Transition from fractal-dendritic to compact islands for the 2D-ferroelectric SnSe on graphene/Ir(111).

Epitaxial growth is a versatile method to prepare two-dimensional van der Waals ferroelectrics like group IV monochalcogenides which have potential for novel electronic devices and sensors. We systematically study SnSe monolayer islands grown by molecular beam epitaxy, especially the effect of annealing temperature on shape and morphology of the edges. Characterization of the samples by scanning tunneling microscopy reveals that the shape of the islands changes from fractal-dendritic after deposition at room temperature to a compact rhombic shape through annealing, but ripening processes are absent up to the desorption temperature. A two-step growth process leads to large, epitaxially aligned rhombic islands bounded by well-defined110-edges (armchair-like), which we claim to be the equilibrium shape of the stoichiometric SnSe monolayer islands. The relaxation of the energetically favorable edges is detected in atomically resolved STM images. The experimental findings are supported by the results of our first-principles calculations, which provide insights into the energetics of the edges, their reconstructions, and yields the equilibrium shapes of the islands which are in good agreement with the experiment.

Autologous corneal graft for the treatment of deep corneal defects in dogs: 15 cases (2014-2017).

OBJECTIVES: To describe the use of corneal autografts for repair of deep corneal defects in dogs. MATERIALS AND METHODS: Retrospective analysis of clinical records of dogs that received autologous corneal grafts. RESULTS: Fifteen dogs (16 eyes) of different breed, age and gender were included. Brachycephalic breeds were overrepresented (10/15 dogs). Defects were unilateral in 14 dogs and bilateral in one dog, extended to at least 80% of the stromal thickness in all eyes, with descemetoceles in four eyes and corneal perforations in five eyes. Most ulcers (13/16 eyes) were located centrally. Corneal autografts were harvested from healthy peripheral cornea of the ipsilateral eye. The thickness of the autograft was limited to a set depth of 0.3 mm. The autograft was sutured into a previously debrided ulcer bed with a continuous or simple interrupted suture pattern using absorbable or non-absorbable suture material. Additional interventions included a partial temporary tarsorrhaphy and bandage contact lenses. Postoperatively patients received topical antibiotics and systemic anti-inflammatory drugs, and 12/15 dogs also received systemic antibiotics. Mean follow-up time was 54 days (2 to 462). In all eyes the donor site healed uneventfully with mild, persistent corneal fibrosis. Postoperative complications included autograft keratomalacia, graft dehiscence and corneal pigmentation. No patient required additional surgery. Good structural and functional outcome was accomplished in 14 of 16 eyes. CLINICAL SIGNIFICANCE: Autologous corneal grafts provide tectonic support and result in good corneal transparency in selected cases of dogs with deep to perforated corneal ulcerations.

Magnetic resonance imaging findings in dogs with orbital inflammation.

OBJECTIVES: To describe MRI features of canine retrobulbar inflammation, their association with clinical findings and outcome and to assess the value of MRI in detecting orbital foreign bodies. MATERIALS AND METHODS: Clinical records of dogs with confirmed (23 of 31) and suspected (eight of 31) retrobulbar inflammation that underwent low field MRI studies were analysed retrospectively. RESULTS: Of the 31 dogs included in the study there was abscessation in 19. Extraocular myositis (27 of 31) was concurrent with strabismus in three cases. Of 25 patients with exophthalmos, 14 had concurrent optic nerve swelling and, of these, five had permanent loss of vision. There was no vision loss in patients without nerve swelling. One case of suspected retinal detachment on MRI was confirmed clinically. Extensive abnormal contrast enhancement in the temporalis, masseter and pterygoideus muscles was associated with facial (n=3) and trigeminal nerve deficits (n=1). Three patients with inflammation extending into the nasal cavity and frontal sinus (one of 31) or meningeal contrast enhancement (two of 31), showed optic and oculomotor nerve deficits. On MRI a foreign body was not visible in 20 of 31 case or "appeared likely" in 11 of 31 dogs. A foreign body was found at surgery in one case. CLINICAL SIGNIFICANCE: MRI outlines the extent of retrobulbar inflammation. Clinical findings were associated with imaging findings. MRI overestimated the presence of foreign bodies.

