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Aplicação de métodos de biofísica no estudo da eficácia de produtos dermocosméticos

GONÇALVES, Gisele Mara Silva; CAMPOS, Patrícia Maria Berardo Gonçalves Maia
Fonte: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
258.43016%
O trabalho aborda a aplicação dos métodos de biofísica no estudo de eficácia de produtos dermocosméticos. A qualidade de um produto cosmético engloba a segurança de seu uso, a estabilidade da formulação, o aspecto, o sensorial e a sua eficácia. As técnicas de biofísica têm sido amplamente empregadas na avaliação do efeito de formulações dermocosméticas, principalmente devido ao fato de possibilitarem a avaliação de produtos em suas reais condições de uso, ou seja, na pele humana. A comprovação dos efeitos de produtos cosméticos e a elucidação de seu mecanismo de ação por meio de protocolos experimentais devidamente elaborados, que utilizem as técnicas de biofísica da pele, dentre outras, tornam-se de fundamental importância e, assim, a serem amplamente exploradas e ainda bastante desenvolvidas, visando à melhoria da qualidade de vida dos usuários de tais produtos.; The authors consider the application of biophysical techniques in the study of cosmetics effectiveness. The quality of a cosmetic product includes the safety of its use, the formulation stability , the visual and other sensorial aspects, and its effectiveness. The biophysical techniques have been widely used in the evaluation of the effect of formulations of topical use...

Teaching biophysics. Strategies for recruiting and retaining minorities in physics and biophysics.

Tanaka, J C; Gladney, L D
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1993 EN
Relevância na Pesquisa
254.25656%
Several strategies directed toward increasing the participation of minority students in physics and biophysics are presented. Since the number of minority students entering college with an interest in science and mathematics must be increased if we expect to see more students graduating in science, several programs aimed at increasing the level of instruction of physics and biology in urban middle schools and high schools are outlined. We also describe approaches designed to increase the retention of science major during the freshman core physics course where many potential science majors are lost. Increasing the number of minority students at the PhD level will rely increasingly on partnerships between research universities and historically black colleges and universities (HBCUs) and several programs already in effect are given as examples of such linkages.

Program Review Challenges and Opportunities for Training the Next Generation of Biophysicists: Perspectives of the Directors of the Molecular Biophysics Training Program at Northwestern University

Neuhaus, Francis; Widom, Jonathan; MacDonald, Robert; Jardetzky, Theodore; Radhakrishnan, Ishwar
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/2008 EN
Relevância na Pesquisa
258.43016%
Molecular biophysics is a broad, diverse, and dynamic field that has presented a variety of unique challenges and opportunities for training future generations of investigators. Having been or currently being intimately associated with the Molecular Biophysics Training Program at Northwestern, we present our perspectives on various issues that we have encountered over the years. We propose no cookie-cutter solutions, as there is no consensus on what constitutes the “ideal” program. However, there is uniformity in opinion on some key issues that might be useful to those interested in establishing a biophysics training program.

New horizons in Biophysics

Moylan, Elizabeth C
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 02/03/2011 EN
Relevância na Pesquisa
258.43016%
This editorial celebrates the re-launch of PMC Biophysics previously published by PhysMath Central, in its new format as BMC Biophysics published by BioMed Central with an expanded scope and Editorial Board. BMC Biophysics will fill its own niche in the BMC series alongside complementary companion journals including BMC Bioinformatics, BMC Medical Physics, BMC Structural Biology and BMC Systems Biology.

