Project description:Esophagitis is mainly a consequence of gastroesophageal reflux disease, one of the most common diseases affecting the upper digestive tract. However the esophageal mucosa can also be targeted by some infectious, systemic or chemical conditions. Eosinophilic esophagitis (EoE) is an immune-mediated inflammatory disease, characterized by eosinophilic infiltration in the mucosa. Esophageal localization of Crohn's disease is not very common, but it should always be considered in patients with inflammatory bowel disease complaining of upper digestive tract symptoms. There are also forms of infectious esophagitis (e.g., Herpes simplex virus or Candida albicans) occurring in patients with a compromised immune system, either because of specific diseases or immunosuppressive therapies. Another kind of damage to esophageal mucosa is due to drug use (including oncologic chemotherapeutic regimens and radiotherapy) or caustic ingestion, usually of alkaline liquids, with colliquative necrosis and destruction of mucosa within a few seconds. Dysphagia is a predominant symptom in EoE, while infectious, drug-induced and caustic damages usually cause chest pain and odynophagia. Endoscopy can be useful for diagnosing esophagitis, although no specific pattern can be identified. In conclusion when a patient refers upper gastrointestinal tract symptoms and the diagnosis of gastro-esophageal reflux disease is not convincing we should always carefully investigate the patient's clinical history to consider possibilities other than the gastric refluxate.
Project description:Problems of flexible mechanical metamaterials, and highly deformable porous solids in general, are rich and complex due to their nonlinear mechanics and the presence of nontrivial geometrical effects. While numeric approaches are successful, analytic tools and conceptual frameworks are largely lacking. Using an analogy with electrostatics, and building on recent developments in a nonlinear geometric formulation of elasticity, we develop a formalism that maps the two-dimensional (2D) elastic problem into that of nonlinear interaction of elastic charges. This approach offers an intuitive conceptual framework, qualitatively explaining the linear response, the onset of mechanical instability, and aspects of the postinstability state. Apart from intuition, the formalism also quantitatively reproduces full numeric simulations of several prototypical 2D structures. Possible applications of the tools developed in this work for the study of ordered and disordered 2D porous elastic metamaterials are discussed.
Project description:Generalized atomic polar tensor (GAPT) has turned into a very popular charge model since it was proposed three decades ago. During this period, several works aiming to compare different partition schemes have included it among their tested models. Nonetheless, GAPT exhibits a set of unique features that prevent it from being directly comparable to "standard" partition schemes. We take this opportunity to explore some of these features, mainly related to the need of evaluating multiple geometries and the dynamic character of GAPT, and show how to obtain the static and dynamic parts of GAPT from any static charge model in the literature. We also present a conceptual evaluation of charge models that aims to explain, at least partially, why GAPT and quantum theory of atoms in molecules (QTAIM) charges are strongly correlated with one another, even though they seem to be constructed under very different frameworks. Similar to GAPT, infrared charges (also derived from atomic polar tensors of planar molecules) are also shown to provide an improved interpretation if they are described as a combination of static charges and changing atomic dipoles rather than just experimental static atomic charges.
Project description:Alcoholic liver disease (ALD), a disorder caused by excessive alcohol intake represents a global health care burden. ALD encompasses a broad spectrum of hepatic injuries including asymptomatic steatosis, alcoholic steatohepatitis (ASH), fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). The susceptibility of alcoholic patients to develop ALD is highly variable and its progression to more advanced stages is strongly influenced by several hits (i.e., amount and duration of alcohol abuse). Among them, the intestinal microbiota and its metabolites have been recently identified as paramount in ALD pathophysiology. Ethanol abuse triggers qualitative and quantitative modifications in intestinal flora taxonomic composition, mucosal inflammation, and intestinal barrier derangement. Intestinal hypermeability results in the translocation of viable pathogenic bacteria, Gram-negative microbial products, and pro-inflammatory luminal metabolites into the bloodstream, further corroborating the alcohol-induced liver damage. Thus, the premise of this review is to discuss the beneficial effect of gut microbiota modulation as a novel therapeutic approach in ALD management.