Retrobulbar cellulitis and abscessation: focus on short- and long-term concurrent ophthalmic diseases in 41 dogs.

OBJECTIVE: To describe concurrent ophthalmic diseases in dogs with retrobulbar cellulitis and abscessation. MATERIALS AND METHODS: Retrospective analysis of clinical records of dogs with retrobulbar inflammation. RESULTS: Forty-one dogs were diagnosed with retrobulbar inflammation; of these, 23 presented with abscessation and two with zygomatic sialoadenitis. Diagnosis was based on orbital ultrasound, MRI, CT and cytological and microbiological examination of fluid or tissue samples. Management involved evacuation of fluid contents using ultrasound-guided fine-needle aspiration via the pterygopalatine fossa or orbitotomy. Patients received systemic antibiotics (except for one with sialoadenitis), glucocorticoids, non-steroidal anti-inflammatory drugs, opioids and fluid therapy. At initial presentation one or more ophthalmic complications were reported in 19 dogs (46%) including internal ophthalmoplegia (n=5), blindness due to optic nerve damage (n=5), facial nerve paralysis (n=3), prolapse of the third eyelid gland (n=3), corneal ulceration (n=8), anterior uveitis (n=4), chorioretinitis (n=3), retinal detachment (n=2) and increased intraocular pressure (n=7). Information on ophthalmic complications after cessation of active inflammation was available for 33 patients. One or more concurrent disease was found in 10 cases (30%): in addition to persistent neurological deficits and third eyelid gland prolapse reported at initial presentation, visual deficits after retinal re-attachment (n=2), loss of corneal sensation (n=1), corneal oedema (n=1), corneal fibrosis (n=4), corneal lipidosis (n=1) and strabismus after suspected fibrosis (n=2) were diagnosed. CLINICAL SIGNIFICANCE: Ophthalmic complications are common in patients with retrobulbar inflammation indicating that these patients should undergo ophthalmic assessment and follow-up.

Accuracy of transcranial brain parenchyma sonography in the diagnosis of dementia with Lewy bodies.

BACKGROUND AND PURPOSE: Transcranial sonography (TCS) of the brain parenchyma is used to visualize alterations in the substantia nigra (SN) and it is applied for early diagnosis of Parkinson's disease. Our aim was to explore specific echogenic alterations of the SN in dementia with Lewy bodies (DLB) compared to Alzheimer's disease (AD). METHODS: Seventy-one subjects underwent TCS: 22 DLB, 28 AD and 21 healthy elderly controls. Cognitive impairment, extrapyramidal signs, visual hallucinations, fluctuations and rapid eye movement sleep behaviour symptoms were investigated. TCS assessed SN hyperechogenicity and symmetry. RESULTS: Transcranial sonography revealed SN hyperechogenicity in 100% of DLB compared to 50% of AD and 30% of controls. Mean SN echogenic area (cm(2) ) was 0.22 ± 0.03 in DLB, 0.15 ± 0.03 in AD and 0.14 ± 0.03 in controls (P < 0.0001). More than 50% of DLB presented a marked hyperechogenicity (cutoff value >0.22 cm(2) ) compared to only 10% of AD (P < 0.0003). DLB had symmetrical SN enlargement, whereas AD were mostly asymmetrical (P = 0.015). A combination of SN echogenic area and asymmetry index had a sensitivity of 88.9% and a specificity of 81.2% in discriminating DLB from AD (positive predictive value 85.7%, negative predictive value 85.7%). No association was found between SN hyperechogenicity and Unified Parkinson's Disease Rating Scale part III, Mini Mental State Examination or the presence of visual hallucinations. CONCLUSIONS: Transcranial sonography may be a valid supportive tool in the diagnostic workup of neurodegenerative dementia helping clinicians to distinguish DLB from AD even at the early stages.

