1,265 research outputs found
Enzymatic synthesis of structured lipids from liquid and fully hydrogenated high oleic sunflower oil
sem informaçãoStructured lipids (SL) were synthesized via enzymatic (EI) and chemical interesterification of high oleic sunflower oil (SO) and fully hydrogenated high oleic SO with Lipozyme TL IM (Thermomyces lanuginose) for 3 h at 70°C, 300 rpm. Reaction showed change211702716sem informaçãosem informaçãosem informaçã
Casimir forces on a silicon micromechanical chip
Quantum fluctuations give rise to van der Waals and Casimir forces that
dominate the interaction between electrically neutral objects at sub-micron
separations. Under the trend of miniaturization, such quantum electrodynamical
effects are expected to play an important role in micro- and nano-mechanical
devices. Nevertheless, utilization of Casimir forces on the chip level remains
a major challenge because all experiments so far require an external object to
be manually positioned close to the mechanical element. Here, by integrating a
force-sensing micromechanical beam and an electrostatic actuator on a single
chip, we demonstrate the Casimir effect between two micromachined silicon
components on the same substrate. A high degree of parallelism between the two
near-planar interacting surfaces can be achieved because they are defined in a
single lithographic step. Apart from providing a compact platform for Casimir
force measurements, this scheme also opens the possibility of tailoring the
Casimir force using lithographically defined components of non-conventional
shapes
Ultrahard carbon film from epitaxial two-layer graphene
Atomically thin graphene exhibits fascinating mechanical properties, although
its hardness and transverse stiffness are inferior to those of diamond. To
date, there hasn't been any practical demonstration of the transformation of
multi-layer graphene into diamond-like ultra-hard structures. Here we show that
at room temperature and after nano-indentation, two-layer graphene on SiC(0001)
exhibits a transverse stiffness and hardness comparable to diamond, resisting
to perforation with a diamond indenter, and showing a reversible drop in
electrical conductivity upon indentation. Density functional theory
calculations suggest that upon compression, the two-layer graphene film
transforms into a diamond-like film, producing both elastic deformations and
sp2-to-sp3 chemical changes. Experiments and calculations show that this
reversible phase change is not observed for a single buffer layer on SiC or
graphene films thicker than 3 to 5 layers. Indeed, calculations show that
whereas in two-layer graphene layer-stacking configuration controls the
conformation of the diamond-like film, in a multilayer film it hinders the
phase transformation.Comment: Published online on Nature Nanotechnology on December 18, 201
A negative screen for mutations in calstabin 1 and 2 genes in patients with dilated cardiomyopathy
<p>Abstract</p> <p>Background</p> <p>Calstabins 1 and 2 bind to Ryanodine receptors regulating muscle excitation-contraction coupling. Mutations in Ryanodine receptors affecting their interaction with calstabins lead to different cardiac pathologies. Animal studies suggest the involvement of calstabins with dilated cardiomyopathy.</p> <p>Results</p> <p>We tested the hypothesis that calstabins mutations may cause dilated cardiomyopathy in humans screening 186 patients with idiopathic dilated cardiomyopathy for genetic alterations in calstabins 1 and 2 genes (<it>FKBP12 </it>and <it>FKBP12.6)</it>. No missense variant was found. Five no-coding variations were found but not related to the disease.</p> <p>Conclusions</p> <p>These data corroborate other studies suggesting that mutations in <it>FKBP12 </it>and <it>FKBP12.6 </it>genes are not commonly related to cardiac diseases.</p
Crystalline Gaq3Nanostructures: Preparation, Thermal Property and Spectroscopy Characterization
Crystalline Gaq31-D nanostructures and nanospheres could be fabricated by thermal evaporation under cold trap. The influences of the key process parameters on formation of the nanostructures were also investigated. It has been demonstrated that the morphology and dimension of the nanostructures were mainly controlled by working temperature and working pressure. One-dimensional nanostructures were fabricated at a lower working temperature, whereas nanospheres were formed at a higher working temperature. Larger nanospheres could be obtained when a higher working pressure was applied. The XRD, FTIR, and NMR analyses evidenced that the nanostructures mainly consisted of δ-phase Gaq3. Their DSC trace revealed two small exothermic peaks in addition to the melting endotherm. The one in lower temperature region was ascribed to a transition from δ to β phase, while another in higher temperature region could be identified as a transition from β to δ phase. All the crystalline nanostructures show similar PL spectra due to absence of quantum confinement effect. They also exhibited a spectral blue shift because of a looser interligand spacing and reduced orbital overlap in their δ-phase molecular structures
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Divided attention selectively impairs memory for self-relevant information
Information that is relevant to oneself tends to be remembered more than information that relates to other people, but the role of attention in eliciting this "self-reference effect" is unclear. In the present study, we assessed the importance of attention in self-referential encoding using an ownership paradigm, which required participants to encode items under conditions of imagined ownership by themselves or by another person. Previous work has established that this paradigm elicits a robust self-reference effect, with more "self-owned" items being remembered than "other-owned" items. Access to attentional resources was manipulated using divided-attention tasks at encoding. A significant self-reference effect emerged under full-attention conditions and was related to an increase in episodic recollection for self-owned items, but dividing attention eliminated this memory advantage. These findings are discussed in relation to the nature of self-referential cognition and the importance of attentional resources at encoding in the manifestation of the self-reference effect in memory
A systematic review of musculoskeletal disorders among school teachers
