Structural and Electronic Properties of Nitrogen-Doped Graphene.

We investigate the structural and electronic properties of nitrogen-doped epitaxial monolayer graphene and quasifreestanding monolayer graphene on 6H-SiC(0001) by the normal incidence x-ray standing wave technique and by angle-resolved photoelectron spectroscopy supported by density functional theory simulations. With the location of various nitrogen species uniquely identified, we observe that for the same doping procedure, the graphene support, consisting of substrate and interface, strongly influences the structural as well as the electronic properties of the resulting doped graphene layer. Compared to epitaxial graphene, quasifreestanding graphene is found to contain fewer nitrogen dopants. However, this lack of dopants is compensated by the proximity of nitrogen atoms at the interface that yield a similar number of charge carriers in graphene.

Surfactant proteins A and D are related to severity of the disease, pathogenic bacteria and comorbidity in patients with chronic rhinosinusitis with and without nasal polyps.

BACKGROUND: Surfactant proteins (SP) A and D play a critical role in the innate defence of respiratory mucosa. Although numerous studies have focused on the importance of surfactant in the lower airways, relatively little is known about its role in the upper respiratory system. METHODS: The prospective study was conducted with 61 subjects divided into patients with chronic rhinosinusitis with nasal polyps (CRSwNP), with chronic rhinosinusitis without nasal polyps (CRSsNP) and healthy controls. SP-A and SP-D were detected in nasal lavage fluid (NALF) by ELISA and in nasal mucosa by immunohistochemical staining. Severity of the diseases assessed by preoperative CT score, presence of comorbidity (allergy and bronchial asthma) and bacterial culture from the middle nasal meatus was evaluated. RESULTS: In nasal mucosa, SPs were localised in ciliated cells of the surface epithelium and serous acini of the submucosal glands. Stronger expression of SPs in submucosal glands was observed in CRSwNP and CRSsNP groups in comparison with controls. In patients with CRSsNP and more severe form of the disease, higher levels of SP-A and SP-D in NALF and stronger immunoreactivity of these proteins in nasal mucosa were detected. Identification of pathogenic bacteria was associated with higher levels of SP-A and SP-D in NALF and nasal mucosa in patients with CRSsNP and control group. Presence of allergy was associated with stronger expression of SP-A in submucosal glands in all CRS patients and with decreased levels of both SPs in NALF in CRSsNP patients. CONCLUSIONS: Surfactant proteins A and D play an important role in innate host defence of upper respiratory tract. Different expression of these proteins in patients with chronic rhinosinusitis indicates possible novel target of therapy in these patients.

Comorbidity has no impact on eosinophil inflammation in the upper airways or on severity of the sinonasal disease in patients with nasal polyps.

OBJECTIVE: The study was designed to determine whether there is an association between the comorbidity as atopy, bronchial asthma, aspirin intolerance and eosinophil infiltration of the upper airways, severity of the sinonasal disease and rate of revision sinus surgery in patients with nasal polyps. MATERIAL AND METHODS: One hundred and fifty patients were enrolled in the prospective study. Differences in CT score, rate of revision surgery, concentration of eotaxin and eosinophil cationic protein in nasal lavage fluid (NALF) and distribution of eosinophils in NALF and nasal tissue in patients with chronic rhinosinusitis with nasal polyps (CRSwNP), chronic rhinosinusitis without nasal polyps (CRSsNP) and control group were investigated. We focused on the relationship between presence of comorbidity (atopy, bronchial asthma and aspirin intolerance) and severity of the disease, the need of revision surgery and markers of eosinophil inflammation in upper airways in patients with CRSwNP. RESULTS: Patients with CRSwNP had more severe form of the sinonasal disease, higher rate of revision FESS and significant higher presence of markers of eosinophil inflammation in NALF and nasal tissue than patients with CRSsNP (P < 0.05). Atopic and non-atopic asthma as well as aspirin sensitivity significantly more often coexisted with CRSwNP. Comorbidity did not influence eosinophil infiltration or severity of the disease in patients with CRSwNP. CONCLUSION: Presence of comorbidity (atopy, bronchial asthma and aspirin intolerance) has no impact on severity of the disease or eosinophil content in the upper airways in patients with CRSwNP.

