Rapid rotation of micron and submicron dielectric particles measured using optical tweezers

We demonstrate the use of a laser trap (‘optical tweezers’) and back-focal-plane position detector to measure rapid rotation in aqueous solution of single particles with sizes in the vicinity of 1 μm. Two types of rotation were measured: electrorotation of polystyrene microspheres and rotation of the flagellar motor of the bacterium Vibrio alginolyticus. In both cases, speeds in excess of 1000 Hz (rev s−1) were measured. Polystyrene beads of diameter about 1 μm labelled with smaller beads were held at the centre of a microelectrode array by the optical tweezers. Electrorotation of the labelled beads was induced by applying a rotating electric field to the solution using microelectrodes. Electrorotation spectra were obtained by varying the frequency of the applied field and analysed to obtain the surface conductance of the beads. Single cells of V. alginolyticus were trapped and rotation of the polar sodium-driven flagellar motor was measured. Cells rotated more rapidly in media containing higher concentrations of Na+, and photodamage caused by the trap was considerably less when the suspending medium did not contain oxygen. The technique allows single-speed measurements to be made in less than a second and separate particles can be measured at a rate of several per minute

Circumscribed choroidal hemangioma: A case report and literature review

AbstractChoroidal hemangioma is a rare congenital ocular tumor that can present as either circumscribed or diffuse. Circumscribed choroidal hemangioma (CCH) typically manifests as a red-orange mass within the posterior pole and appears similar to other ocular conditions, such as choroidal melanoma and choroidal metastasis. Proper diagnosis is crucial and is aided by the use of ancillary testing. CCH itself is benign but can cause secondary complications such as subretinal fluid accumulation and subsequent retinal detachment. If these conditions should arise, several treatment options are available

Circumscribed choroidal hemangioma: A case report and literature review

AbstractChoroidal hemangioma is a rare congenital ocular tumor that can present as either circumscribed or diffuse. Circumscribed choroidal hemangioma (CCH) typically manifests as a red-orange mass within the posterior pole and appears similar to other ocular conditions, such as choroidal melanoma and choroidal metastasis. Proper diagnosis is crucial and is aided by the use of ancillary testing. CCH itself is benign but can cause secondary complications such as subretinal fluid accumulation and subsequent retinal detachment. If these conditions should arise, several treatment options are available

Controlled delivery of membrane proteins to artificial lipid bilayers by nystatin-ergosterol modulated vesicle fusion

The study of ion channels and other membrane proteins and their potential use as biosensors and drug screening targets require their reconstitution in an artificial membrane. These applications would greatly benefit from microfabricated devices in which stable artificial lipid bilayers can be rapidly and reliably formed. However, the amount of protein delivered to the bilayer must be carefully controlled. A vesicle fusion technique is investigated where composite ion channels of the polyene antibiotic nystatin and the sterol ergosterol are employed to render protein-carrying vesicles fusogenic After fusion with an ergosterol-free artificial bilayer the nystatin-ergosterol channels do not dissociate immediately and thus cause a transient current signal that marks the vesicle fusion event. Experimental pitfalls of this method were identified, the influence of the nystatin and ergosterol concentration on the fusion rate and the shape of the fusion event marker was explored, and the number of different lipid was reduced. Under these conditions, the B-amyloid peptide could be delivered in a controlled manner to a standard planar bilayer. Additionally, the electrical recordings were obtained of vesicles fusing with a planar lipid bilayer in a microfabricated device, demonstrating the suitability of nystatin-ergosterol modulated vesicle fusion for protein delivery within microsystems

Health impacts of pesticide exposure in a cohort of outdoor workers.

We compared mortality of 1,999 outdoor staff working as part of an insecticide application program during 1935-1996 with that of 1,984 outdoor workers not occupationally exposed to insecticides, and with the Australian population. Surviving subjects also completed a morbidity questionnaire. Mortality was significantly higher in both exposed and control subjects compared with the Australian population. The major cause was mortality from smoking-related diseases. Mortality was also significantly increased in exposed subjects for a number of conditions that do not appear to be the result of smoking patterns. Compared with the general Australian population, mortality over the total study period was increased for asthma [standardized mortality ratio (SMR) = 3.45; 95% confidence interval (CI), 1.39-7.10] and for diabetes (SMR = 3.57; 95% CI, 1.16-8.32 for subjects working < 5 years). Mortality from pancreatic cancer was more frequent in subjects exposed to 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (SMR = 5.27; 95% CI, 1.09-15.40 for subjects working < 3 years). Compared with the control population, mortality from leukemia was increased in subjects working with more modern chemicals (standardized incidence ratio = 20.90; 95% CI, 1.54-284.41 for myeloid leukemia in the highest exposure group). There was also an increase in self-reported chronic illness and asthma, and lower neuropsychologic functioning scores among surviving exposed subjects when compared with controls. Diabetes was reported more commonly by subjects reporting occupational use of herbicides. These findings lend weight to other studies suggesting an association between adverse health effects and exposure to pesticides