Biophysics and systems biology

Noble, Denis
Fonte: The Royal Society Publishing Publicador: The Royal Society Publishing
Tipo: Artigo de Revista Científica
Publicado em 13/03/2010 EN
Relevância na Pesquisa
254.25656%
Biophysics at the systems level, as distinct from molecular biophysics, acquired its most famous paradigm in the work of Hodgkin and Huxley, who integrated their equations for the nerve impulse in 1952. Their approach has since been extended to other organs of the body, notably including the heart. The modern field of computational biology has expanded rapidly during the first decade of the twenty-first century and, through its contribution to what is now called systems biology, it is set to revise many of the fundamental principles of biology, including the relations between genotypes and phenotypes. Evolutionary theory, in particular, will require re-assessment. To succeed in this, computational and systems biology will need to develop the theoretical framework required to deal with multilevel interactions. While computational power is necessary, and is forthcoming, it is not sufficient. We will also require mathematical insight, perhaps of a nature we have not yet identified. This article is therefore also a challenge to mathematicians to develop such insights.

Biophysics of Cell Membrane Lipids in Cancer Drug Resistance: Implications for Drug Transport and Drug Delivery with Nanoparticles

Peetla, Chiranjeevi; Vijayaraghavalu, Sivakumar; Labhasetwar, Vinod
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
254.25656%
In this review, we focus on the biophysics of cell membrane lipids, particularly when cancers develop acquired drug resistance, and how biophysical changes in resistant cell membrane influence drug transport and nanoparticle-mediated drug delivery. Recent advances in membrane lipid research show the varied roles of lipids in regulating membrane P-glycoprotein function, membrane trafficking, apoptotic pathways, drug transport, and endocytic functions, particularly endocytosis, the primary mechanism of cellular uptake of nanoparticle-based drug delivery systems. Since acquired drug resistance alters lipid biosynthesis, understanding the role of lipids in cell membrane biophysics and its effect on drug transport is critical for developing effective therapeutic and drug delivery approaches to overcoming drug resistance. Here we discuss novel strategies for (a) modulating the biophysical properties of membrane lipids of resistant cells to facilitate drug transport and regain endocytic function and (b) developing effective nanoparticles based on their biophysical interactions with membrane lipids to enhance drug delivery and overcome drug resistance.

Statistics and Related Topics in Single-Molecule Biophysics

Qian, Hong; Kou, S. C.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
261.25742%
Since the universal acceptance of atoms and molecules as the fundamental constituents of matter in the early twentieth century, molecular physics, chemistry and molecular biology have all experienced major theoretical breakthroughs. To be able to actually “see” biological macromolecules, one at a time in action, one has to wait until the 1970s. Since then the field of single-molecule biophysics has witnessed extensive growth both in experiments and theory. A distinct feature of single-molecule biophysics is that the motions and interactions of molecules and the transformation of molecular species are necessarily described in the language of stochastic processes, whether one investigates equilibrium or nonequilibrium living behavior. For laboratory measurements following a biological process, if it is sampled over time on individual participating molecules, then the analysis of experimental data naturally calls for the inference of stochastic processes. The theoretical and experimental developments of single-molecule biophysics thus present interesting questions and unique opportunity for applied statisticians and probabilists. In this article, we review some important statistical developments in connection to single-molecule biophysics...

Designing and Probing Open Quantum Systems: Quantum Annealing, Excitonic Energy Transfer, and Nonlinear Fluorescence Spectroscopy

Perdomo, Alejandro
Fonte: Harvard University Publicador: Harvard University
Tipo: Thesis or Dissertation
EN_US
Relevância na Pesquisa
254.25656%
The 20th century saw the first revolution of quantum mechanics, setting the rules for our understanding of light, matter, and their interaction. The 21st century is focused on using these quantum mechanical laws to develop technologies which allows us to solve challenging practical problems. One of the directions is the use quantum devices which promise to surpass the best computers and best known classical algorithms for solving certain tasks. Crucial to the design of realistic devices and technologies is to account for the open nature of quantum systems and to cope with their interactions with the environment. In the first part of this dissertation, we show how to tackle classical optimization problems of interest in the physical sciences within one of these quantum computing paradigms, known as quantum annealing (QA). We present the largest implementation of QA on a biophysical problem (six different experiments with up to 81 superconducting quantum bits). Although the cases presented here can be solved on a classical computer, we present the first implementation of lattice protein folding on a quantum device under the Miyazawa-Jernigan model. This is the first step towards studying optimization problems in biophysics and statistical mechanics using quantum devices. In the second part of this dissertation...