Ortho and para hydrogen dimers on G/SiC(0001): combined STM and DFT study.

The hydrogen (H) dimer structures formed upon room-temperature H adsorption on single layer graphene (SLG) grown on SiC(0001) are addressed using a combined theoretical-experimental approach. Our study includes density functional theory (DFT) calculations for the full (6√3 × 6√3)R30° unit cell of the SLG/SiC(0001) substrate and atomically resolved scanning tunneling microscopy images determining simultaneously the graphene lattice and the internal structure of the H adsorbates. We show that H atoms normally group in chemisorbed coupled structures of different sizes and orientations. We make an atomic scale determination of the most stable experimental geometries, the small dimers and ellipsoid-shaped features, and we assign them to hydrogen adsorbed in para dimers and ortho dimers configuration, respectively, through comparison with the theory.

Graphene etching on SiC grains as a path to interstellar polycyclic aromatic hydrocarbons formation.

Polycyclic aromatic hydrocarbons as well as other organic molecules appear among the most abundant observed species in interstellar space and are key molecules to understanding the prebiotic roots of life. However, their existence and abundance in space remain a puzzle. Here we present a new top-down route to form polycyclic aromatic hydrocarbons in large quantities in space. We show that aromatic species can be efficiently formed on the graphitized surface of the abundant silicon carbide stardust on exposure to atomic hydrogen under pressure and temperature conditions analogous to those of the interstellar medium. To this aim, we mimic the circumstellar environment using ultra-high vacuum chambers and investigate the SiC surface by in situ advanced characterization techniques combined with first-principles molecular dynamics calculations. These results suggest that top-down routes are crucial to astrochemistry to explain the abundance of organic species and to uncover the origin of unidentified infrared emission features from advanced observations.

Combined AFM and STM measurements of a silicene sheet grown on the Ag(111) surface.

In this paper, we present the first non-contact atomic force microscopy (nc-AFM) of a silicene on a silver (Ag) surface, obtained by combining non-contact atomic force microscopy and scanning tunneling microscopy (STM). STM images over large areas of silicene grown on the Ag(111) surface show both (√13 × âˆš13)R13.9° and (4 × 4) superstructures. For the widely observed (4 × 4) structure, the observed nc-AFM image is very similar to the one recorded by STM. The structure resolved by nc-AFM is compatible with only one out of two silicon atoms being visible. This indicates unambiguously a strong buckling of the silicene honeycomb layer.

Kuttner tumor.

OBJECTIVE: Kuttner tumor or chronic sclerosing sialadenitis is a benign inflammatory condition of the salivary gland. Clinically, it produces a firm swelling of the gland and may be difficult to distinguish from neoplasia. This is an under-recognized entity in the surgical pathology and cytology literature. We describe our experience with Kuttner tumor. METHODS: Retrospectively, we analyzed a group of 7 patients with chronic sclerosing sialadenitis treated from January 1999 to March 2010 at the Department of Otorhinolaryngology, FD Roosevelt Faculty Hospital in Banska Bystrica, Slovakia. The authors evaluated age and sex distribution, patient's history, diagnostic procedures, extent and success of surgical treatment and postoperative complications. RESULTS: Four patients with chronic sclerosing sialadenitis were male and 3 were female. The mean age of patients was 55 years (ranging from 43 to 70 years). Submandibular gland was affected in 6 cases (85.7 %), involvement of both parotid glands was found in one patient (14.3 %). All patients in our study group were treated surgically. In 6 cases submandibular gland extirpation was performed via standard transcervical approach. Total parotidectomy with facial nerve preservation was realized in one patient with bilateral involvement of parotid glands. CONCLUSION: Chronic sclerosing sialadenitis is a condition that is perhaps more common than thought but usually mis-recognised as it is only after excision of the gland that the correct diagnosis is made (Tab. 1, Ref. 17).

Surgical management of submandibulary gland diseases: ten years of experience.

