements via static light scattering (SLS), Fourier transform infrared (FTIR) spectroscopy and confocal microscopy. For this, the precursor dispersion and the microgels containing 0.25 wt.% of Ultrez 10 were sonicated in a commercial ultrasound bath at constant power and at different times. The main rheological properties of the microgel, namely, shear modulus, yield stress and viscosity, all decreased with increasing sonication time, while the microgel's Herschel-Bulkley (H-B) behavior, without thixotropy, was preserved. Also, Mw of Ultrez 10 decreased up to almost one-third (109,212 g/mol) of its original value (300,860 g/mol) after 180 min of sonication. These results evidence a softening of the gel microstructure, which results from the reduction in the Mw of polyacrylic acid with sonication time. Separately, FTIR measurements show that sonication produces scission in the C-C links of the Carbopol® backbone, which results in chains with the same chemistry but lower molecular weight. Finally, confocal microscopy observations revealed a diminution of the size of the microsponge domains and more free solvent with sonication time, which is reflected in a less compact and softer microstructure. The present results indicate that both the microstructure and the rheological behavior of Carbopol® microgels, in particular, and complex fluids, in general, may be manipulated or tailored by systematic high-power ultrasonication.

Epidemiological Overview of Overweight and Obesity Related to Eating Habits, Physical Activity and the Concurrent Presence of Depression and Anxiety in Adolescents from High Schools in Mexico City: A Cross-Sectional Study.

Overweight and obesity in adolescents has become a serious public health problem worldwide and Mexico City is no exception. Therefore, the objective of this study was to investigate the epidemiological panorama of overweight and obesity related to eating habits, physical activity and the concurrent presence of depression and anxiety in adolescents from high schools in Mexico City. Anthropometric measurements were taken from 2710 adolescents from 33 participating high schools. Likewise, a previously validated eating habit and physical activity questionnaire was administered, which consisted of four different sections, where each of the sections focused on key aspects of the participants' lifestyle: (1) eating habits, (2) intake of non-recommended foods, (3) food and company environment, and (4) physical activity. Moreover, the Hospital Anxiety and Depression Scale (HADS) for anxiety and depression was applied. In this study, a high prevalence of overweight and obesity (26.5% overweight and 20.0% obese) was found in adolescents from high schools in Mexico City. Only 13.14% of participants had adequate eating habits and 18.19% physical activity habits. An association was found between having inadequate eating habits and obesity in adolescent women (OR = 1.95; CI 1.009-3.76). Additionally, associations were observed between depression symptoms and obesity (OR = 5.68, CI 1.36-32.81; p = 0.01), while anxiety was associated with underweight and obesity adjusted by other dietary habits and psychological factors. Therefore, it is important to identify adolescents with overweight or obesity and establish prevention strategies for weight control in this age group, promoting healthy eating, physical activity and education in mental health.

Metamaterial adhesives for programmable adhesion through reverse crack propagation.

Adhesives are typically either strong and permanent or reversible with limited strength. However, current strategies to create strong yet reversible adhesives needed for wearable devices, robotics and material disassembly lack independent control of strength and release, require complex fabrication or only work in specific conditions. Here we report metamaterial adhesives that simultaneously achieve strong and releasable adhesion with spatially selectable adhesion strength through programmed cut architectures. Nonlinear cuts uniquely suppress crack propagation by forcing cracks to propagate backwards for 60× enhancement in adhesion, while allowing crack growth in the opposite direction for easy release and reusability. This mechanism functions in numerous adhesives on diverse substrates in wet and dry conditions and enables highly tunable adhesion with independently programmable adhesion strength in two directions simultaneously at any location. We create these multifunctional materials in a maskless, digital fabrication framework to rapidly customize adhesive characteristics with deterministic control for next-generation adhesives.

Microalgae Biomass as a New Potential Source of Sustainable Green Lubricants.

Lubricants are materials able to reduce friction and/or wear of any type of moving surfaces facilitating smooth operations, maintaining reliable machine functions, and reducing risks of failures while contributing to energy savings. At present, most worldwide used lubricants are derived from crude oil. However, production, usage and disposal of these lubricants have significant impact on environment and health. Hence, there is a growing pressure to reduce demand of this sort of lubricants, which has fostered development and use of green lubricants, as vegetable oil-based lubricants (biolubricants). Despite the ecological benefits of producing/using biolubricants, availability of the required raw materials and agricultural land to create a reliable chain supply is still far from being established. Recently, biomass from some microalgae species has attracted attention due to their capacity to produce high-value lipids/oils for potential lubricants production. Thus, this multidisciplinary work reviews the main chemical-physical characteristics of lubricants and the main attempts and progress on microalgae biomass production for developing oils with pertinent lubricating properties. In addition, potential microalgae strains and chemical modifications to their oils to produce lubricants for different industrial applications are identified. Finally, a guide for microalgae oil selection based on its chemical composition for specific lubricant applications is provided.