HST.121 Gastroenterology, Fall 2002; Gastroenterology

Carey, Martin C.; Schapiro, Robert; Badizadegan, Kamran; Chung, Raymond T.; Glickman, Jonathan N.
Fonte: MIT - Massachusetts Institute of Technology Publicador: MIT - Massachusetts Institute of Technology
EN-US
Relevância na Pesquisa
254.25656%
Presents the anatomy, physiology, biochemistry, biophysics, and bioengineering of the gastrointestinal tract and associated pancreatic, liver, and biliary systems. Emphasis on the molecular and pathophysiological basis of disease where known. Covers gross and microscopic pathology and clinical aspects. Formal lectures given by core faculty, with some guest lectures by local experts. Selected seminars conducted by students with supervision of faculty. Permission of instructor required. (Only HST students may register under HST.120, graded P/D/F.) From the course home page: Course Description The most recent knowledge of the anatomy, physiology, biochemistry, biophysics, and bioengineering of the gastrointestinal tract and the associated pancreatic, liver and biliary tract systems is presented and discussed. Gross and microscopic pathology and the clinical aspects of important gastroenterological diseases are then presented, with emphasis on integrating the molecular, cellular and pathophysiological aspects of the disease processes to their related symptoms and signs.

An Ethnographic Study: Becoming a Physics Expert in a Biophysics Research Group

Rodriguez, Idaykis
Fonte: SelectedWorks Publicador: SelectedWorks
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
263.29934%
Expertise in physics has been traditionally studied in cognitive science, where physics expertise is understood through the difference between novice and expert problem solving skills. The cognitive perspective of physics experts only create a partial model of physics expertise and does not take into account the development of physics experts in the natural context of research. This dissertation takes a social and cultural perspective of learning through apprenticeship to model the development of physics expertise of physics graduate students in a research group. I use a qualitative methodological approach of an ethnographic case study to observe and video record the common practices of graduate students in their biophysics weekly research group meetings. I recorded notes on observations and conduct interviews with all participants of the biophysics research group for a period of eight months. I apply the theoretical framework of Communities of Practice to distinguish the cultural norms of the group that cultivate physics expert practices. Results indicate that physics expertise is specific to a topic or subfield and it is established through effectively publishing research in the larger biophysics research community. The participant biophysics research group follows a learning trajectory for its students to contribute to research and learn to communicate their research in the larger biophysics community. In this learning trajectory students develop expert member competencies to learn to communicate their research and to learn the standards and trends of research in the larger research community. Findings from this dissertation expand the model of physics expertise beyond the cognitive realm and add the social and cultural nature of physics expertise development. This research also addresses ways to increase physics graduate student success towards their PhD. and decrease the 48% attrition rate of physics graduate students. Cultivating effective research experiences that give graduate students agency and autonomy beyond their research groups gives students the motivation to finish graduate school and establish their physics expertise.

An ethnographic study: Becoming a physics expert in a biophysics research group

Rodriguez, Idaykis
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
263.29934%
Expertise in physics has been traditionally studied in cognitive science, where physics expertise is understood through the difference between novice and expert problem solving skills. The cognitive perspective of physics experts only create a partial model of physics expertise and does not take into account the development of physics experts in the natural context of research. This dissertation takes a social and cultural perspective of learning through apprenticeship to model the development of physics expertise of physics graduate students in a research group. I use a qualitative methodological approach of an ethnographic case study to observe and video record the common practices of graduate students in their biophysics weekly research group meetings. I recorded notes on observations and conduct interviews with all participants of the biophysics research group for a period of eight months. I apply the theoretical framework of Communities of Practice to distinguish the cultural norms of the group that cultivate physics expert practices. Results indicate that physics expertise is specific to a topic or subfield and it is established through effectively publishing research in the larger biophysics research community. The participant biophysics research group follows a learning trajectory for its students to contribute to research and learn to communicate their research in the larger biophysics community. In this learning trajectory students develop expert member competencies to learn to communicate their research and to learn the standards and trends of research in the larger research community. Findings from this dissertation expand the model of physics expertise beyond the cognitive realm and add the social and cultural nature of physics expertise development. This research also addresses ways to increase physics graduate student success towards their PhD. and decrease the 48% attrition rate of physics graduate students. Cultivating effective research experiences that give graduate students agency and autonomy beyond their research groups gives students the motivation to finish graduate school and establish their physics expertise.^