Project description:Sustained cooperative social interactions are key to successful outcomes in many real-world contexts (e.g., climate change and energy conservation). We explore the self-regulatory roles of anger and guilt, as well as prosocial or selfish social preferences in a repeated social dilemma game framed around shared electricity use at home. We explore the proposal that for sustained cooperation, guilty repair needs to override angry retaliation. We show that anger is damaging to cooperation as it leads to retaliation and an increase of defection, while, through guilt, cooperation is repaired resulting in higher levels of cooperation. We demonstrate a disconnect between the experience of anger and subsequent retaliation which is a function of participants' social preferences. While there is no difference in reports of anger between prosocial and selfish individuals after finding out that others use more energy from the communal resource, prosocials are less likely to act on their anger and retaliate. Selfish individuals are motivated by anger to retaliate but not motivated by guilt to repair and contribute disproportionately to the breakdown of cooperation over repeated interactions. We suggest that guilt is a key emotion to appeal to when encouraging cooperation.
Project description:A major benefit of expansive cancer genome projects is the discovery of new targets for drug treatment and development. To date, cancer driver genes have been primarily identified by methods based on gene mutation frequency. This approach fails to identify culpable genes that are not mutated, rarely mutated, or contribute to the development of rare forms of cancer. Due to the complexity of the disease and the sheer volume of data, computational methods may encounter a NP-complete problem. We have developed a novel pathway and reach (PAR) method that employs a guilty by resemblance approach to identify cancer driver genes that avoids the above problems. Essentially PAR sifts through a list of genes of biological pathways to find those that are common to the same pathways and possess a similar 2-reach topology metric as a reference set of recognized driver genes. This approach leads to faster processing times and eliminates any dependency on gene mutation frequency. Out of the three pathways, signal transduction, immune system, and gene expression, a set of 50 candidate driver genes were identified, 30 of which were new. The top five were HGF, E2F1, C6, MIF, and CDK2.
Project description:Unrestrained p53 activity during development, as occurs upon loss of the p53 negative regulators Mdm2 or Mdmx, causes early embryonic lethality. Surprisingly, co-expression of wild-type p53 and a transcriptionally-dead variant of p53, with mutations in both transactivation domains (p53(L25Q,W26S,F53Q,F54S)), also causes lethality, but later in gestation and in association with a host of very specific phenotypes reminiscent of a syndrome known as CHARGE. Molecular analyses revealed that wild-type p53 is inappropriately activated in p53(5,26,53,54/)(+) embryos, triggering cell-cycle arrest or apoptosis during development to cause CHARGE phenotypes. In addition, CHARGE syndrome is typically caused by mutations in the CHD7 chromatin remodeler, and we have shown that activated p53 contributes to phenotypes caused by CHD7-deficiency. Together, these studies provide new insight into CHARGE syndrome and expand our understanding of the role of p53 in diseases other than cancer.
Project description:Surface charges of proteins have in several cases been found to function as "structural gatekeepers," which avoid unwanted interactions by negative design, for example, in the control of protein aggregation and binding. The question is then if side-chain charges, due to their desolvation penalties, play a corresponding role in protein folding by avoiding competing, misfolded traps? To find out, we removed all 32 side-chain charges from the 101-residue protein S6 from Thermus thermophilus. The results show that the charge-depleted S6 variant not only retains its native structure and cooperative folding transition, but folds also faster than the wild-type protein. In addition, charge removal unleashes pronounced aggregation on longer timescales. S6 provides thus an example where the bias toward native contacts of a naturally evolved protein sequence is independent of charges, and point at a fundamental difference in the codes for folding and intermolecular interaction: specificity in folding is governed primarily by hydrophobic packing and hydrogen bonding, whereas solubility and binding relies critically on the interplay of side-chain charges.