Ion specific effects in bundling and depolymerization of taxol-stabilized microtubules

Needleman, Daniel J.,Ojeda-Lopez, Miguel A.,Raviv, Uri,Miller, Herbert P.,Li, Youli,Song, Chaeyeon,Feinstein, Stuart C.,Wilson, Leslie,Choi, Myung Chul,Safinya, Cyrus R. The Royal Society of Chemistry 2013 Faraday discussions Vol.166 No.-

<P>Microtubules (MTs) are nanometer scale hollow cylindrical biological polyelectrolytes. They are assembled from α/β-tubulin dimers, which stack to form protofilaments (PFs) with lateral interactions between PFs resulting in the curved MT. In cells, MTs and their assemblies are critical components in a range of functions from providing tracks for the transport of cargo to forming the spindle structure during mitosis. Previous studies have shown that while cations with valence equal to or larger than 3+ tend to assemble tight 3D bundles of taxol-stabilized MTs, certain divalent cations induce relatively loose 2D bundles of different symmetry (D. J. Needleman <I>et al.</I>, <I>Proc. Natl. Acad. Sci. U. S. A.</I>, 2004, <B>101</B>, 16099). Similarly, divalent cations form 2D bundles of DNA adsorbed on cationic membranes (I. Koltover <I>et al.</I>, <I>Proc. Natl. Acad. Sci. U. S. A.</I>, 2000, <B>97</B>, 14046). The bundling behavior for these biological polyelectrolyte systems is qualitatively in agreement with current theory. Here, we present results which show that, unlike the case for DNA adsorbed on cationic membranes, bundling of taxol-stabilized MTs occurs only for certain divalent cations above a critical ion concentration (<I>e.g.</I> Ca<SUP>2+</SUP>, Sr<SUP>2+</SUP>, Ba<SUP>2+</SUP>). Instead, many divalent cations pre-empt the bundling transition and depolymerize taxol-stabilized MTs at a lower counterion concentration. Although previous cryogenic TEM has shown that, in the absence of taxol, Ca<SUP>2+</SUP> depolymerizes MTs assembling in buffers containing GTP (guanosine triphosphate), our finding is surprising given the known stabilizing effects of taxol on GDP (guanosine diphosphate)-MTs. The ion concentration required for MT depolymerization decreases with increasing atomic number for the divalents Mg<SUP>2+</SUP>, Mn<SUP>2+</SUP>, Co<SUP>2+</SUP>, and Zn<SUP>2+</SUP>. GdCl<SUB>3</SUB> (3+) is found to be extremely efficient at MT depolymerization requiring ion concentrations of about 1 mM, while oligolysine (2+), is observed not to depolymerize MTs at concentrations as high as 144 mM. The surprising MT depolymerization results are discussed in the context of divalents either disrupting lateral interactions between PFs (which are strengthened for taxol containing β-tubulin), or interfering with taxol's ability to induce flexibility at the interface between two tubulin dimers in the same PF (which has been recently suggested as a mechanism by which taxol stabilizes MTs post-hydrolysis with the induced flexibility counteracting the kink between GDP-tubulin dimers in a PF).</P>

Global and regional emission estimates for HCFC-22

Saikawa, E.,Rigby, M.,Prinn, R. G.,Montzka, S. A.,Miller, B. R.,Kuijpers, L. J. M.,Fraser, P. J. B.,Vollmer, M. K.,Saito, T.,Yokouchi, Y.,Harth, C. M.,Mü,hle, J.,Weiss, R. F.,Salameh, P. K.,Kim, J Copernicus GmbH 2012 Atmospheric chemistry and physics Vol.12 No.21