Oxygen orders differently under graphene: new superstructures on Ir(111).

Using scanning tunneling microscopy, the oxygen adsorbate superstructures on bare Ir(111) are identified and compared to the ones formed by intercalation in between graphene and the Ir(111) substrate. For bare Ir(111) we observe O-(2 × 2) and O-(2 × 1) structures, thereby clarifying a persistent uncertainty about the existence of these structures and the role of defects for their stability. For the case of graphene-covered Ir(111), oxygen intercalation superstructures can be imaged through the graphene monolayer by choosing proper tunneling conditions. Depending on the pressure, temperature and duration of O2 exposure as well as on the graphene morphology, O-(2 × 2), O-(√3×√3)-R30°, O-(2 × 1) and O-(2√3 × 2√3)-R30° superstructures with respect to Ir(111) are observed under the graphene cover. Two of these structures, the O-(√3 × âˆš3)-R30° and the (2√3 × 2√3)-R30° structure are only observed when the graphene layer is on top. Phase coexistence and formation conditions of the intercalation structures between graphene and Ir(111) are analyzed. The experimental results are compared to density functional theory calculations including dispersive forces. The existence of these phases under graphene and their absence on bare Ir(111) are discussed in terms of possible changes in the adsorbate-substrate interaction due to the presence of the graphene cover.

The effect of prophylactic topical carbonic anhydrase inhibitors in canine primary closed-angle glaucoma.

OBJECTIVES: To determine the effect of 1% brinzolamide, 2% dorzolamide hydrochloride or combination 2% dorzolamide hydrochloride/0 · 5% timolol to delay the elevation of the intraocular pressure in second eyes of dogs with primary closed-angle glaucoma. METHODS: Analysis of retrospectively collated data from 40 dogs with primary closed-angle glaucoma, where the non-affected eye was treated prophylactically with brinzolamide (n = 10), dorzolamide (n = 18) or combination dorzolamide/timolol therapy (n = 12). RESULTS: The 40 treated dogs (median age of 76 · 2 months) comprised 25 females/15 males, 19 entire/21 neutered. Twenty dogs developed glaucoma in the contralateral eye (median time of 9 · 2 months). No statistically significant difference was identified during treatment failure between the treatment groups (P = 0 · 66). The second eye remained normotensive in 20 dogs; four dogs until the conclusion of the study (median: 27 · 0 months), three dogs until death (median: 15 · 4 months), seven dogs until lost to follow-up (median: 11 · 6 months). Out of these 20 dogs, treatment was discontinued because of lack of owner compliance in two dogs and following a local drug reaction in four dogs (median: 8 · 9 months). CLINICAL SIGNIFICANCE: There was no evidence that the tested drugs delayed elevation of intraocular pressure in contralateral eyes of dogs with primary closed-angle glaucoma.

Seroprevalence of campylobacteriosis and relevant post-infectious sequelae.

Post-infectious sequelea such as Guillain Barré syndrome (GBS), reactive arthritis (RA), and inflammatory bowel disease (IBD) may arise as a consequence of acute Campylobacter-enteritis (AE). However, reliable seroprevalence data of Campylobacter-associated sequelae has not been established. The objectives of this study were, first, to identify the most specific and sensitive test antigen in an optimized ELISA assay for diagnosing a previous Campylobacter-infection and, second, to compare the prevalence of anti-Campylobacter antibodies in cohorts of healthy blood donors (BD), AE, GBS, RA, and IBD patients with antibodies against known GBS, RA and IBD triggering pathogens. Optimized ELISAs of single and combined Campylobacter-proteins OMP18 and P39 as antigens were prepared and sera from AE, GBS, RA and IBD patients and BD were tested for Campylobcter-specific IgA and IgG antibodies. The results were compared with MIKROGEN™-recomLine Campylobacter IgA/IgG and whole cell lysate-immunoblot. Antibodies specific for Helicobacter pylori, Mycoplasma pneumoniae, Yersinia enterocolitica, and Borrelia afzelii were tested with commercial immunoblots. ROC plot analysis revealed AUC maxima in the combination of OMP18 and P39 for IgA and in the P39-antigen for IgG. As a result, 34-49 % GBS cases, 44-62 % RA cases and 23-40 % IBD cases were associated with Campylobacter-infection. These data show that Campylobcater-seropositivity in these patient groups is significantly higher than other triggering pathogens suggesting that it plays an important role in development of GBS and RA, and supports the hypothesis that recurrent acute campylobacteriosis triggers IBD.

