Stability of quantum-dot excited-state laser emission under simultaneous ground-state perturbation

The impact of ground state amplification on the laser emission of In(Ga)As quantum dot excited state lasers is studied in time-resolved experiments. We find that a depopulation of the quantum dot ground state is followed by a drop in excited state lasing intensity. The magnitude of the drop is strongly dependent on the wavelength of the depletion pulse and the applied injection current. Numerical simulations based on laser rate equations reproduce the experimental results and explain the wavelength dependence by the different dynamics in lasing and non-lasing sub-ensembles within the inhomogeneously broadened quantum dots. At high injection levels, the observed response even upon perturbation of the lasing sub-ensemble is small and followed by a fast recovery, thus supporting the capacity of fast modulation in dual-state devices

Risk perception of arsenic exposure from rice intake in a UK population

In the UK, consumption of rice and rice-based products is on the rise but, notwithstanding public expressed concerns about such products as an exposure route for arsenic (e.g. BBC News report, 2017“Should I worry about arsenic in my rice?”) there are few, if any published data on public perceptions of risks associated with exposure to arsenic in rice. We therefore aimed to determine the risk perception of arsenic exposure from rice intake and factors that are associated with arsenic knowledge and whether or not this knowledge had an influence on rice consumption and cooking practices. A questionnaire, targeting participation of rice-eating ethnic minorities in Greater Manchester, UK, was administered to 184 participants. A multivariate generalized linear model was used to determine the factors associated with rice consumption behaviour, cooking practices, and risk perception. We show for the first time that the general population did not associate arsenic, which they perceive as toxic to health, with rice consumption. More than half of the participants knew about arsenic as a hazardous substance but less than ten percent knew that rice consumption could be an important route of arsenic exposure. Knowledge of arsenic was significantly lower in Asian/Asian British:Pakistanis (Pakistani) (OR: 0.006; 95% CI:0.00-0.03) and Asian/Asian British:Bangladeshis (Bangladeshi) (OR: 0.064; 95% CI:0.01-0.25) compared to White:English/Welsh/Scottish/Northern Irish/British (White British). Moreover, Bangladeshis consumed three times more rice (OR: 2.92; 95% CI:1.73-4.93) compared to White British. Overall higher rice consumption was not associated with higher knowledge of the nutritional value of rice. Rinsing rice before cooking, an effective arsenic removal technique, was practised by 93% of the participants, however the most popular cooking method was the use of adequate water (rice to water ratio of 1:2) but not excess water (rice to water ratio of > 1:4), the latter being more effective in removing arsenic. Better education, higher weekly expenditure on food and prior knowledge of arsenic hazard were all significant factors positively influencing a change in behaviour to reduce arsenic exposure from rice intake

An analysis and comparison of multinational officers of the watch in the global maritime labor market

Officer of the watch (OOW) is an important part of the maritime labor market. For many years, countries have been improving their development of OOWs for the maritime market, in terms of both quantity and quality. As the supply of qualified OOWs for maritime transportation is such an important issue, shipping companies recruit multinational OOWs for both economic and socio-cultural reasons. This study aims to identify the qualifications of an ideal officer that holds office on commercial ships, and to make a comparison among Filipino, Chinese, Indian, Eastern European and Turkish OOWs. The research takes into account expert opinions of a number of shipping companies that employ multinational seafarers. A Fuzzy Analytic Hierarchy Process (FAHP) technique is applied in this study to assist in the comparison of officers. A number of main and sub-criteria are outlined to determine both positive and negative aspects of OOWs from the selected countries for decision making purposes. This study allows maritime countries to evaluate their maritime education and training policies for selection and assessment of OOWs. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group

Vitamin B12 status in patients of Turkish and Dutch descent with depression: A comparative cross-sectional study

Background: Studies have shown a clear relationship between depressive disorders and vitamin B12 deficiency. Gastroenteritis and Helicobacter pylori infections can cause vitamin B12 deficiency. Helicobacter pylori infections are not uncommon among people of Turkish descent in The Netherlands. Aim: To examine the frequency of vitamin B12 deficiency in depressive patients of Turkish descent and compare it to the frequency of vitamin B12 deficiency in depressive patients of Dutch descent. Methods: The present study is a comparative cross-sectional study of 47 patients of Turkish descent and 28 of Dutch descent. The depressive disorder diagnosis and differential diagnosis were made using the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, fourth edition text revision (SCID). The severity of the depressive symptoms was determined using the Beck Depression Inventory (BDI) and the 21-item Hamilton Depression Rating Scale (HAM-D-21). Serum baseline vitamin B6 and B12, folic acid and total serum homocysteine (tHcy) levels were measured. Results: The average ages of the patients of Turkish and Dutch descent were 40.57 and 44.75 years, respectively. There were no demonstrable differences between the serum vitamin B6, folic acid and tHcy levels in the two groups. The serum vitamin B12 levels were however clearly lower in the patients of Turkish descent than in those of Dutch descent. Vitamin B12 deficiency was however observed in 14 patients of Turkish descent and 1 of Dutch descent. This difference was significant. On the BDI, the patients of Turkish descent scored significantly higher than those of Dutch descent. Patients with vitamin B12 deficiency and those with hyperhomocysteinaemia had a significantly higher BDI score than patients with normal vitamin B12 and homocysteine levels. No relationship was observed with vitamin B12 and tHcy. Conclusion: Vitamin B12 deficiency occurs more frequently in depressive patients of Turkish than of Dutch descent. This is why it is advisable to test the vitamin B12 serum level in depressive patients of Turkish descent

