Exciton-polariton emission from organic semiconductor optical waveguides

We photo-excite slab polymer waveguides doped with J-aggregating dye molecules and measure the leaky emission from strongly coupled waveguide exciton polariton modes at room temperature. We show that the momentum of the waveguide exciton polaritons can be controlled by modifying the thickness of the excitonic waveguide. Non-resonantly pumped excitons in the slab excitonic waveguide decay into transverse electric and transverse magnetic strongly coupled exciton waveguide modes with radial symmetry. These leak to cones of light with radial and azimuthal polarizations

Preliminary report on two Triassic dicynodonts from Zambia.

Main articleThe purpose of this communication is to establish the presence of a species of Stahleckeriid, hitherto known only from India, in the Zambian Triassic N'tawere Formation and to establish the new specific name of the Kannemeyeria specimen also recorded from the same locality. The skulls and some post-cranial material of these two dicynodonts were collected by Mr. James Kitching from the Luangwa Valley, Zambia in 1961. The material comes from Locality 16, of the Lower Fossiliferous Horizon in the N'tawere Formation. One large skull has been assigned to genus and species Rechnisaurus cristarhynchus Roy Chowdhury, 1970. The other skull and the postcranial material has been named Kannemeyeria latirostris sp. nov. One other specimen has been described from this locality, Diademodon rhodesiensis (Brink 1963), which marks it as being of near Cynognathus-zone age.Non

Driven to Failure: An Empirical Analysis of Driver’s License Suspension in North Carolina

A person’s interest in a driver’s license is “substantial,” and as the U.S. Supreme Court has observed, the suspension of a license by the state can result in “inconvenience and economic hardship suffered,” including because a license may be “essential in the pursuit of a livelihood.” However, forty-four U.S. states currently require indefinite suspension of driver’s licenses for non-driving-related reasons, such as failure to appear in court or pay fines for traffic infractions. There are no systematic, peer-reviewed analyses of individual-level or county-level data regarding such suspensions. This study describes North Carolina’s population of suspended drivers and assesses how driver’s license suspension statutes operate relative to geography, race, and poverty level. First, it analyzes four decades of active-suspension data in North Carolina and finds over 1,225,000 active suspensions for failures to appear or pay traffic fines, amounting to one in seven adult drivers in the state. Second, it compares these data to county-population data; county-level traffic-stop data, collected as required by statute in North Carolina; and county-level data on the volume and composition of traffic court dockets. This study reveals that driver’s license suspensions are not associated with either the volume of traffic stops or the size of the traffic court docket. In contrast, we find that black and Latinx people are overrepresented relative to the population. Linear mixed-level modeling regression analyses demonstrate that the population of white people below the poverty line and black people above the poverty line are most strongly associated with more suspensions. Finally, this Article explores implications of these results for efforts to reconsider the imposition of driver’s license suspensions for non-driving-related reasons. These patterns raise constitutional concerns and practical challenges for policy efforts to undo such large-scale suspension of driving privileges

Fat transforms ascorbic acid from inhibiting to promoting acid-catalysed N-nitrosation

<b>Background</b>: The major potential site of acid nitrosation is the proximal stomach, an anatomical site prone to a rising incidence of metaplasia and adenocarcinoma. Nitrite, a pre-carcinogen present in saliva, can be converted to nitrosating species and N-nitroso compounds by acidification at low gastric pH in the presence of thiocyanate. <b>Aims</b>: To assess the effect of lipid and ascorbic acid on the nitrosative chemistry under conditions simulating the human proximal stomach. <b>Methods</b>: The nitrosative chemistry was modelled in vitro by measuring the nitrosation of four secondary amines under conditions simulating the proximal stomach. The N-nitrosamines formed were measured by gas chromatography–ion-trap tandem mass spectrometry, while nitric oxide and oxygen levels were measured amperometrically. <b>Results</b>: In absence of lipid, nitrosative stress was inhibited by ascorbic acid through conversion of nitrosating species to nitric oxide. Addition of ascorbic acid reduced the amount of N-nitrosodimethylamine formed by fivefold, N-nitrosomorpholine by .1000-fold, and totally prevented the formation of N-nitrosodiethylamine and N-nitrosopiperidine. In contrast, when 10% lipid was present, ascorbic acid increased the amount of Nnitrosodimethylamine, N-nitrosodiethylamine and N-nitrosopiperidine formed by approximately 8-, 60- and 140-fold, respectively, compared with absence of ascorbic acid. <b>Conclusion</b>: The presence of lipid converts ascorbic acid from inhibiting to promoting acid nitrosation. This may be explained by nitric oxide, formed by ascorbic acid in the aqueous phase, being able to regenerate nitrosating species by reacting with oxygen in the lipid phase

Variations in caffeine and chlorogenic acid contents of coffees: what are we drinking?

