Directed self-organization of graphene nanoribbons on SiC

Realization of post-CMOS graphene electronics requires production of semiconducting graphene, which has been a labor-intensive process. We present tailoring of silicon carbide crystals via conventional photolithography and microelectronics processing to enable templated graphene growth on 4H-SiC{1-10n} (n = 8) crystal facets rather than the customary {0001} planes. This allows self-organized growth of graphene nanoribbons with dimensions defined by those of the facet. Preferential growth is confirmed by Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM) measurements, and electrical characterization of prototypic graphene devices is presented. Fabrication of > 10,000 top-gated graphene transistors on a 0.24 cm2 SiC chip demonstrates scalability of this process and represents the highest density of graphene devices reported to date.Comment: 13 pages, 5 figure

Value priorities and their relations with quality of life in the Baby Boomer generation of Lithuanian nurses: a cross-sectional survey

<p>Abstract</p> <p>Background</p> <p>The understanding of the values of nurses is especially important, since nurses constitute 80% of workforce in the healthcare system in Lithuania. In addition to that, nursing is one of the major constituents of healthcare. The aim of this study was to determine what values predominate in the cohort of Baby Boomer nurses, and to evaluate the relation of these values with quality of life using M. Rokeach's terminal and instrumental values scale. M.Rokeach distinguished terminal values (such as world peace, wisdom, and happiness), which are preferred end-states of existence, and instrumental values (such as responsibility and cooperation), which are preferred modes of conduct.</p> <p>Methods</p> <p>We performed a representative anonymous questionnaire-based inquiry of nurses working in regional hospitals of Lithuania. The nurses who participated in the study were distributed into four work cohorts: the Veterans, the Baby Boomers, the Generation Xers, and the Generation Nexters. The majority of the nurses belonged to the Baby Boomers and the Generation Xers cohorts. Since in Lithuania, like in the whole Europe, the representatives of the Baby Boomers generation are predominating among working people, we selected this cohort (N = 387) for the analysis. The survey data was processed using the SPSS statistical software package</p> <p>Results</p> <p>The main values in life were family security, tranquility, and a sense of accomplishment. However, such values as true friendship, equality, and pleasurable and leisured life were seen as rather insignificant. The most important instrumental values were honesty, skillfulness, and responsibility. Our study showed a statistically significant (albeit weak) correlation between the QOL and terminal values such as the sense of accomplishment, tranquility, equality, and pleasure, as well as the instrumental value – obedience. We detected a statistically significant relationship between good QOL and satisfaction with oneself, relationships with the surrounding people, and friends' support.</p> <p>Conclusion</p> <p>The findings of our study showed that, although Lithuania was under a totalitarian regime for 50 years, both the terminal and the instrumental values of the Baby Boomers generation are very similar to those of the same generation in other countries.</p

Sensing of Fatty Acids for Octanoylation of Ghrelin Involves a Gustatory G-Protein

Ghrelin is an important regulator of energy--and glucose homeostasis. The octanoylation at Ser(3) is essential for ghrelin's biological effects but the mechanisms involved in the octanoylation are unknown. We investigated whether the gustatory G-protein, α-gustducin, and the free fatty acid receptors GPR40 and GPR120 are involved in the fatty acid sensing mechanisms of the ghrelin cell.Wild-type (WT) and α-gustducin knockout (gust(-/-)) mice were fed a glyceryl trioctanoate-enriched diet (OD) during 2 weeks. Ghrelin levels and gastric emptying were determined. Co-localization between GPR40, GPR120 and ghrelin or α-gustducin/α-transducin was investigated by immunofluorescence staining. The role of GPR120 in the effect of medium and long chain fatty acids on the release of ghrelin was studied in the ghrelinoma cell line, MGN3-1. The effect of the GPR40 agonist, MEDICA16, and the GPR120 agonist, grifolic acid, on ghrelin release was studied both in vitro and in vivo.Feeding an OD specifically increased octanoyl ghrelin levels in the stomach of WT mice but not of gust(-/-) mice. Gastric emptying was accelerated in WT but not in gust(-/-) mice. GPR40 was colocalized with desoctanoyl but not with octanoyl ghrelin, α-gustducin or α-transducin positive cells in the stomach. GPR120 only colocalized with ghrelin in the duodenum. Addition of octanoic acid or α-linolenic acid to MGN3-1 cells increased and decreased octanoyl ghrelin levels, respectively. Both effects could not be blocked by GPR120 siRNA. MEDICA16 and grifolic acid did not affect ghrelin secretion in vitro but oral administration of grifolic acid increased plasma ghrelin levels.This study provides the first evidence that α-gustducin is involved in the octanoylation of ghrelin and shows that the ghrelin cell can sense long- and medium-chain fatty acids directly. GPR120 but not GPR40 may play a role in the lipid sensing cascade of the ghrelin cell

Different populations and sources of human mesenchymal stem cells (MSC): A comparison of adult and neonatal tissue-derived MSC

The mesenchymal stroma harbors an important population of cells that possess stem cell-like characteristics including self renewal and differentiation capacities and can be derived from a variety of different sources. These multipotent mesenchymal stem cells (MSC) can be found in nearly all tissues and are mostly located in perivascular niches. MSC have migratory abilities and can secrete protective factors and act as a primary matrix for tissue regeneration during inflammation, tissue injuries and certain cancers

Gait adjustments in obstacle crossing, gait initiation and gait termination after a recent lower limb amputation

Objective: To describe the adjustments in gait characteristics of obstacle crossing, gait initiation and gait termination that occur in subjects with a recent lower limb amputation during the rehabilitation process. Design: Prospective and descriptive study. Subjects: Fourteen subjects with a recent transfemoral, knee disarticulation or transtibial amputation. Methods: Subjects stepped over an obstacle and initiated and terminated gait at four different times during the rehabilitation process. Outcome measures: Success rate, gait velocity and lower limb joint angles in obstacle crossing, centre of pressure shift and peak anteroposterior ground reaction force in gait initiation and termination. Results: In obstacle crossing amputees increased success rate, gait velocity and swing knee flexion of the prosthetic limb. Knee flexion in transfemoral and knee disarticulation amputees was not sufficient for safe obstacle crossing, which resulted in a circumduction strategy. In gait initiation and termination amputees increased the anteroposterior ground reaction force and the centre of pressure shift in the mediolateral direction in both tasks. Throughout the rehabilitation process the centre of pressure was shifted anteriorly before single-limb stance on the trailing prosthetic limb in gait initiation, whereas in gait termination the centre of pressure in single-limb stance remained posterior when leading with the prosthetic limb. Conclusion: Subjects with a recent amputation develop adjustment strategies to improve obstacle crossing, gait initiation and gait termination. Innovations in prosthetic design or training methods may ease the learning process of these tasks