289 research outputs found
Interaction of gases with lunar materials
The surface properties of lunar fines were investigated. Results indicate that, for the most part, these properties are independent of the chemical composition and location of the samples on the lunar surface. The leaching of channels and pores by adsorbed water vapor is a distinguishing feature of their surface chemistry. The elements of air, if adsorbed in conjunction with water vapor or liquid water, severely impedes the leaching process. In the absence of air, liquid water is more effective than water vapor in attacking the grains. The characteristics of Apollo 17 orange fines were evaluated and compared with those of other samples. The interconnecting channels produced by water vapor adsorption were found to be wider than usual for other types of fines. Damage tracks caused by heavy cosmic ray nuclei and an unusually high halogen content might provide for stronger etching conditions upon exposure to water vapor
Talking and Making Meaning About Parental Mental Health Problems: the Role of Children's Family Caregivers
When parents with severe and enduring mental health problems (MHP) are less able to meet their children’s needs, other family members often help with childcare. Research with children and parents with MHP has pointed to the vital role family caregivers play in helping children make meaning and communicate about their parents’ MHP. The caregiver’s perspective on this, however, is barely known. The purpose of this study was to examine how children’s family caregivers contribute to children’s meaning-making about parental MHP. In-depth interviews were conducted with 19 adults living in England and Wales who supported at least one related child aged 4-17 who had a parent with MHP. A substantive theory was developed using constructivist Grounded Theory. It was found that participants engaged in a core social process of providing protection in uncertainty, through which they sought to protect the child, the parent, the self, and the wider family. In making meaning and communicating with children, participants were concerned with shaping the interactional space, communicating through the developmental process, and engendering a sense of safety. Participants appeared to position themselves to the childcare role by assessing the child’s needs, the parent’s needs and their own needs. This was conceptualised as developing a caregiver identity, and seen to shape their contributions to children’s meaning-making. A large amount of communication was found to occur nonverbally, and seemingly without caregiver intent or awareness. The findings support the agenda for family-focused provision of mental health and social care. Clinical recommendations are made for better psychoeducation for caregivers and their inclusion in interventions with children and parents with MHP
Interaction of gases with lunar materials
The surface chemistry of Apollo 17 lunar fines samples 74220 (the orange soil) and 74241 (the gray control soil) has been studied by measuring the adsorption of nitrogen, argon, and oxygen (all at 77 K) and also water vapor (at 20 or 22 C). In agreement with results for samples from other missions, both samples had low initial specific surface areas, consisted of nonporous particles, and were attacked by water vapor at high relative pressure to give an increased specific surface area and create a pore system which gave rise to a capillary condensation hysteresis loop in the adsorption isotherms. In contrast to previous samples, both of the Apollo 17 soils were partially hydrophobic in their initial interaction with water vapor (both samples were completely hydrophilic after the reaction with water). The results are consistent with formation at high temperatures without subsequent exposure to significant amounts of water
Interaction of gases with lunar materials
Quantitative efforts to assess the surface properties of lunar fines, particularly water induced porosity are discussed. Data show that: (1) changes induced in lunar fines are not visible in high energy electron micrographs, (2) scanning micrographs show no change in particle size distribution as a result of reaction with water, (3) water induced changes are internal to the particles themselves, (4) normal laboratory atmosphere blocks alteration reaction with water, and (5) surface properties of mature lunar soils appear to be almost independent of chemical composition and mineralogy, but there are some variations in their reactivity toward water
Research on stimulated exoelectron emission from lunar materials Technical progress report
Preliminary results on thermally stimulated exoelectron emission from Apollo 12 lunar material
Therapeutic Manipulation of mtDNA Heteroplasmy : A Shifting Perspective
Mutations of mitochondrial DNA (mtDNA) often underlie mitochondrial disease, one of the most common inherited metabolic disorders. Since the sequencing of the human mitochondrial genome and the discovery of pathogenic mutations in mtDNA more than 30 years ago, a movement towards generating methods for robust manipulation of mtDNA has ensued, although with relatively few advances and some controversy. While developments in the transformation of mammalian mtDNA have stood still for some time, recent demonstrations of programmable nuclease-based technology suggest that clinical manipulation of mtDNA heteroplasmy may be on the horizon for these largely untreatable disorders. Here we review historical and recent developments in mitochondrially targeted nuclease technology and the clinical outlook for treatment of hereditary mitochondrial disease.Peer reviewe
Genome editing in mitochondria corrects a pathogenic mtDNA mutation in vivo.
