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Yilmaz S, Janelsins MC, Flannery M, Culakova E, Wells M, Lin PJ, Loh KP, Epstein R, Kamen C, Kleckner AS, Norton SA, Plumb S, Alberti S, Doyle K, Porto M, Weber M, Dukelow N, Magnuson A, Kehoe LA, Nightingale G, Jensen-Battaglia M, Mustian KM, Mohile SG. Protocol paper: Multi-site, cluster-randomized clinical trial for optimizing functional outcomes of older cancer survivors after chemotherapy. J Geriatr Oncol 2022; 13:892-903. [PMID: 35292232 PMCID: PMC9283231 DOI: 10.1016/j.jgo.2022.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 02/01/2022] [Accepted: 03/04/2022] [Indexed: 01/07/2023]
Abstract
BACKGROUND Cancer survivors over the age of 65 have unique needs due to the higher prevalence of functional and cognitive impairment, comorbidities, geriatric syndromes, and greater need for social support after chemotherapy. In this study, we will evaluate whether a Geriatric Evaluation and Management-Survivorship (GEMS) intervention improves functional outcomes important to older cancer survivors following chemotherapy. METHODS A cluster-randomized trial will be conducted in approximately 30 community oncology practices affiliated with the University of Rochester Cancer Center (URCC) National Cancer Institute Community Oncology Research Program (NCORP) Research Base. Participating sites will be randomized to the GEMS intervention, which includes Advanced Practice Practitioner (APP)-directed geriatric evaluation and management (GEM), and Survivorship Health Education (SHE) that is combined with Exercise for Cancer Patients (EXCAP©®), or usual care. Cancer survivors will be recruited from community oncology practices (of participating oncology physicians and APPs) after the enrolled clinicians have consented and completed a baseline survey. We will enroll 780 cancer survivors aged 65 years and older who have completed curative-intent chemotherapy for a solid tumor malignancy within four weeks of study enrollment. Cancer survivors will be asked to choose one caregiver to also participate for a total up to 780 caregivers. The primary aim is to compare the effectiveness of GEMS for improving patient-reported physical function at six months. The secondary aim is to compare effectiveness of GEMS for improving patient-reported cognitive function at six months. Tertiary aims include comparing the effectiveness of GEMS for improving: 1) Patient-reported physical function at twelve months; 2) objectively assessed physical function at six and twelve months; and 3) patient-reported cognitive function at twelve months and objectively assessed cognitive function at six and twelve months. Exploratory health care aims include: 1) Survivor satisfaction with care, 2) APP communication with primary care physicians (PCPs), 3) completion of referral appointments, and 4) hospitalizations at six and twelve months. Exploratory caregiver aims include: 1) Caregiver distress; 2) caregiver quality of life; 3) caregiver burden; and 4) satisfaction with patient care at six and twelve months. DISCUSSION If successful, GEMS would be an option for a standardized APP-led survivorship care intervention. TRIAL REGISTRATION ClinicalTrials.govNCT05006482, registered on August 9, 2021.
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Rodrigues I, Porto M, Pimenta F, Costa R. Psychological characteristics and sexual correlates of the resolution experience. J Sex Med 2022. [DOI: 10.1016/j.jsxm.2022.03.544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Caputo P, Porto M, Loise V, Abe A, Teltayev B, Calandra P, Oliviero Rossi C. How Organic Waste Improves Bitumen’s Characteristics. EURASIAN CHEMICO-TECHNOLOGICAL JOURNAL 2021. [DOI: 10.18321/ectj1106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The organic fraction derived from the differentiated collection of urban waste is mainly composed of fatty acids, medium molecular weight hydrocarbons and cellulose. This peculiar composition gave us insight into the possible use of organic waste to improve bitumen’s characteristics (possible antioxidant, regenerating and/ or viscosifying additive for road pavements). The issue of the disposal of organic waste is a global one and it’s constantly of increasing concern. This study looks to alleviate this problem by finding ways for this waste fraction to be utilized for the greater good- in this case, as an additive for bitumen binder in road pavements. The present study is focused on the use of waste as it is and waste treated by the FENTON process (treatment with ferrous sulphate and hydrogen peroxide solution). Dynamic Shear Rheology (DSR) and aging tests (Rolling Thin Film Oven Test, RTFOT) showed that two of the additives tested in this study proved effective: one can be utilised as a viscosifying agent and the other can be us ed as a filler.
