We report the formation of GaAs nanowires (NWs) containing In0.2Ga0.8As/GaAs quantum dots (QDs) on patterned Al0.65Ga0.35As/GaAs distributed Bragg reflectors (DBRs) grown on GaAs(111)B substrates. ...The growth conditions of both GaAs and Al0.65Ga0.35As layers on GaAs(111)B are optimized for the growth of high-quality Al0.65Ga0.35As/GaAs DBRs with (111) orientation in order to obtain high reflectivity at the NW/DBR interface. Moderately high growth temperature and low V/III ratio can mitigate the formation of pyramidal hillocks, resulting in the formation of high-quality DBRs on GaAs(111)B substrates. Optical characterization at 7K of single GaAs NW cavities containing 75-stacked InGaAs/GaAs NWQDs grown on patterned such Al0.65Ga0.35As/GaAs DBRs/GaAs(111)B substrates exhibits lasing oscillation at 1.43eV with a threshold pump pulse fluence of 250 μJ/cm2.
•High-quality AlGaAs/GaAs DBRs are obtained on GaAs(111)B substrates by growth optimization of both GaAs and AlGaAs layers.•The growth of GaAs NWs with InGaAs/GaAs QDs are realized on the patterned DBRs/GaAs(111)B substrates.•Lasing in the single GaAs NW with InGaAs/GaAs QDs grown on the patterned DBRs/GaAs(111)B substrates are demonstrated.
The temperature dependent single photon emission statistics of interface-fluctuation GaN quantum dots are reported. Quantum light emission is confirmed at temperatures up to ~77 K, by which point the ...background emission degrades the emission purity and results in a measured g
(0) in excess of 0.5. A discussion on the extent of the background contamination is also given through comparison to extensive data taken under various ambient and experimental conditions, revealing that the quantum dots themselves are emitting single photons with high purity.
Background
Bloodstream infections (BSI) are frequently observed after allogeneic hematopoietic stem cell transplant (HSCT), and could cause morbidity and mortality.
Methods
We retrospectively ...evaluated the incidence, characteristics of, and risk factors for BSI at both pre‐ and post‐engraftment in 209 adult HSCT patients at our institute between June 2006 and December 2013. The median age at transplantation was 45 years (range, 15–65). A total of 122 patients received bone marrow, 68 received peripheral blood stem cells, and 19 received umbilical cord blood.
Results
The cumulative incidences of pre‐ and post‐engraftment BSI were 38.9% and 17.2%, respectively. Nine patients had both pre‐ and post‐engraftment BSI. In the pre‐ and post‐engraftment periods, respectively, 67.4% and 84.1% of isolates were gram‐positive bacteria (GPB), 28.3% and 11.4% were gram‐negative bacteria (GNB), and 4.3% and 4.5% were fungi. Coagulase‐negative staphylococci were the most commonly isolated GPB, while Stenotrophomonas maltophilia and Pseudomonas aeruginosa were the most commonly isolated GNB. Pre‐engraftment BSI was associated with an increased risk of death. Overall survival at day 180 for patients with or without pre‐engraftment BSI was 70.0% and 82.7%, respectively (P = 0.02).
Conclusions
Risk factors for BSI in the pre‐engraftment period were the interval between diagnosis and transplantation (261 days or more), engraftment failure, and high‐risk disease status at HSCT in a multivariate analysis. No significant risk factor for BSI in the post‐engraftment period was identified by a univariate analysis. These findings may be useful for deciding upon empiric antibacterial treatment for HSCT recipients.
We study by microphotoluminescence the polarization properties of single zinc-blende GaN/AlN quantum dots fabricated by two growth processes: the droplet epitaxy technique and the Stranski-Krastanov ...growth mode. A statistical analysis of their polarization properties both at the mesoscopic and nanoscopic scales indicates that it is possible to modify the phase and amplitude of their valence band mixing by switching on and off the influence of AlN antiphase domains through the growth process, k. p calculations show that the strain effects and quantum dot geometries resulting from the growth process play a major role in shaping their polarization properties.