Influence of age on molecular characteristics and rheological behavior of nopal mucilage.

Nopal mucilages are of interest due to a variety of potential applications, which include their use as thickeners and rheological modifiers. In this work, changes in molecular characteristics of nopal mucilages with their age and its influence on the rheological behavior of their solutions were analyzed by light scattering, high performance liquid chromatography, a colorimetric method, and linear viscoelastic rheometrical measurements. For this, mucilages obtained from cladodes from Opuntia ficus-indica with different ages, namely 20, 80, and 600 days, respectively, were extracted using water as solvent and then subjected to freeze-drying. The weight-average molecular weight (M w) of the mucilages was found to increase along with the age; meanwhile, the concentration of uronic acids increased and the galactose, rhamnose, and xylose contents decreased. Increasing M w with age resulted in enhanced viscoelastic behavior of solutions, namely, higher viscosity and elasticity at lower mucilage concentrations. Also, along with increasing M w, decrease in neutral sugar contents and increase of pectic compounds (uronic acids) and Ca+ cations in mucilages with age promoted formation of weak gels. Overall, the molecular weights and rheological behaviors reported in this work for nopal mucilages are comparable to those of widely used thickeners such as xanthan and guar gums, which suggest their use in similar applications regarding its age.

Neurofunctional correlates of eye to hand motor transfer.

This work investigates the transfer of motor learning from the eye to the hand and its neural correlates by using functional magnetic resonance imaging (fMRI) and a sensorimotor task consisting of the continuous tracking of a virtual target. In pretraining evaluation, all the participants (experimental and control group) performed the tracking task inside an MRI scanner using their right hand and a joystick. After which, the experimental group practiced an eye-controlled version of the task for 5 days using an eye tracking system outside the MRI environment. Post-training evaluation was done 1 week after the first scanning session, where all the participants were scanned again while repeating the manual pretraining task. Behavioral results show that the training in the eye-controlled task produced a better performance not only in the eye-controlled modality (motor learning) but also in the hand-controlled modality (motor transfer). Neural results indicate that eye to hand motor transfer is supported by the motor cortex, the basal ganglia and the cerebellum, which is consistent with previous research focused on other effectors. These results may be of interest in neurorehabilitation to activate the motor systems and help in the recovery of motor functions in stroke or movement disorder patients.

Is it necessary to show virtual limbs in action observation neurorehabilitation systems?

INTRODUCTION: Action observation neurorehabilitation systems are usually based on the observation of a virtual limb performing different kinds of actions. In this way, the activity in the frontoparietal Mirror Neuron System is enhanced, which can be helpful to rehabilitate stroke patients. However, the presence of limbs in such systems might not be necessary to produce mirror activity, for example, frontoparietal mirror activity can be produced just by the observation of virtual tool movements. The objective of this work was to explore to what point the presence of a virtual limb impacts the Mirror Neuron System activity in neurorehabilitation systems. METHODS: The study was conducted by using an action observation neurorehabilitation task during a functional magnetic resonance imaging (fMRI) experiment with healthy volunteers and comparing two action observation conditions that: 1 - included or 2 - did not include a virtual limb. RESULTS: It was found that activity in the Mirror Neuron System was similar during both conditions (i.e. virtual limb present or absent). CONCLUSIONS: These results open up the possibility of using new tasks that do not include virtual limbs in action observation neurorehabilitation environments, which can give more freedom to develop such systems.

The poverty of adult morphology: Bioacoustics, genetics, and internal tadpole morphology reveal a new species of glassfrog (Anura: Centrolenidae: Ikakogi) from the Sierra Nevada de Santa Marta, Colombia.

