Nonparametric estimation of the cumulative incidences of competing risks under double truncation

Registry data typically report incident cases within a certain calendar time interval. Such interval sampling induces double truncation on the incidence times, which may result in an observational bias. In this paper, we introduce nonparametric estimation for the cumulative incidences of competing risks when the incidence time is doubly truncated. Two different estimators are proposed depending on whether the truncation limits are independent of the competing events or not. The asymptotic properties of the estimators are established, and their finite sample performance is investigated through simulations. For illustration purposes, the estimators are applied to childhood cancer registry data, where the target population is peculiarly defined conditional on future cancer development. Then, in our application, the cumulative incidences inform on the distribution by age of the different types of cancer.     

Acetate metabolism in purple non-sulfur bacteria

Abstract The photosynthetic non-sulfur purple bacterium Rhodobacter capsulatus E1F1 can grow on acetate or dl -malate photoheterotrophically under anerobic conditions or chemoheterotrophically in the dark in the presence of dioxygen. Bacterial cells grown under both anaerobic and aerobic conditions exhibited high amounts of the tricarboxylic acid cycle enzymes especially in dark-aerobic cultures. A high activity of isocitrate lyase was found in cells of R. capsulatus E1F1 and, to a lesser extent, in those of R. capsulatus IP2, Rhodobacter sphaeroides and Rhodospirillum rubrum grown photoheterotrophically on acetate under anaerobic conditions. The second enzyme of the glyoxylate shunt, malate synthase, appears to be constitutive. Itaconate, a powerful inhibitor of isocitrate lyase, severely inhibited growth of R. capsulatus, R. rubrum and R. sphaeroides on acetate, thus corroborating a physiological role of the enzyme in acetate metabolism by Rhodospirillaceae.     

Characterization of a highly stable trypsin-like proteinase inhibitor from the seeds of Opuntia streptacantha (O. streptacantha Lemaire)

A trypsin inhibitor from Opuntia streptacantha Lemaire (Prickly pear) seeds was purified and characterized. Of several proteases tested, this inhibitor showed specificity to trypsin-like enzymes. The major inhibitor present in these seeds showed distinctive characteristics, most notably a low molecular weight of 4.19 kDa, as determined by MALDI TOF, and an unusually high thermal stability, retaining most of the activity after heating the sample 1 h to 120 °C with a pressure of 1 kg/cm². Its complete amino acid sequence was obtained through mass spectrometry, this establishing presence a blocked N-terminal region. When comparing its sequence in the MEROPS database for peptidases and peptidase inhibitors, it showed 34.48% identity with a serine-proteinase inhibitor from the I15 family.     

Tocopherol induced angiogenesis in placental vascular network in late pregnant ewes

Background  

Tocopherols have biphasic, proangiogenic and antiangiogenic therapeutic effects. The objective of this clinical trial was to clarify tocopherol's placental angiogenic potential in late pregnant ewes following oral supplementation.     

Ammonium (methylammonium) is the co-repressor of nitrate reductase in Chlamydomonas reinhardii

Methylammonium cannot be used as a nitrogen source by the green alga Chlamydomonas reinhardii and, like ammonia, caused the repression of nitrate reductase without affecting the photosynthetic activity. Glutamine synthetase catalyzed the conversion ofmethylammonium to a single product, identified as γ-N-methylglutamine, which accumulated in the cells. Derepression of nitrate reductase was accompanied by a decrease in the intracellular concentration of methylammonium and a concomitant accumulation of γ-N-methylglutamine inside the cells. These facts strongly suggest that ammonium (methylammonium) per se, and not a product of its metabolism, is the co-repressor of nitrate reductase in C. reinhardii     

Effect of a High-Fat Diet on the Concentration of Antihemophilic Globulin and Factor V

Experiments were carried out to determine whether a diet known to produce coronary thrombosis in rats (Hartroft, O''Neal and Thomas⁶) could produce increases in antihemophilic globulin (AHG), Factor V, and other coagulation factors. In animals continuously fed the thrombogenic diet the concentration of AHG increased to 186% of normal by two weeks and to 373% by eight weeks. The concentration of Factor V rose to a lesser extent, reaching 138% compared to a normal value of 100%. The prothrombin time, stypven time and plasma clotting time also showed significant changes. After thrombin injections, the mortality from massive thrombosis was significantly higher in fat-fed rats. As a considerable number of rats on this diet were shown to develop spontaneous thrombosis, the coagulation disturbances here described acquire added importance.     

Testing Markovianity in the three‐state progressive model via future‐past association

The three‐state progressive model is a special multi‐state model with important applications in Survival Analysis. It provides a suitable representation of the individual’s history when an intermediate event (with a possible influence on the survival prognosis) is experienced before the main event of interest. Estimation of transition probabilities in this and other multi‐state models is usually performed through the Aalen–Johansen estimator. However, Aalen–Johansen may be biased when the underlying process is not Markov. In this paper, we provide a new approach for testing Markovianity in the three‐state progressive model. The new method is based on measuring the future‐past association along time. This results in a deep inspection of the process that often reveals a non‐Markovian behaviour with different trends in the association measure. A test of significance for zero future‐past association at each time point is introduced, and a significance trace is proposed accordingly. The finite sample performance of the test is investigated through simulations. We illustrate the new method through real data analysis.     

Goodness‐of‐fit tests for disorder detection in NGS experiments

Next‐generation sequencing (NGS) experiments are often performed in biomedical research nowadays, leading to methodological challenges related to the high‐dimensional and complex nature of the recorded data. In this work we review some of the issues that arise in disorder detection from NGS experiments, that is, when the focus is the detection of deletion and duplication disorders for homozygosity and heterozygosity in DNA sequencing. A statistical model to cope with guanine/cytosine bias and phasing and prephasing phenomena at base level is proposed, and a goodness‐of‐fit procedure for disorder detection is derived. The method combines the proper evaluation of local p‐values (one for each DNA base) with suitable corrections for multiple comparisons and the discrete nature of the p‐values. A global test for the detection of disorders in the whole DNA region is proposed too. The performance of the introduced procedures is investigated through simulations. A real data illustration is provided.     

Effects of resistance training intensity on sleep quality and strength recovery in trained men: a randomized cross-over study

Resistance training (RT) variables can affect sleep quality, strength recovery and performance. The aim of this study was to examine the acute effect of RT leading to failure vs. non-failure on sleep quality (SQ), heart rate variability (HRV) overnight and one-repetition maximum (1-RM) performance 24 hours after training. Fifteen resistance-trained male athletes (age: 23.4 ± 2.4 years; height 178.0 ± 7.6 cm; weight: 78.2 ± 10.6 kg) performed two training sessions in a randomized order, leading to failure (4x10) or non-failure (5x8(10) repetitions), with 90 seconds for resting between sets at 75% 1-RM in bench press (BP) and half squat (HS). The day after, the participants completed the predicted 1-RM test for both exercises. In addition, the subjective and actigraphic SQ and HRV during sleep were measured after each training session. The day after the training protocol leading to failure, the 1-RM of BP (MD = 7.24 kg; -7.2%; p < 0.001) and HS (MD = 20.20 kg; -11.1%; p < 0.001) decreased. However, this parameter did not decrease after a non-failure RT session. No differences were observed between failure and non-failure training sessions on SQ and HRV; therefore, both types of training sessions similarly affected the SQ and the autonomic modulation during the night after the training session. This study provides an insight into the influence of different training strategies on SQ, strength performance and recovery after moderate- to high-demand training. This information could be useful especially for professional coaches, weightlifters and bodybuilders, due to the potential influence on the programming processes.