Prompt fluorescence from biphenylene in liquid solution: Absence of detectable S2→S0 fluorescence and its implications, vibrational structure and polarization of S1→S0 fluorescence, and orientational relaxation of molecules in S1.

The prompt emission from S0→S2 photoexcited biphenylene in 3-methylpentane has been investigated. No prompt S2→S0 fluorescence has been observed. The implications of this negative result are discussed. It is shown that lengthening of the radiative lifetime of S2 due to intermediate strong S2-S1 coupling is the likely cause of the absence of detectable S2-S0 fluorescence. The observable resonance Raman lines of biphenylene can be assigned to totally symmetric vibrations. The position of S1,0 is determined by a vibrational analysis of the S1→S0 fluorescence. The polarization degree P of the S1→S0 fluorescence is positive. From the dependence of P on temperature and viscosity, orientational relaxation times of biphenylene in S1 are determined with Perrin's formula

Comparative Analysis of the Major Polypeptides from Liver Gap Junctions and Lens Fiber Junctions

Gap junctions from rat liver and fiber junctions from bovine lens have similar septilaminar profiles when examined by thin-section electron microscopy and differ only slightly with respect to the packing of intramembrane particles in freeze-fracture images. These similarities have often led to lens fiber junctions being referred to as gap junctions. Junctions from both sources were isolated as enriched subcellular fractions and their major polypeptide components compared biochemically and immunochemically. The major liver gap junction polypeptide has an apparent molecular weight of 27,000, while a 25,000-dalton polypeptide is the major component of lens fiber junctions. The two polypeptides are not homologous when compared by partial peptide mapping in SDS. In addition, there is not detectable antigenic similarity between the two polypeptides by immunochemical criteria using antibodies to the 25,000-dalton lens fiber junction polypeptide. Thus, in spite of the ultrastructural similarities, the gap junction and the lens fiber junction are comprised of distinctly different polypeptides, suggesting that the lens fiber junction contains a unique gene product and potentially different physiological properties

Self-cooling of a micro-mirror by radiation pressure

We demonstrate passive feedback cooling of a mechanical resonator based on radiation pressure forces and assisted by photothermal forces in a high-finesse optical cavity. The resonator is a free-standing high-reflectance micro-mirror (of mass m=400ng and mechanical quality factor Q=10^4) that is used as back-mirror in a detuned Fabry-Perot cavity of optical finesse F=500. We observe an increased damping in the dynamics of the mechanical oscillator by a factor of 30 and a corresponding cooling of the oscillator modes below 10 K starting from room temperature. This effect is an important ingredient for recently proposed schemes to prepare quantum entanglement of macroscopic mechanical oscillators.Comment: 11 pages, 9 figures, minor correction

Topological and subsystem codes on low-degree graphs with flag qubits

In this work we introduce two code families, which we call the heavy hexagon code and heavy square code. Both code families are implemented by assigning physical data and ancilla qubits to both vertices and edges of low degree graphs. Such a layout is particularly suitable for superconducting qubit architectures to minimize frequency collisions and crosstalk. In some cases, frequency collisions can be reduced by several orders of magnitude. The heavy hexagon code is a hybrid surface/Bacon-Shor code mapped onto a (heavy) hexagonal lattice whereas the heavy square code is the surface code mapped onto a (heavy) square lattice. In both cases, the lattice includes all the ancilla qubits required for fault-tolerant error-correction. Naively, the limited qubit connectivity might be thought to limit the error-correcting capability of the code to less than its full distance. Therefore, essential to our construction is the use of flag qubits. We modify minimum weight perfect matching decoding to efficiently and scalably incorporate information from measurements of the flag qubits and correct up to the full code distance while respecting the limited connectivity. Simulations show that high threshold values for both codes can be obtained using our decoding protocol. Further, our decoding scheme can be adapted to other topological code families.Comment: 20 pages, 21 figures, Comments welcome! V2 conforms to journal specification

Haploidentical bone marrow transplants for hematological malignancies using non-myeloablative conditioning therapy and post-transplant immunosuppression with cyclophosphamide: results from a single Australian centre

