Analytical results and universal behavior in fast thermal equilibration protocols.

When a system deviates from equilibrium, it is possible to manipulate and control it to drive it towards equilibrium within finite time t_{f}, even by reducing its natural relaxation timescale τ_{relax}. Although numerous theoretical and experimental studies have explored these shortcut protocols, few have yielded analytical results for the probability distribution of the work, heat, and produced entropy. In this study, we propose a two-step protocol that captures the essential characteristics of more general protocols and provides an analytical solution for the relevant thermodynamic probability distributions. Additionally, we present evidence that for a very short protocol duration t_{f}≪τ_{relax}, all protocols exhibit universal behavior for the ratio of probability distribution functions of positive and negative work, heat, and the produced entropy.

A Call to Validate the Stress Continuum Model.

INTRODUCTION: Since the start of the Global War on Terrorism, exponential demands have been put on military personnel, their families, and the military health care system. In response to a Department of Defense Task Force on Mental Health, the U.S. military began developing and fielding programs to promote the psychological health of its personnel. As part of these initiatives, the Navy and Marine Corps developed the Stress Continuum model. The Stress Continuum is a stress classification system ("ready," "reacting," "injured," and "ill") that provides a common language for identifying, engaging, and intervening when stress reactions or stress injuries are present in military personnel. It is the foundation for resilience and prevention efforts across the Navy and Marine Corps. Although the Stress Continuum has strong face validity, is consistent with current theory, and has been agreed up by expert consensus, it has yet to be empirically validated. The goal of the current article is to begin to empirically validate the Stress Continuum using validated measures of psychological stress. MATERIALS AND METHODS: We conducted a retrospective analysis of Stress Continuum data (n = 2,049) collected as part of a program evaluation of two Navy operational stress control programs. Receiver operating characteristic (ROC) curves and analyses were conducted to determine the classification quality of the Stress Continuum using a validated measure of stress (a brief version of the Perceived Stress Scale [PSS-4]). RESULTS: For the first ROC curve, we used the "ill" category (vs. the other three categories) to identify the cut point on the PSS-4. PSS-4 cut point values of 9 and 10, respectively, maximized sensitivity and 1-specificity values. Using the chi-square test, we further found that a more accurate prediction for those in the "ill" category was using the cut point of 9 (79%) relative to 10 (71.8%). For the second and the third ROC curves, we used the "ill" and "injured" categories (vs. the other two categories) and "ill," "injured," and "reacting" categories (vs. the "ready" category), respectively. No optimal cut points on the PSS-4 were identified for these models, indicating that the PSS-4 could not reliably differentiate true-positive and false-positive rates. CONCLUSIONS: We found that the "ill" category of the Stress Continuum was predictive of higher levels of stress on the validated measure of perceived stress. Thus, our findings strongly suggest that the individuals in the "ill" zone likely warrant some type of intervention by a trained professional. FUTURE RESEARCH: The Navy has recently leveraged the Stress Continuum to create the Stress-o-Meter to support the fundamental principles of early recognition, peer intervention, and connection to services at the unit level. The Stress-o-Meter serves as a prevention tool that has the capability to collect information about stress levels throughout the entire unit at any time. Continued work on validating the Stress Continuum model and making it easily accessible to military units will ensure service members get the support they need and leaders are able to address the psychological health of their units.

Steady state of a two-species annihilation process with separated reactants.

We describe the steady state of the annihilation process of a one-dimensional system of two initially separated reactants A and B. The parameters that define the dynamical behavior of the system are the diffusion constant, the reaction rate, and the deposition rate. Depending on the ratio between those parameters, the system exhibits a crossover between a diffusion-limited (DL) regime and a reaction-limited (RL) regime. We found that a key quantity to describe the reaction process in the system is the probability p(x_{A},x_{B}) to find the rightmost A (RMA) particle and the leftmost B (LMB) particle at the positions x_{A} and x_{B}, respectively. The statistical behavior of the system in both regimes is described using the density of particles, the gap length distribution x_{B}-x_{A}, the marginal probabilities p_{A}(x_{A}) and p_{B}(x_{B}), and the reaction kernel. For both regimes, this kernel can be approximated by using p(x_{A},x_{B}). We found an excellent agreement between the numerical and analytical results for all calculated quantities despite the reaction process being quite different in both regimes. In the DL regime, the reaction kernel can be approximated by the probability to find the RMA and LMB particles in adjacent sites. In the RL regime, the kernel depends on the marginal probabilities p_{A}(x_{A}) and p_{B}(x_{B}).

