Bose-Einstein Condensation of Microcavity Polaritons in a Trap

We have created polaritons in a harmonic potential trap analogous to atoms in optical traps. The trap can be loaded by creating polaritons 50 micrometers from its center that are allowed to drift into the trap. When the density of polaritons exceeds a critical threshold, we observe a number of signatures of Bose-Einstein condensation: spectral and spatial narrowing, a peak at zero momentum in the momentum distribution, first-order coherence, and spontaneous linear polarization of the light emission. The polaritons, which are eigenstates of the light-matter system in a microcavity, remain in the strong coupling regime while going through this dynamical phase transition.

Branched Grafting for Aortoiliac Aneurysms

PURPOSE

To evaluate a novel approach to preserve pelvic perfusion during endovascular AAA repair in patients with common iliac aneurysms extending to the iliac bifurcation.

MATERIALS AND METHODS

A multicenter prospective analysis of patients undergoing implantation of a branched endograft designed to perfuse the internal iliac artery was conducted. All patients enrolled were considered high risk for open surgical repair and presented with common iliac artery aneurysms greater than 20mm and anatomy amenable to implant the branched device. Preoperative high resolution spiral CT, and follow-up CT studies in addition to abdominal radiographs were obtained at discharge, 1, 6, 12, and 24 months.

RESULTS

Between 2003 and 2006, 52 patients (53 internal iliacs) were implanted with an investigational device. Mean common iliac aneurysm maximal diameter was 38 mm. The branch graft was combined with a proximal standard bifurcated component (61%), a fenestrated or a visceral branch component (33%), an aortouni-iliac component (2%), and alone in 2 patients (4%, following prior aortobi-iliac repair). Technical success was achieved in 94% of patients. Within the first month, 6 (11%) internal iliac branches occluded. No occlusions were noted after 1 month. The mean follow-up was 14.2 months. Common iliac aneurysm shrinkage was noted in 42% and 81% of patients at 6 and 12 months. There were no rupture, aneurysm related deaths or conversions, but there were 7 deaths during follow-up.

CONCLUSIONS

The placement of endovascular prostheses that maintain antegrade perfusion of one or both internal iliac arteries is feasible, and early results provide evidence for optimism with regard to safety and efficacy.

Trapping excitons in a two-dimensional in-plane harmonic potential: experimental evidence for equilibration of indirect excitons

We have trapped a gas of long-lifetime, high-mobility excitons in an in-plane harmonic potential. Trapping is an important step toward the goal of a controlled Bose-Einstein condensate of excitons. We show that the repulsive interaction between the excitons plays a dominant role in the behavior of the excitons, in contrast with the weak interactions in atomic gases. We show that under proper conditions the excitons thermalize in the trap to a well-defined equilibrium spatial distribution.

The European Organisation for Research and Treatment of Cancer (EORTC) translation procedure for standardized quality of life questionnaires

16033

Background: The EORTC Quality of Life (QoL) Group has developed a modular approach to QoL measurement for use in clinical trials in cancer. Questionnaires are used in international trials and standardized translation procedures are therefore required. This report summarizes the EORTC translation procedure, its accomplishments and translation problems. Methods: Translations follow a forward-backward procedure, independently carried out by two native-speakers of the target language. Discrepancies are arbitrated by a third consultant, and solutions are reached by consensus. Translated questionnaires undergo pilot-testing. Suggestions (by patients and users) are incorporated into the final questionnaire version. Most translations are performed by professional translators. The translation procedure is managed and supervised by the Translation Committee within the EORTC QoL Group. Results: To date, the core EORTC QoL questionnaire, the QLQ-C30, has been translated and validated into 62 languages, with a further 12 translations in progress. Translations include all major Western languages, East European languages, Asian languages and also remote languages, such as Xhoza (Africa).The validated, condition-specific questionnaire modules have been translated in up to 37 languages. The following major translation problems were encountered: lack of expressions for specific symptoms in various languages, the quest for formal versus informal versions, recent spelling reforms in several European countries, and different weights of social issues between Western and Eastern cultures. The EORTC measurement system is now registered for use in over 9000 clinical studies in 80 countries worldwide. Conclusions: The EORTC provides a strong infrastructure and methodology to produce high quality translations of their QoL questionnaires for use in international clinical trials. Translation problems have been identified and it will be an important topic for future research to specify whether these problems arise out of procedural/methodological shortcomings or are due to subtle cross-cultural differences in concepts of health, illness and QoL.