Mutations of the mitochondrial genome (mtDNA) underlie a substantial portion of mitochondrial disease burden. These disorders are currently incurable and effectively untreatable, with heterogeneous penetrance, presentation and prognosis. To address the lack of effective treatment for these disorders, we exploited a recently developed mouse model that recapitulates common molecular features of heteroplasmic mtDNA disease in cardiac tissue: the m.5024C>T tRNAAla mouse. Through application of a programmable nuclease therapy approach, using systemically administered, mitochondrially targeted zinc-finger nucleases (mtZFN) delivered by adeno-associated virus, we induced specific elimination of mutant mtDNA across the heart, coupled to a reversion of molecular and biochemical phenotypes. These findings constitute proof of principle that mtDNA heteroplasmy correction using programmable nucleases could provide a therapeutic route for heteroplasmic mitochondrial diseases of diverse genetic origin
The Atrial Fibrillation Risk Score for Hyperthyroidism Patients
Thyrotoxicosis (TT) is associated with an increase in both total and
cardiovascu-lar mortality. One of the main thyrotoxicosis risks is Atrial
Fibrillation (AF). Right AF predicts help medical personal prescribe the
correct medicaments and correct surgical or radioiodine therapy. The main goal
of this study is creating a method for practical treatment and diagnostic AF.
This study proposes a new method for assessing the risk of occurrence atrial
fibrillation for patients with TT. This method considers both the features of
the complication and the specifics of the chronic disease. A model is created
based on case histories of patients with thyrotoxicosis. We used Machine
Learning methods for creating several models. Each model has advantages and
disadvantages depending on the diagnostic and medical purposes. The resulting
models show high results in the different metrics of the prediction of AF.
These models interpreted and simple for use. Therefore, models can be used as
part of the support and decision-making system (DSS) by medical specialists in
the treatment and diagnostic of AF
Near-complete elimination of mutant mtDNA by iterative or dynamic dose-controlled treatment with mtZFNs.
Mitochondrial diseases are frequently associated with mutations in mitochondrial DNA (mtDNA). In most cases, mutant and wild-type mtDNAs coexist, resulting in heteroplasmy. The selective elimination of mutant mtDNA, and consequent enrichment of wild-type mtDNA, can rescue pathological phenotypes in heteroplasmic cells. Use of the mitochondrially targeted zinc finger-nuclease (mtZFN) results in degradation of mutant mtDNA through site-specific DNA cleavage. Here, we describe a substantial enhancement of our previous mtZFN-based approaches to targeting mtDNA, allowing near-complete directional shifts of mtDNA heteroplasmy, either by iterative treatment or through finely controlled expression of mtZFN, which limits off-target catalysis and undesired mtDNA copy number depletion. To demonstrate the utility of this improved approach, we generated an isogenic distribution of heteroplasmic cells with variable mtDNA mutant level from the same parental source without clonal selection. Analysis of these populations demonstrated an altered metabolic signature in cells harbouring decreased levels of mutant m.8993T>G mtDNA, associated with neuropathy, ataxia, and retinitis pigmentosa (NARP). We conclude that mtZFN-based approaches offer means for mtDNA heteroplasmy manipulation in basic research, and may provide a strategy for therapeutic intervention in selected mitochondrial diseases.Medical Research Council, UK; EMBO Fellowship [ALTF 701-2013 to L.V.H.]; PhD fellowship from the Foundation for Science and Technology, Portugal through the GABBA Program, University of Porto (to P.R.G.); Experiments undertaken in the J-PC laboratory were supported by ANR Investissement d’Avenir [ANR-IIINSB-0014] and AFM [18566].This is the final version of the article. It first appeared from Oxford University Press via http://dx.doi.org/10.1093/nar/gkw67
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Use of passive alpha detectors to screen for uranium contamination in a field at Fernald, Ohio
This paper reports the results from a field test of newly developed techniques for inexpensive, in situ screening of soil for alpha contamination. Passive alpha detectors that are commercially available for the detection indoor airborne alpha activity (i.e., {sup 222}Rn) have been modified so they can be applied to the detection of alpha contamination on surfaces or in soils. Results reported here are from an intercomparison involving several different techniques with all measurements being made at the same sites in a field near the formerly used uranium processing facility at Fernald, Ohio, during the summer of 1994. The results for two types of passive alpha detector show that the quality of calibration is improved if soils samples are milled to increase homogeneity within the soil matrices. The correlation between laboratory based radiochemical analyses and quick, field-based screening measurements is acceptable and can be improved if the passive devices are left for longer exposure times in the field. The total cost per measurement for either type of passive alpha detector is probably less than $25 and should provide a cost-effective means for site managers to develop the information needed to find areas with remaining alpha contamination so resources can be allocated efficiently
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