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Peralta T, Pedrozo CNN, Porto M, Imperatori M, Belmonte M, Giunta G, Cuniberti L. A bioinformatic analysis of the aortic valve stenosis transcriptome reveals chances of Rosuvastatin treatment. Atherosclerosis 2021. [DOI: 10.1016/j.atherosclerosis.2021.06.798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Caputo P, Porto M, Loise V, Teltayev B, Oliviero Rossi C. Analysis of Mechanical Performance of Bitumen Modified with Waste Plastic and Rubber Additives by Rheology and Self Diffusion NMR Experiments. EURASIAN CHEMICO-TECHNOLOGICAL JOURNAL 2019. [DOI: 10.18321/ectj864] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
In this study, the mechanical and physico-chemical properties of a new kind of modified bitumen are presented. The bituminous binders have been modified in order to understand the effect on the structural properties of several compounds such as a Polymer elastomer as Styrene Butadiene Rubber (SBR), Polymer thermoplastic polypropylene (PP) and a waste plastic (Waste PP). Laboratory tests have been focused on the characterization of bitumen modified with single product and their binary combinations compared with pristine binder as a reference. Characterization has been conducted by using conventional as well as advanced methods on bitumens. Fundamental rheological tests, based on dynamic shear rheometer in the temperature range from -30 °C to +160 °C have been performed and the structure of a bitumens and modified bitumens has been analysed by the mobility of the oily maltene by self-diffusion Pulsed field gradient spin-echo (PGSE) FT-NMR experiments.
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Zaki MN, Lusk LA, Overcash RT, Rao R, Truong YN, Liebowitz M, Porto M, Porto M. Predicting birth weight in fetuses with gastroschisis. J Perinatol 2018; 38:122-126. [PMID: 29266095 DOI: 10.1038/jp.2017.171] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 07/26/2017] [Accepted: 08/29/2017] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To determine the accuracy of commonly utilized ultrasound formulas for estimating birth weight (BW) in fetuses with gastroschisis. STUDY DESIGN A retrospective review was conducted of all inborn pregnancies with gastroschisis within the five institutions of the University of California Fetal Consortium (UCfC) between 2007 and 2012. Infants delivered at ⩾28 weeks who had an ultrasound within 21 days before delivery were included. Prediction of BW was evaluated for each of the five ultrasound formulas: Hadlock 1 (abdominal circumference (AC), biparietal diameter (BPD), femur length (FL) and head circumference (HC)) and Hadlock 2 (AC, BPD and FL), Shepard (AC and BPD), Honarvar (FL) and Siemer (BPD, occipitofrontal diameter (OFD), and FL) using Pearson's correlation, mean difference and percent error and Bland-Altman analysis. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the ultrasound diagnosis of intrauterine growth restriction (IUGR) were assessed. RESULTS We identified 191 neonates born with gastroschisis within the UCfC, with 111 neonates meeting the inclusion criteria. The mean gestational age at delivery was 36.3±1.7 weeks and the mean BW was 2448±460 g. Hadlock (1) formula was found to have the best correlation (r=0.81), the lowest mean difference (8±306 g) and the lowest mean percent error (1.4±13%). The Honarvar and Siemer formulas performed significantly worse when compared with Hadlock 1, with a 13.7% (P<0.001) and 3.9% (P=0.03) difference, respectively, between estimated and actual BW. This was supported by Bland-Altman plots. For Hadlock 1 and 2, sensitivity was 80% with a NPV of 91%. CONCLUSION The widely used Hadlock (1) and (2) formulas provided the best estimated BW in infants with gastroschisis despite its inclusion of abdominal circumference. Furthermore, this formula performs well with diagnosis of IUGR.
