Photoelectrochemistry using quinone radical anions

The photoelectrochemistry of quinone radical anions has been demonstrated qualitatively by the photoassisted reduction of methyl viologen with benzoquinone and of neutral red with chloranil. Data were then collected for the estimation of quenching rate constants using Marcus-Weller theory. Reduction potentials of seven quinones were obtained in four solvents (and two aqueous mixtures) by cyclic voltammetry. The solvent effects on these potentials were studied by fitting them to the Taft relationship. The effects of proton donors were also noted. Absorption spectra of the radical anions were measured and the solvent effects noted and commented upon. From the molar absorption coefficients of the radical anions, the mean lifetimes of the excited states were estimated. Fluorescence spectra were obtained for anthraquinone and naphthaquinone radical anions and excitation energies were calculated. These values were estimated for the other quinones. Values of redox potentials for the excited radical anions were thence obtained. The Gibbs energies of the electron transfers between the excited quinone radical anions and the various substrates were obtained and hence the Gibbs energies of activation were calculated using the Marcus equation. The quenching rate constants were calculated using the Rehm-Weller equation and plotted vs. ΔG giving a characteristic Marcus plot including some data in the inverted region. The significance of the inverted region is discussed.

Vosaroxin and vosaroxin plus low-dose Ara-C (LDAC) vs low-dose Ara-C alone in older patients with acute myeloid leukemia

The development of new treatments for older patients with acute myeloid leukemia is an active area, but has met with limited success. Vosaroxin, a quinolone-derived intercalating agent has several properties that could prove beneficial. Initial clinical studies showed it to be well-tolerated in older patients with relapsed/refractory disease. In vitro data suggested synergy with cytarabine (Ara-C). To evaluate vosaroxin, we performed 2 randomized comparisons within the "Pick a Winner" program. A total of 104 patients were randomized to vosaroxin vs low-dose Ara-C (LDAC) and 104 to vosaroxin + LDAC vs LDAC. When comparing vosaroxin with LDAC, neither response rate (complete recovery [CR]/complete recovery with incomplete count recovery [CRi], 26% vs 30%; odds ratio [OR], 1.16 (0.49-2.72); P = .7) nor 12-month survival (12% vs 31%; hazard ratio [HR], 1.94 [1.26-3.00]; P = .003) showed benefit for vosaroxin. Likewise, in the vosaroxin + LDAC vs LDAC comparison, neither response rate (CR/CRi, 38% vs 34%; OR, 0.83 [0.37-1.84]; P = .6) nor survival (33% vs 37%; HR, 1.30 [0.81-2.07]; P = .3) was improved. A major reason for this lack of benefit was excess early mortality in the vosaroxin + LDAC arm, most obviously in the second month following randomization. At its first interim analysis, the Data Monitoring and Ethics Committee recommended closure of the vosaroxin-containing trial arms because a clinically relevant benefit was unlikely.

Particle-in-cell simulation study of the interaction between a relativistically moving leptonic micro-cloud and ambient electrons

Context. The jets of compact accreting objects are composed of electrons and a mixture of positrons and ions. These outflows impinge on the interstellar or intergalactic medium and both plasmas interact via collisionless processes. Filamentation (beam-Weibel) instabilities give rise to the growth of strong electromagnetic fields. These fields thermalize the interpenetrating plasmas. 

Aims. Hitherto, the effects imposed by a spatial non-uniformity on filamentation instabilities have remained unexplored. We examine the interaction between spatially uniform background electrons and a minuscule cloud of electrons and positrons. The cloud size is comparable to that created in recent laboratory experiments and such clouds may exist close to internal and external shocks of leptonic jets. The purpose of our study is to determine the prevalent instabilities, their ability to generate electromagnetic fields and the mechanism, by which the lepton micro-cloud transfers energy to the background plasma. 

