Optically Probing Spin and Charge Interactions in an Tunable Artificial Molecule

We optically probe and electrically control a single artificial molecule containing a well defined number of electrons. Charge and spin dependent inter-dot quantum couplings are probed optically by adding a single electron-hole pair and detecting the emission from negatively charged exciton states. Coulomb and Pauli blockade effects are directly observed and hybridization and electrostatic charging energies are independently measured. The inter-dot quantum coupling is confirmed to be mediated predominantly by electron tunneling. Our results are in excellent accord with calculations that provide a complete picture of negative excitons and few electron states in quantum dot molecules.Comment: shortened version: 6 pages, 3 figures, 1 table, to appear in Phys. Rev. Let

Planning reform, land release and the supply of housing

There is a growing interest in academic and policy circles in the relationship between land use planning policy and housing supply. Housing researchers are interested in the extent to which planning policies and practises may be exacerbating housing affordability questions, while planning academics and practitioners focus on what effect their policies actually have on the characteristics of housing supply. Policies seeking a diversity of built form are underpinned by attempts to reduce energy consumption through smaller house sizes and the design of less car dependent suburbs. Urban Growth Boundaries (UGBs) and increased net housing densities seek to slow the expansion of cities into hinterlands and reduce travel costs. The impact of UGBs on house prices is one of a number of issues that remains contested (Nelson et al 2007; Buxton and Scheurer 2007)

Bone age estimation with the Greulich-Pyle atlas using 3T MR images of hand and wrist.

The age estimation of the hand bones by means of X-ray examination is a pillar of the forensic age estimation. Since the associated radiation exposure is controversial, the search for ionizing radiation-free alternatives such as MRI is part of forensic research. The aim of the current study was to use the Greulich-Pyle (GP) atlas on MR images of the hand and wrist to provide reference values for assessing the age of the hand bones. 3T hand MR images of 238 male participants between the ages of 13 and 21 were acquired using 3D gradient echo sequences (VIBE, DESS). Two readers rated the images using the X-ray-based GP atlas method. A descriptive analysis and a transitional analysis were used for the statistical processing of the data. The agreement between and within the raters was assessed. In addition, a comparison was made with the chronological age and with X-ray studies. The descriptive analysis and the transition analysis showed similar results. Both evaluations showed good agreement with X-ray studies. The comparison with the chronological age showed a difference of 0.37 and 0.54 years for the two readers. The age estimate based on the cross-validated transition analysis showed a mean error of -0.28 years. Inter- and intra-rater agreement were good. In summary, it can be concluded that age estimation of hand bones with MR images is routinely applicable with the GP atlas as an alternative without ionizing radiation. However, in order to reduce the estimation error, a multi-factorial assessment based on examinations of several body regions is still recommended

Absolute quantitative real-time polymerase chain reaction for the measurement of human papillomavirus E7 mRNA in cervical cytobrush specimens

BACKGROUND: Few reports of the utilization of an accurate, cost-effective means for measuring HPV oncogene transcripts have been published. Several papers have reported the use of relative quantitation or more expensive Taqman methods. Here, we report a method of absolute quantitative real-time PCR utilizing SYBR-green fluorescence for the measurement of HPV E7 expression in cervical cytobrush specimens. RESULTS: The construction of a standard curve based on the serial dilution of an E7-containing plasmid was the key for being able to accurately compare measurements between cervical samples. The assay was highly reproducible with an overall coefficient of variation of 10.4%. CONCLUSION: The use of highly reproducible and accurate SYBR-based real-time polymerase chain reaction (PCR) assays instead of performing Taqman-type assays allows low-cost, high-throughput analysis of viral mRNA expression. The development of such assays will help in refining the current screening programs for HPV-related carcinomas

Electron irradiation effects on superconductivity in PdTe2_2: an application of a generalized Anderson theorem

Low temperature ($\sim$ 20~K) electron irradiation with 2.5 MeV relativistic electrons was used to study the effect of controlled non-magnetic disorder on the normal and superconducting properties of the type-II Dirac semimetal PdTe$_2$. We report measurements of longitudinal and Hall resistivity, thermal conductivity and London penetration depth using tunnel-diode resonator technique for various irradiation doses. The normal state electrical resistivity follows Matthiessen rule with an increase of the residual resistivity at a rate of $\sim$0.77$\mu \Omega$cm/$(\textrm{C}/\textrm{cm}^2)$. London penetration depth and thermal conductivity results show that the superconducting state remains fully gapped. The superconducting transition temperature is suppressed at a non-zero rate that is about sixteen times slower than described by the Abrikosov-Gor'kov dependence, applicable to magnetic impurity scattering in isotropic, single-band $s$-wave superconductors. To gain information about the gap structure and symmetry of the pairing state, we perform a detailed analysis of these experimental results based on insight from a generalized Anderson theorem for multi-band superconductors. This imposes quantitative constraints on the gap anisotropies for each of the possible pairing candidate states. We conclude that the most likely pairing candidate is an unconventional $A_{1g}^{+-}$ state. While we cannot exclude the conventional $A_{1g}^{++}$ and the triplet $A_{1u}$, we demonstrate that these states require additional assumptions about the orbital structure of the disorder potential to be consistent with our experimental results, e.g., a ratio of inter- to intra-band scattering for the singlet state significantly larger than one. Due to the generality of our theoretical framework, we think that it will also be useful for irradiation studies in other spin-orbit-coupled multi-orbital systems.Comment: 22 pages, 12 figure

