66 research outputs found
Micro-scale surface-patterning influences biofilm formation
The formation of biofilms on indwelling/implanted medical devices is a
common problem. One of the approaches used to prevent biofilm formation
on medical devices is to inhibit bacterial attachment by modification
of the synthetic polymers used to fabricate the device. In this work,
we assessed how micro-scale features (patterns) imprinted onto the
surface of silicone elastomer similar to that used for medical
applications influenced biofilm formation by Staphylococcus aureus ,
Staphylococcus epidermidis , and Pseudomonas aeruginosa . Patterns
were transferred from a multi-patterned oxidized silicon-wafer
master-template to silicone elastomer. Features consisted of bars,
squares, and circles each extending 0.51 \ub5m above the surface.
Feature sizes ranged between 1.78 and 22.25 \ub5m. Distances
separating features ranged between 0.26 and 17.35 \ub5m. Bacterial
biofilm formation on discs cut from imprinted silicone elastomer was
assessed by direct microscopic observation and quantified as the
surface area covered by biofilm. Unpatterned silicone elastomer served
as a control. Several of the micro-scale patterns imprinted into the
silicone elastomer significantly reduced biofilm formation by each
bacterium and interrupted biofilm continuity. Although there were
differences in detail among strains, bacteria tended to attach in the
area between features more than to the surface of the feature itself
Optimally shaped terahertz pulses for phase retrieval in a Rydberg atom data register
We employ Optimal Control Theory to discover an efficient information
retrieval algorithm that can be performed on a Rydberg atom data register using
a shaped terahertz pulse. The register is a Rydberg wave packet with one
consituent orbital phase-reversed from the others (the ``marked bit''). The
terahertz pulse that performs the decoding algorithm does so by by driving
electron probability density into the marked orbital. Its shape is calculated
by modifying the target of an optimal control problem so that it represents the
direct product of all correct solutions to the algorithm.Comment: 6 pages, 3 figure
Quantum computing with mixed states
We discuss a model for quantum computing with initially mixed states.
Although such a computer is known to be less powerful than a quantum computer
operating with pure (entangled) states, it may efficiently solve some problems
for which no efficient classical algorithms are known. We suggest a new
implementation of quantum computation with initially mixed states in which an
algorithm realization is achieved by means of optimal basis independent
transformations of qubits.Comment: 2 figures, 52 reference
Surface stiffening and enhanced photoluminescence of ion implanted cellulose - polyvinyl alcohol - silica composite
Novel Cellulose (Cel) reinforced polyvinyl alcohol (PVA)-Silica (Si) composite which has good stability and in vitro degradation was prepared by lyophilization technique and implanted using N3+ ions of energy 24 keV in the fluences of 1 x 10(15), 5 x 10(15) and 1 x 10(16) ions/cm(2). SEM analysis revealed the formation of microstructures, and improved the surface roughness on ion implantation. In addition to these structural changes, the implantation significantly modified the luminescent, thermal and mechanical properties of the samples. The elastic modulus of the implanted samples has increased by about 50 times compared to the pristine which confirms that the stiffness of the sample surface has increased remarkably on ion implantation. The photoluminescence of the native cellulose has improved greatly due to defect site, dangling bonds and hydrogen passivation. Electric conductivity of the ion implanted samples was improved by about 25%. Hence, low energy ion implantation tunes the mechanical property, surface roughness and further induces the formation of nano structures. MG63 cells seeded onto the scaffolds reveals that with the increase in implantation fluence, the cell attachment, viability and proliferation have improved greatly compared to pristine. The enhancement of cell growth of about 59% was observed in the implanted samples compared to pristine. These properties will enable the scaffolds to be ideal for bone tissue engineering and imaging applications.G.M.S. acknowledges CSIR, India (Grant no: 09/468 (0474)/2013-EMR-I) and S.N.K. thanks the award of Erasmus-Mundus Svaagata for providing financial support to carry out this research. G.M.S., N.S. and S.N.K. acknowledge the support of UGC National facility for characterization facility. J.A.G.T. acknowledges the support of the Spanish Ministry of Economy and Competitiveness (MINECO) through the project DPI2015-65401-C3-2-R (including the FEDER financial support). CIBER-BBN, Spain is an initiative funded by the VI National R&D Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program. CIBER actions are financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund. AFM was conducted by the microscopy service of the UPV, whose advice was greatly appreciated.Shanthini, GM.; Sakthivel, N.; Menon, R.; Nabhiraj, PY.; Gómez-Tejedor, JA.; Meseguer Dueñas, JM.; Gómez Ribelles, JL.... (2016). Surface stiffening and enhanced photoluminescence of ion implanted cellulose - polyvinyl alcohol - silica composite. Carbohydrate Polymers. 153:619-630. https://doi.org/10.1016/j.carbpol.2016.08.016S61963015
Genome-wide association and Meta-analysis of age at onset in Parkinson Disease
Background and Objectives Considerable heterogeneity exists in the literature concerning genetic determinants of the age at onset (AAO) of Parkinson disease (PD), which could be attributed to a lack of well-powered replication cohorts. The previous largest genome-wide association studies (GWAS) identified SNCA and TMEM175 loci on chromosome (Chr) 4 with a significant influence on the AAO of PD; these have not been independently replicated. This study aims to conduct a meta-analysis of GWAS of PD AAO and validate previously observed findings in worldwide populations.