An Ethnographic Study: Becoming a Physics Expert in a Biophysics Research Group

Rodriguez, Idaykis
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
263.29934%
Expertise in physics has been traditionally studied in cognitive science, where physics expertise is understood through the difference between novice and expert problem solving skills. The cognitive perspective of physics experts only create a partial model of physics expertise and does not take into account the development of physics experts in the natural context of research. This dissertation takes a social and cultural perspective of learning through apprenticeship to model the development of physics expertise of physics graduate students in a research group. I use a qualitative methodological approach of an ethnographic case study to observe and video record the common practices of graduate students in their biophysics weekly research group meetings. I recorded notes on observations and conduct interviews with all participants of the biophysics research group for a period of eight months. I apply the theoretical framework of Communities of Practice to distinguish the cultural norms of the group that cultivate physics expert practices. Results indicate that physics expertise is specific to a topic or subfield and it is established through effectively publishing research in the larger biophysics research community. The participant biophysics research group follows a learning trajectory for its students to contribute to research and learn to communicate their research in the larger biophysics community. In this learning trajectory students develop expert member competencies to learn to communicate their research and to learn the standards and trends of research in the larger research community. Findings from this dissertation expand the model of physics expertise beyond the cognitive realm and add the social and cultural nature of physics expertise development. This research also addresses ways to increase physics graduate student success towards their PhD. and decrease the 48% attrition rate of physics graduate students. Cultivating effective research experiences that give graduate students agency and autonomy beyond their research groups gives students the motivation to finish graduate school and establish their physics expertise.

The biophysics of intracellular transport driven by structurally-defined systems of motor proteins

Jamison, Kenneth
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
354.25656%
The number of motor proteins attached to cellular cargos is widely believed to influence intracellular transport processes and may play a role in transport regulation. However, to date, investigating the biophysics of multiple-motor dynamics has been challenging since the number of motors responsible for cargo motion is not easily characterized. This work examines the transport properties of structurally-defined motor complexes containing two kinesin-1 motors, from both an experimental and theoretical perspective. Motor complexes were synthesized using DNA as a molecular scaffold and engineered DNA-conjugated protein polymers as linkers to couple motors to scaffolds. After anchoring the motor complexes to a bead their dynamic properties were measured using an automated optical trapping instrument that could be used to perform both static (increasing load) and force-feedback (constant load) optical trapping experiments. Data from these experiments is compared to predictions from a microscopic transition rate model of multiple kinesin dynamics. Together, these studies uncovered that multiple kinesins typically cannot cooperate since the microtubule-bound configuration of a motor complex often prevents both kinesins from sharing cargo loads. Furthermore...

