1,216 research outputs found
Optical Properties of Graphene Nanoflakes: Shape Matters
In recent years there has been significant debate on whether the edge type of
graphene nanoflakes (GNF) or graphene quantum dots (GQD) are relevant for their
electronic structure, thermal stability and optical properties. Using computer
simulations, we have proven that there is a fundamental difference in the
calculated absorption spectra between samples of the same shape, similar size
but different edge type, namely, armchair or zigzag edges. These can be
explained by the presence of electronic structures near the Fermi level which
are localized on the edges. These features are also evident from the dependence
of band gap on the GNF size, which shows three very distinct trends for
different shapes and edge geometries.Comment: 8 pages, 9 figures. Submitted to The Journal of Chemical Physic
Posterior Auricular Perichondrial Cutaneous Graft Combined With Cartilage Strip in Nostril Reconstruction
Objective: Reconstruction of alar structures of the nose remains difficult. The result has to be not only functional but also aesthetic. Different solutions to reconstruct alar defects are feasible. A good result that meets the specific demands on stability, aesthetics, and stable architecture without shrinkage of the area is not easily achieved. Method: A perichondrial cutaneous graft (PCCG), a graft consisting of a perichondral layer, fatty tissue, and skin that is harvested retroauriculary, is combined with an attached cartilage strip. Case Result: A 72-year-old patient suffering from basal cell carcinoma of the ala of the nose underwent the reconstructive procedure with a good result in 1 year in terms of stability, color match, and graft take. Conclusion: First, a strip of cartilage had been included in a PCCG where tumor resection required sacrifice of more than 50% of the alar rim. The case shows that one can consider a cartilage strip–enhanced PCCG graft to reconstruct alar defects
Bovine Dermal Matrix as Coverage of Facial Nerve Grafts
Introduction. Soft tissue defects over functional structures represent a challenge for the reconstructive surgeon. Often complex, reconstructive procedures are required. Occasionally, elderly or sick patients do not qualify for these extensive procedures. Case. We present the case of a 91-year-old lady with large hemifacial defect with exposed bone and nerves after tumor resection. We first performed radical resection including the fascia of the temporalis muscle and the frontal branch of the facial nerve. Due to the moribund elderly patient with a potentially high perioperative risk, we decided against flap reconstruction but to use bovine collagen/elastin matrix and split thickness skin graft. Results. No postoperative complications occurred and STSG and matrix healed uneventfully. Discussion. In selected cases, where complex reconstruction is not appropriate, this procedure can be a safe, easy, and fast alternative for covering soft tissue defects even on wound grounds containing nerve grafts
Characterization of fecal nitrogen forms produced by a sheep fed with 15N labeled ryegrass
Little is known about nitrogen (N) forms in ruminant feces, although this information is important to understand N dynamics in agro-ecosystems. We fed 15N labeled ryegrass hay to a sheep and collected 15N labeled feces. Nitrogen forms in the feces were characterized by chemical extractions, solid-state cross polarization 15N nuclear magnetic resonance spectroscopy (SS CP/MAS 15N NMR) and Curie-point pyrolysis-gas chromatography/mass spectrometry (Cp Py-GC/MS). A 4months incubation experiment was conducted to assess N release from the feces. Half of the fecal N could be ascribed to bacterial and endogenous debris and a third to undigested dietary N. About a tenth of the fecal N was mineralized during the incubation experiment. The 15N abundance of nitrate released during the incubation remained constant and close to the 15N abundance of the total feces N. The NMR analysis of the feces showed that most of the N was present in proteins, while some was present as heterocyclic N, amino acids and ammonium. The Cp Py-GC/MS analysis confirmed the presence of proteins, amino acids and heterocyclic N in the feces. Comparing these results to those obtained from the 15N labeled hay suggests that some N compounds present in the plant were not digested by the animal, and that the animal excreted de novo synthesized N compounds. The low content in ammonium and amino acids, the low rate of N release from these feces during the incubation and the relatively high fecal protein content, particularly the hard to mineralize undigested and microbially bound forms, can explain the low transfer of N from these feces to crops observed in a previous wor
Modified triangular posterior osteosynthesis of unstable sacrum fracture
We report preliminary results for unstable sacral fractures treated with a modified posterior triangular osteosynthesis. Seven patients were admitted to our trauma center with an unstable sacral fracture. The average age was 31years (22-41). There were four vertical shear lesions of the pelvis and three transverse fracture of the upper sacrum. The vertical shear injuries were initially treated with an anterior external fixator inserted at the time of admission. Definitive surgery was performed at a mean time of 9days after trauma. The operation consisted in a posterior fixation combining a vertebropelvic distraction osteosynthesis with pedicle screws and a rod system, whereby the transverse fixation was obtained using a 6mm rod as a cross-link between the two main rods. Late displacement of the posterior pelvis or fracture was measured on X-ray films according to the criteria of Henderson. The patients were followed-up for a minimum time of 12months. Four patients who presented with a pre-operative perineal neurological impairment made a complete recovery. No iatrogenic nerve injury was reported. One case of deep infection was managed successfully with surgical debridement and local antibiotics. All patients complained of symptoms related to the prominence of the iliac screws. The metalwork was removed in all cases after healing of the fracture, at a mean time of 4.3months after surgery. No loss of reduction of fracture was seen at final radiological follow-up. The preliminary results are promising. The fixation is sufficiently stable to allow an immediate progressive weight-bearing, and safe nursing care in polytrauma cases. The only problem seems to be related to prominent heads of the distal screw
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Midlatitude atmospheric circulation responses under 1.5C and 2.0C warming and implications for regional impacts
This study investigates the global response of the midlatitude atmospheric circulation to 1.5◦C and 5 2.0◦C of warming using the HAPPI “Half a degree Additional warming, Prognosis and Projected Im- pacts” ensemble, with a focus on the winter season. Characterizing and understanding this response is critical for accurately assessing the near-term regional impacts of climate change and the benefits of limiting warming to 1.5◦C above pre-industrial levels, as advocated by the Paris Agreement of the United Nations Framework Convention on Climate Change (UNFCCC). The HAPPI experimental 10 design allows an assessment of uncertainty in the circulation response due to model dependence and internal variability. Internal variability is found to dominate the multi-model mean response of the jet streams, storm tracks and stationary waves across most of the midlatitudes; larger signals in these features are mostly consistent with those seen in more strongly forced warming scenarios. Signals that emerge in the 1.5◦C experiment are a weakening of storm activity over North America, an inland 15 shift of the North American stationary ridge, an equatorward shift of the North Pacific jet exit, and an equatorward intensification of the South Pacific jet. Signals that emerge under an additional 0.5◦C of warming include a poleward shift of the North Atlantic jet exit, an eastward extension of the North Atlantic storm track, and an intensification on the flanks of the Southern Hemisphere storm track.