Methods A meta-analysis was performed on PD AAO GWAS of 30 populations of predominantly European ancestry from the Comprehensive Unbiased Risk Factor Assessment for Genetics and Environment in Parkinson's Disease (COURAGE-PD) Consortium. This was followed by combining our study with the largest publicly available European ancestry dataset compiled by the International Parkinson Disease Genomics Consortium (IPDGC).
Results The COURAGE-PD Consortium included a cohort of 8,535 patients with PD (91.9%: Europeans and 9.1%: East Asians). The average AAO in the COURAGE-PD dataset was 58.9 years (SD = 11.6), with an underrepresentation of females (40.2%). The heritability estimate for AAO in COURAGE-PD was 0.083 (SE = 0.057). None of the loci reached genome-wide significance (p < 5 × 10−8). Nevertheless, the COURAGE-PD dataset confirmed the role of the previously published TMEM175 variant as a genetic determinant of the AAO of PD with Bonferroni-corrected nominal levels of significance (p < 0.025): (rs34311866: β(SE)COURAGE = 0.477(0.203), pCOURAGE = 0.0185). The subsequent meta-analysis of COURAGE-PD and IPDGC datasets (Ntotal = 25,950) led to the identification of 2 genome-wide significant association signals on Chr 4, including the previously reported SNCA locus (rs983361: β(SE)COURAGE+IPDGC = 0.720(0.122), pCOURAGE+IPDGC = 3.13 × 10−9) and a novel BST1 locus (rs4698412: β(SE)COURAGE+IPDGC = −0.526(0.096), pCOURAGE+IPDGC = 4.41 × 10−8).
Discussion Our study further refines the genetic architecture of Chr 4 underlying the AAO of the PD phenotype through the identification of BST1 as a novel AAO PD locus. These findings open a new direction for the development of treatments to delay the onset of PD
Micro-scale surface-patterning influences biofilm formation
The formation of biofilms on indwelling/implanted medical devices is a
common problem. One of the approaches used to prevent biofilm formation
on medical devices is to inhibit bacterial attachment by modification
of the synthetic polymers used to fabricate the device. In this work,
we assessed how micro-scale features (patterns) imprinted onto the
surface of silicone elastomer similar to that used for medical
applications influenced biofilm formation by Staphylococcus aureus ,
Staphylococcus epidermidis , and Pseudomonas aeruginosa . Patterns
were transferred from a multi-patterned oxidized silicon-wafer
master-template to silicone elastomer. Features consisted of bars,
squares, and circles each extending 0.51 µm above the surface.
Feature sizes ranged between 1.78 and 22.25 µm. Distances
separating features ranged between 0.26 and 17.35 µm. Bacterial
biofilm formation on discs cut from imprinted silicone elastomer was
assessed by direct microscopic observation and quantified as the
surface area covered by biofilm. Unpatterned silicone elastomer served
as a control. Several of the micro-scale patterns imprinted into the
silicone elastomer significantly reduced biofilm formation by each
bacterium and interrupted biofilm continuity. Although there were
differences in detail among strains, bacteria tended to attach in the
area between features more than to the surface of the feature itself
- …