3,510 research outputs found

    Alemtuzumab pre-conditioning with tacrolimus monotherapy in pediatric renal transplantation

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    We employed antibody pre-conditioning with alemtuzumab and posttransplant immunosuppression with low-dose tacrolimus monotherapy in 26 consecutive pediatric kidney transplant recipients between January 2004 and December 2005. Mean recipient age was 10.7 ± 5.8 years, 7.7% were undergoing retransplantation, and 3.8% were sensitized, with a PRA >20%. Mean donor age was 32.8 ± 9.2 years. Living donors were utilized in 65% of the transplants. Mean cold ischemia time was 27.6 ± 6.4 h. The mean number of HLA mismatches was 3.3 ± 1.3. Mean follow-up was 25 ± 8 months. One and 2 year patient survival was 100% and 96%. One and 2 year graft survival was 96% and 88%. Mean serum creatinine was 1.1 ± 0.6 mg/dL, and calculated creatinine clearance was 82.3 ± 29.4 mL/min/1.73 m 2. The incidence of pre-weaning acute rejection was 11.5%; the incidence of delayed graft function was 7.7%. Eighteen (69%) of the children were tapered to spaced tacrolimus monotherapy, 10.5 ± 2.2 months after transplantation. The incidence of CMV, PTLD and BK virus was 0%; the incidence of posttransplant diabetes was 7.7%. Although more follow-up is clearly needed, antibody pre-conditioning with alemtuzumab and tacrolimus monotherapy may be a safe and effective regimen in pediatric renal transplantation. © 2007 The Authors

    Radiating dipoles in photonic crystals

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    The radiation dynamics of a dipole antenna embedded in a Photonic Crystal are modeled by an initially excited harmonic oscillator coupled to a non--Markovian bath of harmonic oscillators representing the colored electromagnetic vacuum within the crystal. Realistic coupling constants based on the natural modes of the Photonic Crystal, i.e., Bloch waves and their associated dispersion relation, are derived. For simple model systems, well-known results such as decay times and emission spectra are reproduced. This approach enables direct incorporation of realistic band structure computations into studies of radiative emission from atoms and molecules within photonic crystals. We therefore provide a predictive and interpretative tool for experiments in both the microwave and optical regimes.Comment: Phys. Rev. E, accepte

    Multimodal imaging of pancreatic beta cells in vivo by targeting transmembrane protein 27 (TMEM27)

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    Aims/hypothesis: Non-invasive diagnostic tools specific for pancreatic beta cells will have a profound impact on our understanding of the pathophysiology of metabolic diseases such as diabetes. The objective of this study was to use molecular imaging probes specifically targeting beta cells on human samples and animal models using state-of-the-art imaging modalities (fluorescence and PET) with preclinical and clinical perspective. Methods: We generated a monoclonal antibody, 8/9-mAb, targeting transmembrane protein 27 (TMEM27; a surface N-glycoprotein that is highly expressed on beta cells), compared its expression in human and mouse pancreas, and demonstrated beta cell-specific binding in both. In vivo imaging was performed in mice with subcutaneous insulinomas overexpressing the human TMEM27 gene, or transgenic mice with beta cell-specific hTMEM27 expression under the control of rat insulin promoter (RIP-hTMEM27-tg), using fluorescence and radioactively labelled antibody, followed by tissue ex vivo analysis and fluorescence microscopy. Results: Fluorescently labelled 8/9-mAb showed beta cell-specific staining on human and mouse pancreatic sections. Real-time PCR on islet cDNA indicated about tenfold higher expression of hTMEM27 in RIP-hTMEM27-tg mice than in humans. In vivo fluorescence and PET imaging in nude mice with insulinoma xenografts expressing hTMEM27 showed high 8/9-mAb uptake in tumours after 72h. Antibody homing was also observed in beta cells of RIP-hTMEM27-tg mice by in vivo fluorescence imaging. Ex vivo analysis of intact pancreas and fluorescence microscopy in beta cells confirmed these findings. Conclusions/interpretation: hTMEM27 constitutes an attractive target for in vivo visualisation of pancreatic beta cells. Studies in mouse insulinoma models and mice expressing hTMEM27 demonstrate the feasibility of beta cell-targeted in vivo imaging, which is attractive for preclinical investigations and holds potential in clinical diagnostic

    Resonance fluorescence in a band gap material: Direct numerical simulation of non-Markovian evolution

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    A numerical method of calculating the non-Markovian evolution of a driven atom radiating into a structured continuum is developed. The formal solution for the atomic reduced density matrix is written as a Markovian algorithm by introducing a set of additional, virtual density matrices which follow, to the level of approximation of the algorithm, all the possible trajectories of the photons in the electromagnetic field. The technique is perturbative in the sense that more virtual density matrices are required as the product of the effective memory time and the effective coupling strength become larger. The number of density matrices required is given by 3M3^{M} where MM is the number of timesteps per memory time. The technique is applied to the problem of a driven two-level atom radiating close to a photonic band gap and the steady-state correlation function of the atom is calculated.Comment: 14 pages, 9 figure

