701 research outputs found
Fossilized anuran soft tissues reveal a new taphonomic model for the Eocene Geiseltal Konservat-Lagerstätte, Germany
The Eocene Geiseltal Konservat-Lagerstätte (Germany) is famous for reports of three dimensionally preserved soft tissues with sub-cellular detail. The proposed mode of preservation, direct replication in silica, is not known in other fossils and has not been verified using modern approaches. Here, we investigated the taphonomy of the Geiseltal anurans using diverse microbeam imaging and chemical analytical techniques. Our analyses confirm the preservation of soft tissues in all body regions but fail to yield evidence for silicified soft tissues. Instead, the anuran soft tissues are preserved as two layers that differ in microstructure and composition. Layer 1 comprises sulfur-rich carbonaceous microbodies interpreted as melanosomes. Layer 2 comprises the mid-dermal Eberth-Katschenko layer, preserved in calcium phosphate. In addition, patches of original aragonite crystals define the former position of the endolymphatic sac. The primary modes of soft tissue preservation are therefore sulfurization of melanosomes and phosphatization of more labile soft tissues, i.e., skin. This is consistent with the taphonomy of vertebrates in many other Konservat-Lagerstätten. These findings emphasize an emerging model for pervasive preservation of vertebrate soft tissues via melanosome films, particularly in stagnation-type deposits, with phosphatization of more labile tissues where tissue biochemistry is favorable
Lipid sac area as a proxy for individual lipid content of arctic calanoid copepods
We present an accurate, fast, simple and non-destructive photographic method to estimate wax ester and lipid content in single individuals of the calanoid copepod genus Calanus and test this method against gas-chromatographic lipid measurements
Suppression of crosstalk in superconducting qubits using dynamical decoupling
Currently available superconducting quantum processors with interconnected
transmon qubits are noisy and prone to various errors. The errors can be
attributed to sources such as open quantum system effects and spurious
inter-qubit couplings (crosstalk). The ZZ-coupling between qubits in fixed
frequency transmon architectures is always present and contributes to both
coherent and incoherent crosstalk errors. Its suppression is therefore a key
step towards enhancing the fidelity of quantum computation using transmons.
Here we propose the use of dynamical decoupling to suppress the crosstalk, and
demonstrate the success of this scheme through experiments performed on several
IBM quantum cloud processors. In particular, we demonstrate improvements in
quantum memory as well as the performance of single-qubit and two-qubit gate
operations. We perform open quantum system simulations of the multi-qubit
processors and find good agreement with the experimental results. We analyze
the performance of the protocol based on a simple analytical model and
elucidate the importance of the qubit drive frequency in interpreting the
results. In particular, we demonstrate that the XY4 dynamical decoupling
sequence loses its universality if the drive frequency is not much larger than
the system-bath coupling strength. Our work demonstrates that dynamical
decoupling is an effective and practical way to suppress crosstalk and open
system effects, thus paving the way towards higher-fidelity logic gates in
transmon-based quantum computers.Comment: Updated version includes additional results on improving the
performance of single and two-qubit gates using dynamical decoupling. 22
pages and 12 figure
Reporting of adverse events in muscle strengthening interventions in youth: A systematic review
To document the extent to which AEs, resulting from intervention studies targeting
muscle-strengthening training (MST) in youth, are reported by researchers
An inflamed necrotic appendix epiploicum with immediate contact to a non-inflamed appendix vermiformis: a case report
<p>Abstract</p> <p>Introduction</p> <p>Epiploic appendagitis is a rare cause of focal abdominal pain which, depending on its localisation, can mimic a variety of abdominal diseases. We describe a patient with an inflamed necrotic appendix epiploicum with immediate contact to a non-inflamed appendix vermiformis mimicking acute appendicitis. Considering the rare localization, this is the first report of this kind in the literature.</p> <p>Case presentation</p> <p>We present the case of a 50-year-old Caucasian man who presented with classic signs of acute appendicitis. On clinical exam, McBurney and Blumberg signs were positive. Additionally he had fever, leucocytosis (12/nl) and a slight increase in C-reactive protein (1 mg/dl). Based on the clinical presentation, the patient was taken to the operating room to perform an appendicectomy. Surprisingly, we found an inflamed necrotic appendix epiploicum, located immediately on a non-inflamed appendix vermiformis, which was ligated and excised.</p> <p>Conclusion</p> <p>This case report demonstrates that epiploic appendagitis can mimic acute appendicitis on clinical exam and should be considered in the broad spectrum of abdominal disease presenting with right lower quadrant pain.</p
High-risk human papillomavirus (HPV) screening and detection in normal, healthy patient saliva samples: a pilot cluster randomized study
Background: The human papillomaviruses (HPV) are a large family of non-enveloped DNA viruses, mainly associated with cervical cancers. Recent epidemiologic evidence has suggested that HPV may be an independent risk factor for oropharyngeal cancers. Evidence now suggests HPV may modulate the malignancy process in some tobacco- and alcohol-induced oropharynx tumors, but might also be the primary oncogenic factor for inducing carcinogenesis among some non-smokers. More evidence, however, is needed regarding oral HPV prevalence among healthy adults to estimate risk. The goal of this study was to perform an HPV screening of normal healthy adults to assess oral HPV prevalence.
Methods: Healthy adult patients at a US dental school were selected to participate in this pilot study. DNA was isolated from saliva samples and screened for high-risk HPV strains HPV16 and HPV18 and further processed using qPCR for quantification and to confirm analytical sensitivity and specificity.