<P>Abstract. HCFC-22 (CHClF2, chlorodifluoromethane) is an ozone-depleting substance (ODS) as well as a significant greenhouse gas (GHG). HCFC-22 has been used widely as a refrigerant fluid in cooling and air-conditioning equipment since the 1960s, and it has also served as a traditional substitute for some chlorofluorocarbons (CFCs) controlled under the Montreal Protocol. A low frequency record on tropospheric HCFC-22 since the late 1970s is available from measurements of the Southern Hemisphere Cape Grim Air Archive (CGAA) and a few Northern Hemisphere air samples (mostly from Trinidad Head) using the Advanced Global Atmospheric Gases Experiment (AGAGE) instrumentation and calibrations. Since the 1990s high-frequency, high-precision, in situ HCFC-22 measurements have been collected at these AGAGE stations. Since 1992, the Global Monitoring Division of the National Oceanic and Atmospheric Administration/Earth System Research Laboratory (NOAA/ESRL) has also collected flasks on a weekly basis from remote sites across the globe and analyzed them for a suite of halocarbons including HCFC-22. Additionally, since 2006 flasks have been collected approximately daily at a number of tower sites across the US and analyzed for halocarbons and other gases at NOAA. All results show an increase in the atmospheric mole fractions of HCFC-22, and recent data show a growth rate of approximately 4% per year, resulting in an increase in the background atmospheric mole fraction by a factor of 1.7 from 1995 to 2009. Using data on HCFC-22 consumption submitted to the United Nations Environment Programme (UNEP), as well as existing bottom-up emission estimates, we first create globally-gridded a priori HCFC-22 emissions over the 15 yr since 1995. We then use the three-dimensional chemical transport model, Model for Ozone and Related Chemical Tracers version 4 (MOZART v4), and a Bayesian inverse method to estimate global as well as regional annual emissions. Our inversion indicates that the global HCFC-22 emissions have an increasing trend between 1995 and 2009. We further find a surge in HCFC-22 emissions between 2005 and 2009 from developing countries in Asia - the largest emitting region including China and India. Globally, substantial emissions continue despite production and consumption being phased out in developed countries currently. </P>

Extreme wind prediction and zoning

C. A. Miller,J. D. Holmes,M. Kasperski,J. A. Zuranski,E. C. C. Choi 한국풍공학회 2005 Wind and Structures, An International Journal (WAS Vol.8 No.4

High-density single-nucleotide polymorphism maps of the human genome

Miller, Raymond D.,Phillips, Michael S.,Jo, Inho,Donaldson, Miriam A.,Studebaker, Joel F.,Addleman, Nicholas,Alfisi, Steven V.,Ankener, Wendy M.,Bhatti, Hamid A.,Callahan, Chad E.,Carey, Benjamin J.,C Elsevier 2005 Genomics Vol.86 No.2

<P><B>Abstract</B></P><P>Here we report a large, extensively characterized set of single-nucleotide polymorphisms (SNPs) covering the human genome. We determined the allele frequencies of 55,018 SNPs in African Americans, Asians (Japanese–Chinese), and European Americans as part of The SNP Consortium's Allele Frequency Project. A subset of 8333 SNPs was also characterized in Koreans. Because these SNPs were ascertained in the same way, the data set is particularly useful for modeling. Our results document that much genetic variation is shared among populations. For autosomes, some 44% of these SNPs have a minor allele frequency ≥10% in each population, and the average allele frequency differences between populations with different continental origins are less than 19%. However, the several percentage point allele frequency differences among the closely related Korean, Japanese, and Chinese populations suggest caution in using mixtures of well-established populations for case–control genetic studies of complex traits. We estimate that ∼7% of these SNPs are private SNPs with minor allele frequencies <1%. A useful set of characterized SNPs with large allele frequency differences between populations (>60%) can be used for admixture studies. High-density maps of high-quality, characterized SNPs produced by this project are freely available.</P>

U.S. FUEL CYCLE TECHNOLOGIES R&D PROGRAM FOR NEXT GENERATION NUCLEAR MATERIALS MANAGEMENT

Miller, M.C.,Vega, D.A. Korean Nuclear Society 2013 Nuclear Engineering and Technology Vol.45 No.6

The U.S. Department of Energy's Fuel Cycle Technologies R&D program under the Office of Nuclear Energy is working to advance technologies to enhance both the existing and future fuel cycles. One thrust area is in developing enabling technologies for next generation nuclear materials management under the Materials Protection, Accounting and Control Technologies (MPACT) Campaign where advanced instrumentation, analysis and assessment methods, and security approaches are being developed under a framework of Safeguards and Security by Design. An overview of the MPACT campaign's activities and recent accomplishments is presented along with future plans.