Ikakogi is a behaviorally and morphologically intriguing genus of glassfrog. Using tadpole morphology, vocalizations, and DNA, a new species is described from the Sierra Nevada de Santa Marta (SNSM), an isolated mountain range in northern Colombia. The new taxon is the second known species of the genus Ikakogi and is morphologically identical to I. tayrona (except for some larval characters) but differs by its genetic distance (14.8% in mitochondrial encoded cytochrome b MT-CYB; ca. 371 bp) and by the dominant frequency of its advertisement call (2928-3273 Hz in contrast to 2650-2870 Hz in I. tayrona). They also differ in the number of lateral buccal floor papillae, and the position of the buccal roof arena papillae. Additionally, the new species is differentiated from all other species of Centrolenidae by the following traits: tympanum visible, vomerine teeth absent, humeral spines present in adult males, bones in life white with pale green in epiphyses, minute punctuations present on green skin dorsum, and flanks with lateral row of small, enameled dots that extend from below eye to just posterior to arm insertion. We describe the external and internal larval morphology of the new species and we redescribe the larval morphology of Ikakogi tayrona on the basis of field collected specimens representing several stages of development from early to late metamorphosis. We discuss the relevance of larval morphology for the taxonomy and systematics of Ikakogi and other centrolenid genera. Finally, we document intraspecific larval variation in meristic characters and ontogenetic changes in eye size, coloration, and labial tooth-rows formulas, and compare tadpoles of related species. Ikakogi tayrona has been proposed as the sister taxon of all other Centrolenidae; our observations and new species description offers insights about the ancestral character-states of adults, egg clutches, and larval features in this lineage of frogs.

Clinical and Radiographic Characteristics as Predictive Factors of Swelling and Trismus after Mandibular Third Molar Surgery: A Longitudinal Approach.

Introduction: Factors that contribute to swelling and trismus are complex, and they are originated by surgical trauma. The aim of the present study was to determine whether clinical and radiographic factors could predict the level of swelling and trismus after lower third molar surgery, through longitudinal approach. Methodology: A prospective longitudinal trial was carried out. Forty-five patients of both genders with clinical and radiographic diagnosis of asymptomatic mandibular impacted third molar and with no intake of analgesic or anti-inflammatory drugs 12 h prior to surgery were recruited and evaluated in a 72 h follow-up period. A mixed repeated measures model and backward and restricted maximal likelihood methods were used to analyze the data. Results: Male gender, body mass index (BMI), the relation to the lingual and buccal walls, and age were determinants for predicting postoperative swelling and for exerting a significant influence (P < 0.05). Conclusions: This study suggests the association of male gender, the relation to lingual and buccal walls, BMI, and age with measurement of swelling.

Fibroblast populated collagen lattices exhibit opposite biophysical conditions by fibrin or hyaluronic acid supplementation.

Fibrin and hyaluronic acid are important components of the provisional wound matrix. Through interactions with fibroblasts, they provide biophysical cues that regulate the viscoelastic properties of the extracellular matrix. To understand the roles of fibrin and hyaluronic acid in a collagenous environment, we used fibroblast populated collagen lattices (collagen, collagen-fibrin, and collagen-hyaluronic acid). Compared with collagen and collagen-hyaluronic acid cultures, collagen-fibrin cultures showed less contraction, which is correlated with increased elastic (G') and complex (|G*|) moduli, and reduced proportions of dendritic fibroblasts, despite increased αv integrin expression. Stiffness decreased during culture in collagen-fibrin environment, meanwhile phase shift (δ) values increased, clearly associated with the rise in fibrinolytic and gelatinolytic activities. These processes changed the viscoelastic properties of the system toward G' and |G*| values observed on day 5 in collagen cultures. Although less collagen turnover was observed in collagen-fibrin cultures than in collagen and collagen-hyaluronic acid cultures, collagen neosynthesis was apparently insufficient to contribute to the overall viscoelastic properties of the system. Collagen-hyaluronic acid cultures showed very limited changes during time. Firstly, they exhibited the highest δ values, suggesting an increase in the viscous behavior due to the hygroscopic properties of hyaluronic acid. These results showed that fibrin and hyaluronic acid not only affect differently the viscoelastic properties of the culture, they can tune fibroblastic activity by regulating cell attachment and extracellular matrix remodeling.

[Intravenous iron, functional recovery and delirium in patients with hip fracture. FEDEREF study. Single-centre randomised, placebo-controlled, and double-blind clinical trial. 2014-001923-53: EudraCT number]. / Hierro intravenoso, recuperación funcional y delirium en pacientes con fractura de cadera. Estudio FEDEREF. Ensayo clínico unicéntrico aleatorizado, controlado con placebo, doble ciego. Número EudraCT: 2014-001923-53.

