Three-Dimensional Numerical Modeling of Acoustic Trapping in Glass Capillaries

Acoustic traps are used to capture and handle suspended microparticles and cells in microfluidic applications. A particular simple and much-used acoustic trap consists of a commercially available, millimeter-sized, liquid-filled glass capillary actuated by a piezoelectric transducer. Here, we present a three-dimensional numerical model of the acoustic pressure field in the liquid coupled to the displacement field of the glass wall, taking into account mixed standing and traveling waves as well as absorption. The model predicts resonance modes well suited for acoustic trapping, their frequencies and quality factors, the magnitude of the acoustic radiation force on a single test particle as a function of position, and the resulting acoustic retention force of the trap. We show that the model predictions are in agreement with published experimental results, and we discuss how improved and more stable acoustic trapping modes might be obtained using the model as a design tool.Comment: 13 pages, 15 pdf figures, pdfLatex/Revte

Nonlocal First-Order Hamilton-Jacobi Equations Modelling Dislocations Dynamics

We study nonlocal first-order equations arising in the theory of dislocations. We prove the existence and uniqueness of the solutions of these equations in the case of positive and negative velocities, under suitable regularity assumptions on the initial data and the velocity. These results are based on new $L^1$-type estimates on the viscosity solutions of first-order Hamilton-Jacobi Equations appearing in the so-called ``level-sets approach''. Our work is inspired by and simplifies a recent work of Alvarez, Cardaliaguet and Monneau

Global Existence Results and Uniqueness for Dislocation Equations

We are interested in nonlocal Eikonal Equations arising in the study of the dynamics of dislocations lines in crystals. For these nonlocal but also non monotone equations, only the existence and uniqueness of Lipschitz and local-in-time solutions were available in some particular cases. In this paper, we propose a definition of weak solutions for which we are able to prove the existence for all time. Then we discuss the uniqueness of such solutions in several situations, both in the monotone and non monotone case

Transmission of integrin β7 transmembrane domain topology enables gut lymphoid tissue development.

Integrin activation regulates adhesion, extracellular matrix assembly, and cell migration, thereby playing an indispensable role in development and in many pathological processes. A proline mutation in the central integrin β3 transmembrane domain (TMD) creates a flexible kink that uncouples the topology of the inner half of the TMD from the outer half. In this study, using leukocyte integrin α4β7, which enables development of gut-associated lymphoid tissue (GALT), we examined the biological effect of such a proline mutation and report that it impairs agonist-induced talin-mediated activation of integrin α4β7, thereby inhibiting rolling lymphocyte arrest, a key step in transmigration. Furthermore, the α4β7(L721P) mutation blocks lymphocyte homing to and development of the GALT. These studies show that impairing the ability of an integrin β TMD to transmit talin-induced TMD topology inhibits agonist-induced physiological integrin activation and biological function in development

Physician-scientists in the United States at 2020: Trends and concerns

Physician-scientists comprise a unique and valuable part of the biomedical workforce, but for decades there has been concern about the number of physicians actively engaged in research. Reports have outlined the challenges facing physician-scientists, and programs have been initiated to encourage and facilitate research careers for medically trained scientists. Many of these initiatives have demonstrated successful outcomes, but there has not been a recent summary of the impact of the past decade of effort. This report compiles available data from surveys of medical education and physician research participation to assess changes in the physician-scientist workforce from 2011-2020. Several trends are positive: rising enrollments in MD-PhD programs, greater levels of interest in research careers among matriculating medical students, more research experience during medical school and rising numbers of physicians in academic medicine, and an increase in first R01 grants to physician-scientists. However, there are now decreased levels of interest in research careers among graduating medical students, a steady decline in MDs applying for NIH loan repayment program support, an increased age at first R01 grant success for physicians, and fewer physicians reporting research as their primary work activity: all of these indicators create concern for the stability of the career path. Despite a recommendation by the Physician-Scientist Workforce in 2014 to create real-time reporting on NIH grants and grantees to help the public assess trends, this initiative has not been completed. Better information is still needed to fully understand the status of the physician-scientist workforce, and to assess efforts to stabilize this vulnerable career path

MicroRNAs and extracellular vesicles in the gut::New host modulators of the microbiome?