Biophysics of protein evolution and evolutionary protein biophysics

Sikosek, Tobias; Chan, Hue Sun
Fonte: The Royal Society Publicador: The Royal Society
Tipo: Artigo de Revista Científica
Publicado em 06/11/2014 EN
Relevância na Pesquisa
258.43016%
The study of molecular evolution at the level of protein-coding genes often entails comparing large datasets of sequences to infer their evolutionary relationships. Despite the importance of a protein's structure and conformational dynamics to its function and thus its fitness, common phylogenetic methods embody minimal biophysical knowledge of proteins. To underscore the biophysical constraints on natural selection, we survey effects of protein mutations, highlighting the physical basis for marginal stability of natural globular proteins and how requirement for kinetic stability and avoidance of misfolding and misinteractions might have affected protein evolution. The biophysical underpinnings of these effects have been addressed by models with an explicit coarse-grained spatial representation of the polypeptide chain. Sequence–structure mappings based on such models are powerful conceptual tools that rationalize mutational robustness, evolvability, epistasis, promiscuous function performed by ‘hidden’ conformational states, resolution of adaptive conflicts and conformational switches in the evolution from one protein fold to another. Recently, protein biophysics has been applied to derive more accurate evolutionary accounts of sequence data. Methods have also been developed to exploit sequence-based evolutionary information to predict biophysical behaviours of proteins. The success of these approaches demonstrates a deep synergy between the fields of protein biophysics and protein evolution.

Role of membrane biophysics in Alzheimer's–related cell pathways

Zhu, Donghui; Bungart, Brittani L.; Yang, Xiaoguang; Zhumadilov, Zhaxybay; Lee, James C-M.; Askarova, Sholpan
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 27/05/2015 EN
Relevância na Pesquisa
254.25656%
Cellular membrane alterations are commonly observed in many diseases, including Alzheimer's disease (AD). Membrane biophysical properties, such as membrane molecular order, membrane fluidity, organization of lipid rafts, and adhesion between membrane and cytoskeleton, play an important role in various cellular activities and functions. While membrane biophysics impacts a broad range of cellular pathways, this review addresses the role of membrane biophysics in amyloid-β peptide aggregation, Aβ-induced oxidative pathways, amyloid precursor protein processing, and cerebral endothelial functions in AD. Understanding the mechanism(s) underlying the effects of cell membrane properties on cellular processes should shed light on the development of new preventive and therapeutic strategies for this devastating disease.

Introducing interdisciplinary science to second year undergraduates in a Current Topics in Biophysics course

Jerzak, Stanislaw; Lew, Roger R.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/04/2015
Relevância na Pesquisa
258.43016%
We offer second year students the opportunity to explore Current Topics in Biophysics in a course co-taught by a physicist and a biologist. The interdisciplinary course allows university students to engage in analytical thinking that integrates physics and biology. The students are either biophysics majors (50%) or from a diversity of science majors (about 30% life sciences). All will have taken first year courses in biology, physics and mathematics. The course is divided into: 1) The application of physical approaches to biological problems using case studies (how high can a tree grow? and biological pumps are two examples); 2) An introduction to physics concepts for which potential applications are explored (biophotonics and its application in fluorescence microscopy and photodynamic therapy is one example); and 3) Presentations from industry and university researchers who describe careers, research and clinical applications of biophysics. Over the six years the course has been offered, students have achieved a B average independent of declared major. In course evaluations, students expressed a high level of satisfaction the course overall (91% were positive). However, students expressed reservations about the open-ended nature of assignments and test questions that approach biological problems using an analytical framework grounded in physics -the real challenge when implementing an open-ended problem solving approach to pedagogy.

"The Physics of Life," an undergraduate general education biophysics course

Parthasarathy, Raghuveer
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 01/10/2014
Relevância na Pesquisa
258.43016%
Improving the scientific literacy of non-scientists is an important goal, both because of the ever-increasing impact of science and technology on our lives, and because understanding science enriches our experience of the natural world. One route to improving scientific literacy is via general education undergraduate courses -- i.e. courses intended for students not majoring in the sciences or engineering -- which in many cases provide these students' last formal exposure to science. I describe here a course on biophysics for non-science-major undergraduates recently developed at the University of Oregon (Eugene, OR, USA). Biophysics, I claim, is a particularly useful vehicle for addressing scientific literacy. It involves important and general scientific concepts, demonstrates connections between basic science and tangible, familiar phenomena related to health and disease, and illustrates that scientific insights develop by applying tools and perspectives from disparate fields in creative ways. In addition, biophysics highlights the far-reaching impact of physics research. I describe the general design of this course, which spans both macroscopic and microscopic topics, and the specific content of a few of its modules. I also describe evidence-based pedagogical approaches adopted in teaching the course...