INTRODUCTION: There are no previous studies evaluating the effect of intravenous iron therapy on functional and cognitive status of patients with hip fracture (HF). MATERIAL AND METHODS: A single-centre randomised, placebo-controlled, double-blind and parallel treatment, clinical trial has been designed to assess the efficacy of intravenous iron therapy during the peri-operative period in elderly patients suffering from a HF. Blinding will be ensured by the packaging of the drug infusion system. On days 1, 3, and 5 from admission, the intervention group will receive 200mg Venofer® (iron sucrose) diluted in 100ml saline, and the control group 100ml saline, also on days 1, 3 and 5. Patients will received conventional treatment in ortho-geriatric unit of the Hospital Infanta Sofia. Functional variables (activities of daily living and walking), cognitive (cognitive status and delirium), surgical, demographic and clinical characteristics will be collected during admission in order to assess the impact of treatment. A safety analysis of the treatment will also performed. Patients will be followed-up at 3, 6, and 12 months. RESULTS: The study will attempt to provide evidence on the impact of the intravenous iron administration on functional recovery. It will be determined whether iron therapy negatively affects the incidence of post-operative delirium. Finally, report will be presented on the safety data of intravenous iron in elderly HF patients, as well as the impact on allogenic blood transfusion savings. CONCLUSIONS: The inclusion of elderly HF patients admitted to an ortho-geriatric unit, in a clinical trial, will help to improve the knowledge of the treatment impact on a usual scenario, and provide useful data for use in other units.

Sex-specific charts for abdominal circumference in term and near-term Caucasian newborns.

AIMS: Abdominal circumference (AC) assessment may be used as an index of abdominal visceral size, fetal fat store, and intrauterine nutrition. The aim of this study is to construct sex-specific references and smoothed percentiles for AC at birth in term and near-term Caucasian infants. METHODS: AC was measured in 4542 singleton newborns (2323 males, 2219 females), at a gestational age > or =35 weeks. Smoothed percentiles for AC were constructed by sex and gestational age according to the LMS method. RESULTS: Males had higher AC than females but differences were only statistically significant beyond 37 weeks. AC increased from 35 to 41 weeks in both sexes. CONCLUSIONS: Sex-specific references constructed for AC in term and near-term Caucasian newborns might be used, as other anthropometric parameters, in the assessment of nutritional status at birth.

Rheometry-PIV of shear-thickening wormlike micelles.

The shear-thickening behavior of an equimolar semidilute aqueous solution of 40 mM/L cetylpyridinium chloride and sodium salicylate was studied in this work by using a combined method of rheometry and particle image velocimetry (PIV). Experiments were conducted at 27.5 degrees C with Couette, vane-bob, and capillary rheometers in order to explore a wide shear stress range as well as the effect of boundary conditions and time of flow on the creation and destruction of shear-induced structures (SIS). The use of the combined method of capillary rheometry with PIV allowed the detection of fast spatial and temporal variations in the flow kinematics, which are related to the shear-thickening behavior and the dynamics of the SIS but are not distinguished by pure rheometrical measurements. A rich-in-details flow curve was found for this solution, which includes five different regimes. Namely, at very low shear rates a Newtonian behavior was found, followed by a shear thinning one in the second regime. In the third, shear banding was observed, which served as a precursor of the SIS and shear-thickening. The fourth and fifth regimes in the flow curve were separated by a spurtlike behavior, and they clearly evidenced the existence of shear-thickening accompanied by stick-slip oscillations at the wall of the rheometer, which subsequently produced variations in the shear rate under shear stress controlled flow. Such a stick-slip phenomenon prevailed up to the highest shear stresses used in this work and was reflected in asymmetric velocity profiles with spatial and temporal variations linked to the dynamics of creation and breakage of the SIS. The presence of apparent slip at the wall of the rheometer provides an energy release mechanism which leads to breakage of the SIS, followed by their further reformation during the stick part of the cycles. In addition, PIV measurements allowed the detection of apparent slip at the wall, as well as mechanical failures in the bulk of the fluid, which suggests an extra contribution of the shear stress field to the SIS dynamics. Increasing the residence time of the fluid in the flow system enhanced the shear-thickening behavior. Finally, the flow kinematics is described in detail and the true flow curve is obtained, which only partially fits into the scheme of existing theoretical models for shear-thickening solutions.

A further case of opsismodysplasia with hydrocephalus.

We present a case of opsismodysplasia, a very rare skeletal dysplasia, in a term newborn female who had short length, short extremities and markedly short fingers. Radiological studies demonstrated severe platyspondyly, absence of epiphyseal ossification centers, short tubular bones, especially severe in hands and feet, with metaphyseal cupping. She also had hydrocephaly, a rare finding in opsismodysplasia. In our literature review we have found 24 cases, 17 born alive and seven terminations of pregnancy (TOPs).

