On the Accuracy of Equivalent Antenna Representations

The accuracy of two equivalent antenna representations, near-field sources and far-field sources, are evaluated for an antenna installed on a simplified platform in a series of case studies using different configurations of equivalent antenna representations. The accuracy is evaluated in terms of installed far-fields and surface currents on the platform. The results show large variations between configurations. The root-mean-square installed far-field error is 4.4% for the most accurate equivalent representation. When using far-field sources, the design parameters have a large influence of the achieved accuracy. There is also a varying accuracy depending on the type of numerical method used. Based on the results, some recommendations on the choice of sub-domain for the equivalent antenna representation are given. In industrial antenna applications, the accuracy in determining e.g. installed far-fields and antenna isolation on large platforms are critical. Equivalent representations can reduce the fine-detail complexity of antennas and thus give an efficient numerical descriptions to be used in large-scale simulations. The results in this paper can be used as a guideline by antenna designers or system engineers when using equivalent sources

The rate-limiting step and nonhyperbolic kinetics in the oxidation of ferrocytochrome c catalyzed by cytochrome c oxidase

AbstractThe level of reduction of cytochrome a and cua during the oxidation of ferrocytochrome c has been determined in stopped-flow experiments. Both components are partially reduced but become progressively more oxidized as the reaction proceeds. When all cytochrome c has been oxidized, cua is also completely oxidized, whereas cytochrome a is still partially reduced. These results can be simulated on the basis of a model which requires that the intramolecular electron transfer from cytochrome a and cua to cytochrome a3-Cub is a two-electron process and, in addition, that the binding of oxidized cytochrome c to the electron-transfer site decreases the rate constants for intramolecular electron transfer from cytochrome a. The first requirement is related to the function of the oxidase as a proton pump. Product dissociation is not by itself rate-limiting, making it less likely that the source of the nonhyperbolic substrate kinetics is an effect on this step from electrostatic interaction with ferricytochrome c bound to a second site. It is pointed out that nonhyperbolic kinetics is, in fact, an intrinsic property of ion pumps

The structure of human dermatan sulfate epimerase 1 emphasizes the importance of C5 epimerization of glucuronic acid in higher organisms

Dermatan sulfate epimerase 1 DS epi1, EC 5.1.3.19 catalyzes the conversion of D glucuronic acid to L iduronic acid on the polymer level, a key step in the biosynthesis of the glycosaminoglycan dermatan sulfate. Here, we present the first crystal structure of the catalytic domains of DS epi1, solved at 2.4 resolution, as well as a model of the full length luminal protein obtained by a combination of macromolecular crystallography and targeted cross linking mass spectrometry. Based on docking studies and molecular dynamics simulations of the protein structure and a chondroitin substrate, we suggest a novel mechanism of DS epi1, involving a His double Tyr motif. Our work uncovers detailed information about the domain architecture, active site, metal coordinating center and pattern of N glycosylation of the protein. Additionally, the structure of DS epi1 reveals a high structural similarity to proteins from several families of bacterial polysaccharide lyases. DS epi1 is of great importance in a range of diseases, and the structure provides a necessary starting point for design of active site inhibitor

Serum Calcium and the Risk of Breast Cancer: Findings from the Swedish AMORIS Study and a Meta-Analysis of Prospective Studies

