DNA/RNA Degradation Rate in Long Term Fixed Museum Specimens

In today’s research driven society, it has become commonplace for institutions to rely upon DNA and RNA extraction techniques to help obtain genomic data from old specimens. Generally, specimens were commonly preserved for future gross examination and/or teaching. Using histological examination of specimens from museum jars from the Pathology Department at the Indiana University School of Medicine, the sequential and chronological degradation of DNA and RNA has been studied. We examined gross specimens from nine decades from 1920 until 2000. We evaluated histologic preservation of kidney, liver, heart, lung, spleen, uterus, and brain for nuclear structure in these samples. Nuclear preservation was based on amount of nuclei per 20x microscopic field and the crispness of the nuclear membrane and internal features. The nuclei in high lipid tissues such as the brain were found to degrade at a quicker rate than dense tissues such as the heart and uterus. Our study has shown specimens preserved beyond fifty years were likely to have little to no nuclei left, thus indicating that there was little to no DNA and RNA remaining. This technique of histologic evaluation first is an important finding and a general guideline which may save research institutions from the expensive process of DNA and RNA extraction

DNA/RNA Degradation Rate in Fixed Tissue

poster abstractIn today’s research driven society, it has become commonplace for institutions to rely upon DNA and RNA extraction techniques to help obtain genomic data from old specimens. Generally, specimens were commonly preserved for future gross examination and/or teaching. Using histological examination of specimens from museum jars from the Pathology Department at the Indiana University School of Medicine, the sequential and chronological degradation of DNA and RNA has been studied. We examined gross specimens from nine decades from 1920 until 2000. We evaluated histologic preservation of nuclear structure in these samples. Nuclear preservation was based on amount of nuclei per 20x microscopic field, the crispness of the nuclear membrane and internal features. The nuclei in high lipid tissues such as the brain were found to degrade at a quicker rate than dense proteinaceous structures such as the heart and uterus. Our study has shown specimens preserved beyond roughly fifty years are likely to have little to no nuclei left, thus indicating that there was little to no DNA and RNA remaining. This technique of histologic evaluation is an important finding and general guideline which may save research institutions from the expensive process of DNA and RNA extractio

Bostonia: The Boston University Alumni Magazine. Volume 32

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

Bostonia

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

The ConSurf-DB: pre-calculated evolutionary conservation profiles of protein structures

ConSurf-DB is a repository for evolutionary conservation analysis of the proteins of known structures in the Protein Data Bank (PDB). Sequence homologues of each of the PDB entries were collected and aligned using standard methods. The evolutionary conservation of each amino acid position in the alignment was calculated using the Rate4Site algorithm, implemented in the ConSurf web server. The algorithm takes into account the phylogenetic relations between the aligned proteins and the stochastic nature of the evolutionary process explicitly. Rate4Site assigns a conservation level for each position in the multiple sequence alignment using an empirical Bayesian inference. Visual inspection of the conservation patterns on the 3D structure often enables the identification of key residues that comprise the functionally important regions of the protein. The repository is updated with the latest PDB entries on a monthly basis and will be rebuilt annually. ConSurf-DB is available online at http://consurfdb.tau.ac.il

Technology-Mediated Communication in Familial Relationships: Moderated-Mediation Models of Isolation and Loneliness

Background and ObjectivesWe examined whether technology-mediated communication has functional or emotional equivalence to face-to-face (FtF) contact in familial relationships, by scrutinizing the effects of phone, text/e-mail, and video contact on isolation and loneliness.Research Design and MethodsWe tested whether FtF contact with a relative would mediate the pathway between proximity to family and (i) isolation and (ii) loneliness. We then tested hypotheses that telephone, text/e-mails, and video contact would moderate this mediated pathway. We compared models for younger (<75) and older (≥75) cohorts, expecting to observe moderation effects for text/e-mail and video contact in the younger cohort only. Data were drawn from Wave 2 of CFAS Wales (United Kingdom) study (N = 2,099).ResultsProximity to a relative had a significant indirect effect on isolation and loneliness through the mediating variable FtF contact. Phone and text/e-mail contact moderated the effect of FtF contact on isolation for all samples. None of the technologies moderated the impact of FtF contact on loneliness for the full sample. Telephone contact had a moderating influence on loneliness for the younger cohort only. Video calls had no significant moderation effect.Discussion and ImplicationsTelephone and text/e-mail contact have functional equivalence to FtF contact in familial relationships. None of the forms of technological communication have emotional equivalence to the “gold standard” of embodied presence. The study demonstrates the importance of theorizing about the pathways to isolation and loneliness to better understand the likelihood of implementing successful interventions using technology-mediated communication within families

Early respiratory morbidity in a multicultural birth cohort: the Generation R Study

