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Influence of Silicon and Phosphorus on Structural and Magnetic Properties of Synthetic Goethite and Related Oxides
- Thomas G. Quin, Gary J. Long, Christopher G. Benson, Stephen Mann, Robert J. P. Williams
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- Journal:
- Clays and Clay Minerals / Volume 36 / Issue 2 / April 1988
- Published online by Cambridge University Press:
- 02 April 2024, pp. 165-175
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A series of synthetic goethites containing varying amounts of Si and P dopants were characterized by X-ray powder diffraction, electron diffraction, microbeam electron diffraction, and Mössbauer spectroscopy. Very low level incorporation produced materials having structural and spectral properties similar to those of poorly crystalline synthetic or natural goethite. At higher incorporation levels, mixtures of noncrystalline materials were obtained which exhibited Mössbauer spectra typical of noncrystalline materials mixed with a superparamagnetic component. Microbeam electron diffraction indicated that these mixtures contained poorly crystalline goethite, poorly crystalline ferrihydrite, and a noncrystalline component. If the material was prepared with no aging of the alkaline Fe3+ solution before the addition of Na2HPO4 or Na2SiO3, materials were obtained containing little if any superparamagnetic component. If the alkaline Fe3+ solution was aged for 48 hr before the addition, goethite nuclei formed and apparently promoted the precipitation of a superparamagnetic phase. The Mössbauer-effect hyperfme parameters and the saturation internal-hyperfine field obtained at 4.2 K were typical of those of goethite; however, the Mössbauer spectra indicated that the ordering temperature, as reflected in the relaxation rate and/or the blocking temperature, decreased with increasing incorporation of Si and P. The complete loss of crystallinity indicates that Si and P did not substitute for Fe, but rather adsorbed on crystal-growth sites, thereby preventing uniform crystal growth.
Advocacy at the Eighth World Congress of Pediatric Cardiology and Cardiac Surgery
- Bistra Zheleva, Amy Verstappen, David M. Overman, Farhan Ahmad, Sulafa K.M. Ali, Zohair Y. Al Halees, Joumana Ghandour Atallah, Isabella E. Badhwar, Carissa Baker-Smith, Maria Balestrini, Amy Basken, Jonah S. Bassuk, Lee Benson, Horacio Capelli, Santo Carollo, Devyani Chowdhury, M. Sertaç Çiçek, Mitchell I. Cohen, David S. Cooper, John E. Deanfield, Joseph Dearani, Blanca del Valle, Kathryn M. Dodds, Junbao Du, Frank Edwin, Ekanem Ekure, Nurun Nahar Fatema, Anu Gomanju, Babar Hasan, Lewis Henry, Christopher Hugo-Hamman, Krishna S. Iyer, Marcelo B. Jatene, Kathy J. Jenkins, Tara Karamlou, Tom R. Karl, James K. Kirklin, Christián Kreutzer, Raman Krishna Kumar, Keila N. Lopez, Alexis Palacios Macedo, Bradley S. Marino, Eva M. Marwali, Folkert J. Meijboom, Sandra S. Mattos, Hani Najm, Dan Newlin, William M. Novick, Sir Shakeel A. Qureshi, Budi Rahmat, Robert Raylman, Irfan Levent Saltik, Craig Sable, Nestor Sandoval, Anita Saxena, Emma Scanlan, Gary F. Sholler, Jodi Smith, James D. St Louis, Christo I. Tchervenkov, Koh Ghee Tiong, Vladimiro Vida, Susan Vosloo, Douglas J. “DJ” Weinstein, James L. Wilkinson, Liesl Zuhlke, Jeffrey P. Jacobs
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- Journal:
- Cardiology in the Young / Volume 33 / Issue 8 / August 2023
- Published online by Cambridge University Press:
- 24 August 2023, pp. 1277-1287
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The Eighth World Congress of Pediatric Cardiology and Cardiac Surgery (WCPCCS) will be held in Washington DC, USA, from Saturday, 26 August, 2023 to Friday, 1 September, 2023, inclusive. The Eighth World Congress of Pediatric Cardiology and Cardiac Surgery will be the largest and most comprehensive scientific meeting dedicated to paediatric and congenital cardiac care ever held. At the time of the writing of this manuscript, The Eighth World Congress of Pediatric Cardiology and Cardiac Surgery has 5,037 registered attendees (and rising) from 117 countries, a truly diverse and international faculty of over 925 individuals from 89 countries, over 2,000 individual abstracts and poster presenters from 101 countries, and a Best Abstract Competition featuring 153 oral abstracts from 34 countries. For information about the Eighth World Congress of Pediatric Cardiology and Cardiac Surgery, please visit the following website: [www.WCPCCS2023.org]. The purpose of this manuscript is to review the activities related to global health and advocacy that will occur at the Eighth World Congress of Pediatric Cardiology and Cardiac Surgery.