U.S. Fuel Cycle Technologies R&D Program for Next Generation Nuclear Materials Management

M.C. MILLER,D.A. Vega 한국원자력학회 2013 Nuclear Engineering and Technology Vol.45 No.6

The U.S. Department of Energy’s Fuel Cycle Technologies R&D program under the Office of Nuclear Energy is workingto advance technologies to enhance both the existing and future fuel cycles. One thrust area is in developing enablingtechnologies for next generation nuclear materials management under the Materials Protection, Accounting and ControlTechnologies (MPACT) Campaign where advanced instrumentation, analysis and assessment methods, and securityapproaches are being developed under a framework of Safeguards and Security by Design. An overview of the MPACTcampaign’s activities and recent accomplishments is presented along with future plans.

Structure ofSn107studied through single-neutron knockout reactions

Cerizza, G.,Ayres, A.,Jones, K. L.,Grzywacz, R.,Bey, A.,Bingham, C.,Cartegni, L.,Miller, D.,Padgett, S.,Baugher, T.,Bazin, D.,Berryman, J. S.,Gade, A.,McDaniel, S.,Ratkiewicz, A.,Shore, A.,Stroberg, S American Physical Society 2016 Physical Review C Vol.93 No.2

<P>The neutron-deficient nucleus Sn-107 has been studied by using the one-neutron knockout reaction. By measuring the decay gamma rays and momentum distributions of reaction residues, the spins of the ground, 5/2(+), and first-excited, 7/2(+), states of Sn-107 have been assigned by comparisons to eikonal-model reaction calculations. Limits on the inclusive and exclusive cross sections have been measured and transitions due to neutron removals from below the N = 50 closed shell have been observed. New excited states up to 5.5 MeV in Sn-107 have been identified.</P>

Treatment of In-Stent Stenosis Following Flow Diversion of Intracranial Aneurysms with Cilostazol and Clopidogrel

Ehsan Dowlati,Kory B. Dylan Pasko,Jiaqi Liu,Charles A. Miller,Daniel R. Felbaum,Samir Sur,Jason J. Chang,Ai-Hsi Liu,Rocco A. Armonda,Jeffrey C. Mai 대한신경중재치료의학회 2021 Neurointervention Vol.16 No.3

In-stent stenosis is a feared complication of flow diversion treatment for cerebral aneurysms. We present 2 cases of patients treated with pipeline flow diversion for unruptured cerebral aneurysms. Initial perioperative dual antiplatelet therapy (DAPT) consisted of standard aspirin plus clopidogrel. At 6-month follow-up cerebral angiography, the patients were noted to have developed significant in-stent stenosis (63% and 53%). The patients were treated with cilostazol and clopidogrel for at least 6 months. Subsequent angiography at 1-year post-treatment showed significant improvement of the in-stent stenosis from 63% to 34% and 53% to 21%. The role of cilostazol as treatment of intracranial in-stent stenosis has not been previously described. Cilostazol’s vasodilatory effect and suppression of vascular smooth muscle proliferation provides ideal benefits in this setting. Cilostazol plus clopidogrel may be a safe and effective alternative to standard DAPT for treatment of in-stent stenosis following flow diversion and warrants further consideration and investigation.

Extreme wind prediction and zoning

Holmes, J.D.,Kasperski, M.,Miller, C.A.,Zuranski, J.A.,Choi, E.C.C. Techno-Press 2005 Wind and Structures, An International Journal (WAS Vol.8 No.4

The paper describes the work of the IAWE Working Group WGF - Extreme Wind Prediction and Zoning, one of the international codification working groups set up in 2000. The topics covered are: the international database of extreme winds, quality assurance and data quality, averaging times, return periods, probability distributions and fitting methods, mixed wind climates, directionality effects, the influence of orography, rare events and simulation methods, long-term climate change, and zoning and mapping. Recommendations are given to promote the future alignment of international codes and standards for wind loading.

Molecular Mechanisms Mediating Inhibition of G Protein-coupled Inwardly-rectifying K+ Channels

Douglas A. Bayliss,Qiubo Lei,Miller B. Jones,Edmund M. Talley,James C. Garrison 한국분자세포생물학회 2003 Molecules and cells Vol.15 No.1