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Cosmochemistry is a rapidly evolving field of planetary science and the second edition of this classic text reflects the exciting discoveries made over the past decade from new spacecraft missions. Topics covered include the synthesis of elements in stars, behaviour of elements and isotopes in the early solar nebula and planetary bodies, and compositions of extra-terrestrial materials. Radioisotope chronology of the early Solar System is also discussed, as well as geochemical exploration of planets by spacecraft, and cosmochemical constraints on the formation of solar systems. Thoroughly updated throughout, this new edition features significantly expanded coverage of chemical fractionation and isotopic analyses; focus boxes covering basic definitions and essential background material on mineralogy, organic chemistry and quantitative topics; and a comprehensive glossary. An appendix of analytical techniques and end-of-chapter review questions, with solutions available at www.cambridge.org/cosmochemistry2e, also contribute to making this the ideal teaching resource for courses on the Solar System's composition as well as a valuable reference for early career researchers.
ABSTRACT IMPACT: Examining lipid immunity for Mycobacterium tuberculosis in a translatable Guinea pig model may serve as a critical foundation for the creation of an efficacious human lipid based vaccine against tuberculosis. OBJECTIVES/GOALS: CD1 is a group of glycoproteins on antigen-presenting cells (APCs) that present lipid antigens to T cells. Mycobacterium tuberculosis (Mtb) has a lipid-rich cell wall which is essential for the pathogenesis of tuberculosis. Our goal is to determine the frequency, phenotypes, and functionality of CD1 T cells against Mtb using the guinea pig model. METHODS/STUDY POPULATION: Guinea pigs serve as the best translational model for CD1 immunology as they have both group 1 and group 2 CD1 complexes, comparable to human CD1. We performed ex-vivo and in-vivo experiments to analyze lipid antigen-specific CD1 T cell responses with Mtb infection. Assays to detect lipid-specific CD1 T cell activation include cellular proliferation, cytotoxicity assays, and interferon-gamma (IFNγ) release assay (Elispot) using both synthetic and Mtb-derived lipids. We isolated and characterized CD1 T cells using tetramerized CD1 complexes loaded with specific Mtb lipids. Spatial interaction between lipid loaded CD1 APCs with CD1 T cells were demonstrated by immunohistochemistry (IHC). Lastly, we will investigate the impact of lipid-based immunology via knockdown and overexpression of CD1 complexes. RESULTS/ANTICIPATED RESULTS: The cytotoxicity assay demonstrated that the CD1b1 and CD1b3 complexes play roles in the presentation of Mtb lipids, specifically glucose monomycolate, and mycolic acid, as noted by T cell killing of fibroblasts that express specific CD1 complexes that can present Mtb lipids. Similarly, cellular proliferation exhibited lipid specific T cell proliferation. IFNγ production by the stimulated CD1-restricted T cells (Elispot) was weak indicating CD1 T cells may not produce IFNγ. IHC successfully showed CD1 APCs in lungs and spleens of infected guinea pigs. It is anticipated that knocking out CD1 expression will lead to impaired immunity, and increase severity of disease as noted by pathologic lesions/bacterial burden, and systemic spread; in contrast, CD1 enhancement will limit the severity of tuberculosis. DISCUSSION/SIGNIFICANCE OF FINDINGS: We characterized CD1 T cells in infected guinea pigs at the tissue level, demonstrating Mtb lipid immunology. As a result, we laid the groundwork for investigating whether augmenting lipid immunity in the guinea pig model will enhance immunity against tuberculosis. Fruition of such work may lead to the development of effective tuberculosis vaccines.
The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.
To date, there have been no detailed reports of patients developing persistent psychotic symptoms following Coronavirus disease 2019 (COVID-19) infection. There have been reports of patients developing transient delirium (with and without hypoxia) after COVID-19 infection as well as other neurological manifestations. We report on a female patient who, post-COVID-19 infection, developed an initial delirium followed by persistent and florid psychotic symptoms consisting of persecutory delusion, complex visual and auditory hallucinations and Capgras phenomenon in the absence of hypoxia but elevated tumour necrosis factor (TNF)-α. The psychotic symptoms persisted for about 40 days. Her magnetic resonance imaging brain scan, electroencephalogram, cerebrospinal fluid examination and extensive autoimmune panel did not show any abnormalities. The cause of the psychotic symptoms in this patient were not ascertained but we propose either an inflammatory state, characterised by the patient's elevated TNF-alpha levels as a possible contributing mechanism for her psychosis in line with the proinflammatory changes observed in some cases of psychosis. Or, an alternative, but unproven, hypothesis is one of an antibody-mediated encephalitic event induced by viral infection.