Promoting resilience and psychological wellbeing of military providers: The Navy Medicine Caregiver Occupational Stress Control (CgOSC) program.

Military Medicine providers (sometimes referred to as caregivers) not only endure the stress of supporting the medical readiness of operational commands, they take on the continuous demands involved in providing direct care to military beneficiaries. Research shows that occupational stress and burnout impacts the health and wellbeing of providers, increases job turnover, and reduces the quality of patient care. Thus, interventions have aimed to reduce burnout and enhance the wellbeing of military providers. Although these efforts have shown promise, there is much room for improvement. Navy Medicine has implemented the Caregiver Occupational Stress Control (CgOSC) program at its commands, with the objectives to enhance provider wellbeing and resilience, improve retention, and ensure the quality of patient care. This article introduces the Navy Medicine CgOSC program, describes the implementation of the CgOSC program at Navy Medicine commands, and delineates how the program is tracked for program adherence. This tracking method can serve as a model for other healthcare organizations that are establishing programs that aim to promote the wellbeing of their providers.

One-particle engine with a porous piston.

We propose a variation of the classical Szilard engine that uses a porous piston. Such an engine requires neither information about the position of the particle, nor the removal and subsequent insertion of the piston when resetting the engine to continue doing work by lifting a mass against a gravitational field. Though the engine operates in contact with a single thermal reservoir, the reset mechanism acts as a second reservoir, dissipating energy when a mass that has been lifted by the engine is removed to initiate a new operation cycle.

Serglycin Is Involved in TGF-ß Induced Epithelial-Mesenchymal Transition and Is Highly Expressed by Immune Cells in Breast Cancer Tissue.

Serglycin is a proteoglycan highly expressed by immune cells, in which its functions are linked to storage, secretion, transport, and protection of chemokines, proteases, histamine, growth factors, and other bioactive molecules. In recent years, it has been demonstrated that serglycin is also expressed by several other cell types, such as endothelial cells, muscle cells, and multiple types of cancer cells. Here, we show that serglycin expression is upregulated in transforming growth factor beta (TGF-ß) induced epithelial-mesenchymal transition (EMT). Functional studies provide evidence that serglycin plays an important role in the regulation of the transition between the epithelial and mesenchymal phenotypes, and it is a significant EMT marker gene. We further find that serglycin is more expressed by breast cancer cell lines with a mesenchymal phenotype as well as the basal-like subtype of breast cancers. By examining immune staining and single cell sequencing data of breast cancer tissue, we show that serglycin is highly expressed by infiltrating immune cells in breast tumor tissue.

Monte Carlo simulations of two-component Coulomb gases applied in surface electrodes.

In this work, we study the gapped surface electrode (SE), a planar system composed of two-conductor flat regions at different potentials with a gapGbetween both sheets. The computation of the electric field and the surface charge density requires solving Laplace's equation subjected to Dirichlet conditions (on the electrodes) and Neumann boundary conditions over the gap. In this document, the gapless surface electrode is modeled as a two-dimensional classical Coulomb gas having punctual charges +qand -qon the inner and outer electrodes, respectively, interacting with an inverse power law 1/r-potential. The coupling parameter Γ between particles inversely depends on temperature and is proportional toq2. Precisely, the density charge arises from the equilibrium states via Monte Carlo (MC) simulations. We focus on the coupling and the gap geometry effect. Mainly on the distribution of particles in the circular and the harmonically-deformed gapped SE. MC simulations differ from electrostatics in the strong coupling regime. The electrostatic approximation and the MC simulations agree in the weak coupling regime where the system behaves as two interacting ionic fluids. That means that temperature is crucial in finite-size versions of the gapped SE where the density charge cannot be assumed fully continuous as the coupling among particles increases. Numerical comparisons are addressed against analytical descriptions based on an electric vector potential approach, finding good agreement.