Methods. A square micro-cloud of equally dense electrons and positrons impinges in our particle-in-cell (PIC) simulation on a spatially uniform plasma at rest. The latter consists of electrons with a temperature of 1 keV and immobile ions. The initially charge- and current neutral micro-cloud has a temperature of 100 keV and a side length of 2.5 plasma skin depths of the micro-cloud. The side length is given in the reference frame of the background plasma. The mean speed of the micro-cloud corresponds to a relativistic factor of 15, which is relevant for laboratory experiments and for relativistic astrophysical outflows. The spatial distributions of the leptons and of the electromagnetic fields are examined at several times. 

Results. A filamentation instability develops between the magnetic field carried by the micro-cloud and the background electrons. The electromagnetic fields, which grow from noise levels, redistribute the electrons and positrons within the cloud, which boosts the peak magnetic field amplitude. The current density and the moduli of the electromagnetic fields grow aperiodically in time and steadily along the direction that is anti-parallel to the cloud's velocity vector. The micro-cloud remains conjoined during the simulation. The instability induces an electrostatic wakefield in the background plasma. 

Conclusions. Relativistic clouds of leptons can generate and amplify magnetic fields even if they have a microscopic size, which implies that the underlying processes can be studied in the laboratory. The interaction of the localized magnetic field and high-energy leptons will give rise to synchrotron jitter radiation. The wakefield in the background plasma dissipates the kinetic energy of the lepton cloud. Even the fastest lepton micro-clouds can be slowed down by this collisionless mechanism. Moderately fast charge- and current neutralized lepton micro-clouds will deposit their energy close to relativistic shocks and hence they do not constitute an energy loss mechanism for the shock.

Cost Effectiveness of Tooth Replacement Strategies for Partially Dentate Elders

Objectives: This study aimed to compare the cost effectiveness of conventional treatment using partial dentures with functionally-orientated treatment based on the shortened dental arch concept to replace missing teeth for partially dentate elders.
Methods: 44 partially dentate patients aged 65 years and older were recruited following routine dental assessment at a university dental hospital. Patients consented to and were randomly assigned to the two treatment arms. The conventional treatment group received a removable partial denture to replace all missing natural teeth. The functionally-orientated group were restored to a shortened dental arch of 10 occluding contacts using resin bonded bridgework. The costs associated with each treatment were recorded including laboratory charges, treatment time and opportunity costs. The impact on quality of life (OHRQoL) was measured using the 14-item Oral Health Impact Profile.
Results: Both groups reported improvements in OHRQoL after completion of treatment. For the conventional group, the mean OHIP-14 score decreased from 12.4 pre-operatively to 3.3 post-operatively (p<0.001). In the functionally-orientated group the OHIP-14 score decreased from 11.4 to 1.8 following treatment (p<0.001). On average the conventional treatment group required 8.3 clinic visits as compared to 4.4 visits for the functionally-orientated group. The mean total treatment time was 183 minutes 19 seconds for the conventional group versus 124 minutes 8 seconds for the functionally-orientated group. The conventional treatment group had an average of 6.33 teeth replaced at a laboratory cost of 337.31 Euros. The functionally-orientated group had an average of 2.64 teeth replaced at a laboratory cost of 244.05 Euros.
Conclusions: Restoration to a shortened dental arch using functionally-orientated treatment resulted in a similar improvement in OHRQoL with fewer clinic visits, less operative time and at a lower laboratory cost compared with conventional treatment.

A feasibility study of auricular therapy and self-administered acupressure for insomnia following cancer treatment

Introduction: Many cancer patients experience sleeping difficulties which can persist several years after the completion of cancer treatment. Previous research suggests that acupuncture, and variants of acupuncture (acupressure, auricular therapy) may be effective treatment options for sleep disturbance. However, current evidence is limited for cancer patients.

Methods: Feasibility study with 3 arms. Seven cancer patients with insomnia randomised to receive either auricular therapy (attaching semen vaccariae seeds to ear acupoints) (n=4), self-acupressure (n=1) or no treatment (n=2). Participants assigned to receive auricular therapy or self-acupressure stimulated the acupoints each night an hour before retiring to bed. The duration of participant involvement was 5 weeks. Subjective sleep quality was measured at baseline and post-treatment using the Pittsburgh Sleep Quality Index (PSQI). The impact of treatment on concerns of importance to the participants themselves was measured using the Measure Yourself Concerns and Wellbeing (MYCaW). Each participant also completed a treatment log book.