No significant financial relationships to disclose.

Long-term stability of a patient-convenient 1 mg/ml suspension of tacrolimus for accurate maintenance of stable therapeutic levels

Tacrolimus (Prograf, FK506, Fujisawa Healthcare) is a widely used immunosuppressive agent that is used both for the prevention and treatment of solid organ transplant rejection as well as for the prevention and treatment of graft-versus-host disease after allogeneic blood and marrow transplant. Oral preparations of tacrolimus are commercially available in 0.5, 1 and 5 mg gelatin capsules. Previously, only a 0.5 mg/ml oral suspension has been demonstrated to be stable for use in pediatric patients. On our bone marrow transplant service, we found that using this concentration of tacrolimus led to confusion, with patients and their caregivers confusing milligrams and milliliters, thus increasing errors with this formulation. We postulated that a 1 mg/ml oral formulation of tacrolimus would decrease the potential for medication errors. Our findings support new stability information of approximately 4 months for an extemporaneous oral suspension of tacrolimus at a concentration of 1 mg/ml.

Early recurrence of primary focal segmental glomerulosclerosis in an older cadaveric renal allograft recipient resistant to plasmapheresis

We report an unusual case of recurrent primary focal segmental glomerulosclerosis in an apparent low-risk cadaveric renal allograft recipient only 2 days after transplantation, who did not respond to repeated courses of plasmapheresis.

Circular-polarization-dependent study of the microwave photoconductivity in a two-dimensional electron system

The polarization dependence of the low field microwave photoconductivity and absorption of a two-dimensional electron system has been investigated in a quasioptical setup in which linear and any circular polarization can be produced in situ. The microwave induced resistance oscillations and the zero resistance regions are notably immune to the sense of circular polarization. This observation is discrepant with a number of proposed theories. Deviations between different polarizations occur only near the cyclotron resonance where an unprecedented large resistance response is observed.

Long-distance diffusion of excitons in double quantum well structures

In this Letter we report on lateral diffusion measurements of excitons at low temperature in double quantum wells of various widths. The structure is designed so that excitons live up to 30 micros and diffuse up to 500 microm. Particular attention is given to establishing that the transport occurs by exciton motion. The deduced exciton diffusion coefficients have a very strong well width dependence, and obey the same power law as the diffusion coefficient for electrons.

Validation of the Korean version of the EORTC QLQ-C30

This study evaluated the Korean version of the EORTC QLQ-C30 (version 3.0) in terms of psychometric properties and its validation. One hundred and seventy patients completed three questionnaires EORTC QLQ-C30, the Beck depression inventory (BDI), and a brief pain inventory (BPI). Multitrait scaling analyses demonstrated that all scales met multidimensional conceptualization criteria, in terms of convergence and discrimination validity. Cronbach's alpha coefficients for eight multiple-item scales were greater than 0.70, with the exception of cognitive functioning. All interscale correlations were statistically significant in the expected direction (p < 0.01). Multivariate analyses showed that physical and emotional functioning were significant explanatory variables for the global quality-of-life (QOL) scale (regression coefficients: 0.36, p < 0.001; and 0.37, p < 0.001; respectively). All scales were significantly associated with pain severity and interference of the BPI, and with the cognitive-affective and somatic scales of the BDI. The emotional-functioning scale was substantially correlated with the cognitive-affective scale and somatic scale of the BDI. These results demonstrate that the Korean version of the EORTC QLQ-C30 is a valid instrument for evaluating Korean-speaking patients with cancer, and can be used to distinguish clearly between subgroups of patients of differing performance status.