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Celebre G, D'Urso C, Porto M. Extensive molecular field theoretical investigation of thermotropic biaxial nematics composed of board-like (D) molecules in the partially repulsive regime of orientational interactions. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.10.093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Perez S, Iñarrea A, Pérez-Tanoira R, Gil M, López-Díez E, Valenzuela O, Porto M, Alberte-Lista L, Peteiro-Cancelo MA, Treinta A, Carballo R, Reboredo MC, Alvarez-Argüelles ME, Purriños MJ. Fraction of high-grade cervical intraepithelial lesions attributable to genotypes targeted by a nonavalent HPV vaccine in Galicia, Spain. Virol J 2017; 14:214. [PMID: 29110680 PMCID: PMC5674742 DOI: 10.1186/s12985-017-0879-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 10/27/2017] [Indexed: 11/24/2022] Open
Abstract
Background Human papillomavirus (HPV) bivalent and quadrivalent vaccines have been widely implemented in worldwide organized immunization programs. A nonavalent HPV vaccine is now available in several countries. The objective was to describe the fraction of squamous non-invasive high-grade cervical intraepithelial lesions attributable to genotypes targeted by bi-quadrivalent vaccines and by nonavalent vaccine according to age and diagnosis in women living in the city of Vigo (Galicia, Spain). Methods Cervical scrapings (2009–2014) of women with histological diagnosis of cervical intraepithelial neoplasia grade 2 (CIN2, n = 145) and grade 3-carcinoma in situ (CIN3-CIS, n = 244) were tested with Linear Array HPV Genotyping test (Roche diagnostics, Mannheim, Germany). Hierarchical estimation of the fraction attributable to HPV 16/18 or HPV 31/33/45/52/58 detected alone or in combination was calculated. Absolute additional fraction attributable to genotypes targeted by nonavalent vaccine compared to genotypes targeted by bi-quadrivalent vaccines was calculated as the increment of attributable cases with respect to all studied cases. Age group 1, 2 and 3 included women 18 to 34, 35–44 and ≥45 years old, respectively. EPIDAT 3.1 was used. Results Fraction attributable to genotypes targeted by bi-quadrivalent vaccines was 59% CIN2 vs. 69% CIN3-CIS (p < 0.001). It was 63/51/50% of CIN2 and 78/66/45% of CIN3-CIS in age group 1, 2, 3, respectively. Fraction attributable to genotypes targeted by nonavalent vaccine was 86% CIN2 and 86% CIN3-CIS. It was 87/91/75% of CIN2 and 90/86/76% of CIN3-CIS in age group 1, 2, 3, respectively. Fraction attributable to genotypes targeted by these vaccines tended to decrease as age increased (p-trend <0.05). Globally, absolute additional attributable fraction was 16%, 26% and 29% in age group 1, 2 and 3, respectively (p < 0.005). Conclusions Absolute additional fraction of CIN2 and CIN3-CIS attributable to genotypes targeted by nonavalent vaccine was observed in women of any age, especially in those over 35 years old.