Transmitted antiretroviral drug resistance mutations in newlydiagnosed HIV-1 positive patients in Turkey

Introduction: The objective of this study was to determine the transmitted drug resistance mutations (TDRMs) in newly diagnosed HIV-1 positive patients in Turkey. Materials and Methods: The study was carried out between 2009 and 2014 and antiretroviral naïve 774 HIV-1 infected patients from 19 Infectious Diseases and Clinical Microbiology Departments in Turkey were included; gender: 664 (86%) male, median age: 37 (range; 1–77), median CD4+T-cell: 360 (range; 1–1320) count/mm3, median HIV-RNA load: 2.10+E6 (range; 4.2+E2–7.41+E8) IU/mL. HIV-1 drug resistance mutations were detected by population based sequencing of the reverse transcriptase (codon 41–238) and protease (codon 1–99) domains of pol gene of HIV-1, and analyzed according to the criteria by the World Health Organization 2009 list of surveillance drug resistance mutations [1]. Results: The patients had TDRMs to NRTIs (K65R, M184V), NNRTIs (K101E, K103N/S, G190A/E/S, Y181I/C, Y188H/L) and PIs (M46L, I54V, L76V, V82L/T, N83D, I84V, L90M). The prevalence of overall TDRMs was 6.7% (52/774). Resistance mutations were found to be 0.7% (6/774), 4.1% (32/774) and 2.1% (17/774) to NRTIs, NNRTIs and PIs drug groups, respectively. Three patients had NRTIs+NNRTs resistance mutations (M184V+K103N) as multi-class drug resistance. However, thymidine analogue resistance mutations (TAMs) determined two distinct genotypic profiles in the HIV-1 reverse transcriptase: TAM1: M41L, L210W and T215Y, and TAM2: D67N, K70R, K219E/Q, and T215F. The prevalence of TAM1 and TAM2 were 7.7% (60/774) and 4.3% (34/774), respectively. Conclusions: The TDRMs prevalence of antiretroviral naïve HIV-1 infected patients may be suggested current situation of Turkey. These long-term and large-scale results show that the resistance testing must be an integral part of the management of HIV infection in Turkey

An update on vitamin B12-related gene polymorphisms and B12 status.

Vitamin B12 is an essential micronutrient in humans needed for health maintenance. Deficiency of vitamin B12 has been linked to dietary, environmental and genetic factors. Evidence for the genetic basis of vitamin B12 status is poorly understood. However, advancements in genomic techniques have increased the knowledge-base of the genetics of vitamin B12 status. Based on the candidate gene and genome-wide association (GWA) studies, associations between genetic loci in several genes involved in vitamin B12 metabolism have been identified. The objective of this literature review was to identify and discuss reports of associations between single-nucleotide polymorphisms (SNPs) in vitamin B12 pathway genes and their influence on the circulating levels of vitamin B12. Relevant articles were obtained through a literature search on PubMed through to May 2017. An article was included if it examined an association of a SNP with serum or plasma vitamin B12 concentration. Beta coefficients and odds ratios were used to describe the strength of an association, and a  < 0.05 was considered as statistically significant. Two reviewers independently evaluated the eligibility for the inclusion criteria and extracted the data. From 23 studies which fulfilled the selection criteria, 16 studies identified SNPs that showed statistically significant associations with vitamin B12 concentrations. Fifty-nine vitamin B12-related gene polymorphisms associated with vitamin B12 status were identified in total, from the following populations: African American, Brazilian, Canadian, Chinese, Danish, English, European ancestry, Icelandic, Indian, Italian, Latino, Northern Irish, Portuguese and residents of the USA. Overall, the data analyzed suggests that ethnic-specific associations are involved in the genetic determination of vitamin B12 concentrations. However, despite recent success in genetic studies, the majority of identified genes that could explain variation in vitamin B12 concentrations were from Caucasian populations. Further research utilizing larger sample sizes of non-Caucasian populations is necessary in order to better understand these ethnic-specific associations