Ethnic disparities in the prevalence of asthma symptoms in children have been described. We evaluated to what extent the association between ethnic background and respiratory symptoms during the first 2 years of life could be explained by the mediating effect of risk factors for respiratory morbidity. The Generation R Study is a multiethnic, population-based birth cohort study. Pre and postnatal risk factors for respiratory morbidity were prospectively assessed by questionnaires. Information about ethnicity was available for 5,684 infants. The associations between ethnic background and lower respiratory symptoms at 12 and 24 months were evaluated with log-binomial regression models. Relative risks and 95 % confidence intervals (RR [95 % CI]) were computed for Cape Verdean, Moroccan, Antillean, Surinamese and Turkish ethnicity with Dutch ethnicity as the reference category. We found an increased risk of lower respiratory symptoms at 24 months in Antillean infants (1.32 [95 % CI 1.12–1.57]) that was mediated by early postnatal exposures (pets keeping, siblings, breastfeeding, daycare attendance, smoke exposure). Turkish infants also had an increased risk of lower respiratory symptoms at 12 and 24 months (1.14 [95 % CI 1.02–1.27] and 1.21 [95 % CI 1.07–1.38], respectively), partly explained by previous morbidity (eczema, infections and upper respiratory symptoms). There were no differences for Cape Verdean, Moroccan or Surinamese, as compared to Dutch infants. Hence, ethnic background was associated with respiratory symptoms during the first 2 years of life and this association was largely explained by mediating effects of known pre and postnatal risk factors for respiratory morbidity

QUALITY, TECHNOLOGY, AND GLOBAL MANUFACTURING

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73074/1/j.1937-5956.1997.tb00423.x.pd

Transient integral boundary layer method to calculate the translesional pressure drop and the fractional flow reserve in myocardial bridges

BACKGROUND: The pressure drop – flow relations in myocardial bridges and the assessment of vascular heart disease via fractional flow reserve (FFR) have motivated many researchers the last decades. The aim of this study is to simulate several clinical conditions present in myocardial bridges to determine the flow reserve and consequently the clinical relevance of the disease. From a fluid mechanical point of view the pathophysiological situation in myocardial bridges involves fluid flow in a time dependent flow geometry, caused by contracting cardiac muscles overlying an intramural segment of the coronary artery. These flows mostly involve flow separation and secondary motions, which are difficult to calculate and analyse. METHODS: Because a three dimensional simulation of the haemodynamic conditions in myocardial bridges in a network of coronary arteries is time-consuming, we present a boundary layer model for the calculation of the pressure drop and flow separation. The approach is based on the assumption that the flow can be sufficiently well described by the interaction of an inviscid core and a viscous boundary layer. Under the assumption that the idealised flow through a constriction is given by near-equilibrium velocity profiles of the Falkner-Skan-Cooke (FSC) family, the evolution of the boundary layer is obtained by the simultaneous solution of the Falkner-Skan equation and the transient von-Kármán integral momentum equation. RESULTS: The model was used to investigate the relative importance of several physical parameters present in myocardial bridges. Results have been obtained for steady and unsteady flow through vessels with 0 – 85% diameter stenosis. We compare two clinical relevant cases of a myocardial bridge in the middle segment of the left anterior descending coronary artery (LAD). The pressure derived FFR of fixed and dynamic lesions has shown that the flow is less affected in the dynamic case, because the distal pressure partially recovers during re-opening of the vessel in diastole. We have further calculated the wall shear stress (WSS) distributions in addition to the location and length of the flow reversal zones in dependence on the severity of the disease. CONCLUSION: The described boundary layer method can be used to simulate frictional forces and wall shear stresses in the entrance region of vessels. Earlier models are supplemented by the viscous effects in a quasi three-dimensional vessel geometry with a prescribed wall motion. The results indicate that the translesional pressure drop and the mean FFR compares favourably to clinical findings in the literature. We have further shown that the mean FFR under the assumption of Hagen-Poiseuille flow is overestimated in developing flow conditions

Controls on mid‐ocean ridge normal fault seismicity across spreading rates from rate‐and‐state friction models

Author Posting. © American Geophysical Union., 2018. This article is posted here by permission of American Geophysical Union.for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 123 (2018): 6719-6733, doi:10.1029/2018JB015545.Recent seismic and geodetic observations have led to a growing realization that a significant amount of fault slip at plate boundaries occurs aseismically and that the amount of aseismic slip varies across tectonic settings. Seismic moment release rates measured along the fast‐spreading East Pacific Rise suggest that the majority of fault slip occurs aseismically. By contrast, at the slow‐spreading Mid‐Atlantic Ridge seismic slip may represent up to 60% of total fault displacement. In this study, we use rate‐and‐state friction models to quantify the seismic coupling coefficient, defined as the fraction of total fault slip that occurs seismically, on mid‐ocean ridge normal faults and investigate controls on fault behavior that might produce variations in coupling observed at oceanic spreading centers. We find that the seismic coupling coefficient scales with the ratio of the downdip width of the seismogenic area (W) to the critical earthquake nucleation size (h*). At mid‐ocean ridges, W is expected to increase with decreasing spreading rate. Thus, the relationship between seismic coupling and W/h* predicted from our models explains the first‐order variations in seismic coupling coefficient as a function of spreading rate.National Science Foundation (NSF) Grant Numbers: EAR‐10‐10432, OCE‐10‐61203; NSF | GEO | Division of Earth Sciences (EAR); NSF | GEO | Division of Ocean Sciences (OCE)2019-02-1