Case studies explore the implications of these circulation responses for precipitation impacts in the 20 Mediterranean, western Europe and on the North American west coast, paying particular attention to possible outcomes at the tails of the response distributions. For example, the projected weakening of the Mediterranean storm track emerges in the 2◦C warmer world, with exceptionally dry decades becoming five times more likely
Evidence for extensive polymorphism of class I genes in the rat major histocompatibility complex (RT1).
The major histocompatibility complex of the rat (RT1) has been poorly characterized with respect to the number, linkage, and polymorphism of class I genes. To estimate the number of class I RT1 genes and the relative extent of their polymorphism, we performed Southern blot analysis with liver DNA from rat strains expressing eight RT1 haplotypes. After digestion with EcoR1 and BamHI, the DNA was separated on agarose gels, blotted onto nitrocellulose, and hybridized with mouse H-2 cDNA probes, pH-2III and pH-2IIa. Ten to 20 EcoRI and 13 to 20 BamHI bands hybridized with pH-2III and pH-2IIa; restriction fragment length patterns were observed to be highly polymorphic. The restriction fragments associated with different RT1 haplotypes differed by 17-70%; this range is similar to the differences observed between mouse H-2 haplotypes. The same restriction fragment pattern was observed in DNA from three different rat strains sharing the same RT1 allele, confirming that the patterns were RT1-associated. Further, the RT11 and RT11v1 haplotypes, which differ at a single previously identified RT1-linked locus, were associated with EcoRI restriction pattern differences of 39-50%, confirming the supposition that RT1 class I genes identified by previous serological and T-cell-mediated assays have identified only a minority of the actual number of RT1-linked class I genes. In summary, the results reported in this communication demonstrate that the RT1 complex encompasses a large family of highly polymorphic class I genes similar to the H-2 and HL-A complexes of mouse and man
Ethanol consumption impairs vestibulo-ocular reflex function measured by the video head impulse test and dynamic visual acuity
Ethanol affects many parts of the nervous system, from the periphery to higher cognitive functions. Due to the established effects of ethanol on vestibular and oculomotor function, we wished to examine its effect on two new tests of the vestibulo-ocular reflex (VOR): the video head impulse test (vHIT) and dynamic visual acuity (DVA). We tested eight healthy subjects with no history of vestibular disease after consumption of standardized drinks of 40% ethanol. We used a repeated measures design to track vestibular function over multiple rounds of ethanol consumption up to a maximum breath alcohol concentration (BrAC) of 1.38‰. All tests were normal at baseline. VOR gain measured by vHIT decreased 25% by the highest BrAC level tested in each subject. Catch-up saccades were negligible at baseline and increased in number and size with increasing ethanol consumption (from 0.13° to 1.43° cumulative amplitude per trial). DVA scores increased by 86% indicating a deterioration of acuity, while static visual acuity (SVA) remained unchanged. Ethanol consumption systematically impaired the VOR evoked by high-acceleration head impulses and led to a functional loss of visual acuity during head movement.NHMR
Hemiface rhytidectomy.
In the current study, skin flaps raised in the subcutaneous plane were applied for 22 patients who underwent reconstruction for unilateral upper facial skin defects after skin tumor surgery. The defect was reconstructed with flaps designed via procedures similar to classic rhytidectomy techniques using periauricular and temporal skin incisions. Objective assessment of the aesthetic result was possible by comparison with the healthy contralateral side of the face. Immediate postoperative evaluation confirmed facial asymmetry due to unilateral skin tension. High patient acceptance of the procedure, uneventful flap healing, and good aesthetic results were achieved, with almost complete restoration of facial symmetry 1 year postoperatively. In conclusion, unilateral rhytidectomy without plication or resection of the subcutaneous musculoaponeurotic system (SMAS) is an ideal application of aesthetic surgical techniques for the reconstruction of unilateral skin defects
Induction of Mutants with Ectopic Expression of Condensed Tannins
Leaves of 47,000 Lotus japonicus plants were screened using a butanol:HCl histochemical test to select “gain of function” mutants. These plants were progeny from L. japonicus lines which were transformed with T-DNA constructs containing either the maize Ds or Ac transposon (Thykjaer et al., 1995). Among 21 putative leaf tannin mutants, five (tan1-5) were characterized for synthesis of condensed tannins, leucocyanidin reductase activity and the presence of Ac and the selectable marker gene, nptII . A range of leaf tannin content among other Lotus species was also characterized
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