Prolactin delays hair regrowth in mice

Mammalian hair growth is cyclic, with hair-producing follicles alternating between active (anagen) and quiescent (telogen) phases. The timing of hair cycles is advanced in prolactin receptor (PRLR) knockout mice, suggesting that prolactin has a role in regulating follicle cycling. In this study, the relationship between profiles of circulating prolactin and the first post-natal hair growth cycle was examined in female Balb/c mice. Prolactin was found to increase at 3 weeks of age, prior to the onset of anagen 1 week later. Expression of PRLR mRNA in skin increased fourfold during early anagen. This was followed by upregulation of prolactin mRNA, also expressed in the skin. Pharmacological suppression of pituitary prolactin advanced dorsal hair growth by 3.5 days. Normal hair cycling was restored by replacement with exogenous prolactin for 3 days. Increasing the duration of prolactin treatment further retarded entry into anagen. However, prolactin treatments, which began after follicles had entered anagen at 26 days of age, did not alter the subsequent progression of the hair cycle. Skin from PRLR-deficient mice grafted onto endocrine-normal hosts underwent more rapid hair cycling than comparable wild-type grafts, with reduced duration of the telogen phase. These experiments demonstrate that prolactin regulates the timing of hair growth cycles in mice via a direct effect on the skin, rather than solely via the modulation of other endocrine factors

Detecting 6 MV X-rays using an organic photovoltaic device

An organic photovoltaic (OPV) device has been used in conjunction with a flexible inorganic phosphor to produce a radiation tolerant, efficient and linear detector for 6 MV Xrays. The OPVs were based on a blend of poly(3-hexylthiophene-2,5-diyl) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM). We show that the devices have a sensitivity an order of magnitude higher than a commercial silicon detector used as a reference. Exposure to 360 Grays of radiation resulted in a small (2%) degradation in performance demonstrating that these detectors have the potential to be used as flexible, real-time, in vivo dosimeters for oncology treatments. (C) 2009 Elsevier B.V. All rights reserved

An X-ray scattering and electron microscopy study of methylammonium bismuth perovskites for solar cell applications

Photovoltaics made from organic–inorganic hybrid perovskite semiconductors are attracting significant interest due to their ability to harvest sunlight with remarkable efficiency. The presence of lead in the best performing devices raises concerns regarding their toxicity, a problem that may create barriers to commercialization. Hybrid perovskites with reduced lead content are being investigated to overcome this issue and here we evaluate bismuth as a possible lead substitute. For a series of hybrid perovskite films with the general composition CH3NH3(PbyBi1−y)I3−xClx, we characterize their optical and structural properties using UV–Vis spectroscopy, scanning electron microscopy and grazing incidence wide angle X-ray scattering. We show that they form crystalline structures with an optical band gap, around 2 eV for CH3NH3BiI3. However, preliminary solar cell tests show low power conversion efficiencies (<0.01%) due to both incomplete precursor conversion and material de-wetting from the substrate. The overall outcome is severely limited photocurrent. With current processing methods the general applicability of hybrid bismuth perovskites in photovoltaics may be limited

Monitoring the Formation of a CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3-</inf><inf>x</inf>Cl<inf>x</inf> Perovskite during Thermal Annealing Using X-Ray Scattering

Grazing incidence wide and small angle X-ray scattering (GIWAXS and GISAXS) measurements have been used to study the crystallization kinetics of the organolead halide perovskite CH3NH3PbI3-xClx during thermal annealing. In situ GIWAXS measurements recorded during annealing are used to characterize and quantify the transition from a crystalline precursor to the perovskite structure. In situ GISAXS measurements indicate an evolution of crystallite sizes during annealing, with the number of crystallites having sizes between 30 and 400 nm increasing through the annealing process. Using ex situ scanning electron microscopy, this evolution in length scales is confirmed and a concurrent increase in film surface coverage is observed, a parameter crucial for efficient solar cell performance. A series of photovoltaic devices are then fabricated in which perovskite films have been annealed for different times, and variations in device performance are explained on the basis of X-ray scattering measurements

Qualitative study of paramedics' experiences of managing seizures: A national perspective from England

