The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.

Nitrous oxide (N2O) misuse is widespread in the UK. Although it is well-known that it can cause devastating myeloneuropathy, psychiatric presentations are poorly described. There is little understanding of who it affects, how it presents, its mechanism of action and principles of treatment. We begin this article with a case study. We then review the literature to help psychiatrists understand this area and deal with this increasing problem, and make diagnosis and treatment recommendations. We describe a diagnostic pentad of weakness, numbness, paraesthesia, psychosis and cognitive impairment to alert clinicians to the need to urgently treat these patients. Nitrous oxide misuse is a pending neuropsychiatric emergency requiring urgent treatment with vitamin B12 to prevent potentially irreversible neurological and psychiatric symptoms.

Genetic diversity within and among populations of yellow nutsedge (Cyperus esculentus L. # CYPES) was analyzed to evaluate and quantify the genetic consequences of the reported predominance of asexually-produced tubers as colonizing agents. Ten populations were examined using starch gel electrophoresis for allozyme analysis. Four populations of purple nutsedge (Cyperus rotundus L. # CYPRO) were surveyed for comparison. Twelve loci were identified in yellow nutsedge among the eight enzyme systems examined; ten of these loci were found in purple nutsedge. Yellow nutsedge showed relatively low genetic diversity. Most of the genetic diversity occurred as differences among individuals within populations (Hs), compared to differences among populations (Dst) for the four variable loci identified in this species. Thus, most genetic distances between its populations were small. Generally, only a few genotypes occurred within each population. Purple nutsedge was found to possess even lower within- and among-population gene and genotypic diversity. This study supports the view that tubers account for most of the establishment of new populations of both species.

The Parasitic Plant Genome Project has sequenced transcripts from three parasitic species and a nonparasitic relative in the Orobanchaceae with the goal of understanding genetic changes associated with parasitism. The species studied span the trophic spectrum from free-living nonparasite to obligate holoparasite. Parasitic species used were Triphysaria versicolor, a photosynthetically competent species that opportunistically parasitizes roots of neighboring plants; Striga hermonthica, a hemiparasite that has an obligate need for a host; and Orobanche aegyptiaca, a holoparasite with absolute nutritional dependence on a host. Lindenbergia philippensis represents the closest nonparasite sister group to the parasitic Orobanchaceae and was included for comparative purposes. Tissues for transcriptome sequencing from each plant were gathered to identify expressed genes for key life stages from seed conditioning through anthesis. Two of the species studied, S. hermonthica and O. aegyptiaca, are economically important weeds and the data generated by this project are expected to aid in research and control of these species and their relatives. The sequences generated through this project will provide an abundant resource of molecular markers for understanding population dynamics, as well as provide insight into the biology of parasitism and advance progress toward understanding parasite virulence and host resistance mechanisms. In addition, the sequences provide important information on target sites for herbicide action or other novel control strategies such as trans-specific gene silencing.

Resilience after a nuclear power plant or other radiation emergency requires response and recovery activities that are appropriately safe, timely, effective, and well organized. Timely informed decisions must be made, and the logic behind them communicated during the evolution of the incident before the final outcome is known. Based on our experiences in Tokyo responding to the Fukushima Daiichi nuclear power plant crisis, we propose a real-time, medical decision model by which to make key health-related decisions that are central drivers to the overall incident management. Using this approach, on-site decision makers empowered to make interim decisions can act without undue delay using readily available and high-level scientific, medical, communication, and policy expertise. Ongoing assessment, consultation, and adaption to the changing conditions and additional information are additional key features. Given the central role of health and medical issues in all disasters, we propose that this medical decision model, which is compatible with the existing US National Response Framework structure, be considered for effective management of complex, large-scale, and large-consequence incidents. (Disaster Med Public Health Preparedness. 2012;0:1-10)

Homework assignments have been a key component of cognitive behavioural therapy (CBT) for decades, but very few studies examined the effect of compliance on outcome in regard to smoking behaviour. To fill this gap in the existing literature, the present report evaluated the role of homework compliance on short-term outcome in the context of evidence-based care for smoking cessation. Compliance with out-of-session assignments was assessed in a four-session CBT-nicotine replacement therapy protocol for smoking cessation among adult daily smokers (n= 94). Consistent with expectation, homework compliance was associated with better short-term outcomes, including amount of cigarettes consumed as well as abstinence. Importantly, these effects remained after controlling for a wide range of potentially confounding variables (e.g., motivation to quit, nicotine dependence at intake, attendance problems, and in-session participation). Estimates of quantity versus quality of homework compliance did not differentially predict outcomes. Out-of-session homework assignments incrementally predict short-term smoking abstinence in the context of evidence-based care for smoking cessation.