Results: All participants completed their treatment. All auricular therapy and self-acupressure participants recorded clinically significant improvements in global PSQI scores. In the auricular therapy arm mean global PSQI reduced from 12.5 at baseline to 8 following completion of treatment. In the self-acupressure arm PSQI reduced from 15 to 11. While in the no treatment arm the mean PSQI score was 14.5 at both baseline and follow up.

Conclusions: Despite the limited sample size, both auricular therapy and self-acupressure may represent potentially effective treatments for cancer patients with insomnia. The positive findings suggest further research is warranted into both treatment modalities.

Cyclosporin A and short-term methotrexate versus cyclosporin A as graft versus host disease prophylaxis in patients with severe aplastic anemia given allogeneic bone marrow transplantation from an HLA-identical sibling:results of a GITMO/EBMT randomized trial

A randomized trial was carried out comparing cyclosporin A (CsA) and short-term methotrexate (MTX) versus CsA alone for graft versus host disease (GVHD) prophylaxis in patients with severe aplastic anemia (SAA) undergoing allogeneic bone marrow transplantation (BMT) from a compatible sibling. Seventy-one patients (median age, 19 years; range, 4-46 years) were randomized to receive either CsA and MTX or CsA alone for the first 3 weeks after BMT. Subsequently, both groups received CsA orally, with gradual drug reduction until discontinuation 8 to 12 months after BMT. Patients randomized in both arms had comparable characteristics and received the same preparative regimen (ie, cyclophosphamide 200 mg/kg over 4 days). The median time for neutrophil engraftment was 17 days (range, 11-31 days) and 12 days (range, 4-45 days) for patients in the CsA/MTX group and the CsA alone group, respectively (P =.01). No significant difference was observed in the probability of either grade 2, grade 3, or grade 4 acute GVHD or chronic GVHD developing in the 2 groups. The Kaplan-Meier estimates of 1-year transplantation-related mortality rates for patients given either CsA/MTX or CsA alone were 3% and 15%, respectively (P =.07). With a median follow-up of 48 months from BMT, the 5-year survival probability is 94% for patients in the CsA/MTX group and 78% for those in the CsA alone group (P =. 05). These data indicate that the use of CsA with MTX is associated with improved survival in patients with SAA who receive transplants from compatible siblings. (Blood. 2000;96:1690-1697)

Evaluating fault tolerance on asymmetric multicore systems-on-chip using iso-metrics

The end of Dennard scaling has promoted low power consumption into a firstorder concern for computing systems. However, conventional power conservation schemes such as voltage and frequency scaling are reaching their limits when used in performance-constrained environments. New technologies are required to break the power wall while sustaining performance on future processors. Low-power embedded processors and near-threshold voltage computing (NTVC) have been proposed as viable solutions to tackle the power wall in future computing systems. Unfortunately, these technologies may also compromise per-core performance and, in the case of NTVC, xreliability. These limitations would make them unsuitable for HPC systems and datacenters. In order to demonstrate that emerging low-power processing technologies can effectively replace conventional technologies, this study relies on ARM’s big.LITTLE processors as both an actual and emulation platform, and state-of-the-art implementations of the CG solver. For NTVC in particular, the paper describes how efficient algorithm-based fault tolerance schemes preserve the power and energy benefits of very low voltage operation.

Aging in personal and social immunity: do immune traits senesce at the same rate?