Effects of siRNA-mediated knockdown of GSK3β on retinal ganglion cell survival and neurite/axon growth

There are contradictory reports on the role of the serine/threonine kinase isoform glycogen synthase kinase-3&beta; (GSK3&beta;) after injury to the central nervous system (CNS). Some report that GSK3 activity promotes axonal growth or myelin disinhibition, whilst others report that GSK3 activity prevents axon regeneration. In this study, we sought to clarify if suppression of GSK3&beta; alone and in combination with the cellular-stress-induced factor RTP801 (also known as REDD1: regulated in development and DNA damage response protein), using translationally relevant siRNAs, promotes retinal ganglion cell (RGC) survival and neurite outgrowth/axon regeneration. Adult mixed retinal cell cultures, prepared from rats at five days after optic nerve crush (ONC) to activate retinal glia, were treated with siRNA to GSK3&beta; (siGSK3&beta;) alone or in combination with siRTP801 and RGC survival and neurite outgrowth were quantified in the presence and absence of Rapamycin or inhibitory Nogo-A peptides. In in vivo experiments, either siGSK3&beta; alone or in combination with siRTP801 were intravitreally injected every eight days after ONC and RGC survival and axon regeneration was assessed at 24 days. Optimal doses of siGSK3&beta; alone promoted significant RGC survival, increasing the number of RGC with neurites without affecting neurite length, an effect that was sensitive to Rapamycin. In addition, knockdown of GSK3&beta; overcame Nogo-A-mediated neurite growth inhibition. Knockdown of GSK3&beta; after ONC in vivo enhanced RGC survival but not axon number or length, without potentiating glial activation. Knockdown of RTP801 increased both RGC survival and axon regeneration, whilst the combined knockdown of GSK3&beta; and RTP801 significantly increased RGC survival, neurite outgrowth, and axon regeneration over and above that observed for siGSK3&beta; or siRTP801 alone. These results suggest that GSK3&beta; suppression promotes RGC survival and axon initiation whilst, when in combination with RTP801, it also enhanced disinhibited axon elongation

Paraxial and nonparaxial polynomial beams and the analytic approach to propagation

We construct solutions of the paraxial and Helmholtz equations which are polynomials in their spatial variables. These are derived explicitly using the angular spectrum method and generating functions. Paraxial polynomials have the form of homogeneous Hermite and Laguerre polynomials in Cartesian and cylindrical coordinates respectively, analogous to heat polynomials for the diffusion equation. Nonparaxial polynomials are found by substituting monomials in the propagation variable $z$ with reverse Bessel polynomials. These explicit analytic forms give insight into the mathematical structure of paraxially and nonparaxially propagating beams, especially in regards to the divergence of nonparaxial analogs to familiar paraxial beams.Comment: 3 pages, Optics Letters styl

