Surface plasmon enhanced absorption and suppressed transmission in periodic arrays of graphene ribbons

Resonance diffraction in the periodic array of graphene micro-ribbons is theoretically studied following a recent experiment [L. Ju et al, Nature Nanotech. 6, 630 (2011)]. Systematic studies over a wide range of parameters are presented. It is shown that a much richer resonant picture would be observable for higher relaxation times of charge carriers: more resonances appear and transmission can be totally suppressed. The comparison with the absorption cross-section of a single ribbon shows that the resonant features of the periodic array are associated with leaky plasmonic modes. The longest-wavelength resonance provides the highest visibility of the transmission dip and has the strongest spectral shift and broadening with respect to the single-ribbon resonance, due to collective effects.Comment: 5 pages, 3 figure

Rumen-protected choline supplementation in periparturient dairy goats: effects on liver and mammary gland

The current study investigated the effects of supplementing rumen-protected choline (RPC) on metabolic profile, selected liver constituents and transcript levels of selected enzymes, transcription factors and nuclear receptors involved in mammary lipid metabolism in dairy goats. Eight healthy lactating goats were studied: four received no choline supplementation (CTR group) and four received 4 g RPC chloride/day (RPC group). The treatment was administered individually starting 4 weeks before expected kidding and continuing for 4 weeks after parturition. In the first month of lactation, milk yield and composition were measured weekly. On days 7, 14, 21 and 27 of lactation, blood samples were collected and analysed for glucose, β-hydroxybutyrate, non-esterified fatty acids and cholesterol. On day 28 of lactation, samples of liver and mammary gland tissue were obtained. Liver tissue was analysed for total lipid and DNA content; mammary tissue was analysed for transcripts of lipoprotein lipase (LPL), fatty acid synthase (FAS), sterol regulatory binding proteins 1 and 2, peroxisome proliferator-activated receptor γ and liver X receptor α. Milk yield was very similar in the two groups, but RPC goats had lower (P<0·05) plasma β-hydroxybutyrate. The total lipid content of liver was unaffected (P=0·890), but the total lipid/DNA ratio was lower (both P<0·05) in RPC than CTR animals. Choline had no effect on the expression of the mammary gland transcripts involved in lipid metabolism. The current plasma and liver data indicate that choline has a positive effect on liver lipid metabolism, whereas it appears to have little effect on transcript levels in mammary gland of various proteins involved in lipid metabolism. Nevertheless, the current results were obtained from a limited number of animals, and choline requirement and function in lactating dairy ruminants deserve further investigatio

Superradiance mediated by Graphene Surface Plasmons

We demonstrate that the interaction between two emitters can be controlled by means of the efficient excitation of surface plasmon modes in graphene. We consider graphene surface plasmons supported by either two-dimensional graphene sheets or one-dimensional graphene ribbons, showing in both cases that the coupling between the emitters can be strongly enhanced or suppressed. The super- and subradiant regimes are investigated in the reflection and transmission configurations. Importantly, the length scale of the coupling between emitters, which in vacuum is fixed by the free space wavelength, is now determined by the wavelength of the graphene surface plasmons that can be extremely short and be tuned at will via a gate voltage

Rumen-protected choline and vitamin E supplementation in periparturient dairy goats: effects on milk production and folate, vitamin B12 and vitamin E status

We investigated the effects of rumen-protected choline (RPC) and vitamin E (VITE) administration on milk production and status of folate, vitamin B12 and vitamin E during the periparturient period of dairy goats. Forty-eight Saanen multiparous goats were selected for the 72-day experiment, being moved to a maternity pen 30 days before expected parturition and assigned to one of the four experimental groups: control (CTR), no choline or vitamin E supplementation; choline (RPC), supplemented with 4 g/day choline chloride in rumen-protected form; vitamin E (VITE), supplemented with 200 IU/day vitamin E in rumen-protected form; and choline and vitamin E (RPCE), supplemented with 4 g/day RPC chloride and 200 IU/day vitamin E. Supplements were administered individually before the morning feed to ensure complete consumption, starting 30 days before kidding and continuing for 35 days after. During the experiment, milk yield and 4% fat-corrected milk (FCM) yield were, respectively, 210 and 350 g/day higher in RPC-supplemented goats than in non-supplemented goats. Milk fat concentration and fat yield were also increased by RPC treatment. Milk yield and composition were unaffected by vitamin E supplementation. There were no significant interactions between RPC and VITE for any of the variables measured. Plasma metabolites did not differ between treatments before and after kidding except that plasma folate at parturition was higher in RPC-supplemented goats. Neither choline nor vitamin E affected vitamin B12 plasma concentrations, while a time effect was evident after the second week of lactation, when B12 levels in each treatment group started to increase. Vitamin E administration resulted in plasma α-tocopherol levels that were 2 to 2.5 times higher than in non-supplemented goats. Overall, these results suggest that greater choline availability can improve milk production and methyl group metabolism in transition dairy goats

Co-inherited mutations of Fas and caspase-10 in development of the autoimmune lymphoproliferative syndrome

