Etch Induced Microwave Losses in Titanium Nitride Superconducting Resonators

We have investigated the correlation between the microwave loss and patterning method for coplanar waveguide titanium nitride resonators fabricated on Si wafers. Three different methods were investigated: fluorine- and chlorine-based reactive ion etches and an argon-ion mill. At high microwave probe powers the reactive etched resonators showed low internal loss, whereas the ion-milled samples showed dramatically higher loss. At single-photon powers we found that the fluorine-etched resonators exhibited substantially lower loss than the chlorine-etched ones. We interpret the results by use of numerically calculated filling factors and find that the silicon surface exhibits a higher loss when chlorine-etched than when fluorine-etched. We also find from microscopy that re-deposition of silicon onto the photoresist and side walls is the probable cause for the high loss observed for the ion-milled resonator

Mortality benefit of angiotensin-converting enzyme inhibitors after cardiac events in patients with end-stage renal disease

Hypothesis/introduction. The risks and benefits of angiotensin-converting enzyme (ACE) inhibitors in patients with end-stage renal disease (ESRD) after cardiac events are unknown. We sought to determine the independent effect of ACE inhibitors (ACE-I) on long-term mortality in ESRD patients after cardiac events. Materials and methods. We analysed a prospective coronary care unit registry and identified 527 ESRD patients, 368 with complete data on medications prescribed, over eight years at a single, tertiary centre. Results. The overall mean age was 64.4±13.8 years with 54.9% men, and 59.2% African-American. A total of 143/386 (37.0%) were prescribed ACE-I during the hospital stay for cardiac reasons, including congestive heart failure (CHF) 52.8% and acute coronary syndromes (ACS) 47.2%. There were no significant differences in the rates of hypotension or arrhythmias in those who were treated with ACE-I versus those who were not. Survival analysis over three years, adjusted for known confounders, demonstrated a 37% reduction in all-cause mortality in those who received ACE-I, (p=0.0145). Conclusions. In the setting of coronary care unit admission for CHF and ACS, ESRD patients selected for ACE-I, did not have increased rates of adverse haemodynamic or arrhythmic complications. The use of ACE-I conferred an independent mortality reduction over long-term follow-up

Coherence in a transmon qubit with epitaxial tunnel junctions

We developed transmon qubits based on epitaxial tunnel junctions and interdigitated capacitors. This multileveled qubit, patterned by use of all-optical lithography, is a step towards scalable qubits with a high integration density. The relaxation time T1 is .72-.86mu sec and the ensemble dephasing time T2 is slightly larger than T1. The dephasing time T2 (1.36mu sec) is nearly energy-relaxation-limited. Qubit spectroscopy yields weaker level splitting than observed in qubits with amorphous barriers in equivalent-size junctions. The qubit's inferred microwave loss closely matches the weighted losses of the individual elements (junction, wiring dielectric, and interdigitated capacitor), determined by independent resonator measurements

The independent association of renal dysfunction and arrhythmias in critically ill patients

Study objectives: The purpose of this study was to quantify the impact of baseline renal dysfunction on incidence and occurrence of cardiac arrhythmias in the coronary ICU. Background: Renal dysfunction is an established predictor of all-cause mortality in the ICU setting. We set out to evaluate the independent contributory effect of renal dysfunction to arrhythmias and mortality in this population. Design and setting: We analyzed a prospective coronary care unit registry of 12, 648 admissions by 9, 557 patients over 8 years at a single, tertiary center. An admission serum creatinine level was available for 9, 544 patients. Those patients not receiving long-term dialysis were classified into quartiles of corrected creatinine clearance with cutpoints of 46.2 mL/min/72 kg (group 1), 63.1 mL/min/72 kg, and 81.5 mL/min/72 kg. Dialysis patients (n = 527) were considered as a fifth comparison group (group 5). Measurements and results: Baseline characteristics including older age, African-American race, diabetes, hypertension, history of previous coronary disease, and heart failure were incrementally more common with increasing renal dysfunction strata. There were graded, independent increased risks for accelerated idioventricular rhythm (relative risk [RR], 2.43; 95% confidence interval [CI], 1.40 to 4.20; p = 0.002), sustained ventricular tachycardia (RR, 2.07; 95% CI, 1.02 to 4.22; p = 0.04), ventricular fibrillation (RR, 2.42; 95% CI, 1.13 to 5.15; p = 0.02), and complete heart block (RR, 3.64; 95% CI, 1.77 to 7.48; p = 0.0004, group 5 vs group 1). Conclusions: We conclude that baseline renal function is a powerful, independent predictor of cardiac arrhythmias in the coronary ICU population

Dynamic MAIT cell response with progressively enhanced innateness during acute HIV-1 infection.