RUINED SETTLEMENTS AND NEW GARDENS: GENDER AND SOIL?RIPENING AMONG KURANKO FARMERS IN THE FOREST?SAVANNA TRANSITION ZONE

Summary Focusing on a particular field?soil?vegetation complex ( tombondu ), this article considers how changing patterns of gendered resource use ? changing routines and sites of women's and men's work, and shifts in responsibilities and control over production ? impact on its prevalence within overall land use patterns, and hence on the environment. Ruined settlements, offering improved land productivity on ‘ripened’ soils, provide Kuranko farmers in Guinea with a potent metaphor for the effects of new gardening on their savannas. Farming patterns have come to incorporate more ‘gardening?like’ practices, largely carried out by women, concentrating agriculture in particular places and enduringly improving their soils and vegetation. This history overturns received wisdom that farming only degrades soils and vegetation in the forest?savanna transition zone. Within it, conceptual links between women and gardens have been re?worked, and socially?differentiated experiences engender different opinions about the basis of land productivity and use entitlements. RESUME Les sites anciens et les jardins nouveaux: le genre et le mûrissement de la terre parmi les agriculteurs Kuranko dans la zone de contact forêt?savane Cet article se concentre sur les tombondu , des complexes champs?sols?végétation particuliers, pour démontrer la mesure dans laquelle les changements dans les systèmes d'exploitation qui ont trait au genre ? par exemple, les changements dans les routines et dans les sites de travail des femmes et des hommes, ainsi que les décalages dans les responsabilités et dans le contrôle de la production, affectent la prévalence de ces complexes dans le cadre de l'exploitation agricole en général, et quelles sont donc leur répercussions sur l'environnement. Les villages anciens offrent des possibilités de productivité meilleures du fait que la terre y est plus “mûre”: et cela offre un puissant symbole aux agriculteurs Kuranko des possibilités que leur offrent les pratiques horticoles nouvelles dans la savane. Les pratiques agricoles incorporent de plus en plus de techniques horticoles, exploitées par les femmes, qui concentrent l'agriculture dans des zones particulières et produisent ainsi des améliorations suivies et soutenues des sols et de la végétation. Cet histoire remet en question les idées reçues selon lesquelles l'exploitation agricole dégrade inéluctablement les sols et la végétation dans les zones de contact la forêt savane. Dans ce contexte, les rapports conceptuels entre les femmes et les exploitations horticoles ont dû faire l'objet d'une réévaluation, et les expériences différentiées au niveau social engendrent des différences d'opinion quant aux bases de la productivité des terres et aux droits d'exploitation y afférant. RESUMEN Pueblos en ruinas, huertas florecientes: género y maduración del terreno entre los labradores Kuranko en la zona de transición bosque?sabana Concentrándose en un complejo vegetacion?tierraáreas (tombondu), el artículo considera cómo el cambio de pautas en el uso generizado de recursos afecta la preponderancia de éstas sobre patrones generates del uso de la tierra, y por lo tanto del medio ambiente. Algunos ejemplos de estos cambios son: rutinas y lugares de trabajo variables para el hombre y la mujer, y traspaso de responsabilidades y control sobre la producción. Los antiguos asentamientos abandonados ofrecen mayor productividad en terrenos ‘maduros’ y proveen a los labradores Kuranko de una potente metáfora para los efectos de la nueva horticultura en las sabanas. Los sistemas de cultivo tradicionales van incorporando prácticas de horticultura, llevadas a cabo en su mayor parte por las mujeres, concentrando la agricultura en areas específicas y mejorando terreno y vegetación en la zona de transición bosque?sabana. Los lazos conceptuales entre la mujer y las huertas han sido re?elaborados, y las opiniones socialmente diferenciadas engendran diversas opiniones sobre las bases de los derechos al uso y productividad de la tierra

New times, new politics: history and memory during the final years of the CPGB

This article examines the relationship between collective memory, historical interpretation and political identity. It focuses on the dissolution of the Communist Party of Great Britain (CPGB) as constructed through collective narrative memory, and on Marxist interpretations of history. The divisions within the party and the wider Marxist community, stretching from 1956 until 1991, were often framed around questions of historical interpretation. The events of 1989–1991 created an historical and mnemonic crisis for CPGB members who struggled to reconcile their past identities with their present situation. Unlike the outward-facing revisionism of other political parties, this was an intensely personal affair. The solution for many was to emphasise the need to find new ways to progress socialist aims, without relying on a discredited grand narrative. In contrast, other Communist parties, such as the Communist Party of Britain, which had been established (or ‘re-established’) in 1988, fared rather better. By adhering to the international party line of renewal and continued struggle, the party was able to hold its narrative together, condemning the excesses of totalitarian regimes, while reaffirming the need for international class struggle

Critical Care Admissions following Total Laryngectomy: Is It Time to Change Our Practice?

Critical Care Unit (CCU) beds are a limited resource and in increasing demand. Studies have shown that complex head and neck patients can be safely managed on a ward setting given the appropriate staffing and support. This retrospective case series aims to quantify the CCU care received by patients following total laryngectomy (TL) at a District General Hospital (DGH) and compare patient outcomes in an attempt to inform current practice. Data relating to TL were collected over a 5-year period from 1st January 2010 to 31st December 2015. A total of 22 patients were included. All patients were admitted to CCU postoperatively for an average length of stay of 25.5 hours. 95% of these patients were admitted to CCU for the purpose of close monitoring only, not requiring any active treatment prior to discharge to the ward. 73% of total complications were encountered after the first 24 hours postoperatively at which point patients had been stepped down to ward care. Avoiding the use of CCU beds and instead providing the appropriate level of care on the ward would result in a potential cost saving of approximately £8,000 with no influence on patient morbidity and mortality