Objectives: The UK ambulance service is expected to now manage more patients in the community and avoid unnecessary transportations to hospital emergency departments (ED). Most people it attends who have experienced seizures have established epilepsy, have experienced uncomplicated seizures and so do not require the full facilities of an ED. Despite this, most are transported there. To understand why, we explored paramedics experiences of managing seizures. Design and setting: Semistructured interviews were conducted with a purposive sample of paramedics from the English ambulance service. Interviews were transcribed and thematically analysed. Participants: A diverse sample of 19 professionals was recruited from 5 different ambulance NHS trusts and the College of Paramedics. Results: Participants confirmed how most seizure patients attended to do not clinically require an ED. They explained, however, that a number of factors influence their care decisions and create a momentum for these patients to still be taken. Of particular importance was the lack of access paramedics have to background medical information on patients. This, and the limited seizure training paramedics receive, meant paramedics often cannot interpret with confidence the normality of a seizure presentation and so transport patients out of precaution. The restricted time paramedics are expected to spend on scene due to the way the ambulance services performance is measured and that are few alternative care pathways which can be used for seizure patients also made conveyance likely. Conclusions: Paramedics are working within a system that does not currently facilitate nonconveyance of seizure patients. Organisational, structural, professional and educational factors impact care decisions and means transportation to ED remains the default option. Improving paramedics access to medical histories, their seizure management training and developing performance measures for the service that incentivise care that is cost-effective for all of the health service might reduce unnecessary conveyances to ED

Real time thermal propagtors for massive gauge bosons

We derive Feynman rules for gauge theories exhibiting spontaneous symmetry breaking using the real-time formalism of finite temperature field theory. We also derive the thermal propagators where only the physical degrees of freedom are given thermal boundary conditions. We analyse the abelian Higgs model and find that these new propagators simplify the calculation of the thermal contribution to the self energy.Comment: 7 pages, late

Correlating nanoscale morphology with device performance in conventional and inverted PffBT4T-2OD:PC71BM polymer solar cells

Nanoscale morphology has been established as one of the controlling factors in the device performance of bulk heterojunction polymer solar cells. We report in this work morphology changes in both lateral and vertical directions in PffBT4T-2OD:PC71BM solar cells, as well as their effects on device performance. Thermal annealing was found to increase the crystallinity of PffBT4T-2OD and domain size of PC71BM clusters without any observable impact on vertical component redistribution, while methanol rinsing reduces the crystallinity of PffBT4T-2OD, which encourages the migration of PC71BM toward the mixed polymer-rich phase as well as toward the film surface on both PEDOT:PSS and TiO2 substrates. The polymer-rich surface region in vacuum- and thermal-annealing-treated conventional devices obstructs electron injection toward the cathode, and reduces the maximum achievable device efficiency, while this polymer-rich surface region is beneficial in the inverted devices. However, although a PC71BM-rich region will locate at the cathode or anode interface upon methanol-rinsing treatment in conventional and inverted devices, respectively, holes can still be effectively injected from both sides of the device to ensure effective charge transport, as supported by a number of optoelectronic property investigations

The robot vibrissal system: Understanding mammalian sensorimotor co-ordination through biomimetics

Chapter 10 The Robot Vibrissal System: Understanding Mammalian Sensorimotor Co-ordination Through Biomimetics Tony J. Prescott, Ben Mitchinson, Nathan F. Lepora, Stuart P. Wilson, Sean R. Anderson, John Porrill, Paul Dean, Charles&nbsp;..

An X-ray photoelectron spectroscopy investigation of chromium conversion coatings and chromium compounds

Hexavalent and trivalent chromium based conversion coatings on zinc electrodeposited steel have been investigated using X-ray photoelectron spectroscopy (XPS) with the aim of elucidating their film chemistry. Furthermore, a monochromatic Al Kα X-ray source was utilised and the spectra produced evaluated using curve fitting software to elucidate oxidation state information. In addition, a number of chromium compounds were investigated and used to complement the curve fitting analysis for the conversion coatings. High resolution Cr2p spectra from chromium compounds exhibited multiplet splitting for Cr2O3. Additional satellite emissions can also be observed for Cr2O3 and Cr(OH)3. Curve fitting of hexavalent chromium conversion coating (CCC) 2p3/2 spectra contained both Cr(VI) and Cr(III) species with the content of the former slightly higher when the X-ray beam take-off angle (TOA) was reduced to determine more surface specific information. The Cr(III) content was determined to be mainly composed of Cr(OH)3 with some Cr2O3. In comparison, trivalent CCCs were largely composed of Cr2O3 as opposed to Cr(OH)3. Survey scans of both coatings revealed that the trivalent CCCs had a higher relative zinc content