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Mehra A, Zahra A, Thompson V, Sirisaengtaksin N, Wells A, Porto M, Köster S, Penberthy K, Kubota Y, Dricot A, Rogan D, Vidal M, Hill DE, Bean AJ, Philips JA. Mycobacterium tuberculosis type VII secreted effector EsxH targets host ESCRT to impair trafficking. PLoS Pathog 2013; 9:e1003734. [PMID: 24204276 PMCID: PMC3814348 DOI: 10.1371/journal.ppat.1003734] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 09/12/2013] [Indexed: 11/19/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) disrupts anti-microbial pathways of macrophages, cells that normally kill bacteria. Over 40 years ago, D'Arcy Hart showed that Mtb avoids delivery to lysosomes, but the molecular mechanisms that allow Mtb to elude lysosomal degradation are poorly understood. Specialized secretion systems are often used by bacterial pathogens to translocate effectors that target the host, and Mtb encodes type VII secretion systems (TSSSs) that enable mycobacteria to secrete proteins across their complex cell envelope; however, their cellular targets are unknown. Here, we describe a systematic strategy to identify bacterial virulence factors by looking for interactions between the Mtb secretome and host proteins using a high throughput, high stringency, yeast two-hybrid (Y2H) platform. Using this approach we identified an interaction between EsxH, which is secreted by the Esx-3 TSSS, and human hepatocyte growth factor-regulated tyrosine kinase substrate (Hgs/Hrs), a component of the endosomal sorting complex required for transport (ESCRT). ESCRT has a well-described role in directing proteins destined for lysosomal degradation into intraluminal vesicles (ILVs) of multivesicular bodies (MVBs), ensuring degradation of the sorted cargo upon MVB-lysosome fusion. Here, we show that ESCRT is required to deliver Mtb to the lysosome and to restrict intracellular bacterial growth. Further, EsxH, in complex with EsxG, disrupts ESCRT function and impairs phagosome maturation. Thus, we demonstrate a role for a TSSS and the host ESCRT machinery in one of the central features of tuberculosis pathogenesis. Mycobacterium tuberculosis (Mtb) causes the disease tuberculosis, one of the world's most deadly infections. The host immune system can't eradicate Mtb because it grows within macrophages, cells that normally kill bacteria. One of the intracellular survival strategies of Mtb is to avoid delivery to lysosomes, a phenomenon described over 40 years ago, but for which the mechanism and molecular details remain incomplete. Mtb possess specialized secretion systems (Type VII secretion systems; TSSS) that transfer particular proteins out of the bacteria, but how these proteins promote infection is not well understood. In this study, we used a high stringency yeast two-hybrid system to identify interactions between secreted effectors from Mtb and human host factors. We identified ninety-nine such interactions and focused our attention on the interaction between EsxH, secreted by Esx-3, a TSSS of Mtb, and Hrs, a component of the host ESCRT machinery. We provide evidence that Mtb EsxH directly targets host Hrs to disrupt delivery of bacteria to lysosomes. Thus, this study demonstrates the role of a TSSS effector and the ESCRT machinery in what is one of the central features of tuberculosis pathogenesis, thereby providing molecular insight into why humans can't clear Mtb infection.
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Breves P, Porto M, Pissinatti A, Luz D, Menezes R. Helmintos oxiuridae parasitos de Iguana iguana (Squamata, Lacertilia, Iguanidae) procedentes do Brasil. ARQ BRAS MED VET ZOO 2011. [DOI: 10.1590/s0102-09352011000600040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Friedman AA, Tucker G, Singh R, Yan D, Vinayagam A, Hu Y, Binari R, Hong P, Sun X, Porto M, Pacifico S, Murali T, Finley RL, Asara JM, Berger B, Perrimon N. Proteomic and functional genomic landscape of receptor tyrosine kinase and ras to extracellular signal-regulated kinase signaling. Sci Signal 2011; 4:rs10. [PMID: 22028469 DOI: 10.1126/scisignal.2002029] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Characterizing the extent and logic of signaling networks is essential to understanding specificity in such physiological and pathophysiological contexts as cell fate decisions and mechanisms of oncogenesis and resistance to chemotherapy. Cell-based RNA interference (RNAi) screens enable the inference of large numbers of genes that regulate signaling pathways, but these screens cannot provide network structure directly. We describe an integrated network around the canonical receptor tyrosine kinase (RTK)-Ras-extracellular signal-regulated kinase (ERK) signaling pathway, generated by combining parallel genome-wide RNAi screens with protein-protein interaction (PPI) mapping by tandem affinity purification-mass spectrometry. We found that only a small fraction of the total number of PPI or RNAi screen hits was isolated under all conditions tested and that most of these represented the known canonical pathway components, suggesting that much of the core canonical ERK pathway is known. Because most of the newly identified regulators are likely cell type- and RTK-specific, our analysis provides a resource for understanding how output through this clinically relevant pathway is regulated in different contexts. We report in vivo roles for several of the previously unknown regulators, including CG10289 and PpV, the Drosophila orthologs of two components of the serine/threonine-protein phosphatase 6 complex; the Drosophila ortholog of TepIV, a glycophosphatidylinositol-linked protein mutated in human cancers; CG6453, a noncatalytic subunit of glucosidase II; and Rtf1, a histone methyltransferase.