OBJECTIVE: The surgical management of submandibular gland diseases has always been a challenge because it carries a considerable risk of nerve injury. The aim of the study was to evaluate the history, diagnostic procedure, extent and success of the surgical treatment as well as possible complications in patients with submandibulary gland disorder. METHODS: We carried out a retrospective analysis of 86 patients (42 males, 44 females) with submandibular gland disorder treated between 1999 and 2008 at the Department of Otorhinolaryngology, FD Roosevelt Faculty Hospital in Banska Bystrica, Slovakia. Average age of patients was 52.3 years (range 13-80 years). RESULTS: All patients in our study were treated surgically with the use of standard transcervical approach. The most common indication for submandibulary gland extirpation was sialolithiasis (39.6%). 33.7% of all lesions were sialadenitis, and 26.7% were neoplasms. The morbidity of surgical treatment was low. Transient palsy of marginal mandibular nerve was observed to be the most common complication after the surgery (14%). CONCLUSION: Surgical removal of entire submandibulary gland is a safe operation with a low rate of complications (Tab. 5, Fig. 1, Ref. 17).

Genome-wide analysis of rice (Oryza sativa L. subsp. japonica) TATA box and Y Patch promoter elements.

The TATA box is one of the best characterized transcription factor binding sites. However, it is not a ubiquitous element of core promoters, and other sequence motifs such as Y Patches seem to play a major role in plants. Here, we present a first genome-wide computational analysis of the TATA box and Y Patch distribution in rice (Oryza sativa L. subsp. japonica) promoter sequences. Utilizing a probabilistic sequence model, we ascertain that only approximately 19% of rice genes possess the TATA box, but approximately 50% contain one or more Y Patches in their core promoters. By computational processing of identified elements, we generated extended TATA box and Y Patch nucleotide frequency matrices capable of predicting these motifs in plants with a high degree of confidence.

Risk of lymphatic or haematopoietic cancer mortality with occupational exposure to animals or the public.

BACKGROUND: Occupational exposure to animals or the public could result in exposure to infectious agents, which may play a role in the aetiology of lymphohaematopoietic (LH) cancers. AIMS: To conduct a population based, case-control study of death certificate data from 1984 to 1998 in 24 US states in order to evaluate the risk of mortality from LH neoplasms associated with occupational exposure to animals or the public. METHODS: Cases were selected as those with an underlying cause of death of non-Hodgkin's lymphoma (NHL, n = 72,589), Hodgkin's disease (HD, n = 5479), multiple myeloma (n = 35,857), or leukaemia (n = 68,598); 912 615 controls were randomly selected from all remaining deaths, frequency matched on age, sex, race, and geographic region. RESULTS: Occupational exposure to animals was associated with modest increased risks of mortality from all four LH cancers; these associations varied by region. Occupational exposure to the public was associated with only negligible increased risk with LH cancer outcomes. Occupations involving animal exposure were predominantly agricultural, and the risks associated with employment in the livestock industry exceeded the corresponding risks associated with the crop industry for all outcomes except HD. CONCLUSIONS: Increased risks of NHL, HD, multiple myeloma, and leukaemia were associated with occupations that involved animal exposure. Regional differences in risk imply that the risks may be associated with exposure to specific livestock or farming practices. However, these associations may be confounded by other farming related exposures, such as pesticides. Because the use of death certificates to classify occupation may result in misclassification during aetiologically relevant time periods, these hypotheses should be further explored in studies with detailed information on lifetime occupation.

[Acute reversible liver necrosis after valproate therapy (immunologic hypersensitivity)]. / Akute Reversible Lebernekrose nach Valproat-Behandlung (immunologisch bedingte Idiosynkrasie).

We describe a case of a 9-year-old boy with the severe acute liver injury caused by idiosyncrasy after the administration of valproate. The liver biopsy performed during the first days after the onset of the disease revealed the necrosis of more than 50% of hepatocytes but the injury was almost fully reversible which was well demonstrated by the second biopsy five months later. After five years an evidence for the immunologic idiosyncrasy caused by valproate was still present, which was demonstrated in vitro by blastic transformation of lymphocytes from the patient. The boy is quite healthy and epilepsy is under control of suximide. The family was informed that the boy could be treated with valproate never more.