The mechanism of caesium intercalation of graphene.

Properties of many layered materials, including copper- and iron-based superconductors, topological insulators, graphite and epitaxial graphene, can be manipulated by the inclusion of different atomic and molecular species between the layers via a process known as intercalation. For example, intercalation in graphite can lead to superconductivity and is crucial in the working cycle of modern batteries and supercapacitors. Intercalation involves complex diffusion processes along and across the layers; however, the microscopic mechanisms and dynamics of these processes are not well understood. Here we report on a novel mechanism for intercalation and entrapment of alkali atoms under epitaxial graphene. We find that the intercalation is adjusted by the van der Waals interaction, with the dynamics governed by defects anchored to graphene wrinkles. Our findings are relevant for the future design and application of graphene-based nano-structures. Similar mechanisms can also have a role for intercalation of layered materials.

Atomic structure and crystalline order of graphene-supported ir nanoparticle lattices.

We present the atomic structure of Ir nanoparticles with 1.5 nm diameter at half height and three layers average height grown on graphene/Ir(111). Using surface x-ray diffraction, we demonstrate that Ir nanoparticles on graphene/Ir(111) form a crystallographic superlattice with high perfection. The superlattice arrangement allows us to obtain detailed information on the atomic structure of the nanoparticles themselves, such as size, shape, internal layer stacking and strain. Our experiments disclose that the nanoparticles reside epitaxially on top of the graphene moiré structure on Ir(111), resulting in significant lateral compressive intraparticle strain. Normal incidence x-ray standing wave experiments deliver additional information on the particle formation induced restructuring of the graphene layer.

Wave-function mapping of graphene quantum dots with soft confinement.

Using low-temperature scanning tunneling spectroscopy, we map the local density of states of graphene quantum dots supported on Ir(111). Because of a band gap in the projected Ir band structure around the graphene K point, the electronic properties of the QDs are dominantly graphenelike. Indeed, we compare the results favorably with tight binding calculations on the honeycomb lattice based on parameters derived from density functional theory. We find that the interaction with the substrate near the edge of the island gradually opens a gap in the Dirac cone, which implies soft-wall confinement. Interestingly, this confinement results in highly symmetric wave functions. Further influences of the substrate are given by the known moiré potential and a 10% penetration of an Ir surface resonance into the graphene layer.

Dirac cones and minigaps for graphene on Ir(111).

Epitaxial graphene on Ir(111) prepared in excellent structural quality is investigated by angle-resolved photoelectron spectroscopy. It clearly displays a Dirac cone with the Dirac point shifted only slightly above the Fermi level. The moiré resulting from the overlaid graphene and Ir(111) surface lattices imposes a superperiodic potential giving rise to Dirac cone replicas and the opening of minigaps in the band structure.

Electrochemically deposited Pd islands on an organic surface: the presence of Coulomb blockade in STM I(V) curves at room temperature.

Palladium islands with a thickness of a few monolayers were deposited on top of a self-assembled monolayer (SAM) fabricated from 4-mercaptopyridine. In the I(V) curves obtained using the scanning tunneling microscope (STM) clearly the signature of Coulomb blockade is observed, explicitly demonstrating that these islands are coupled to the underlying gold substrate only via a tunneling barrier; this spectroscopic feature also allows to distinguish the palladium islands from similar morphological features present on the gold substrate prior to palladium deposition.

p53 deficiency rescues apoptosis and differentiation of multiple cell types in zebrafish flathead mutants deficient for zygotic DNA polymerase delta1.