Results: Chi-square analysis revealed the patient sample was representative of the general clinic population with respect to gender, race and age (p \u3c 0.05). Four patient samples were found to harbor HPV16 DNA, representing 2.6% of the total (n = 151). Three of the four HPV16-positive samples were from patients under 65 years of age and all four were female and Hispanic (non-White). No samples tested positive for HPV18.
Conclusions: The successful recruitment and screening of healthy adult patients revealed HPV16, but not HPV18, was present in a small subset. These results provide new information about oral HPV status, which may help to contextualize results from other studies that demonstrate oral cancer rates have risen in the US among both females and minorities and in some geographic areas that are not solely explained by rates of tobacco and alcohol use. The results of this study may be of significant value to further our understanding of oral health and disease risk, as well as to help design future studies exploring the role of other factors that influence oral HPV exposure, as well as the short- and long-term consequences of oral HPV infection
Social Preferences and the Efficiency of Bilateral Exchange
Under what conditions do social preferences, such as altruism or a concern for fair outcomes, generate efficient trade? I analyze theoretically a simple bilateral exchange game: Each player sequentially takes an action that reduces his own material payoff but increases the other player’s. Each player’s preferences may depend on both his/her own material payoff and the other player’s. I identify necessary conditions and sufficient conditions on the players’ preferences for the outcome of their interaction to be Pareto efficient. The results have implications for interpreting the rotten kid theorem, gift exchange in the laboratory, and gift exchange in the field
Alcohol use disorder is associated with DNA methylation-based shortening of telomere length and regulated by TESPA1:implications for aging
Chronic heavy alcohol consumption is associated with increased mortality and morbidity and often leads to premature aging; however, the mechanisms of alcohol-associated cellular aging are not well understood. In this study, we used DNA methylation derived telomere length (DNAmTL) as a novel approach to investigate the role of alcohol use on the aging process. DNAmTL was estimated by 140 cytosine phosphate guanines (CpG) sites in 372 individuals with alcohol use disorder (AUD) and 243 healthy controls (HC) and assessed using various endophenotypes and clinical biomarkers. Validation in an independent sample of DNAmTL on alcohol consumption was performed (N = 4219). Exploratory genome-wide association studies (GWAS) on DNAmTL were also performed to identify genetic variants contributing to DNAmTL shortening. Top GWAS findings were analyzed using in-silico expression quantitative trait loci analyses and related to structural MRI hippocampus volumes of individuals with AUD. DNAmTL was 0.11-kilobases shorter per year in AUD compared to HC after adjustment for age, sex, race, and blood cell composition (p = 4.0 × 10(−12)). This association was partially attenuated but remained significant after additionally adjusting for BMI, and smoking status (0.06 kilobases shorter per year, p = 0.002). DNAmTL shortening was strongly associated with chronic heavy alcohol use (ps < 0.001), elevated gamma-glutamyl transferase (GGT), and aspartate aminotransferase (AST) (ps < 0.004). Comparison of DNAmTL with PCR-based methods of assessing TL revealed positive correlations (R = 0.3, p = 2.2 × 10(−5)), highlighting the accuracy of DNAmTL as a biomarker. The GWAS meta-analysis identified a single nucleotide polymorphism (SNP), rs4374022 and 18 imputed ones in Thymocyte Expressed, Positive Selection Associated 1(TESPA1), at the genome-wide level (p = 3.75 × 10(−8)). The allele C of rs4374022 was associated with DNAmTL shortening, lower hippocampus volume (p < 0.01), and decreased mRNA expression in hippocampus tissue (p = 0.04). Our study demonstrates DNAmTL-related aging acceleration in AUD and suggests a functional role for TESPA1 in regulating DNAmTL length, possibly via the immune system with subsequent biological effects on brain regions negatively affected by alcohol and implicated in aging
PU.1 controls fibroblast polarization and tissue fibrosis
Fibroblasts are polymorphic cells with pleiotropic roles in organ morphogenesis, tissue homeostasis and immune responses. In fibrotic diseases, fibroblasts synthesize abundant amounts of extracellular matrix, which induces scarring and organ failure. By contrast, a hallmark feature of fibroblasts in arthritis is degradation of the extracellular matrix because of the release of metalloproteinases and degrading enzymes, and subsequent tissue destruction. The mechanisms that drive these functionally opposing pro-fibrotic and pro-inflammatory phenotypes of fibroblasts remain unknown. Here we identify the transcription factor PU.1 as an essential regulator of the pro-fibrotic gene expression program. The interplay between transcriptional and post-transcriptional mechanisms that normally control the expression of PU.1 expression is perturbed in various fibrotic diseases, resulting in the upregulation of PU.1, induction of fibrosis-associated gene sets and a phenotypic switch in extracellular matrix-producing pro-fibrotic fibroblasts. By contrast, pharmacological and genetic inactivation of PU.1 disrupts the fibrotic network and enables reprogramming of fibrotic fibroblasts into resting fibroblasts, leading to regression of fibrosis in several organs
Social preferences, accountability, and wage bargaining
We assess the extent of preferences for employment in a collective wage bargaining situation with heterogeneous workers. We vary the size of the union and introduce a treatment mechanism transforming the voting game into an individual allocation task. Our results show that highly productive workers do not take employment of low productive workers into account when making wage proposals, regardless of whether insiders determine the wage or all workers. The level of pro-social preferences is small in the voting game, while it increases as the game is transformed into an individual allocation task. We interpret this as an accountability effect
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