Electron refraction at lateral atomic interfaces

We present theoretical simulations of electron refraction at the lateral atomic interface between a “homogeneous” Cu(111) surface and the “nanostructured” one-monolayer (ML) Ag/Cu(111) dislocation lattice. Calculations are performed for electron binding energies barely below the 1 ML Ag/ Cu(111) M-point gap (binding energy EB ¼53 meV, below the Fermi level) and slightly above its C -point energy (EB ¼160 meV), both characterized by isotropic/circular constant energy surfaces. Using plane-wave-expansion and boundary-element methods, we show that electron refraction occurs at the interface, the Snell law is obeyed, and a total internal reflection occurs beyond the critical angle. Additionally, a weak negative refraction is observed for EB ¼53 meV electron energy at beam incidence higher than the critical angle. Such an interesting observation stems from the interface phase-matching and momentum conservation with the umklapp bands at the second Brillouin zone of the dislocation lattice. The present analysis is not restricted to our Cu-Ag/Cu model system but can be readily extended to technologically relevant interfaces with spinpolarized, highly featured, and anisotropic constant energy contours, such as those characteristic for Rashba systems and topological insulators. Published by AIP Publishing.Peer ReviewedPostprint (published version

Prevalence and Health Adverse Effects of Khat Chewing Among College Students in Jazan Region, Saudi Arabia

Khat chewing is a social habit which has stimulatory action due to its cathinone content, but its adverse effects on health are a source of growing concern. The aim of our study is to evaluate the prevalence and health adverse effects of khat chewing among students in Jazan region in the Kingdom of Saudi Arabia (KSA). The study sample included 195 students from Applied Medical Science College, who were randomly selected and were asked through questionnaire and with a signed consent. About 5 ml of venous blood was collected in plain vacutainer tubes from 38 khat chewers and 20 non khat chewers as normal control. Serum was used to determine alanine aminotransferase (ALT), alkaline phosphatase (ALP), total and direct bilirubin, total protein, urea, creatinine, uric acid, and albumin. The sample consisted of 134 males and 61 females, with age range 19-27 years, and their mean age was 21.1 year. 40% of students were from urban area, and 81.5% of them from Jazan region. Out of 195 students, only 38 (19.5%) were found to chew khat. Biochemical results revealed highly significant differences among chewers in ALT, ALP, uric acid, and urea (p<0.005) compared to nonchewers group. There is also a significant difference in the total protein level (<0.05), while no significant differences were noticed in other biochemical traits analyzed. We concluded that the prevalence of khat chewing among students is fairly high (19.5 %), and that adverse effects of khat chewing on health are very clear, so all efforts should be contributed to solve this problem by increasing awareness of all members of the society to khat chewing risk

Detection of multiple respiratory pathogens during primary respiratory infection: nasal swab versus nasopharyngeal aspirate using real-time polymerase chain reaction

In this study, we present the multiple detection of respiratory viruses in infants during primary respiratory illness, investigate the sensitivity of nasal swabs and nasopharyngeal aspirates, and assess whether patient characteristics and viral load played a role in the sensitivity. Healthy infants were included at signs of first respiratory tract infection. Paired nasopharyngeal aspirates and nasal swabs were collected. Real-time polymerase chain reaction (PCR) was carried out for 11 respiratory pathogens. Paired nasopharyngeal aspirates and nasal swabs were collected in 98 infants. Rhinovirus (n = 67) and respiratory syncytial virus (n = 39) were the most frequently detected. Co-infection occurred in 48% (n = 45) of the infants. The sensitivity of the nasal swab was lower than the nasopharyngeal aspirate, in particular, for respiratory syncytial virus (51% vs. 100%) and rhinovirus (75% vs. 97%). The sensitivity of the nasal swab was strongly determined by the cycle threshold (CT) value (p < 0.001). The sensitivity of the swab for respiratory syncytial virus, but not rhinovirus, was 100% in children with severe symptoms (score ≥11). It is concluded that, for community-based studies and surveillance purposes, the nasal swab can be used, though the sensitivity is lower than the aspirate, in particular, for the detection of mild cases of respiratory syncytial virus (RSV) infection

RNA and DNA Bacteriophages as Molecular Diagnosis Controls in Clinical Virology: A Comprehensive Study of More than 45,000 Routine PCR Tests