The effect of roasting of coffee beans and the extraction of ground coffee with different volumes of hot pressurised water on the caffeine and the total caffeoylquinic acids (CQAs) content of the resultant beverages was investigated. While caffeine was stable higher roasting temperatures resulted in a loss of CQAs so that the caffeine/CQA ratio was a good marker of the degree of roasting. The caffeine and CQA content and volume was determined for 104 espresso coffees obtained from coffee shops in Scotland, Italy and Spain, limited numbers of cappuccino coffees from commercial outlets and several instant coffees. The caffeine content ranged from 48–317 mg per serving and CQAs from 6–188 mg. It is evident that the ingestion of 200 mg of caffeine per day can be readily and unwittingly exceeded by regular coffee drinkers. This is the upper limit of caffeine intake from all sources recommended by US and UK health agencies for pregnant women. In view of the variable volume of serving sizes, it is also clear that the term “one cup of coffee” is not a reproducible measurement for consumption, yet it is the prevailing unit used in epidemiology to assess coffee consumption and to link the potential effects of the beverage and its components on the outcome of diseases. More accurate measurement of the intake of coffee and its potentially bioactive components are required if epidemiological studies are to produce more reliable information

The experiences of midwives and women during intrapartum transfer from one-to-one midwife-led birth environments to obstetric-led units

Objective: To explore the transition from midwifery one-to-one support in labour within a midwife-led birth environment to an obstetricled unit from the perspectives of midwives and women. Design: Ethnographic study. Data was collected from eleven transfers to an obstetric-led unit. The transfer process was observed for four women. Semi-structured interviews were completed following the births with eleven women and eleven midwives. Nine maternity records were also analysed. Setting: An alongside midwife-led unit, freestanding midwife-led unit, women's homes in England. Findings: Territorial behaviour was the main theme experienced by midwives when transferring women to obstetric-led units. Territorial behaviour manifested itself as a feeling of 'us versus them' behaviours, 'feeling under scrutiny' and being aware of 'conflicting ideologies'. For women there were four themes that had an impact on their experiences of transfer obstetric-led units including: (1) their midwife continuing the care on the labour ward, (2) having time to adjust to their new situation, (3) all staff introducing themselves and (4) not being separated from their baby for long periods of time. Conclusion and implications for practice: Transfer from a midwife-led birth environment to an obstetric-led unit is a stressful situation for midwives and women. This paper highlights how territorial behaviours impacted negatively for midwives during transfer to an obstetric-led unit. More research is required to understand territorial behaviours within the maternity services and how more respectful compassionate working relationships can be created. Additionally, from the perspective of women this paper highlights four aspects of care that positively impacted on the experiences of women and even helped them to build resilience to cope with the change of location, situation, medical interventions and new carers when transferring to an obstetric-led unit

FDTD Investigations into UWB Radar Technique of Breast Tumor Detection and Location

In this paper, a finite difference time domain (FDTD) method is applied to investigate capabilities of an ultra-wide band (UWB) radar system to detect and locate a breast tumor. The investigations are divided into three parts. The first part concerns an EM field analysis of a phantom formed by a plastic container with liquid and a small highly reflecting target. In the second part, a three-dimensional numerical breast model is used to perform more advanced studies. In the carried out 3D FDTD simulations, a quasi-plane wave is used as an incident wave. Various time snap shots of the electromagnetic field are recorded to learn about the physical phenomenon of reflection and scattering in different layers of the phantoms. The third part of the investigations concerns a two dimensional (cylindrical) image reconstruction, which is performed by means of 2D FDTD. The obtained results should form the ground for working out suitable guidelines for designing an optimal microwave breast imaging apparatus based on the UWB radar technique