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Combs C, Garite T, Porto M, Maurel K. 441: 17-hydroxyprogesterone for triplet pregnancy does not reduce prematurity or neonatal morbidity, may increase midtrimester loss. Am J Obstet Gynecol 2009. [DOI: 10.1016/j.ajog.2009.10.607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Pissinatti L, Tortelly R, Porto M, Burity C, Pissinatti A. Morfologia macroscópica do aparelho reprodutor feminino de Leontopithecus cativos (Lesson, 1840) Primates-Callitrichidae. ARQ BRAS MED VET ZOO 2008. [DOI: 10.1590/s0102-09352008000600025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Descreveu-se o sistema reprodutor feminino em três espécies de mico-leão Leontopithecus (Lesson 1840), cativos: L. rosalia, L. chrysopygus e L. chrysomelas. A vulva está delimitada pelos lábios vulvares menores e com clitóris conspícuo. A superfície do períneo urogenital apresenta elevações papilares mais concentradas nos lábios vulvares, conferindo-lhe aspecto rugoso. O vestíbulo vaginal constitui um tubo muscular de parede espessa que se estende da rima da vulva até o óstio da vagina. A vagina é um tubo muscular alongado e achatado dorsoventralmente, que comunica o vestíbulo vaginal ao colo uterino. O útero piriforme está localizado na porção caudal da cavidade abdominal. Craniolateralmente abrem-se tubas uterinas convolutas e ovários grosseiramente fusiformes de superfície lisa.
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Mattos Jr D, Amaral J, Porto M, Fedullo L, Balthazar L, Tucunduva P. Registro de ácaros em avestruz no estado do Rio de Janeiro. ARQ BRAS MED VET ZOO 2007. [DOI: 10.1590/s0102-09352007000200043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Fleishman D, Klafter J, Porto M, Urbakh M. Mesoscale engines by nonlinear friction. NANO LETTERS 2007; 7:837-42. [PMID: 17309318 DOI: 10.1021/nl070003a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
A new approach to build mesoscopic-size engines that move translationally or rotationally and can perform useful functions such as the pulling of a cargo is presented. The approach is based on the transformation of internal vibrations of the moving object into directed motion, making use of the nonlinear properties of friction. This can be achieved by superimposing time-dependent external fields that break the spatial symmetry. The motion can be controlled and optimized by adjusting the system parameters.
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Moayeri S, Werlin L, Brewster W, Allen R, Kim M, Porto M. O-15. Fertil Steril 2006. [DOI: 10.1016/j.fertnstert.2006.02.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Allen R, Brewster W, Moayeri S, Nass T, Kim M, Porto M, Werlin L. P-25. Fertil Steril 2006. [DOI: 10.1016/j.fertnstert.2006.02.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Porto M. Prediction of Site-Specific Amino Acid Distributions and Limits of Divergent Evolutionary Changes in Protein Sequences. Mol Biol Evol 2005. [DOI: 10.1093/molbev/msi116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Porto M. Rectification by hopping motion through nonsymmetric potentials: local versus global bias. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2001; 64:021109. [PMID: 11497564 DOI: 10.1103/physreve.64.021109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2001] [Indexed: 05/23/2023]
Abstract
The hopping motion of noninteracting classical particles through nonsymmetric potentials is investigated in the case of alternating local bias. Different to the case of alternating global bias, a resonancelike behavior is observed. The system exhibits rectification effects in the regime of small to medium bias, whereas rectification effects are absent in the strong bias regime. Possible generalizations and applications are outlined.
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Roman HE, Porto M. Self-generated power-law tails in probability distributions. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2001; 63:036128. [PMID: 11308730 DOI: 10.1103/physreve.63.036128] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2000] [Indexed: 05/23/2023]
Abstract
We consider random processes characterized by the presence of correlations in their variance, or more generally in some of their moments. Typical examples are constituted by autoregressive conditional heteroskedasticity (ARCH) processes which are known to display power-law tails in the associated probability distributions. Here, we determine the corresponding exponents exactly and extend these results to relaxation phenomena which can be expected to play a role in natural sciences.