Carbapenem-resistant Enterobacteriaceae (CRE) are a significant clinical and public health concern. Understanding the distribution of CRE colonization and developing a coordinated approach are key components of control efforts. The prevalence of CRE in the District of Columbia is unknown. We sought to determine the CRE colonization prevalence within healthcare facilities (HCFs) in the District of Columbia using a collaborative, regional approach.
This study included 16 HCFs in the District of Columbia: all 8 acute-care hospitals (ACHs), 5 of 19 skilled nursing facilities, 2 (both) long-term acute-care facilities, and 1 (the sole) inpatient rehabilitation facility.
Inpatients on all units excluding psychiatry and obstetrics-gynecology.
CRE identification was performed on perianal swab samples using real-time polymerase chain reaction, culture, and antimicrobial susceptibility testing (AST). Prevalence was calculated by facility and unit type as the number of patients with a positive result divided by the total number tested. Prevalence ratios were compared using the Poisson distribution.
Of 1,022 completed tests, 53 samples tested positive for CRE, yielding a prevalence of 5.2% (95% CI, 3.9%–6.8%). Of 726 tests from ACHs, 36 (5.0%; 95% CI, 3.5%–6.9%) were positive. Of 244 tests from long-term-care facilities, 17 (7.0%; 95% CI, 4.1%–11.2%) were positive. The relative prevalence ratios by facility type were 0.9 (95% CI, 0.5–1.5) and 1.5 (95% CI, 0.9–2.6), respectively. No CRE were identified from the inpatient rehabilitation facility.
A baseline CRE prevalence was established, revealing endemicity across healthcare settings in the District of Columbia. Our study establishes a framework for interfacility collaboration to reduce CRE transmission and infection.
A trend toward greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in mean values and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins), and included 842,951 height and BMI measurements from twins aged 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Similarly, a greater mean BMI of up to 0.3 kg/m2 in childhood and adolescence and up to 0.2 kg/m2 in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast, the variance of BMI was significantly higher in DZ than in MZ twins, particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes.
For over 100 years, the genetics of human anthropometric traits has attracted scientific interest. In particular, height and body mass index (BMI, calculated as kg/m2) have been under intensive genetic research. However, it is still largely unknown whether and how heritability estimates vary between human populations. Opportunities to address this question have increased recently because of the establishment of many new twin cohorts and the increasing accumulation of data in established twin cohorts. We started a new research project to analyze systematically (1) the variation of heritability estimates of height, BMI and their trajectories over the life course between birth cohorts, ethnicities and countries, and (2) to study the effects of birth-related factors, education and smoking on these anthropometric traits and whether these effects vary between twin cohorts. We identified 67 twin projects, including both monozygotic (MZ) and dizygotic (DZ) twins, using various sources. We asked for individual level data on height and weight including repeated measurements, birth related traits, background variables, education and smoking. By the end of 2014, 48 projects participated. Together, we have 893,458 height and weight measures (52% females) from 434,723 twin individuals, including 201,192 complete twin pairs (40% monozygotic, 40% same-sex dizygotic and 20% opposite-sex dizygotic) representing 22 countries. This project demonstrates that large-scale international twin studies are feasible and can promote the use of existing data for novel research purposes.
Thin diamond foils are needed in many particle accelerator experiments regarding nuclear and atomic physics, as well as in some interdisciplinary research. Particularly, nanodiamond texture is attractive for this purpose as it possesses a unique combination of diamond properties such as high thermal conductivity, mechanical strength and high radiation hardness; therefore, it is a potential material for energetic ion beam stripper foils. At the ORNL Spallation Neutron Source (SNS), the installed set of foils must be able to survive a nominal five-month operation period, without the need for unscheduled costly shutdowns and repairs. Thus, a single nanodiamond foil about the size of a postage stamp is critical to the entire operation of SNS and similar sources in U.S. laboratories and around the world. We are investigating nanocrystalline, polycrystalline and their admixture films fabricated using a hot filament chemical vapor deposition (HFCVD) system for H- stripping to support the SNS at Oak Ridge National Laboratory. Here we discuss optimization of process variables such as substrate temperature, process gas ratio of H2/Ar/CH4, substrate to filament distance, filament temperature, carburization conditions, and filament geometry to achieve high purity diamond foils on patterned silicon substrates with manageable intrinsic and thermal stresses so that they can be released as free standing foils without curling. An in situ laser reflectance interferometry tool (LRI) is used for monitoring the growth characteristics of the diamond thin film materials. The optimization process has yielded free standing foils with no pinholes. The sp3/sp2 bonds are controlled to optimize electrical resistivity to reduce the possibility of surface charging of the foils. The integrated LRI and HFCVD process provides real time information on the growth of films and can quickly illustrate growth features and control over film thickness. The results are discussed in the light of development of nanodiamond foils that will be able to withstand a few MW proton beam and hopefully will be able to be used after possible future upgrades to the SNS to greater than a 3MW beam.