Relaxation dynamics of two interacting electrical double-layers in a 1D Coulomb system.

We consider an out-of-equilibrium one-dimensional model for two electrical double-layers. With a combination of exact calculations and Brownian dynamics simulations, we compute the relaxation time (τ) for an electroneutral salt-free suspension, made up of two fixed colloids, withNneutralizing mobile counterions. ForNodd, the two double-layers never decouple, irrespective of their separationL; this is the regime of like-charge attraction, whereτexhibits a diffusive scaling inL2for largeL. On the other hand, for evenN,Lno longer is the relevant length scale for setting the relaxation time; this role is played by the Bjerrum length. This leads to distinctly different dynamics: forNeven, thermal effects are detrimental to relaxation, increasingτ, while they accelerate relaxation forNodd. Finally, we also show that the mean-field theory is recovered for largeNand moreover, that it remains an operational treatment down to relatively small values ofN(N> 3).

Epicatechin treatment generates resilience to chronic mild stress-induced depression in a murine model.

Several studies have proposed that cocoa products-enriched in flavonoids reduce anxiety and depressive symptoms. (-)-Epicatechin (Epi), a flavonoid present in high concentration in cocoa, has been associated with many dark chocolate effects and has been postulated as an exercise mimetic. Physical exercise is used as an adjuvant treatment for many depressive patients. This study aimed to evaluate the impact of Epi on resilience in depression-like behavior in a murine model. Male mice were randomly selected and divided into four groups (n = 8/group). Beginning at the age of 8-9 weeks, the mice were subjected to Chronic Mild Stress (CMS) and/or treatment Epi for five weeks. Epi was administered by oral gavage twice daily/5 weeks. The control group was housed in conditions without stress and Epi treatment. Depressive behavior was evaluated by sucrose preference and open field tests. Interestingly, Epi reduced anhedonia and anxiogenic behavior in the murine stress model. These results suggest that Epi induces resilience to stress-induced depression. Furthermore, our findings propose that muscles respond to Epi treatment according to their type of metabolism and that kynurenine aminotransferases (KATs) could play a role in modulating this response.

One-dimensional colloidal model with dielectric inhomogeneity.

We consider a one-dimensional model allowing analytical derivation of the effective interactions between two charged colloids. We evaluate exactly the partition function for an electroneutral salt-free suspension with dielectric jumps at the colloids' position. We derive a contact relation with the pressure that shows there is like-charge attraction, whether or not the counterions are confined between the colloids. In contrast to the homogeneous dielectric case, there is the possibility for the colloids to attract despite the number of counterions (N) being even. The results are shown to recover the mean-field prediction in the limit N→∞.

Current Status of Circulating Tumor Cells, Circulating Tumor DNA, and Exosomes in Breast Cancer Liquid Biopsies.

Breast cancer is the most common cancer among women worldwide. Although the five-, ten- and fifteen-year survival rates are good for breast cancer patients diagnosed with early-stage disease, some cancers recur many years after completion of primary therapy. Tumor heterogeneity and clonal evolution may lead to distant metastasis and therapy resistance, which are the main causes of breast cancer-associated deaths. In the clinic today, imaging techniques like mammography and tissue biopsies are used to diagnose breast cancer. Even though these methods are important in primary diagnosis, they have limitations when it comes to longitudinal monitoring of residual disease after treatment, disease progression, therapy responses, and disease recurrence. Over the last few years, there has been an increasing interest in the diagnostic, prognostic, and predictive potential of circulating cancer-derived material acquired through liquid biopsies in breast cancer. Thanks to the development of sensitive devices and platforms, a variety of tumor-derived material, including circulating cancer cells (CTCs), circulating DNA (ctDNA), and biomolecules encapsulated in extracellular vesicles, can now be extracted and analyzed from body fluids. Here we will review the most recent studies on breast cancer, demonstrating the clinical potential and utility of CTCs and ctDNA. We will also review literature illustrating the potential of circulating exosomal RNA and proteins as future biomarkers in breast cancer. Finally, we will discuss some of the advantages and limitations of liquid biopsies and the future perspectives of this field in breast cancer management.