The gut microbiota plays an integral role in human health and its dysbiosis is associated with many chronic diseases. There are still large gaps in understanding the host and environmental factors that directly regulate the gut microbiota, and few effective strategies exist to modulate the microbiota in therapeutic applications. Recent reports suggest that certain microRNAs (miRNAs) released by mammalian cells can regulate bacterial gene expression to influence the microbiome composition and propose extracellular vesicles as one natural mechanism for miRNA transport in the gut. These new findings interface with a burgeoning body of data showing that miRNAs are present in a stable form in extracellular environments and can mediate cell-to-cell communication in mammals. Here, we review the literature on RNA-mediated modulation of the microbiome to bring cross-disciplinary perspective to this new type of interaction and its potential implications in biology and medicine

Expression profiling of snoRNAs in normal hematopoiesis and AML

Key Points A subset of snoRNAs is expressed in a developmental- and lineage-specific manner during human hematopoiesis. Neither host gene expression nor alternative splicing accounted for the observed differential expression of snoRNAs in a subset of AML.</jats:p

Molecular epidemiologic investigations of Mycoplasma gallisepticum conjunctivitis in songbirds by random amplified polymorphic DNA analyses.

An ongoing outbreak of conjunctivitis in free-ranging house finches (Carpodacus mexicanus) began in 1994 in the eastern United States. Bacterial organisms identified as Mycoplasma gallisepticum (MG) were isolated from lesions of infected birds. MG was also isolated from a blue jay (Cyanocitta cristata) that contracted conjunctivitis after being housed in a cage previously occupied by house finches with conjunctivitis, and from free-ranging American goldfinches (Carduelis tristis) in North Carolina in 1996. To investigate the molecular epidemiology of this outbreak, we produced DNA fingerprints of MG isolates by random amplification of polymorphic DNA (RAPD). We compared MG isolates from songbirds examined from 1994 through 1996 in 11 states, representing three host species, with vaccine and reference strains and with contemporary MG isolates from commercial poultry. All MG isolates from songbirds had RAPD banding patterns identical to each other but different from other strains and isolates tested. These results indicate that the outbreak of MG in songbirds is caused by the same strain, which suggests a single source; the outbreak is not caused by the vaccine or reference strains analyzed; and MG infection has not been shared between songbirds and commercial poultry

The reaction 2H(p,pp)n in three kinematical configurations at E_p = 16 MeV

We measured the cross sections of the $^2$H(p,pp)n breakup reaction at E$_p$=16 MeV in three kinematical configurations: the np final-state interaction (FSI), the co-planar star (CST), and an intermediate-star (IST) geometry. The cross sections are compared with theoretical predictions based on the CD Bonn potential alone and combined with the updated 2$\pi$-exchange Tucson-Melbourne three-nucleon force (TM99'), calculated without inclusion of the Coulomb interaction. The resulting excellent agreement between data and pure CD Bonn predictions in the FSI testifies to the smallness of three-nucleon force (3NF) effects as well as the insignificance of the Coulomb force for this particular configuration and energy. The CST also agrees well whereas the IST results show small deviations between measurements and theory seen before in the pd breakup space-star geometries which point to possible Coulomb effects. An additional comparison with EFT predictions (without 3NF) up to order N$^3$LO shows excellent agreement in the FSI case and a rather similar agreement as for CD Bonn in the CST and IST situations.Comment: 20 pages, 11 figure

Bromelain and Cardiovascular Risk Factors in Diabetes: An Exploratory Randomized, Placebo Controlled, Double Blind Clinical Trial

Objective: The objective of this trial was to assess whether the dietary supplement (bromelain) had the potential to reduce plasma fibrinogen and other Cardiovascular Disease (CVD) risk factors in patients with diabetes. Methods: This randomized placebo controlled, double blind, parallel design, efficacy study was carried out in China and investigated the effect of 12 weeks of bromelain (1.05g/day) on plasma fibrinogen . This randomized controlled trial (RCT) recruited 68 Chinese diabetic patients (32 males and 36 females; Han origin, mean age of 61.26 years (Standard Deviation, 12.62 years)) with at least one CVD risk factor. Patients were randomized into either bromelain or placebo group. While bromelain group received bromelain capsule, the placebo group received placebo capsule which consisted inert ingredient and has no treatment effect. Patients and researcher were blinded and did not know whether they received bromelain or placebo capsules. Plasma fibrinogen, CVD risk factors and anthropometric indicators were determined at baseline and at 12 weeks. Results: The change in the fibrinogen level in the placebo group at the end of the study showed a mean reduction of 0.36g/L (Standard Deviation (SD) 0.96g/L) compared with the mean reduction of 0.13g/L (SD 0.86g/L) for the bromelain group. However, there was no significant difference in the mean change in fibrinogen between the placebo and bromelain groups (mean difference=0.23g/L (SD 0.22g/L), p=0.291). Similarly, the difference in mean change in other CVD risk factors (blood lipids, blood pressure), blood glucose, C - reactive protein (CRP) and anthropometric measures between the bromelain and placebo groups was also not statistically significant. Conclusions: This RCT failed to show a beneficial effect in reducing fibrinogen or influencing other selected CVD risk factors but suggests other avenues for subsEquent research on bromelain