Acknowledging the need for urgent change, we wanted to take the opportunity to bring a common voice to the global community and issue the Washington DC WCPCCS Call to Action on Addressing the Global Burden of Pediatric and Congenital Heart Diseases. A copy of this Washington DC WCPCCS Call to Action is provided in the Appendix of this manuscript. This Washington DC WCPCCS Call to Action is an initiative aimed at increasing awareness of the global burden, promoting the development of sustainable care systems, and improving access to high quality and equitable healthcare for children with heart disease as well as adults with congenital heart disease worldwide.
Sleep-wake disorders in Alzheimer’s disease: further genetic analyses in relation to objective sleep measures
- Jerome A. Yesavage, Art Noda, Alesha Heath, M. Windy McNerney, Benjamin W. Domingue, Yozen Hernandez, Gary Benson, Joachim Hallmayer, Ruth O’Hara, Leanne M. Williams, Andrea N. Goldstein-Piekarski, Jamie M. Zeitzer, J. Kaci Fairchild
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- Journal:
- International Psychogeriatrics / Volume 32 / Issue 7 / July 2020
- Published online by Cambridge University Press:
- 19 November 2019, pp. 807-813
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This paper presents updated analyses on the genetic associations of sleep disruption in individuals with Alzheimer’s disease (AD). We published previously a study of the association between single nucleotide polymorphisms (SNPs) found in eight genes related to circadian rhythms and objective measures of sleep-wake disturbances in 124 individuals with AD. Here, we present new relevant analyses using polygenic risk scores (PRS) and variable number tandem repeats (VNTRs) enumerations. PRS were calculated using the genetic data from the original participants and relevant genome wide association studies (GWAS). VNTRs for the same circadian rhythm genes studied with SNPs were obtained from a separate cohort of participants using whole genome sequencing (WGS). Objectively (wrist actigraphy) determined wake after sleep onset (WASO) was used as a measure of sleep disruption. None of the PRS were associated with sleep disturbance. Computer analyses using VNTRseek software generated a total of 30 VNTRs for the circadian-related genes but none appear relevant to our objective sleep measure. In addition, of 71 neurotransmitter function-related genes, 29 genes had VNTRs that differed from the reference VNTR, but it was not clear if any of these might affect circadian function in AD patients. Although we have not found in either the current analyses or in our previous published analyses of SNPs any direct linkages between identified genetic factors and WASO, research in this area remains in its infancy.