Background: HLA haploidentical bone marrow transplantation is a treatment option in patients with hematological malignancies who have no available HLA matched donor, but is limited by conditioning regimen toxicity, graft failure, relapse and graft versus host disease. Aims: To demonstrate safety and efficacy of haploidentical bone marrow transplantation with nonmyeloablative conditioning and high-dose post-transplant cyclophosphamide in adult patients with leukaemia or lymphoma. Methods: 12 patients, median age of 51 years, underwent transplantation with T cell replete bone marrow from a haplotype matched relative. The conditioning regimen consisted of cyclophosphamide, fludarabine, and low-dose TBI. Post-transplant immunosuppression consisted of a single dose of cyclophosphamide 50 mg/kg on day 3, followed by oral tacrolimus and mycophenolate mofetil. Outcomes reported are overall survival, engraftment and chimerism, toxicity, and clinical outcome. Results: All patients had neutrophil recovery (median 14.5 days), and 11 of 12 had platelet engraftment (median 17 days). Two patients had autologous reconstitution. Seven of 9 assessable patients had complete donor chimerism. Four patients had grade II-III GvHD, and none had grade IV GvHD. Four patientsdeveloped limited stage chronic GvHD. Five patients with AML relapsed. Two patients died of non-relapse causes, both from other malignancies, and 5 patients remain alive and relapse free. Median overall survival was 324 days (range 88-1163). Conclusion: This regimen is feasible and well-tolerated in older patients with high risk leukemia or lymphoma, with minimal short-term toxicity, and low rates of GVHD. The proportion of disease-free survivors indicates a graft versus malignancy effect is present in survivors. Keywords: hematological malignancy, bone marrow transplant, haploidentical, post-transplant cyclophosphamid

Haploidentical bone marrow transplants for hematological malignancies using non-myeloablative conditioning therapy and post-transplant immunosuppression with cyclophosphamide: results from a single Australian centre

Background: HLA haploidentical bone marrow transplantation is a treatment option in patients with hematological malignancies who have no available HLA matched donor, but is limited by conditioning regimen toxicity, graft failure, relapse and graft versus host disease. Aims: To demonstrate safety and efficacy of haploidentical bone marrow transplantation with nonmyeloablative conditioning and high-dose post-transplant cyclophosphamide in adult patients with leukaemia or lymphoma. Methods: 12 patients, median age of 51 years, underwent transplantation with T cell replete bone marrow from a haplotype matched relative. The conditioning regimen consisted of cyclophosphamide, fludarabine, and low-dose TBI. Post-transplant immunosuppression consisted of a single dose of cyclophosphamide 50 mg/kg on day 3, followed by oral tacrolimus and mycophenolate mofetil. Outcomes reported are overall survival, engraftment and chimerism, toxicity, and clinical outcome. Results: All patients had neutrophil recovery (median 14.5 days), and 11 of 12 had platelet engraftment (median 17 days). Two patients had autologous reconstitution. Seven of 9 assessable patients had complete donor chimerism. Four patients had grade II-III GvHD, and none had grade IV GvHD. Four patientsdeveloped limited stage chronic GvHD. Five patients with AML relapsed. Two patients died of non-relapse causes, both from other malignancies, and 5 patients remain alive and relapse free. Median overall survival was 324 days (range 88-1163). Conclusion: This regimen is feasible and well-tolerated in older patients with high risk leukemia or lymphoma, with minimal short-term toxicity, and low rates of GVHD. The proportion of disease-free survivors indicates a graft versus malignancy effect is present in survivors. Keywords: hematological malignancy, bone marrow transplant, haploidentical, post-transplant cyclophosphamid

Structural investigation of MOVPE-Grown GaAs on Ge by X-ray techniques

The selection of appropriate characterisation methodologies is vital for analysing and comprehending the sources of defects and their influence on the properties of heteroepitaxially grown III-V layers. In this work we investigate the structural properties of GaAs layers grown by Metal-Organic Vapour Phase Epitaxy (MOVPE) on Ge substrates – (100) with 6⁰ offset towards – under various growth conditions. Synchrotron X-ray topography (SXRT) is employed to investigate the nature of extended linear defects formed in GaAs epilayers. Other X-ray techniques, such as reciprocal space mapping (RSM) and triple axis ω-scans of (00l)-reflections (l = 2, 4, 6) are used to quantify the degree of relaxation and presence of antiphase domains (APDs) in the GaAs crystals. The surface roughness is found to be closely related to the size of APDs formed at the GaAs/Ge heterointerface, as confirmed by X-ray diffraction (XRD), as well as atomic force microscopy (AFM), and transmission electron microscopy (TEM)

Structural investigation of MOVPE-Grown GaAs on Ge by X-ray techniques

The selection of appropriate characterisation methodologies is vital for analysing and comprehending the sources of defects and their influence on the properties of heteroepitaxially grown III-V layers. In this work we investigate the structural properties of GaAs layers grown by Metal-Organic Vapour Phase Epitaxy (MOVPE) on Ge substrates – (100) with 6⁰ offset towards – under various growth conditions. Synchrotron X-ray topography (SXRT) is employed to investigate the nature of extended linear defects formed in GaAs epilayers. Other X-ray techniques, such as reciprocal space mapping (RSM) and triple axis ω-scans of (00l)-reflections (l = 2, 4, 6) are used to quantify the degree of relaxation and presence of antiphase domains (APDs) in the GaAs crystals. The surface roughness is found to be closely related to the size of APDs formed at the GaAs/Ge heterointerface, as confirmed by X-ray diffraction (XRD), as well as atomic force microscopy (AFM), and transmission electron microscopy (TEM)