Work done on a single-particle gas during an adiabatic compression and expansion process.

We compute the average work done by an external agent, driving a piston at constant speed, over a single-particle gas going through an adiabatic compression and expansion process. To do so, we get the analytical expression relating the number of collisions between the piston and the particle with the position of the piston during the process. The ergodicity breaking of the system during the process is identified as the source of its irreversibility. In addition, we observe that by using particular initial distributions for the state of the particle, it is possible to preclude the possibility of a net energy transfer from the agent to the particle during the process.

Free energy of cylindrical polyions: Analytical results.

Within the Poisson-Boltzmann (PB) framework useful for a wealth of charged soft matter problems, we work out the Coulombic grand potential of a long cylindrical charged polyion in a binary electrolyte solution of arbitrary valency and for low salt concentration. We obtain the exact analytical low-salt asymptotic expression for the grand potential, derived from the known properties of the exact solutions to the cylindrical PB equation. These results are relevant for understanding nucleic acid processes. In practice, our expressions are accurate for arbitrary polyion charges, provided their radius is smaller than the Debye length defined by the electrolyte.

Circulating Tumor Cells as a Tool for Assessing Tumor Heterogeneity.

Tumor heterogeneity is the major cause of failure in cancer prognosis and prediction. Accurately detecting heterogeneity for the development of biomarkers and the detection of the clones resistant to therapy is one of the main goals of contemporary medicine. Metastases belong to the natural history of cancer. The present review gives an overview on the origin of tumor heterogeneity. Recent progress has made it possible to isolate and characterize circulating tumor cells (CTCs), which are the drivers of the disease between the primary sites and metastatic foci. The most recent methods for characterizing CTCs are summarized and we discuss the power of CTC profiling for analyzing tumor heterogeneity in early and advanced diseases.

The combined use of EFS, GPX2, and SPRR1A expression could distinguish favorable from poor clinical outcome among epithelial-like head and neck carcinoma subtypes.

BACKGROUND: We aimed at identifying molecular markers predictive of clinical outcome in patients with head and neck cancer based on the expression profile of cells showing epithelial-like (EL) or mesenchymal-like (ML) phenotypes. MATERIALS AND METHODS: We analyzed the association between EL and ML cells and migration, drug resistance, or tumor growth. The differential gene expression profile between cell types was used to build a model to stratify patients according to survival. RESULTS: EL cells were sensitive to cisplatin and cetuximab, showed low migration, and generated squamous differentiated tumors in mouse. A differential 93-gene expression signature between ML and EL cells was used to build a three-gene (EFS, GPX2, and SPRR1A) survival model by analyzing the RNA-seq data of the TCGA-HNSC project. Its prognostic value was confirmed in two independent cohorts. CONCLUSION: EFS, GPX2, and SPRR1A are prognostic markers able to distinguish clinical outcome among subtypes sharing an EL phenotype.

Exosomal lncRNAs: the newest promising liquid biopsy.

LncRNAs are defined as RNA transcripts greater than 200 nucleotides in length that have no or limited protein-coding potential. Basal expression of lncRNAs appeared important for various homeostatic processes, like gene imprinting cell differentiation and organogenesis. Moreover, it has been demonstrated that lncRNAs play an important role in tumorigenesis and metastasis. Some lncRNAs were stably detected in exosomes, which are widely found in body fluids. Several studies validated the use of exosomal lncRNAs as minimally invasive diagnostic and prognostic markers in several types of cancers. In addition, exosomal lncRNAs have been associated with drug resistance of tumor cells, suggesting a clinical application in cancer-targeted therapy. Despite the recent increase of studies on exosomal lncRNAs, their clinical significance in cancer diagnosis, prognosis and treatment needs to be fully explored. The methodologies for their detection with high purity and accuracy must be also improved in order to implement their use in clinical routine. This review aims to summarize the main recent technologies available for the isolation of exosomal lncRNAs, their status as a liquid biopsy as well as their future perspectives.