The catalytic subunit of Plasmodium falciparum casein kinase 2 is essential for gametocytogenesis

Casein kinase 2 (CK2) is a pleiotropic kinase phosphorylating substrates in different cellular compartments in eukaryotes. In the malaria parasite Plasmodium falciparum, PfCK2 is vital for asexual proliferation of blood-stage parasites. Here, we applied CRISPR/Cas9-based gene editing to investigate the function of the PfCK2alpha catalytic subunit in gametocytes, the sexual forms of the parasite that are essential for malaria transmission. We show that PfCK2alpha localizes to the nucleus and cytoplasm in asexual and sexual parasites alike. Conditional knockdown of PfCK2alpha expression prevented the transition of stage IV into transmission-competent stage V gametocytes, whereas the conditional knockout of pfck2a completely blocked gametocyte maturation already at an earlier stage of sexual differentiation. In summary, our results demonstrate that PfCK2alpha is not only essential for asexual but also sexual development of P. falciparum blood-stage parasites and encourage studies exploring PfCK2alpha as a potential target for dual-active antimalarial drugs

Antifungal Prophylaxis and Risk for Invasive Mold Infections in Children with Hematologic Malignancies

Introduction: Invasive mold infections (IMI) are a leading cause of mortality in immunocompromised hosts. Children diagnosed with hematologic malignancies experience profound, prolonged neutropenia following intensive chemotherapy, and are at increased risk for infection-related outcomes. Depending on the anticipated therapeutic intensity, antimicrobial prophylaxis may be employed to mitigate risk for infection. We conducted a retrospective review of children diagnosed with acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), or lymphoma between 2006-2015 and determined the incidence of IMI to be 4.8% (47/976), with an exceptionally high incidence observed in patients with AML (8.1%). This observation prompted a change in clinical practice that broadened prophylaxis for high risk patients to include coverage of molds, and resulted in development of a risk-stratified algorithm for antifungal prophylaxis in children with hematologic malignancies. The objective of this study was to evaluate the change in IMI incidence post-implementation of this algorithm, and to identify host factors contributing to risk for IMI in children with hematologic malignancies. Objective: The objective was to compare the incidence of IMI pre/post implementation of antifungal prophylaxis decision tree. Also, it was planned to evaluate the impact of race/ethnicity on the development of IMI in children with hematologic malignancies. Methods: We conducted a retrospective review of children ≤ 21 years old and diagnosed with ALL, AML, or lymphoma between 2016-2019, and were treated for IMI between 2016 and June 2020. To identify potential cases, we employed a strategy identical to the one used in the 2006-2015 review, specifically, a search of the electronic medical record utilizing ICD9 codes broadly inclusive of relevant cancer and fungal diagnoses. Each potentially eligible case was then reviewed for the following inclusion/exclusion criteria (also identical to the prior review): diagnosis and treatment of ALL, AML, or lymphoma at Texas Children’s Hospital, diagnosis of IMI that met criteria for ‘proven’ or ‘probable’ per the European Organization for Research and Treatment of Cancer/Mycoses Study Group and occurring prior to stem cell transplant, and no underlying immunodeficiency or history of solid organ transplant. Host and disease-related factors, as well as IMI incidence, were compared for 2006-2015 vs. 2016-2020 using a Chi-square, Fisher, or Student t-test as appropriate, and host factors predictive of IMI were assessed by multivariable linear regression. Results: The overall incidence of proven/probable IMI in children diagnosed with hematological malignancies between 2006-2019 was 4.2% (61/1456). The incidence of IMI decreased from 4.8% to 2.9% between 2006-2015 and 2016-2020. For specific diagnoses, the rate of IMI decreased from 5.0% to 3.6% (ALL, 35/705 vs. 10/276), from 1.9% to 1.4% (lymphoma, 47/976 vs. 14/480), and from 8.1% to 3.2% (AML, 9/111 vs. 2/62). No significant differences in host factor or disease-related characteristics were noted when comparing IMI cases in 2006-2015 vs. 2016-2020, nor were there differences in the proportion of patients in relapse at the time of IMI or taking antifungal prophylaxis. Substantial differences in representative mold species were noted between the two-time periods, e.g. Aspergillus spp. accounted for 19/47 IMI from 2006-2015, but accounted for none of the IMIs diagnosed 2016-2020. In 2016-2020, 5/14 IMI were due to Trichosporon spp., with 4/14 Rhizopus spp., 2/14 Fusarium spp., 1/14 Curvularia spp., 1/14 Histoplasma spp., and 1 that met criteria for probable IMI. In multivariable analyses (Table 1), Hispanics were more likely to develop an IMI than non-Hispanics (p=0.04, OR 1.94, CI 1.03-3.66), and those with lymphoma were less likely to develop an IMI than those with ALL (p=0.03, OR 0.33, CI 0.12-0.87). Patients diagnosed between 2016- 2019 were substantially less likely to develop IMI than those diagnosed 2006-2015 (p=0.003, OR 0.33, CI 0.16-0.69). Discussion and Conclusion: In this single institution study, risk for IMI in children with hematologic malignancies declined significantly after implementation of an antifungal prophylaxis algorithm that broadened coverage for high risk populations. Hispanics were at higher risk for IMI than non-Hispanics, suggesting a need to investigate relevant factors contributing to this disparity. This project can be used to further investigate the factors that contributed to invasive mold infections using a larger study populations. We can then continue to explore the potential contributing factors to the racial and ethnic disparities by including potential contributing factors such as socioeconomic factors and genetic risk