Previous studies have suggested that tacrolimus (TAC) is more potent than cyclosporine (CSA) for prophylaxis against acute GVHD after allogeneic hematopoietic stem cell transplantation (HSCT). ...However, the target blood concentrations of these drugs in these studies were not consistent with the current recommendations. Therefore, we performed a randomized controlled trial to compare CSA and TAC with target blood concentrations of 500 and 15 ng/ml, respectively, to prevent acute GVHD after unrelated HSCT. A total of 107 patients were randomized into a CSA group (n=53) or a TAC group (n=54). During the first 4 weeks after HSCT, more than 90% of the patients achieved a mean blood concentration of between 80 and 120% of the target concentration. The incidences of grade II-IV and grade III-IV acute GVHD were 39.6 and 7.5% for the CSA group and 33.3 and 9.4% for the TAC group, respectively (P=0.41 and P=0.76). Other clinical outcomes, including overall survival, disease-free survival and the incidences of relapse, non-relapse mortality, and organ toxicities, were also equivalent. We concluded that the combinations of CSA and TAC with strict dose adjustment showed similar efficacies and toxicities as prophylaxis against acute GVHD after unrelated HSCT.
The ecotropic viral integration site-1 (EVI-1) is a nuclear transcription factor and has an essential function in the proliferation/maintenance of haematopoietic stem cells. Aberrant expression of ...EVI-1 has been frequently found in myeloid leukaemia as well as in several solid tumours, and is associated with a poor patient survival. It was recently shown that EVI-1 associates with two different histone methyltransferases (HMTs), SUV39H1 and G9a. However, the functional roles of these HMTs in EVI-1-mediated leukemogenesis remain unclear. In this study, we showed that EVI-1 physically interacts with SUV39H1 and G9a, but not with Set9. Immunofluorescence analysis revealed that EVI-1 colocalizes with these HMTs in nuclei. We also found that the catalytically inactive form of SUV39H1 abrogates the transcriptional repression mediated by EVI-1, suggesting that SUV39H1 is actively involved in EVI-1-mediated transcriptional repression. Furthermore, RNAi-based knockdown of SUV39H1 or G9a in Evi-1-expressing progenitors significantly reduced their colony-forming activity. In contrast, knockdown of these HMTs did not impair bone marrow immortalization by E2A/HLF. These results indicate that EVI-1 forms higher-order complexes with HMTs, and this association has a role in the transcription repression and bone marrow immortalization. Targeting these HMTs may be of therapeutic benefit in the treatment for EVI-1-related haematological malignancies.
Background: A growing number of studies demonstrate the utility of 18fluoro-2-deoxyglucose positron emission tomography (FDG-PET) in the management of malignant lymphoma. The results of FDG-PET, ...however, have not been studied extensively for T-cell and natural killer (NK)-cell neoplasms. Patients and methods: We retrospectively evaluated pretreatment FDG-PET scans in 41 patients with T/NK-cell neoplasms diagnosed according to the World Health Organization (WHO) classification. Histological subtypes frequently included were peripheral T-cell lymphoma, unspecified (PTCLu, n = 11), extranodal NK/T-cell lymphoma, nasal type (ENKL, n = 8), primary cutaneous anaplastic large cell lymphoma (C-ALCL, n = 5), and angioimmunoblastic T-cell lymphoma (AILT, n = 4). Results: FDG-PET detected a lymphoma lesion in at least one site in 36 out of 41 patients. The positive rate was equally high in most histological subtypes except for cutaneous lymphomas: PTCLu 91%, ENKL 100%, C-ALCL 60%, AILT 100%. All the patients without an FDG-avid lesion had lesions restricted to skin. Among patients who had cutaneous lesions, only 50% had FDG-avid cutaneous lesions, all of which were tumorous. The positive rate of FDG-PET for bone marrow involvement was only 20%. Conclusion: T/NK-cell neoplasms incorporated in this study were generally FDG-avid except for cutaneous lesions and bone marrow involvement.
Various biomarkers have been investigated with regard to their ability to predict the outcome of allogeneic hematopoietic SCT (HSCT). In this study, we retrospectively reviewed 90 recipients who ...received HSCT between 2007 and 2011 in our institution, and evaluated the predictive value of the baseline serum C-reactive protein (CRP) levels just before the initiation of conditioning for transplant-related complications after allogeneic HSCT. A receiver-operating characteristic curve revealed that the baseline serum CRP levels had an excellent predictive value for non-relapse mortality (NRM), with an area under the curve of 0.83. The sensitivity and specificity for NRM were 80% and 87%, respectively, with a cutoff of 0.6 mg/dL. With this cutoff value, multivariate analyses revealed that a higher baseline CRP level was an independent risk factor for NRM (HR 6.21, P<0.01), grade III-IV acute GVHD (HR 3.91, P=0.03) and poor overall survival (HR 3.27, P=0.0018). On the other hand, the baseline CRP level did not predict infectious events. These findings suggested that CRP levels before conditioning may be a useful predictive biomarker for poor survival.
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