Recently there have been reports of hot carrier thermoelectric response in nanostructured materials like graphene and MoS. We report observing that thermoelectric nanowire junctions detect light. In these experiments we employed devices composed of bismuth nanowire arrays which are capped with a transparent indium tin oxide electrode. The incident surface features very low optical reflectivity and enhanced light trapping. The unique attributes of the thermoelectric arrays are the combination of strong temporal and optical wavelength dependences of the photocurrent. Under infrared illumination, the signal can be completely described by “quasi-equilibrium” thermoelectric effects considering cooling rates given by heat diffusion through the array. The thermal diffusivity is found to be less (by a factor of 3.5) than in the bulk, a result that we discuss in terms of phonon confinement effects. In addition to a thermoelectric response, under visible illumination, we observe a photovoltaic response.
To measure support for seasonal influenza vaccination requirements among US healthcare personnel (HCP) and its associations with attitudes regarding influenza and influenza vaccination and self-reported coverage by existing vaccination requirements.
Between lune 1 and June 30, 2010, we surveyed a sample of US HCP (n = 1,664) recruited using an existing probability-based online research panel of participants representing the US general population as a sampling frame.
Eligible HCP who (1) reported having worked as medical doctors, health technologists, healthcare support staff, or other health practitioners or who (2) reported having worked in hospitals, ambulatory care facilities, long-term care facilities, or other health-related settings.
We analyzed support for seasonal influenza vaccination requirements for HCP using proportion estimation and multivariable probit models.
A total of 57.4% (95% confidence interval, 53.3%–61.5%) of US HCP agreed that HCP should be required to be vaccinated for seasonal influenza. Support for mandatory vaccination was statistically significantly higher among HCP who were subject to employer-based influenza vaccination requirements, who considered influenza to be a serious disease, and who agreed that influenza vaccine was safe and effective.
A majority of HCP support influenza vaccination requirements. Moreover, providing HCP with information about the safety of influenza vaccination and communicating that immunization of HCP is a patient safety issue may be important for generating staff support for influenza vaccination requirements.
Many asteroids are dry, as evidenced by meteorites in which water is virtually absent. These samples include many classes of chondrites, as well as melted chunks of the crusts, mantles, and cores of differentiated objects. Anhydrous bodies were important building blocks of the rocky terrestrial planets, and their chemical compositions reveal details of processes that occurred within our own planet on a larger scale. The distributions of these asteroids within the solar system also provide insights into their formation and evolution.
Dry asteroids and meteorites
Anhydrous planetesimals formed within the inner solar system, unlike the ice-bearing bodies discussed in the next chapter. These objects, composed of rock and metal, were the primary building blocks of the terrestrial planets. Relics of that population may survive today as asteroids that dominate the inner portions of the main belt.
Asteroids have been a focus of spectroscopic studies for decades. Spectra obtained from telescopes on the Earth can identify some of the minerals that make up asteroids, but do not measure asteroid chemistry. Nevertheless, spectroscopic matches can be used to link some meteorite classes to their probable parent bodies, and thus allow indirect assessments of their chemical compositions. A few asteroids have been visited and analyzed by spacecraft. Chemical analyses require long data integrations from orbit or actually landing on the surface, and analyses of only two small near-Earth asteroids have been reported.
Most meteorites (~86%) are chondrites, which are primitive rocks that have elemental compositions similar to that of the Sun. They are named for the millimeter-sized droplets of quenched silicate melt, called chondrules, that are particularly abundant in these meteorites. Chondrites come from the asteroid belt. They are physical mixtures of accreted components (chondrules, refractory inclusions, metal and sulfide, dust) whose characteristics and mineralogy we will describe. The classification of chondrites utilizes a combination of primary features (bulk chemical composition, oxygen isotopes) and secondary features (thermal metamorphism or aqueous alteration). About 14% of meteorites arriving on Earth consist of differentiated materials. Their compositions have been affected by melting and crystallization, and they include various kinds of achondritic meteorites, irons, and stony irons from the asteroid belt, along with lunar samples and Martian me