To investigate the association between serum calcium and risk of breast cancer using a large cohort and a systematic review with meta-analysis. From the Swedish Apolipoprotein Mortality Risk (AMORIS) Study we included 229,674 women who had baseline measurements of serum total calcium and albumin. Multivariable Cox regression was used to assess the association between total and albumin-corrected calcium and breast cancer risk. For the systematic review, an electronic search of MEDLINE and EMBASE databases was performed to identify other prospective cohorts assessing the relationship between serum calcium and breast cancer risk. We pooled the results of our AMORIS cohort with other eligible studies in a meta-analysis using a random effects model. I² test was used to assess heterogeneity. In the AMORIS study, 10,863 women were diagnosed with breast cancer (mean follow-up: 19 years). We found an inverse association between total serum calcium and breast cancer when comparing the fourth quartile to the first quartile (HR: 0.94, 95% CI: 0.88-0.99, p value for trend 0.04) and similar results using albumin-corrected calcium. In the systematic review, we identified another two prospective cohorts evaluating pre-diagnostic serum total calcium and breast cancer. Combining these studies and our findings in AMORIS in a meta-analysis showed a protective effect of serum calcium against breast cancer, with a summary RR of 0.80 (95% CI: 0.66-0.97). No substantial heterogeneity was observed. Our findings in AMORIS and the meta-analysis support an inverse association between serum calcium and breast cancer risk, which warrants mechanistic investigations

Elevated levels of MMP12 sourced from macrophages are associated with poor prognosis in urothelial bladder cancer

Abstract Background Urothelial bladder cancer is most frequently diagnosed at the non-muscle-invasive stage (NMIBC). However, recurrences and interventions for intermediate and high-risk NMIBC patients impact the quality of life. Biomarkers for patient stratification could help to avoid unnecessary interventions whilst indicating aggressive measures when required. Methods In this study, immuno-oncology focused, multiplexed proximity extension assays were utilised to analyse plasma (n = 90) and urine (n = 40) samples from 90 newly-diagnosed and treatment-naïve bladder cancer patients. Public single-cell RNA-sequencing and microarray data from patient tumour tissues and murine OH-BBN-induced urothelial carcinomas were also explored to further corroborate the proteomic findings. Results Plasma from muscle-invasive, urothelial bladder cancer patients displayed higher levels of MMP7 (p = 0.028) and CCL23 (p = 0.03) compared to NMIBC patients, whereas urine displayed higher levels of CD27 (p = 0.044) and CD40 (p = 0.04) in the NMIBC group by two-sided Wilcoxon rank-sum tests. Random forest survival and multivariable regression analyses identified increased MMP12 plasma levels as an independent marker (p < 0.001) associated with shorter overall survival (HR = 1.8, p < 0.001, 95% CI:1.3–2.5); this finding was validated in an independent patient OLINK cohort, but could not be established using a transcriptomic microarray dataset. Single-cell transcriptomics analyses indicated tumour-infiltrating macrophages as a putative source of MMP12. Conclusions The measurable levels of tumour-localised, immune-cell-derived MMP12 in blood suggest MMP12 as an important biomarker that could complement histopathology-based risk stratification. As MMP12 stems from infiltrating immune cells rather than the tumor cells themselves, analyses performed on tissue biopsy material risk a biased selection of biomarkers produced by the tumour, while ignoring the surrounding microenvironment

Transient massive hyperlipidaemia in a type 2 diabetic subject

A 50-year-old man, in apparently good health, was referred to the Lipid Center of San Luigi Gonzaga Hospital, Orbassano (Turin, Italy), by his primary care physician (PCP) because clinical tests at the time of blood donation showed milky plasma with serious hypertriglyceridaemia (>5000 mg/dl) and hyperglycaemia (381 mg/dl), diagnostic for diabetes. It was not possible to perform further blood chemical analyses because hypertriglyceridaemia would have provided abnormal results. The patient entered the hospital to prevent acute pancreatitis, which is often associated with severe hypertriglyceridaemi

Bias-voltage dependence of the magneto-resistance in ballistic vacuum tunneling: Theory and application to planar Co(0001) junctions

Motivated by first-principles results for jellium and by surface-barrier shapes that are typically used in electron spectroscopies, the bias voltage in ballistic vacuum tunneling is treated in a heuristic manner. The presented approach leads in particular to a parameterization of the tunnel-barrier shape, while retaining a first-principles description of the electrodes. The proposed tunnel barriers are applied to Co(0001) planar tunnel junctions. Besides discussing main aspects of the present scheme, we focus in particular on the absence of the zero-bias anomaly in vacuum tunneling.Comment: 19 pages with 8 figure