Mutation Master: Profiles of substitutions in hepatitis C virus RNA of the core, alternate reading frame, and NS2 coding regions
- JOSÉ L. WALEWSKI, JULIO A. GUTIERREZ, WESTYN BRANCH-ELLIMAN, DECHERD D. STUMP, TOBY R. KELLER, ALFREDO RODRIGUEZ, GARY BENSON, ANDREA D. BRANCH
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The RNA genome of the hepatitis C virus (HCV) undergoes rapid evolutionary change. Efforts to control this virus would benefit from the advent of facile methods to identify characteristic features of HCV RNA and proteins, and to condense the vast amount of mutational data into a readily interpretable form. Many HCV sequences are available in GenBank. To facilitate analysis, consensus sequences were constructed to eliminate the overrepresentation of certain genotypes, such as genotype 1, and a novel package of sequence analysis tools was developed. Mutation Master generates profiles of point mutations in a population of sequences and produces a set of visual displays and tables indicating the number, frequency, and character of substitutions. It can be used to analyze hundreds of sequences at a time. When applied to 255 HCV core protein sequences, Mutation Master identified variable domains and a series of mutations meriting further investigation. It flagged position 4, for example, where 90% or more of all sequences in genotypes 1, 2, 4, and 5, have N4, whereas those in genotypes 3, 6, 7, 8, 9, and 10 have L4. This pattern is noteworthy: L (hydrophobic) to N (polar) substitutions are generally rare, and genotypes 1, 2, 4, and 5 do not form a recognized super family of sequences. Thus, the L4N substitution probably arose independently several times. Moreover, not one member of genotypes 1, 2, 4, or 5 has L4 and not one member of genotypes 3, 6, 7, 8, 9, or 10 has N4. This nonoverlapping pattern suggests that coordinated changes at position 4 and a second site are required to yield a viable virus. The package generated a table of genotype-specific substitutions whose future analysis may help to identify interacting amino acids. Three substitutions were present in 100% of genotype 2 members and absent from all others: A68D, R74K, and R114H. Finally, this study revealed that ARFP, a novel protein encoded in an overlapping reading frame, is as conserved as conventional HCV proteins, a result supporting a role for ARFP in the viral life cycle. Whereas most conventional programs for phylogenetic analysis of sequences provide information about overall relatedness of genes or genomes, this program highlights and profiles point mutations. This is important because determinants of pathogenicity and drug susceptibility are likely to result from changes at only one or two key nucleotides or amino acid sites, and would not be detected by the type of pairwise comparisons that have usually been performed on HCV to date. This study is the first application of Mutation Master, which is now available upon request (http://tandem.biomath.mssm.edu/mutationmaster.html).
More than 10 Years of Unrecognized Nosocomial Transmission of Legionnaires' Disease Among Transplant Patients
- Jacob L. Kool, Anthony E. Fiore, Clare M. Kioski, Ellen W. Brown, Robert F. Benson, Janet M. Pruckler, Constance Glasby, Jay C. Butler, Gary D. Cage, Joseph C. Carpenter, Richard M. Mandel, Bob England, Robert F. Breiman
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- Journal:
- Infection Control & Hospital Epidemiology / Volume 19 / Issue 12 / December 1998
- Published online by Cambridge University Press:
- 02 January 2015, pp. 898-904
- Print publication:
- December 1998
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Objective:
To investigate a cluster of cases of legionnaires' disease among patients at a hospital.
Setting:A university hospital that is a regional transplant center.
Design:Retrospective review of microbiology and serology data from the hospital laboratories and prospective surveillance via the radiology department; a case-control study and environmental sampling within the hospital and from nearby cooling towers.
Results:Diagnosis of seven cases of legionnaires' disease in the first 9 months of 1996 led to recognition of a nosocomial outbreak that may have begun as early as 1979. Review of charts from 1987 through September 1996 identified 25 culture-confirmed cases of nosocomial or possibly nosocomial legionnaires' disease, including 18 in bone marrow and heart transplant patients. Twelve patients (48%) died. During the first 9 months of 1996, the attack rate was 6% among cardiac and bone marrow transplant patients. For cases that occurred before 1996, intubation was associated with increased risk for disease. High-dose corticosteroid medication was strongly associated with the risk for disease, but other immunosuppressive therapy or cancer chemotherapy was not. Several species and serogroups of Legionella were isolated from numerous sites in the hospital's potable water system. Six of seven available clinical isolates were identical and were indistinguishable from environmental isolates by pulsed-field gel electrophoresis. Initial infection control measures failed to interrupt nosocomial acquisition of infection. After extensive modifications to the water system, closely monitored repeated hyperchlorinations, and reduction of patient exposures to aerosols, transmission was interrupted. No cases have been identified since September 1996.
Conclusions:Legionella can colonize hospital potable water systems for long periods of time, resulting in an ongoing risk for patients, especially those who are immunocompromised. In this hospital, nosocomial transmission possibly occurred for more than 17 years and was interrupted in 1996, after a sudden increase in incidence led to its recognition. Hospitals specializing in the care of immunocompromised patients (eg, transplant centers) should prioritize surveillance for cases of legionnaires' disease. Aggressive control measures can interrupt transmission of this disease successfully.