Porcine circovirus-2 and concurrent infections in the field

Porcine circovirus-2 (PCV-2) is the necessary cause of post-weaning multisystemic wasting syndrome (PMWS) in swine; however, a variety of co-factors, including other infectious agents, are thought to be necessary in the full expression of disease. Porcine parvovirus (PPV) was found in the inoculum used in the first experiments to reproduce PMWS in gnotobiotic swine. Retrospective and prospective studies in the field and laboratory have demonstrated PCV-2 can act synergistically with PPV to enhance the severity of PMWS. PCV-2 has been shown to play a role in the porcine infectious disease complex (PRDC). Other co-infecting agents with PCV-2 in the lung include, porcine reproductive and respiratory syndrome virus (PRRSV), swine influenza virus (SIV) and Mycoplasma hyopneumoniae. Exposure of pregnant sows to PPV, PRRSV, or encephalomyocarditis virus may interact with PCV-2 infected foetuses. The severity of hepatic lesions in PCV-2 infected pigs may be enhanced by co-infection with agents such as swine hepatitis E virus and Aujezsky's disease virus. Additional studies are required to determine the mechanistic basis for the interaction of PCV-2 with other agents in the pathogenesis of the various clinical syndromes that have been associated with PCV-2 infection.

Charge separation of dense two-dimensional electron-hole gases: mechanism for exciton ring pattern formation

We report on new experiments and theory that unambiguously resolve the recent puzzling observation of large diameter exciton emission halos around a laser excitation spot in two dimensional systems. We find a novel separation of plasmas of opposite charge with emission from the sharp circular boundary between these two regions. This charge separation allows for cooling of initially hot optically generated carriers as they dwell in the charge reservoirs for very long times.

Correlation lengths of the wigner-crystal order in a two-dimensional electron system at high magnetic fields

The insulator terminating the fractional quantum Hall series at low Landau level filling nu is generally taken to be a pinned Wigner crystal (WC), and exhibits a microwave resonance that is interpreted as a WC pinning mode. For a high quality sample at several densities, n, we find maxima in resonance peak frequency, f(pk), vs magnetic field, B. L, the correlation length of WC order, is calculated from f(pk). For each n, L vs nu tends at low nu toward a line with positive intercept; the fit is accurate over as much as a factor of 5 range of nu. The linear behavior is interpreted as due to B compressing the electron wave functions, to alter the effective electron-impurity interaction.

Long-range transport in excitonic dark states in coupled quantum wells

During the past ten years, coupled quantum wells have emerged as a promising system for experiments on Bose condensation of excitons, with numerous theoretical and experimental studies aimed at the demonstration of this effect. One of the issues driving these studies is the possibility of long-range coherent transport of excitons. Excitons in quantum wells typically diffuse only a few micrometres from the spot where they are generated by a laser pulse; their diffusion is limited by their lifetime (typically a few nanoseconds) and by scattering due to disorder in the well structure. Here we report photoluminescence measurements of InGaAs quantum wells and the observation of an effect by which luminescence from excitons appears hundreds of micrometres away from the laser excitation spot. This luminescence appears as a ring around the laser spot; almost none appears in the region between the laser spot and the ring. This implies that the excitons must travel in a dark state until they reach some critical distance, at which they collectively revert to luminescing states. It is unclear whether this effect is related to macroscopic coherence caused by Bose condensation of excitons.

Death certification: an audit of practice entering the 21st century

AIMS

Death certification, a legal duty of doctors, continues to be poorly performed despite Royal College recommendations and increased education at an undergraduate level. Therefore, the current performance of certifying doctors was audited within a large teaching hospital entering the new century.

METHODS

A total of 1000 completed certificate counterfoils were examined retrospectively for appropriateness of completion and the ability to construct a logical cause of death cascade.

RESULTS

Only 55% of certificates were completed to a minimally accepted standard, and many of these failed to provide relevant information to allow adequate ICD-10 coding. Nearly 10% were completed to a poor standard, being illogical or inappropriately completed.

CONCLUSIONS

The results show no improvement in the state of certification. Possible interventions to improve outcomes are discussed; however, in light of a recent high profile legal case a current Home Office review of death certification may suggest the passing of statutory law to ensure accurate completion.