The Principle of Stationary Action in Biophysics: Stability in Protein Folding

Simmons, Walter; Weiner, Joel L.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
254.25656%
Processes that proceed reliably from a variety of initial conditions to a unique final form, regardless of moderately changing conditions, are of obvious importance in biophysics. Protein folding is a case in point. We show that the action principle can be applied directly to study the stability of biological processes. The action principle in classical physics starts with the first variation of the action and leads immediately to the equations of motion. The second variation of the action leads in a natural way to powerful theorems that provide quantitative treatment of stability and focusing and also explain how some very complex processes can behave as though some seemingly important forces drop out. We first apply these ideas to the non-equilibrium states involved in two-state folding. We treat torsional waves and use the action principle to talk about critical points in the dynamics. For some proteins the theory resembles TST. We reach several quantitative and qualitative conclusions. Besides giving an explanation of why TST often works in folding, we find that the apparent smoothness of the energy funnel is a natural consequence of the putative critical points in the dynamics. These ideas also explain why biological proteins fold to unique states and random polymers do not. The insensitivity to perturbations which follows from the presence of critical points explains how folding to a unique shape occurs in the presence of dilute denaturing agents in spite of the fact that those agents disrupt the folded structure of the native state. This paper contributes to the theoretical armamentarium by directing attention to the logical progression from first physical principles to the stability theorems related to catastrophe theory as applied to folding. This can potentially have the same success in biophysics as it has enjoyed in optics.; Comment: 35 pages

Biophysics software for interdisciplinary education and research

Deutsch, J. M.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 02/03/2013
Relevância na Pesquisa
258.43016%
Biophysics is a subject that is spread over many disciplines and transcends the skills and knowledge of the individual student. This makes it challenging both to teach and to learn. Educational materials are described to aid in teaching undergraduates biophysics in an interdisciplinary manner. Projects have been devised on topics that range from x-ray diffraction to the Hodgkin Huxley equations. They are team-based and encourage collaboration. The projects make extensive use of software written in Python/Scipy which can be modified to explore a large range of possible phenomena. The software can also be used in lectures and in the teaching of more traditional biophysics courses.; Comment: 22 pages, 13 figures

Aplicação de métodos de biofísica no estudo da eficácia de produtos dermocosméticos

Gonçalves, Gisele Mara Silva; Campos, Patrícia Maria Berardo Gonçalves Maia
Fonte: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/03/2009 POR
Relevância na Pesquisa
254.25656%
O trabalho aborda a aplicação dos métodos de biofísica no estudo de eficácia de produtos dermocosméticos. A qualidade de um produto cosmético engloba a segurança de seu uso, a estabilidade da formulação, o aspecto, o sensorial e a sua eficácia. As técnicas de biofísica têm sido amplamente empregadas na avaliação do efeito de formulações dermocosméticas, principalmente devido ao fato de possibilitarem a avaliação de produtos em suas reais condições de uso, ou seja, na pele humana. A comprovação dos efeitos de produtos cosméticos e a elucidação de seu mecanismo de ação por meio de protocolos experimentais devidamente elaborados, que utilizem as técnicas de biofísica da pele, dentre outras, tornam-se de fundamental importância e, assim, a serem amplamente exploradas e ainda bastante desenvolvidas, visando à melhoria da qualidade de vida dos usuários de tais produtos.; The authors consider the application of biophysical techniques in the study of cosmetics effectiveness. The quality of a cosmetic product includes the safety of its use, the formulation stability , the visual and other sensorial aspects, and its effectiveness. The biophysical techniques have been widely used in the evaluation of the effect of formulations of topical use...