A method for volume stabilization of single, dye-doped water microdroplets with femtoliter resolution

A self-control mechanism that stabilizes the size of Rhodamine B-doped water microdroplets standing on a superhydrophobic surface is demonstrated. The mechanism relies on the interplay between the condensation rate that was kept constant and evaporation rate induced by laser excitation which critically depends on the size of the microdroplets. The radii of individual water microdroplets (>5 um) stayed within a few nanometers during long time periods (up to 455 seconds). By blocking the laser excitation for 500 msec, the stable volume of individual microdroplets was shown to change stepwise.Comment: to appear in the J. Op. Soc. Am.

Transcription-replication conflicts: How they occur and how they are resolved

The frequent occurrence of transcription and DNA replication in cells results in many encounters, and thus conflicts, between the transcription and replication machineries. These conflicts constitute a major intrinsic source of genome instability, which is a hallmark of cancer cells. How the replication machinery progresses along a DNA molecule occupied by an RNA polymerase is an old question. Here we review recent data on the biological relevance of transcription-replication conflicts, and the factors and mechanisms that are involved in either preventing or resolving them, mainly in eukaryotes. On the basis of these data, we provide our current view of how transcription can generate obstacles to replication, including torsional stress and non-B DNA structures, and of the different cellular processes that have evolved to solve them

XRN2 Links Transcription Termination to DNA Damage and Replication Stress

We thank the Proteomics Core Facility. We thank Dr. Robert J. Crouch for providing us with GFP- and GFP-RNase H expression plasmids. We also thank Dr. Stephen H. Leppla for providing us with antibodies directed against RNA:DNA hybrids (R loops) (S9.6). We thank Novus Biologicals for generously providing XRN2 and Rrp45 antibodies. We also thank the members of the Boothman lab for critical reading of this manuscript.Author Summary Genomic instability is one of the primary causes of disease states, in particular cancer. One major cause of genomic instability is the formation of DNA double strand breaks (DSBs), which are one of the most dangerous types of DNA lesions the cell can encounter. If not repaired in a timely manner, one DSB can lead not only to cell death. If misrepaired, one DSB can lead to a hazardous chromosomal aberration, such as a translocation, that can eventually lead to cancer. The cell encounters and repairs DSBs that arise from naturally occurring cellular processes on a daily basis. A number of studies have demonstrated that aberrant structures that form during transcription under certain circumstances, in particular RNA:DNA hybrids (R loops), can lead to DSB formation and genomic instability, especially during DNA synthesis. Thus, it is important to understand how the cell responds and repairs transcription-mediated DNA damage in general and R loop-related DNA damage in particular. This paper both demonstrates that the XRN transcription termination factor links transcription and DNA damage, but also provides a better understanding of how the cell prevents transcription-related DNA damage.Yeshttp://www.plosgenetics.org/static/editorial#pee

The effect of nanoparticles on the surface hydrophobicity of polystyrene

The surface hydrophobicity of polystyrene-nanoparticle nanocomposites has been investigated as a function of the nanoparticle content. The addition of hydrophobically coated nanoparticles in polystyrene increased the contact angle θ of a water drop with respect to that on polystyrene surface due to change of surface composition and/or surface roughness. When the nanoparticles dispersed well in the polymer, $\cos\theta$ decreased linearly with increasing amount of nanoparticles indicating a composite surface consisting of smooth polystyrene regions and rough nanoparticle regions. In case of formation of nanoparticle aggregates in polystyrene, $\cos\theta$ decreased sharply at a critical concentration of nanoparticles. The observed behaviour was modeled in terms of a transition from Wenzel regime to Cassie-Baxter regime at a critical roughness length scale below which the Laplace pressure prevented the penetration of the water drop into the surface undulations. We argue that multiple length scales are needed below the critical roughness length scale to increase the contact angle further by decreasing the fraction of surface area of solid material (increasing the fraction of surface area of air) underlying the water drop

Can hematological and biochemical parameters fasten the diagnosis of COVID-19 in emergency departments?