Spatial and temporal variance of river discharge on Okinawa (Japan): inferring the temporal impact on adjacent coral reefs

Land-use changes and associated river discharges in coastal tropical regions present a global threat to coral reef environments. This study investigated the temporal variation in biological oxygen demand (BOD5) and suspended particulate matter (SPM) at the mouths of seven rivers on Okinawa Island (Japan) over 20 years. We report strong positive relationships between human population densities within river catchment areas and both average BOD5 concentration (r2 = 0.968; p < 0.001) and SPM (r2 = 0.659; p < 0.003) at the mouths of the rivers. At the reef adjacent to one river (Hija River, 50.2 km2 catchment area) we applied moving window analysis to assess an optimal sampling strategy for elucidating transitional boundaries in coral composition from the river mouth to a point where the effect of river discharge was minimal. The optimal window width for Okinawan rivers was five 1 m2 quadrats spaced over 5 m intervals. This sampling strategy clearly showed dissimilarity spikes in coral community composition up to 400 m from the Hija River mouth, beyond which no significant differences in coral composition were detected using analysis of similarities (ANOSIM). We developed a simple diffusion model linking the rivers' maximum discharge rate, and the average concentration of BOD5 and SPM with the spatial impact on the coral communities. The diffusion model can aid in predicting negative shifts in coral communities expected to result from detrimental land-use changes and is an important tool for monitoring coral reefs.

Spongiotic vesicular dermatitis as a cutaneous reaction pattern in seven horses

Over a 6-year period seven adult horses of different breeds and genders developed multifocal, exudative, oozing dermatitis characterized histologically by epidermal spongiotic vesicles and perivascular eosinophilic, neutrophilic and mixed mononuclear inflammation. Three horses were pruritic. Systemic disease was not noted. Two horses had a history of recurrent urticaria (hives) and one horse had nodules or welt-type lesions that progressed to exudative, oozing lesions. Interepithelial immunoglobulin (Ig)G was detected by avidin-biotin complex-peroxidase staining, but the pattern of staining was more consistent with epithelial oedema than specific IgG deposition associated with pemphigus. The exudative oozing lesions developed under circumstances suggesting that dermal oedema progressed to intracellular and intercellular epidermal oedema, which in turn progressed to the spongiotic vesicular epidermal lesions.

Induction of T lymphocyte responses to dengue virus by a candidate tetravalent live attenuated dengue virus vaccine

Development of a safe and immunogenic tetravalent dengue virus (DV) vaccine has been designated as a priority by the World Health Organization. We characterized the T cell response to DV induced by a candidate live attenuated tetravalent DV vaccine as part of a phase I study. Proliferation and cytotoxic T lymphocyte (CTL) responses to multiple DV serotypes were detected in six of six and four of four subjects studied, respectively. Proliferation responses were higher to DV serotypes 1 and 3 than to serotypes 2 and 4. CTL responses were higher to DV serotypes 2 and 3 than to serotype 1, and included serotype cross-reactive responses. Production of interferon-gamma, but not IL-4, was observed in response to DV stimulation. This candidate vaccine is immunogenic for both CD4+ and CD8+ T lymphocytes. However, T cell responses to the four DV serotypes were not equivalent, suggesting that the vaccine could be further optimized.

Effect of maternal antibodies on induction and persistence of vaccine-induced immune responses against bovine viral diarrhea virus type II in young calves

OBJECTIVE

To determine the effect of maternally derived antibodies on induction of protective immune responses against bovine viral diarrhea virus (BVDV) type II in young calves vaccinated with a modified-live bovine viral diarrhea virus (BVDV) type I vaccine.

DESIGN

Blinded controlled challenge study.

ANIMALS

24 neonatal Holstein and Holstein-cross calves that were deprived of maternal colostrum and fed pooled colostrum that contained a high concentration of (n = 6) or no (18) antibodies to BVDV.

PROCEDURE

At 10 to 14 days of age, 6 seropositive and 6 seronegative calves were given a combination vaccine containing modified-live BVDV type I. All calves were kept in isolation for 4.5 months. Six calves of the remaining 12 untreated calves were vaccinated with the same combination vaccine at approximately 4 months of age. Three weeks later, all calves were challenged intranasally with a virulent BVDV type II.