Real-time PCR techniques are now commonly used for the detection of viral genomes in various human specimens and require for validation both external and internal controls (ECs and ICs). In particular, ICs added to clinical samples are necessary to monitor the extraction, reverse transcription, and amplification steps in order to detect false-negative results resulting from PCR-inhibition or errors in the technical procedure. Here, we performed a large scale evaluation of the use of bacteriophages as ICs in routine molecular diagnosis. This allowed to propose simple standardized procedures (i) to design specific ECs for both DNA and RNA viruses and (ii) to use T4 (DNA) or MS2 (RNA) phages as ICs in routine diagnosis. Various technical formats for using phages as ICs were optimised and validated. Subsequently, T4 and MS2 ICs were evaluated in routine real-time PCR or RT-PCR virological diagnostic tests, using a series of 8,950 clinical samples (representing 36 distinct specimen types) sent to our laboratory for the detection of a variety of DNA and RNA viruses. The frequency of inefficient detection of ICs was analyzed according to the nature of the sample. Inhibitors of enzymatic reactions were detected at high frequency in specific sample types such as heparinized blood and bone marrow (>70%), broncho-alveolar liquid (41%) and stools (36%). The use of T4 and MS2 phages as ICs proved to be cost-effective, flexible and adaptable to various technical procedures of real-time PCR detection in virology. It represents a valuable strategy for enhancing the quality of routine molecular diagnosis in laboratories that use in-house designed diagnostic systems, which can conveniently be associated to the use of specific synthetic ECs. The high rate of inhibitors observed in a variety of specimen types should stimulate the elaboration of improved technical protocols for the extraction and amplification of nucleic acids

Critical Review of Theoretical Models for Anomalous Effects (Cold Fusion) in Deuterated Metals

We briefly summarize the reported anomalous effects in deuterated metals at ambient temperature, commonly known as "Cold Fusion" (CF), with an emphasis on important experiments as well as the theoretical basis for the opposition to interpreting them as cold fusion. Then we critically examine more than 25 theoretical models for CF, including unusual nuclear and exotic chemical hypotheses. We conclude that they do not explain the data.Comment: 51 pages, 4 Figure

What does regional studies study? From subnational to supra-national regional spaces or Grossraum of sovereign governance

This article makes a case for expanding the scope of current versions of “regional studies” to include greater emphasis upon transnational regions as of equal if not greater importance compared with an exclusive focus upon sub-national regions. The latter more restrictive approach is typically predicated on the continued centrality of state borders against which the dominant notion of regions as subnational entities is constituted and reiterated. Drawing upon a case study of the African Union our study provides a framework, a critically revised Grossraum theory, for addressing the emergence of a new pluralistic and multipolar world order characterised by supra-national regions and regional organizations. Traditional Schmittian notions of Grossraum are shown to be in need of substantial revision before they are able to adequately accommodate and explain the empirical details of our case study

Syndromic Recognition of Influenza A Infection in a Low Prevalence Community Setting

BACKGROUND: With epidemics of influenza A virus infection, people and medical professionals are all concerned about symptoms or syndromes that may indicate the infection with influenza A virus. METHODOLOGY/PRINCIPAL FINDINGS: A prospective study was performed at a community clinic of a metropolitan area. Throat swab was sampled for 3-6 consecutive adult patients with new episode (<3 days) of respiratory tract infection every weekday from Dec. 8, 2005 to Mar. 31, 2006. Demographic data, relevant history, symptoms and signs were recorded. Samples were processed with multiplex real time PCR for 9 common respiratory tract pathogens and by virus culture. Throat swab samples were positive for Influenza A virus with multiplex real time PCR system in 12 of 240 patients. The 12 influenza A positive cases were with more clusters and chills than the other 228. Certain symptoms and syndromes increased the likelihood of influenza A virus infection. The syndrome of high fever plus chills plus cough, better with clustering of cases in household or workplace, is with the highest likelihood (positive likelihood ratio 95; 95% CI 12-750). Absence of both cluster and chills provides moderate evidence against the infection (negative likelihood ratio 0.51; 95% CI 0.29-0.90). CONCLUSIONS/SIGNIFICANCE: Syndromic recognition is not diagnostic but is useful for discriminating between influenza A infection and common cold. In addition to relevant travel history, confirmatory molecular test can be applied to subjects with high likelihood when the disease prevalence is low

The Effect of A Geriatric Assessment on Treatment Decisions for Patients with Lung Cancer

BACKGROUND: Decision-making for older patients with lung cancer can be complex and challenging. A geriatric assessment (GA) may be helpful and is increasingly being used since 2005 when SIOG advised to incorporate this in standard work-up for the elderly with cancer. Our aim was to evaluate the value of a geriatric assessment in decision-making for patients with lung cancer. METHODS: Between January 2014 and April 2016, data on patients with lung cancer from two teaching hospitals in the Netherlands were entered in a prospective database. Outcome of geriatric assessment, non-oncologic interventions, and suggested adaptations of oncologic treatment proposals were evaluated. RESULTS: 83 patients (median age 79 years) were analyzed with a geriatric assessment, of which 59% were treated with a curative intent. Half of the patients were classified as ECOG PS 0 or 1. The majority of the patients (78%) suffered from geriatric impairments and 43% (n = 35) of the patients suffered from three or more geriatric impairments (out of eight analyzed domains). Nutritional status was most frequently impaired (52%). Previously undiagnosed impairments were identified in 58% of the patients, and non-oncologic interventions were advised for 43%. For 33% of patients, adaptations of the oncologic treatment were proposed. Patients with higher number of geriatric impairments more often were advised a reduced or less intensive treatment (p < 0.001). CONCLUSION: A geriatric assessment uncovers previously unknown health impairments and provides important guidance for tailored treatment decisions in patients with lung cancer. More research on GA-stratified treatment decisions is needed