Determining the duration and timing of spermatogenesis in Mytilus californianus Conrad became key questions in our study of carcinogen-mutagen indices in the marine environment. We had postulated that the murine sperm deformation assay of Bruce, Furrer & Wyrobek (1974) should have marine analogues, and we assayed a number of marine invertebrates sampled near potentially carcinogenic waste flows, and by γ-ray dose-response experiments. Our field results demonstrated some deformation but only at a very low level (less than 5 % in Mytilus edulis L.). Development of a γ-ray doseresponse (90–900 rads) procedure for M. californianus by radium needle inserted through a drilled hole closed with a plastic plug, and subsequent biopsy of gonadal tissue at measured distances from the site of irradiation, did not show deformations from a pilot test in June 1979. If a viable dose-response procedure was to be developed it was necessary to establish seasonal reproductive timing so that specimens could be collected or cultured to maximize spermatogenesis and hence response potential, and also to establish the duration of spermatogenesis so that response measures via a gonadal tissue extraction could be appropriately timed.

A new allele of microphthalmia (mi) in the mouse was discovered among the progeny of a male that had been treated with the potent mutagen ethylnitrosourea. Homozygotes have white coats, mildly defective bone resorption and small eyes (about 60% of the normal size) with very little pigmentation. The iris and retina are abnormal, there is no vitreous body and iris pigmentation is restricted to a rim around the pupil. No haematopoietic defect was detected. Genetic studies showed that the mutation is linked to lurcher (Lc) on chromosome 6 and crosses with Miwh/ + and mi/ + mice indicate that the mutation is allelic with these two alleles of the microphthalmia (mi) locus. We designate the new allele microphthalmia-defective iris (midi). Some midi/+ heterozygotes (including the original mutant animal showed a bright ‘red-reflex’ when light was shone directly into the eye and this may have been caused by reduced choroidal pigmentation. Otherwise midi/ + mice appeared normal. The midi/mi compound heterozygotes had white coats, small eyes, and small teeth; bone resorption was more severely defective than in midi/mi homozygotes. The osteopetrosis was corrected by treatment of midi/mi mice with parental mi/ + bone marrow which suggests that the defect is intrinsic to midi/mi marrow cells. The coats of midi/Miwh compound heterozygotes were white; the irises were more symmetrical and iris pigmentation was less severely reduced than in midi/midi homozygotes but pupil dilation appeared to be restricted. Partial complementation occurred in the midi/Miwh compound heterozygotes with respect to eye size, which was usually near normal.

It is generally accepted that the very first stars in the universe were significantly more massive and formed much more in isolation than stars observed today. This suggests that there was a transition in star formation modes that was most likely related to the metallicity of the star-forming environment. We study how the addition of heavy elements alters the dynamics of collapsing gas by performing a series of numerical simulations of primordial star formation with various levels of pre-enrichment, using the adaptive mesh refinement, hydrodynamic + N-body code, Enzo. At high redshifts, the process of star formation is heavily influenced by the cosmic microwave background (CMB), which creates a temperature floor for the gas. Our results show that cloud-collapse can follow three distinct paths, depending on the metallicity. For very low metallicities (log10(Z/Z⊙) < −3.5), star formation proceeds in the primordial mode, producing only massive, singular objects. For high metallicities (log10(Z/Z⊙) > −3), efficient cooling from the metals cools the gas to the CMB temperature when the core density is still very low. When the gas temperature reaches the CMB temperature, the core becomes very thermally stable, and further fragmentation is heavily suppressed. In our simulations with log10(Z/Z⊙) > −3, only a single object forms with a mass-scale of a few hundred M⊙. We refer to this as the CMB-regulated star formation mode. For metallicities between these two limits (−3.5 < log10(Z/Z⊙) < −3), the gas cools efficiently, but never reaches the CMB temperature. In this mode, termed the metallicity-regulated star formation mode, the minimum gas temperature is reached at much higher densities, allowing the core to fragment and form multiple objects with mass-scales of only a few M⊙. Our results imply that the stellar initial mass function was top-heavy at very high redshift due to stars forming in the CMB-regulated mode. As the CMB temperature lowers with time, the metallicity-regulated star formation mode (producing multiple low-mass stars) operates at higher metallicities and eventually becomes the sole mode of star formation.

NASA has been developing very high temperature semiconductor integrated circuits for use in the hot sections of aircraft engines and for Venus exploration. This paper reports on long-term 500 °C electrical operation of prototype 6H-SiC integrated circuits based on epitaxial 6H-SiC junction field effect transistors (JFETs). As of this writing, some devices have surpassed 4000 hours of continuous 500 °C electrical operation in oxidizing air atmosphere with minimal change in relevant electrical parameters.