Cardiac findings in adolescents with anorexia nervosa at diagnosis and after weight restoration.

UNLABELLED: The aim of this study was to compare heart abnormalities in a group of young women with anorexia nervosa at diagnosis and after weight restoration. A total of 40 young women with anorexia nervosa were evaluated, at baseline, (diagnosis) and follow-up (9 to 18 months later) and matched with 40 healthy women of the same age and of normal weight. QT interval was measured from surface electrocardiograms. QT dispersion was defined as the difference between maximum QT and minimum QT occurring in any of the 12 leads. Left ventricular end-diastolic diameter, left ventricular end-systolic diameter, left ventricular mass, left ventricular mass index, cardiac output, fractional shortening and fractional ejection, were measured by echocardiography. In anorexia nervosa patients, corrected QT interval and QT dispersion, significantly decreased from baseline to follow-up. Left ventricular end-diastolic dimension, left ventricular mass index, and cardiac output, in anorexia nervosa were significantly lower at diagnosis than at follow-up after weight restoration. CONCLUSION: Adolescents with anorexia nervosa have significant functional and structural cardiac abnormalities; weight gain was associated with improvement. Appropriate attention should be paid to cardiac involvement.

Gender differences in newborn subcutaneous fat distribution.

UNLABELLED: The pattern and distribution of subcutaneous fat in term and preterm newborns has been assessed by skinfold thicknesses (ST), describing gender and gestational age variations. Weight, length and ST (triceps, biceps, subscapular and suprailiac) were measured in 4634 neonates (2445 males and 2189 females) aged from 32 to 41 gestational weeks. Central to total skinfold ratio (CTS), (suprailiac + subscapular)/sum of 4 ST, was calculated. Males were heavier and longer than females. The sum of 4 ST and CTS was higher in females at every gestational age (with significant differences from 35 weeks) and also the sum of 4 ST per kg body weight (P < 0.05 from 32-33 weeks). Throughout the gestational period, ST increased significantly (P < 0.0001) but CTS did not show variations, neither in males nor in females. CONCLUSION: term and preterm females have a more centralised pattern and more amount of subcutaneous fat than males. Central to total skinfold ratio must be considered as an index of centripetal fat store which is independant of gestational age.

Identifying patients without favourable long-term outcome among those with medically stabilized unstable angina and a negative dipyridamole stress echocardiogram.

AIMS: Patients with medically stabilized unstable angina and a negative stress echocardiogram have a favourable outcome as a whole. This study sought to identify which subsets of patients are associated with serious events at long-term within this population. METHODS AND RESULTS: We studied and followed-up 128 patients (mean 2.2 +/- 1.3 years) with medically stabilized unstable angina and a negative dipyridamole stress echocardiogram. Cumulative survival rates were 98.2 +/- 1.3%, 96.0 +/- 2.2% and 93.2 +/- 3.2%, at 1, 2 and 4 years, respectively. Freedom from events (death, myocardial infarction, and revascularization) were 98.2 +/- 1.3%, 96.0 +/- 2.2% and 86.3 +/- 6.0%, at 1, 2, and 4 years, respectively. Cumulative mortality rate was higher in men (3.6 +/- 2.5%, 8.5 +/- 4.1%, and 12.2 +/- 5.4% at 1, 2, and 4 years, vs. 0% at the end of the follow-up in women; p = 0.034), and in those with previous myocardial infarction (4.3 +/- 4.3%, 9.1 +/- 6.2%, and 18.2 +/- 2.3% at 1, 2 and 4 years, vs. 1.1 +/- 1.1%, 2.9 +/- 2.1%, and 2.9 +/- 2.1% in those without previous myocardial infarction, respectively; p = 0.047). CONCLUSION: Among patients with medically stabilized unstable angina and a negative dipyridamole stress echocardiogram, male gender and previous myocardial infarction are associated with a non-favourable outcome.

Encephalocraniocutaneous lipomatosis: neurologic manifestations.

We report a new case of encephalocraniocutaneous lipomatosis, a rare neurocutaneous syndrome of unknown etiology with involvement of tissues arising from the mesoderm and ectoderm: skin, eye, adipose tissue, and brain. We also review the neurologic manifestations of the syndrome, the most frequent of which include seizures, ventricular enlargement, calcifications, mental retardation, and cerebellopontine angle tumor. Our patient had an extensive extradural spinal cord lipomatous lesion, emphasizing the importance of screening for spinal abnormalities in asymptomatic patients with this condition.