Characterization of circulating tumor cells as a reflection of the tumor heterogeneity: myth or reality?

The current main goal of diagnostic medicine is to detect crucial events in 'infinitely' small samples. The key question now is how to determine whether the rare cell events isolated and characterized from these samples reliably reflect the disease and heterogeneity of the tumor. In this review, we provide a short overview of the most recent methods developed for the isolation and characterization of rare cell events in clinical practice, with a specific focus on circulating tumor cells. We discuss the biological value to studying these cells at the single cell level and how these rare cell events can reflect tumor heterogeneity. The potential biomedical applications are also critically discussed in light of precision medicine.

Circulating Tumor Cell-Derived Pre-Clinical Models for Personalized Medicine.

The main cause of death from cancer is associated with the development of metastases, resulting from the inability of current therapies to cure patients at metastatic stages. Generating preclinical models to better characterize the evolution of the disease is thus of utmost importance, in order to implement effective new cancer biomarkers and therapies. Circulating Tumor Cells (CTCs) are good candidates for generating preclinical models, making it possible to follow up the spatial and temporal heterogeneity of tumor tissues. This method is a non-invasive liquid biopsy that can be obtained at any stage of the disease. It partially summarizes the molecular heterogeneity of the corresponding tumors at a given time. Here, we discuss the CTC-derived models that have been generated so far, from simplified 2D cultures to the most complex CTC-derived explants (CDX models). We highlight the challenges and strengths of these preclinical tools, as well as some of the recent studies published using these models.

Isolation of circulating tumor cells in a preclinical model of osteosarcoma: Effect of chemotherapy.

Osteosarcoma is a rare primary bone tumor, which mainly affects children and adolescents and has a poor prognosis, especially for patients with metastatic disease. A poor therapeutic response to the conventional chemotherapy is observed with the development of lung metastases, highlighting the need for improving the current regimens and the identification of early markers of the recurrent and metastatic disease. Circulating Tumour Cells (CTCs) play a key role in the metastatic process and could be powerful biomarkers of the progressive disease. The present study aimed to isolate CTCs by using a pre-clinical model of human osteosarcoma and to monitor their kinetic of release and their modulation by ifosfamide. CTCs were detectable into the bloodstream before any palpable primary tumors. Ifosfamide increased CTCs count and in contrast decreased the number of lung tumor nodules. On established tumors, ifosfamide slowed down the tumour growth and did not modulate CTC count that could be explained by a release of cancer cells from the primary tumour with reduced properties for inducing lung metastases. This report highlights the biological interest of CTCs in osteosarcoma.

Circulating Tumor Cells: The Importance of Single Cell Analysis.

Cancer cells that have shed from the primary tumor are able to invade into surrounding tissues, to intravasate into the bloodstream to become circulating tumor cells (CTCs), at least one part of that cells will be able to generate distant metastases. The discovery of CTCs has improved the study of cancer disease as it represents a non invasive biopsy that can be used as prognostic and prediction biomarkers. Tumour heterogeneity is a concept related to differences in tumor cells within the same tumor or between tumours in terms of genetic and phenotypic profiles, such as morphology, metabolic activity, proliferation rate, migration and metastatic abilities. Characterization of heterogeneity among CTCs at the single cell level may be useful to better understand the causes and progression of disease and for an accurate selection of molecular prognostic/prediction markers. In this chapter we aimed to describe methods for CTC enrichment and isolation as well as current methodologies for single cell analysis at different levels, including RNA, DNA, protein and epigenetic events. Finally we wanted to stress clinical and biological importance of single CTC analysis by reviewing some studies carried out in different cancer subtypes.