    Novel Collective Effects in Integrated Photonics

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    Superradiance, the enhanced collective emission of energy from a coherent ensemble of quantum systems, has been typically studied in atomic ensembles. In this work we study theoretically the enhanced emission of energy from coherent ensembles of harmonic oscillators. We show that it should be possible to observe harmonic oscillator superradiance for the first time in waveguide arrays in integrated photonics. Furthermore, we describe how pairwise correlations within the ensemble can be measured with this architecture. These pairwise correlations are an integral part of the phenomenon of superradiance and have never been observed in experiments to date.Comment: 7 pages, 3 figure

    The steady state quantum statistics of a non-Markovian atom laser

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    We present a fully quantum mechanical treatment of a single-mode atomic cavity with a pumping mechanism and an output coupling to a continuum of external modes. This system is a schematic description of an atom laser. In the dilute limit where atom-atom interactions are negligible, we have been able to solve this model without making the Born and Markov approximations. When coupling into free space, it is shown that for reasonable parameters there is a bound state which does not disperse, which means that there is no steady state. This bound state does not exist when gravity is included, and in that case the system reaches a steady state. We develop equations of motion for the two-time correlation in the presence of pumping and gravity in the output modes. We then calculate the steady-state output energy flux from the laser.Comment: 14 pages (twocloumn), 6 figure

    Non-Markovian quantum trajectories for spectral detection

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    We present a formulation of non-Markovian quantum trajectories for open systems from a measurement theory perspective. In our treatment there are three distinct ways in which non-Markovian behavior can arise; a mode dependent coupling between bath (reservoir) and system, a dispersive bath, and by spectral detection of the output into the bath. In the first two cases the non-Markovian behavior is intrinsic to the interaction, in the third case the non-Markovian behavior arises from the method of detection. We focus in detail on the trajectories which simulate real-time spectral detection of the light emitted from a localized system. In this case, the non-Markovian behavior arises from the uncertainty in the time of emission of particles that are later detected. The results of computer simulations of the spectral detection of the spontaneous emission from a strongly driven two-level atom are presented

    MCV Truncated Large T antigen interacts with BRD4 in tumors.

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    Among Polyomaviridae family of viruses, Merkel Cell Polyomavirus (MCV) is the only human polyomavirus with convincing data supporting its classification as a direct causative agent of a human skin malignancy, Merkel Cell Carcinoma. Oncogenic transformation by MCV requires the integration of the viral genome into the human genome, truncation of the large T antigen (LT) to render the viral genome replication deficient and expression of small T antigen oncoprotein. The chromatin binding protein BRD4, was recently shown to transcriptionally regulate the expression of virus oncoproteins, thereby enhancing the tumorigenesis of virus-associated cancers, such as HPV associated cervical cancer. Previous work by Wang et al. revealed that BRD4 interacts with MCV full length LT during viral replication. In this study, we demonstrated that MCV truncated tumor LT antigen also interacts with BRD4 protein. We showed that the MCV tumor LT antigen and BRD4 protein complex co-localizes within the nucleus. Furthermore, we tested whether BRD4 protein transcriptionally regulates MCV Non Coding Control Region (NCCR), where we found that though full length LT and sT together, along with the BRD4 protein showed enhanced transcriptional activity whereas tumor truncated LT did not. These findings on the interactions of the MCV tumor truncated LT antigen with the BRD4 protein add to existing knowledge about interactions with LT and its role in tumorigenesis, and assist in efforts to more precisely define new therapy targets for this disease

    Evaluation of soil quality of a coal mine affected forest at Changki, Nagaland, India

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    The present study was conducted at a coal mining affected forest and a non-affected forest to analyze the seasonal changes in soil physico-chemical properties, incorporate additive and weighted soil quality index (SQI) to determine the soil quality and check the affected forest soil pollution status. Comparative SQI shows that the non-affected forest presented higher SQI in all the seasons (winter, spring, summer and autumn). However, in both the forest the seasonal additive and weighted SQI was categorised as autumn > summer > spring > winter and the overall SQI of the soil depth was ranked as 0–10 > 10–20 > 20–30 cm. The Single pollution index (PI) points out that cadmium (Cd) was the main potential contributor to soil pollution while the Pollution load index (PLI) and Nemerow integrated pollution index (NIPI) revealed moderate soil pollution status. The result summarized that coal mining activities can elevate soil deterioration rate, such as loss in soil organic carbon, reduction in nutrient availability, and slowing down the rejuvenating process of forest soil

    Synthesis and Antifungal Activity of 2-Ketophenyl-3-substituted aryl-1-thiazolidin-4-ones

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    A new series of 2-ketophenyl-3-substituted aryl-1- thiazolidin-4-ones were synthesized by cyclocondensation of ketoazomethines and thioglycolic acid. Ketoazomethines were synthesized by condensation of phenyl glyoxal (prepared by partial oxidation of acetophenone) and various para-substituted anilines. Their structures were elucidated by elemental analysis, IR and H1 NMR; they were screened for their antifungal activity against hazardous fungi namely Fusarium Oxysporum, Pythium, Sclerotium and Alternaria brassicola
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