INTRODUCTION: The primary aim of the study was to compare the laboratory and radiological parameters of COVID-19 positive and negative patients confirmed by Real-Time Reverse Transcription Polymerase Chain Reaction (RT-PCR), and Chest Computed Tomography (CCT) of patients admitting with the suspicion of COVID-19. The secondary purpose of the study was to find objective parameters to speed up the clinician for further examination, treatment or referral decision in COVID-19 suspicion. MATERIAL AND METHODS: A total of 61 COVID-19 suspected patients were evaluated in the study. Swab samples were taken for RT-PCR analysis. CCT was taken for 42 patients who described dyspnea. According to CCT and RT-PCR results, the patient population was divided into 2 groups as COVID-19 positive group (n = 32); and COVID-19 negative group (n = 29). Between two groups; demographic, clinical, laboratory and radiological parameters were compared. RESULTS: Male gender (p = 0.03), PLR value (p = 0.021) and CO-RADS scores were higher in the COVID-19 positive group. Oxygen saturation (SaO2) (p = 0.027) and PCT, WBC, Neutrophil count, Lymphocyte count values were significantly low in COVID-19 positive group (p = 0.03, p = 0.001, p = 0.017, p = 0.021, respectively). PLR showed a positive correlation with fever, CRP, neutrophil count and NLR, which are indicators of inflammation. CONCLUSIONS: SaO2, WBC, lymphocyte count, neutrophil count and low PCT levels, and PLR elevation showed a significant difference in COVID-19 patients in our retrospective cohort study examining the Turkish population. We believe that these results will allow clinicians to make quick decisions in patient management more simply. Copyright © 2020 Via Medic

Os direitos fundamentais sociais, "reserva do poss?vel" e proporcionaliade : desafios ? concretiza??o da constitu???o do estado democr?tico e social brasileiro

Made available in DSpace on 2015-04-14T14:33:27Z (GMT). No. of bitstreams: 1 410459.pdf: 178311 bytes, checksum: f68a22a8a59baed25edcad3031404b94 (MD5) Previous issue date: 2008-12-22Esta pesquisa investiga os direitos fundamentais sociais a partir de uma breve an?lise da sua perspectiva hist?rica e passa a desenvolver suas caracter?sticas frente aos limites e restri??es que buscam harmonizar a concretiza??o daqueles direitos. Iniciaremos pelo estudo da evolu??o hist?rica dos direitos fundamentais sociais, verificando que o fen?meno da transi??o do Estado Liberal para o Estado Democr?tico de Direito serviu de base estruturante para uma prote??o dos direitos fundamentais sociais que fosse mais efetiva. Neste contexto, a estrutura normativa destes direitos, em sua dupla dimens?o de princ?pios e regras, permite abordar com maior amplitude e desenvoltura algumas formas de harmoniza??o no exerc?cio dos direitos fundamentais, bem como n?o restringe, de plano, o ?mbito de prote??o normativo, mas remete ao aplicador do direito a tarefa de identificar, caso a caso, estes limites, sempre com respaldo constitucional. Os limites dos direitos fundamentais ser?o estudados conforme as teorias externa e interna, buscando suas vincula??es com o tema da reserva do poss?vel, com o princ?pio da proporcionalidade e com a prote??o do m?nimo existencial como um limite material a qualquer forma de restri??o, pugnando pela ado??o da teoria externa das restri??es como a constitucionalmente adequada para o sistema jur?dico brasileiro. A reserva do poss?vel ser? estudada como um elemento externo ao conte?do dos direitos fundamentais sociais, sendo que a proporcionalidade exercer? um importante papel no desenvolvimento do conte?do de ambos, especialmente atrav?s da correta aplica??o de seus tr?s elementos operativos. Com isto, defenderemos que o Judici?rio tem compet?ncia e legitimidade democr?tica para decidir casos acerca da prote??o e promo??o dos direitos fundamentais sociais, mesmo que tais decis?es venham a revelar algum conte?do pol?tico, pois a prote??o daqueles direitos significa, acima de tudo, a prote??o do ser humano na m?xima extens?o de sua dignidad

A 3-D look into the atmosphere?

The atmospheres of chemically peculiar stars can be highly structured in both the horizontal and vertical dimensions. While most prevalent in the magnetic stars, these structures can also exist in non-magnetic stars. In addition to providing an important window to understanding the physical processes at play in these complex atmospheres, they can also be exploited to study stellar pulsations. This article reviews contributions to the session “A 3D look into the atmosphere” of the Joint Discussion “Progress in understanding the physics of Ap and related stars”. It is divided into 3 sections: “Magnetic field and surface structures”, “Pulsations in the atmospheres of roAp stars/inversions”, and “Spectral synthesis/atmospheric models”