Cell culture work has identified the tumor suppressor p53 as a component of the S-phase checkpoint control system, while in vivo studies of this role of p53 in whole-vertebrate systems were limited. Here, we describe zebrafish mutants in the DNA polymerase delta catalytic subunit 1, based on the positional cloning of the flathead (fla) gene. fla mutants display specific defects in late proliferative zones, such as eyes, brain and cartilaginous elements of the visceral head skeleton, where cells display compromised DNA replication, followed by apoptosis, and partial or complete loss of affected tissues. Antisense-mediated knockdown of p53 in fla mutants leads to a striking rescue of all phenotypic traits, including completion of replication, survival of cells, and normal differentiation and tissue formation. This indicates that under replication-compromised conditions, the p53 branch of the S-phase checkpoint is responsible for eliminating stalled cells that, given more time, would have otherwise finished their normal developmental program.

The IPM Wheat Model--results of a three-year study in North Rhine-Westphalia, Lower Saxony and Schleswig-Holstein.

Under the primary utilisation of phytosanitary production factors such as selection of variety, crop rotation and N fertilisation according to plant requirements, the IPM Wheat Model comprises the elements diagnosis (qualitative = type of pathogen, quantitative = disease severity), scientifically grounded treatment thresholds which, as critical values in pathogen development, can be applied to define the optimum time of fungicide application, and pathogen-specific effective fungicides and application amounts. This leads to the location and year-specific optimised control of the pathogen and of the associated yield performance. After several years of development in Bavaria (from 1985 on) and Schleswig-Holstein (1993-1999), the model was tested as part of a project involving the Universities of Bonn and Kiel and the plant protection services of the German states of Lower Saxony, North Rhine-Westphalia and Schleswig-Holstein in a three-year study (1999-2001) in interregional locations (usually nine per state) with the winter wheat variety Ritmo (interregional indicator variety) and a further variety of regional importance in different variations (untreated control, three to four times growth stage-oriented variants for the determination of the absolute damage potential, IPM-variant). In exact records (approx. 12 dates per vegetation period), the disease epidemics were recorded weekly. With the genetically uniform indicator variety Ritmo, the results documented substantially differing year- and location-specific disease and yield patterns. Interregionally, a broad wheat pathogen spectrum (Puccinia striiformis, P. recondita, Septoria tritici, Stagonospora (syn. Septoria) nodorum, Blumeria (syn. Erysiphe) graminis, Pseudocercosporella herpotrichoides, Drechslera tritici-repentis) in differing composition, disease severity and damage effect was demonstrated. The heterogeneity of the infection and damage patterns was increased in the case of the second variety, in association with the genetic variability. The epidemiologically-orientated indications (average two, reduced application amounts) according to the IPM Wheat Model in association with time-diverging progressions led, on an interregional basis, with minimum input and in association with the diverging dynamics, to a biologically and economically optimised fungicide application. In the context of economic and ecological performance, the comprehensive results of the project demonstrated the valuable functionality of the IPM Wheat Model.

Reduced stress-induced hyperthermia in mGluR5 knockout mice.

It hs been suggested that metabotropic glutamate receptor subtype 5 (mGluR5) play a role in the expression of anxiety, based on anxiolytic-like effects of the selective mGluR5 antagonist MPEP (2-methyl-6-(phenylethynyl)pyridine) in rodent models of anxiety, including stress-induced hyperthermia (SIH). To examine the suggested role of mGlu5 receptors in the expression of anxiety, we examined the stress response in mice lacking mGluR5 in several variations of the SIH procedure. In this paradigm, stress causes a mild increase in body temperature that can be blocked by known anxiolytic agents. Three procedures were employed: classical SIH using rectal-probe measurement of body temperature, and radiotelemetric measurement of body temperature in response to either saline injection or to the introduction of an intruder into the home cage. In all three procedures the mGluR5-knockout mice displayed a significant attenuation of the hyperthermic response to stress compared to littermate wild-type control mice. To confirm that our observations were likely to be due to the absence of mGluR5 in the knockout mice we also tested the effect of the recently described selective mGluR5 antagonist MTEP (3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]pyridine) in both the wild-type and mGluR5 knockout mice. Administration of MTEP in the wild-type mice, but not the mGluR5 knockout mice, attenuated SIH. That the mGluR5 knockout mice displayed an anxiolytic-like phenotype and that the mGluR5 antagonist, MTEP, showed a anxiolytic-like effect only in mice possessing mGluR5 further supports the suggestion that mGluR5 antagonists may be useful in the treatment of anxiety.