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Porto M. Molecular motor based entirely on the Coulomb interaction. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2001; 63:030102. [PMID: 11308618 DOI: 10.1103/physreve.63.030102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2000] [Indexed: 05/23/2023]
Abstract
A molecular motor is introduced which is composed of charges only and which does not contain any potential or interaction besides the Coulomb one. The motor is shown to transform efficiently a driven random rotation into a directed translational motion. The direction of translational motion can be chosen dynamically, so that a "forward gear," a "reverse gear," and even a "neutral gear" exist. The high efficiency stems from the fact that this motor only steps in the direction determined by the chosen gear.
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Ordemann A, Porto M, Eduardo Roman H, Havlin S. "Generalized des Cloizeaux" exponent for self-avoiding walks on the incipient percolation cluster. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2001; 63:020104. [PMID: 11308451 DOI: 10.1103/physreve.63.020104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2000] [Indexed: 05/23/2023]
Abstract
We study the asymptotic shape of self-avoiding random walks (SAW) on the backbone of the incipient percolation cluster in d-dimensional lattices analytically. It is generally accepted that the configurational averaged probability distribution function <P(B)(r,N)> for the end-to-end distance r of an N step SAW behaves as a power law for r-->0. In this work, we determine the corresponding exponent using scaling arguments, and show that our suggested "generalized des Cloizeaux" expression for the exponent is in excellent agreement with exact enumeration results in two and three dimensions.
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Naylor CS, Porto M, Cohen B, Garite TJ. Pregnancy outcome in Hispanic patients with unexplained positive triple marker screening for Down syndrome. THE JOURNAL OF MATERNAL-FETAL MEDICINE 2001; 10:20-2. [PMID: 11332414 DOI: 10.1080/714052710] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 09/30/2022]
Abstract
OBJECTIVE The objective of this study was to compare pregnancy outcomes in Hispanic patients with a positive serum triple marker screen for Down syndrome and normal fetal karyotype with Hispanic women who had a negative triple marker screen. METHODS This prospective investigation involved Hispanic gravidas who underwent maternal serum screening. A power analysis was performed to determine the sample size. Fifty women with false-positive screens for Down syndrome were matched with a control group of 100 women with a negative screen. Adverse pregnancy outcomes were compared between the two groups. RESULTS An adverse pregnancy outcome occurred in 14% of the study group and in 13% of controls. There were no statistically significant differences between the two groups in the incidence of preterm labor (p > 0.5), pre-eclampsia (p > 0.1), intrauterine growth restriction (p > 0.5), or fetal demise (p > 0.5). CONCLUSION Hispanic patients with unexplained positive triple marker screen for Down syndrome do not appear to be at increased risk for adverse pregnancy outcomes.
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Naylor CS, Porto M, Cohen B, Garite TJ. Pregnancy outcome in Hispanic patients with unexplained positive triple marker screening for Down syndrome. J Matern Fetal Neonatal Med 2001. [DOI: 10.1080/jmf.10.1.20.22-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Porto M, Urbakh M, Klafter J. Molecular motor that never steps backwards. PHYSICAL REVIEW LETTERS 2000; 85:491-494. [PMID: 10991323 DOI: 10.1103/physrevlett.85.491] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2000] [Indexed: 05/23/2023]
Abstract
We investigate the dynamics of a classical particle in a one-dimensional two-wave potential composed of two periodic potentials that are time independent and of the same amplitude and periodicity. One of the periodic potentials is externally driven and performs a translational motion with respect to the other. It is shown that, if one of the potentials is of the ratchet type, translation of the potential in a given direction leads to motion of the particle in the same direction, whereas translation in the opposite direction leaves the particle localized at its original location. Moreover, even if the translation is random, but still has a finite velocity, an efficient directed transport of the particle occurs.
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