How much should an individual invest in immunity as it grows older? Immunity is costly and its value is likely to change across an organism's lifespan. A limited number of studies have focused on how personal immune investment changes with age in insects, but we do not know how social immunity, immune responses that protect kin, changes across lifespan, or how resources are divided between these two arms of the immune response. In this study, both personal and social immune functions are considered in the burying beetle, Nicrophorus vespilloides. We show that personal immune function declines (phenoloxidase levels) or is maintained (defensin expression) across lifespan in nonbreeding beetles but is maintained (phenoloxidase levels) or even upregulated (defensin expression) in breeding individuals. In contrast, social immunity increases in breeding burying beetles up to middle age, before decreasing in old age. Social immunity is not affected by a wounding challenge across lifespan, whereas personal immunity, through PO, is upregulated following wounding to a similar extent across lifespan. Personal immune function may be prioritized in younger individuals in order to ensure survival until reproductive maturity. If not breeding, this may then drop off in later life as state declines. As burying beetles are ephemeral breeders, breeding opportunities in later life may be rare. When allowed to breed, beetles may therefore invest heavily in "staying alive" in order to complete what could potentially be their final reproductive opportunity. As parental care is important for the survival and growth of offspring in this genus, staying alive to provide care behaviors will clearly have fitness payoffs. This study shows that all immune traits do not senesce at the same rate. In fact, the patterns observed depend upon the immune traits measured and the breeding status of the individual.

Old Town Glasgow: Squalor, Agitation and City Improvements

In 1862, Glasgow Corporation initiated the first of a series of three legislative acts which would become known collectively as the City Improvements Acts. Despite having some influence on the nature of the built fabric on the expanding city as a whole, the most extensive consequences of these acts was reserved for one specific area of the city, the remnants of the medieval Old Town. As the city had expanded towards all points of the compass in a regular, grid-iron structure throughout the nineteenth century, the Old Town remained singularly as a densely wrought fabric of medieval wynds, vennels, oblique passageways and accelerated tenementalisation. Here, as the rest of the city began to assume the form of an ordered entity, visible and classifiable, one could still find and addresses such as ‘Bridgegate, No. 29, backland, stair first left, three up, right lobby, door facing’ (quoted in Pacione, 1995).

Unsurprisingly, this place, where proximity to the midden (dung-heap) was considered an enviable position, was seen by the authorities as a major health hazard and a source not only of cholera, but also of the more alarming typhoid epidemic of 1842. Accordingly, the demolitions which occurred in the backlands of the Old Town under the first of the acts, the Glasgow Police Act of 1862, were justified on health and medical grounds. But disease was not the only social problem thought to issue from this district. Reports from social reformers including Fredrick Engels suggested that the decay of the area’s physical fabric could be extended to the moral profile of its inhabitants. This was in such a state of degeneracy that there were calls for a nearby military barracks to be relocated to more salubrious climes because troops were routinely coming into contact ‘with the most dissolute and profligate portion of the population’ (Peter Clonston, Lord Provost, June 1861). Perhaps more worrying for the city fathers, however, was that the barracks’ arsenal was seen as a potential source of arms for the militant and often illegal cotton workers’ unions and organisations who inhabited the Old Town as well as the districts to the east. In fact, the Old Town and East End had been the site of numerous working class actions and riots since 1787, including a strike of 60,000 workers in 1820, 100,000 in 1838, and the so-called Bread Riots of 1848 where shouts of ‘Vive La Revolution’ were reported in the Gallowgate.

The events in Paris in 1848 precipitated Baron Hausmann’s interventions into that city. The boulevards were in turn visited by members of Glasgow Corporation and ultimately, it can be argued, provided an example for Old Town Glasgow. This paper suggests that the city improvement acts carried a similarly complex and pervasive agenda, one which embodied not only health, class conflict and sexual morality but also the more local condition of sectarianism. And, like in Paris, these were played out spatially in a extensive reconfiguration of the urban fabric of the Old Town which, through the creation of new streets and a railway yard, not only made it more amenable to large scale military manoeuvres but also, opened up the area to capitalist accumulation. By the end of the works, the medieval heritage of the Old Town had been almost completely razed, the working class and Catholic East End had, through the insertion of the railway yard, been isolated from the city centre and approximately 70,000 people had been made homeless.

Why Putin has pulled Russia out of Syria

By formally quitting during a ceasefire he himself masterminded – and on the back of significant military gains – Putin can leave with his head held high. Having proven his critics wrong and demonstrated the capability of Russia’s military (and its new weapons – a splendid advert to any buyers of Russian arms), Putin can now concentrate on the diplomatic aspect of the peace process, something at which Moscow usually excels.