INK4a-ARF alterations in liver cell adenoma.

BACKGROUND: The INK4a-ARF (CDKN2A) locus on chromosome 9p21 encodes two tumour suppressor proteins, p16(INK4a) and p14(ARF), whose functions are inactivated in many human cancers. AIMS: To evaluate p14(ARF) and p16(INK4a) alterations in liver cell adenoma. METHODS: After microdissection, DNA from 25 liver cell adenomas and corresponding normal liver tissue were analysed for INK4-ARF inactivation by DNA sequence analysis, methylation specific polymerase chain reaction, restriction enzyme related-polymerase chain reaction (RE-PCR), mRNA expression, microsatellite analysis, and immunohistochemistry. In addition, microdeletion of p14(ARF) and p16(INK4a) were assessed by differential PCR. RESULTS: Methylation of p14(ARF) was found in 3/25 cases (12%) and alterations in p16(INK4a) occurred in 6/25 liver cell adenomas (24%) which correlated with loss of mRNA transcription. We failed to detect microdeletions or specific mutations of both exons. p16(INK4a) methylation appeared in the context of an unmethylated p14(ARF) promoter in six cases. In normal liver tissue, p14(ARF) or p16(INK4a) alterations were not observed. CONCLUSIONS: Our data suggest that p14(ARF) methylation occurs independently of p16(INK4a) alterations in liver cell adenomas. Furthermore, methylation of p14(ARF) and p16(INK4a) may be a result of cell cycle deregulation and does not seem to be a prerequisite of malignancy.

INK4a-ARF alterations and p53 mutations in hepatocellular carcinomas.

The INK4a-ARF (CDKN2A)- locus on chromosome 9p21 encodes for two tumour suppressor proteins, p16(INK4a) and p14(ARF), that act as upstream regulators of the Rb-CDK4 and p53 pathways. To study the contribution of each pathway in tumorigenesis of hepatocellular carcinoma (HCC), we analysed the alterations of p14(ARF), p16(INC4a) and p53. After microdissection, DNA of 71 hepatocellular carcinomas was analysed for INK4-ARF inactivation and p53 mutation by DNA sequence analysis, methylation-specific PCR (MSP), restriction-enzyme related polymerase chain reaction (RE-PCR), mRNA expression and immunohistochemistry. In addition, microdeletion of p14(ARF) and p16(INC4a) were assessed by differential PCR. Inactivation of p14(ARF) was found in 11/71 cases (15%), alterations of p16(INK4a) occurred in 47/71 carcinomas (66%), which correlated with loss of mRNA transcription. Five tumours (7%) had homozygous deletions of the INK4a-ARF locus. We failed to detect specific mutations of both exons. P16(INK4a) methylation with an unmethylated p14(ARF) promotor appeared in 39 cases. Mutations of p53 were found in 30 of 71 HCC (42%), and only one of them harboured p14(ARF) inactivation. We failed to establish alterations of the INK4a-ARF locus or p53 status as independent prognostic factor in these tumours. Our data indicate, that p14(ARF) methylation occurs independently of p16(INK4a) alterations in a subset of HCC together with wild type p53. The INK4a-ARF-/p53-pathway was disrupted in 86% of HCC, either by p53 mutations or by INK4a-ARF inactivation, and may have co-operative effects in hepatocarcinogenesis.