RESULTS

Seronegative unvaccinated calves and seropositive calves that were vaccinated at 2 weeks of age developed severe disease, and 4 calves in each of these groups required euthanasia. Seronegative calves that were vaccinated at 2 weeks or 4 months of age developed only mild or no clinical signs of disease.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicate that a single dose of a modified-live BVDV type-I vaccine given at 10 to 14 days of age can protect susceptible young calves from virulent BVDV type II infection for at least 4 months, but high concentrations of BVDV-specific maternally derived antibodies can block the induction of the response.

Multiple porcine circovirus 2-associated abortions and reproductive failure in a multisite swine production unit

Porcine circovirus type 2 was detected in several stillborn and nonviable neonatal piglets presenting with chronic passive congestion, cardiac hypertrophy, and severe diffuse myocarditis. The presence of the virus in the heart and other tissues of affected piglets was confirmed by polymerase chain reaction, immunohistochemistry, and virus isolation techniques. Other reproductive losses and associated infectious agents in the herd are discussed.

Association of porcine circovirus 2 with reproductive failure in pigs: a retrospective study, 1995-1998

In order to determine if vertically transmitted porcine circovirus (PCV) has played a role in reproductive failure in pigs in areas of endemic infection, archival fixed tissues were examined by polymerase chain reaction (PCR) and immunohistochemistry. Tissues tested were from routine cases of abortion or reproductive failure submitted between 1995 and 1998 to the diagnostic laboratory at the Western College of Veterinary Medicine, Saskatoon. They originated from 29 high-health herds in the provinces of Alberta and Saskatchewan and comprised a total of 36 individual submissions. Porcine circovirus type 1 (PCV1) was not detected by PCR in any submitted tissues. Porcine circovirus type 2 (PCV2) was not detected by PCR or immunohistochemistry in any of the submitted tissue. The effect of extended formalin fixation on the detection of PCV2 by PCR was assessed and fixation for up to one week had no gross effect on sensitivity of detection using this PCR technique. Failure to detect porcine circoviruses in cases of reproductive failure prior to 1999 in areas of endemic infections, suggests that reproductive disease may be a new clinical manifestation of PCV2 infection, and that vertical transmission may not have been the primary mechanism of initial dissemination of the virus in the pig population.

Efficacy of an inactivated respiratory syncytial virus vaccine in calves

OBJECTIVE

To determine whether an inactivated bovine respiratory syncytial virus (BRSV) vaccine would protect calves from infection with virulent BRSV.

DESIGN

Randomized controlled trial.

ANIMALS

27 nine-week-old calves seronegative for BRSV exposure.

PROCEDURE

Group-1 calves (n = 9) were not vaccinated. Group-2 calves (n = 9) were vaccinated on days 0 and 21 with an inactivated BRSV vaccine containing a minimum immunizing dose of antigen. Group-3 calves (n = 9) were vaccinated on days 0 and 21 with an inactivated BRSV vaccine containing an amount of antigen similar to that in a commercial vaccine. All calves were challenged with virulent BRSV on day 42. Clinical signs and immune responses were monitored for 8 days after challenge. Calves were euthanatized on day 50, and lungs were examined for lesions.

RESULTS

Vaccination elicited increases in BRSV-specific IgG and virus neutralizing antibody titers and in production of interferon-gamma. Virus neutralizing antibody titers were consistently less than IgG titers. Challenge with BRSV resulted in severe respiratory tract disease and extensive pulmonary lesions in control calves, whereas vaccinated calves had less severe signs of clinical disease and less extensive pulmonary lesions. The percentage of vaccinated calves that shed virus in nasal secretions was significantly lower than the percentage of control calves that did, and peak viral titer was lower for vaccinated than for control calves.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that the inactivated BRSV vaccine provided clinical protection from experimental infection with virulent virus and decreased the severity of pulmonary lesions. Efficacy was similar to that reported for modified-live BRSV vaccines.