<p>Abstract</p> <p>Background</p> <p>Musculoskeletal disorders (MSD) represent one of the most common and most expensive occupational health problems in both developed and developing countries. School teachers represent an occupational group among which there appears to be a high prevalence of MSD. Given that causes of MSD have been described as multi-factorial and prevalence rates vary between body sites and location of study, the objective of this systematic review was to investigate the prevalence and risk factors for MSD among teaching staff.</p> <p>Methods</p> <p>The study involved an extensive search of MEDLINE and EMBASE databases in 2011. All studies which reported on the prevalence and/or risk factors for MSD in the teaching profession were initially selected for inclusion. Reference lists of articles identified in the original search were then examined for additional publications. Of the 80 articles initially located, a final group of 33 met the inclusion criteria and were examined in detail.</p> <p>Results</p> <p>This review suggests that the prevalence of self-reported MSD among school teachers ranges between 39% and 95%. The most prevalent body sites appear to be the back, neck and upper limbs. Nursery school teachers appear to be more likely to report suffering from low back pain. Factors such as gender, age, length of employment and awkward posture have been associated with higher MSD prevalence rates.</p> <p>Conclusion</p> <p>Overall, this study suggests that school teachers are at a high risk of MSD. Further research, preferably longitudinal, is required to more thoroughly investigate the issue of MSD among teachers, with a greater emphasis on the possible wider use of ergonomic principles. This would represent a major step forward in the prevention of MSD among teachers, especially if easy to implement control measures could be recommended.</p
Circuit dissection of the role of somatostatin in itch and pain
Stimuli that elicit itch are detected by sensory neurons that innervate the skin. This information is processed by the spinal cord; however, the way in which this occurs is still poorly understood. Here we investigated the neuronal pathways for itch neurotransmission, particularly the contribution of the neuropeptide somatostatin. We find that in the periphery, somatostatin is exclusively expressed in Nppb+ neurons, and we demonstrate that Nppb+somatostatin+ cells function as pruriceptors. Employing chemogenetics, pharmacology and cell-specific ablation methods, we demonstrate that somatostatin potentiates itch by inhibiting inhibitory dynorphin neurons, which results in disinhibition of GRPR+ neurons. Furthermore, elimination of somatostatin from primary afferents and/or from spinal interneurons demonstrates differential involvement of the peptide released from these sources in itch and pain. Our results define the neural circuit underlying somatostatin-induced itch and characterize a contrasting antinociceptive role for the peptide
Genetic screening and democracy: lessons from debating genetic screening criteria in the Netherlands
Recent decades have witnessed increasing possibilities for genetic testing and screening. In clinical genetics, the doctor’s office defined a secluded space for discussion of sensitive reproductive options in cases of elevated risk for genetic disorders in individuals or their offspring. When prenatal screening for all pregnant women became conceivable, the potential increase in scale made social and ethical concerns relevant for the whole of society. Whereas genetic testing in clinical genetic practice was widely accepted, prenatal screening at a population level met with unease. Concerns were raised regarding social pressure to screen: the sum of individual choice might result in a ‘collective eugenics’. The government’s involvement also raised suspicion: actively offering screening evoked associations with eugenic population policies from the first half of the 20th century. By reconstructing elements of policy and public debate on prenatal screening in the Netherlands from the past 30 years, this article discusses how the government has gradually changed its role in balancing the interest of the individual and the collective on genetic reproductive issues. Against a background of increasing knowledge about and demand for prenatal screening among the population, governmental policy changed from focusing on protection by banning screening toward facilitating screening in a careful and ethically sound way by providing adequate information, decision aids and quality assessment instruments. In the meanwhile, invigorating democracy in public debate may entail discussing concepts of ‘the good life’ in relation to living with or without impairments and dealing with genetic information about oneself or one’s offspring
HURP Expression-Assisted Risk Scores Identify Prognosis Distinguishable Subgroups in Early Stage Liver Cancer
Hepatoma up-regulated protein (HURP) is a component of the chromatin-dependent pathway for spindle assembly. We examined the prognostic predictive value of HURP in human hepatocellular carcinoma (HCC).HURP expression was evaluated by immunocytochemistry of fine needle aspirated hepatoma cells in 97 HCC patients with Barcelona Clinic Liver Cancer (BCLC) stage A. Subsequently, these patients underwent partial hepatectomy (n = 18) or radiofrequency ablation (n = 79) and were followed for 2 to 35 months. The clinicopathological parameters were submitted for survival analysis.HURP expression in aspirated HCC cells was detected in 19.6% patients. Kaplan-Meier survival analysis showed that positive HURP expression (P = 0.023), cytological grading ≥3 (P = 0.008), AFP ≥35 ng/mL (P = 0.039), bilirubin ≥1.3 mg/dL (P = 0.010), AST ≥50 U/L (P = 0.003) and ALT ≥35 U/L (P = 0.005) were all associated with a shorter disease-free survival. A stepwise multivariate Cox proportional hazard model revealed that positive HURP expression (HR, 2.334; 95% CI, 1.165-4.679, P = 0.017), AST ≥50 U/L (HR, 3.697; 95% CI, 1.868-7.319, p<0.001), cytological grade ≥3 (HR, 4.249; 95% CI, 2.061-8.759, P<0.001) and tumor number >1 (HR, 2.633; 95% CI, 1.212-5.722, P = 0.014) were independent predictors for disease-free survival. By combining the 4 independent predictors, patients with different risk scores (RS) showed distinguishable disease-free survival (RS≤1 vs. RS = 2, P = 0.001; RS = 2 vs. RS = 3, P<0.001). In contrast, the patients cannot be separated into prognosis distinguishable subgroups by using AJCC/UICC TNM staging system.HCC patients with BCLC stage A can be separated into three prognosis-distinguishable groups by use of a risk score that is based upon HURP expression in aspirated HCC cells, ALT, cytological grade and tumor number
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