<p>Abstract</p> <p>Background</p> <p>Autoimmune lymphoproliferative syndrome (ALPS) is a rare inherited disorder characterized by defective function of Fas, autoimmune manifestations that predominantly involve blood cells, polyclonal accumulation of lymphocytes in the spleen and lymph nodes with lymphoadenomegaly and/or splenomegaly, and expansion of TCRαβ+ CD4/CD8 double-negative (DN) T cells in the peripheral blood. Most frequently, it is due to Fas gene mutations, causing ALPS type Ia (ALPS-Ia). However, other mutations, namely of the FasL gene (ALPS-Ib) and the caspase-10 gene (ALPS-II) are occasionally detected, whereas some patients do not present any known mutations (ALPS-III). Recently, mutations of the NRAS gene have been suggested to cause ALPS-IV.</p> <p>Results</p> <p>This work reports two patients that are combined heterozygous for single nucleotide substitutions in the Fas and caspase-10 genes. The first patient carried a splice site defect suppressing allele expression in the Fas gene and the P501L substitution in caspase-10. The second had a mutation causing a premature stop codon (Q47X) in the Fas gene and the Y446C substitution in caspase-10. Fas expression was reduced and caspase-10 activity was decreased in both patients. In both patients, the mutations were inherited from distinct healthy parents.</p> <p>Conclusion</p> <p>These data strongly suggest that co-transmission of these mutation was responsible for ALPS.</p

Kinematic markers of skill in first-person shooter video games

Video games present a unique opportunity to study motor skill. First-person shooter (FPS) games have particular utility because they require visually guided hand movements that are similar to widely studied planar reaching tasks. However, there is a need to ensure the tasks are equivalent if FPS games are to yield their potential as a powerful scientific tool for investigating sensorimotor control. Specifically, research is needed to ensure that differences in visual feedback of a movement do not affect motor learning between the two contexts. In traditional tasks, a movement will translate a cursor across a static background, whereas FPS games use movements to pan and tilt the view of the environment. To this end, we designed an online experiment where participants used their mouse or trackpad to shoot targets in both visual contexts. Kinematic analysis showed player movements were nearly identical between contexts, with highly correlated spatial and temporal metrics. This similarity suggests a shared internal model based on comparing predicted and observed displacement vectors rather than primary sensory feedback. A second experiment, modeled on FPS-style aim-trainer games, found movements exhibited classic invariant features described within the sensorimotor literature. We found the spatial metrics tested were significant predictors of overall task performance. More broadly, these results show that FPS games offer a novel, engaging, and compelling environment to study sensorimotor skill, providing the same precise kinematic metrics as traditional planar reaching tasks

Fibroblasts from patients with Diamond-Blackfan anaemia show abnormal expression of genes involved in protein synthesis, amino acid metabolism and cancer

Background: Diamond-Blackfan anaemia (DBA) is a rare inherited red cell hypoplasia characterised by a defect in the maturation of erythroid progenitors and in some cases associated with malformations. Patients have an increased risk of solid tumors. Mutations have been found in several ribosomal protein (RP) genes, i.e RPS19, RPS24, RPS17, RPL5, RPL11, RPL35A. Studies in haematopoietic progenitors from patients show that haplo-insufficiency of an RP impairs rRNA processing and ribosome biogenesis. DBA lymphocytes show reduced protein synthesis and fibroblasts display abnormal rRNA processing and impaired proliferation. Results: To evaluate the involvement of non-haematopoietic tissues in DBA, we have analysed global gene expression in fibroblasts from DBA patients compared to healthy controls. Microarray expression profiling using Affymetrix GeneChip Human Genome U133A 2.0 Arrays revealed that 421 genes are differentially expressed in DBA patient fibroblasts. These genes include a large cluster of ribosomal proteins and factors involved in protein synthesis and amino acid metabolism, as well as genes associated to cell death, cancer and tissue development. Conclusion: This analysis reports for the first time an abnormal gene expression profile in a non-haematopoietic cell type in DBA. These data support the hypothesis that DBA may be due to a defect in general or specific protein synthesis. \ua9 2009 Avondo et al; licensee BioMed Central Ltd

Olfactometric techniques in feed analysis: preliminary calibration of DON in durum wheat

Approcci olfattometrici nell\u2019analisi dei mangimi: calibrazione preliminare per il rilievo di DON nel grano duro. Le analisi olfattometriche, attraverso l\u2019uso del naso elettronico, trovano sempre pi\uf9 spazio nella valutazione della qualit\ue0 e sicurezza in campo alimentare. I principali vantaggi di tale approccio risiedono nella sua flessibilit\ue0 di impiego. Una volta messi a punto adeguati protocolli d\u2019analisi e modelli statistici di tipo multivariato, infatti, il naso elettronico si pu\uf2 rivelare uno strumento adatto alle realt\ue0 di campo in quanto caratterizzato da rapidit\ue0 e basso costo d\u2019esercizio. Lo scopo di questo lavoro \ue8 stato quello di verificare, a livello preliminare, l\u2019efficienza del naso elettronico nel riconoscere la presenza di micotossina deossinivalenolo (DON) in 10 campioni di grano duro (Triticum durum) di diversa provenienza geografica. I risultati hanno dimostrato che il protocollo applicato consente di riconoscere la presenza di DON nonch\ue9 di discriminare i diversi campioni in funzione del loro livello di contaminazione