Mucosa-associated invariant T (MAIT) cell loss in chronic HIV-1 infection is a significant insult to antimicrobial immune defenses. Here we investigate the response of MAIT cells during acute HIV-1 infection utilizing the RV217 cohort with paired longitudinal pre- and post-infection samples. MAIT cells are activated and expand in blood and mucosa coincident with peak HIV-1 viremia, in a manner associated with emerging microbial translocation. This is followed by a phase with elevated function as viral replication is controlled to a set-point level, and later by their functional decline at the onset of chronic infection. Interestingly, enhanced innate-like pathways and characteristics develop progressively in MAIT cells during infection, in parallel with TCR repertoire alterations. These findings delineate the dynamic MAIT cell response to acute HIV-1 infection, and show how the MAIT compartment initially responds and expands with enhanced function, followed by progressive reprogramming away from TCR-dependent antibacterial responses towards innate-like functionality

CheXpert: A Large Chest Radiograph Dataset with Uncertainty Labels and Expert Comparison

Large, labeled datasets have driven deep learning methods to achieve expert-level performance on a variety of medical imaging tasks. We present CheXpert, a large dataset that contains 224,316 chest radiographs of 65,240 patients. We design a labeler to automatically detect the presence of 14 observations in radiology reports, capturing uncertainties inherent in radiograph interpretation. We investigate different approaches to using the uncertainty labels for training convolutional neural networks that output the probability of these observations given the available frontal and lateral radiographs. On a validation set of 200 chest radiographic studies which were manually annotated by 3 board-certified radiologists, we find that different uncertainty approaches are useful for different pathologies. We then evaluate our best model on a test set composed of 500 chest radiographic studies annotated by a consensus of 5 board-certified radiologists, and compare the performance of our model to that of 3 additional radiologists in the detection of 5 selected pathologies. On Cardiomegaly, Edema, and Pleural Effusion, the model ROC and PR curves lie above all 3 radiologist operating points. We release the dataset to the public as a standard benchmark to evaluate performance of chest radiograph interpretation models. The dataset is freely available at https://stanfordmlgroup.github.io/competitions/chexpert .Comment: Published in AAAI 201

AAV-Mediated Gene Delivery in Adult GM1-Gangliosidosis Mice Corrects Lysosomal Storage in CNS and Improves Survival

Background: GM1-gangliosidosis is a glycosphingolipid (GSL) lysosomal storage disease caused by a genetic deficiency of acid β-galactosidase (βgal), which results in the accumulation of GM1-ganglioside and its asialo-form (GA1) primarily in the CNS. Age of onset ranges from infancy to adulthood, and excessive ganglioside accumulation produces progressive neurodegeneration and psychomotor retardation in humans. Currently, there are no effective therapies for the treatment of GM1-gangliosidosis. Methodology/Principal Findings: In this study we examined the effect of thalamic infusion of AAV2/1-βgal vector in adult GM1 mice on enzyme distribution, activity, and GSL content in the CNS, motor behavior, and survival. Six to eight week-old GM1 mice received bilateral injections of AAV vector in the thalamus, or thalamus and deep cerebellar nuclei (DCN) with pre-determined endpoints at 1 and 4 months post-injection, and the humane endpoint, or 52 weeks of age. Enzyme activity was elevated throughout the CNS of AAV-treated GM1 mice and GSL storage nearly normalized in most structures analyzed, except in the spinal cord which showed ∼50% reduction compared to age-matched untreated GM1 mice spinal cord. Survival was significantly longer in AAV-treated GM1 mice (52 wks) than in untreated mice. However the motor performance of AAV-treated GM1 mice declined over time at a rate similar to that observed in untreated GM1 mice. Conclusions/Significance: Our studies show that the AAV-modified thalamus can be used as a ‘built-in’ central node network for widespread distribution of lysosomal enzymes in the mouse cerebrum. In addition, this study indicates that thalamic delivery of AAV vectors should be combined with additional targets to supply the cerebellum and spinal cord with therapeutic levels of enzyme necessary to achieve complete correction of the neurological phenotype in GM1 mice

Search for a correlation between telomere length and severity of retinitis pigmentosa due to the dominant rhodopsin Pro23His mutation

Purpose: Great variation exists in the age of onset of symptoms and the severity of disease at a given age in patients with retinitis pigmentosa ( RP). The final pathway for this disease may involve apoptotic photoreceptor cell death. Telomere length is associated with biologic aging, senescence, and apoptosis. We evaluated whether the length of telomeres in leukocytes correlated with the severity of RP in patients with the Pro23His rhodopsin mutation who have shown marked heterogeneity in disease severity. Methods: We evaluated 122 patients with the Pro23His rhodopsin mutation. The patients' retinal function was stratified according to their 30-Hz cone electroretinogram (ERG). The length of telomeres in leukocytes was measured by the quantitative real time polymerase chain reaction (qRT-PCR) method in the 15 patients with the highest age-adjusted 30Hz ERG amplitudes and in the 15 patients with the lowest amplitudes. Results: Mean leukocyte telomere length was similar in the 15 patients with the highest cone ERG amplitudes (median: 0.40 units; interquartile range 0.36-0.56) and the 15 patients with the lowest cone amplitudes (median: 0.41 units; inter quartile range 0.34-0.64; p=0.95). Conclusions: We found no evidence for an association between telomere length and the severity of RP as monitored by the cone ERG in patients with the Pro23His rhodopsin mutation

CD8 T cell effector maturation in HIV-1-infected children

AbstractHIV-1 infection generates maturational responses in overall CD4 and CD8 T cell populations in adults, with elevated expression of lytic effector molecules perforin and granzyme B, and reduced expression of CCR7 and CD45RA. Here, we have found that these marked effects were significantly less pronounced in children, both in terms of the skewed CCR7/CD45RA expression profile as well as the increased perforin expression. Similar to adults, HIV-specific CD8 cells in children were largely CD27+ CD45RA− and lacked perforin. However, one pediatric subject with late-stage infection displayed robust expansion of Gag 77–85-specific CD8 T cells which were perforin+ and lytic, but lacked expression of CD27 and IFNγ. Our data indicate that the T cell effector maturation induced by HIV-1 infection is markedly weaker in children as compared to adults. The data also suggest, however, that the perforin-deficient state of HIV-specific CD8 T cells in children may be reversible