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1.
J Med Philos ; 48(3): 243-251, 2023 05 16.
Artículo en Inglés | MEDLINE | ID: mdl-37078977

RESUMEN

The frequency of death from miscarriage is very high, greater than the number of deaths from induced abortion or major diseases. Berg (2017 , Philosophical Studies 174:1217-26) argues that, given this, those who contend that personhood begins at conception (PAC) are obliged to reorient their resources accordingly-towards stopping miscarriage, in preference to stopping abortion or diseases. This argument depends on there being a basic moral similarity between these deaths. I argue that, for those that hold to PAC, there are good reasons to think that there is no such similarity. There is a morally relevant difference between preventing killing and letting die, giving PAC supporters reasons to prioritize reducing abortion over reducing miscarriage. And the time-relative interest account provides a morally relevant difference in the badness of death of miscarriages and deaths of born adults, justifying attempts to combat major diseases over attempts to combat miscarriage. I consider recent developments in the literature and contend that these new arguments are unsuccessful in establishing moral similarities between deaths from miscarriage and abortion, and deaths from miscarriage and disease.


Asunto(s)
Aborto Inducido , Aborto Espontáneo , Embarazo , Adulto , Femenino , Humanos , Personeidad , Principios Morales , Disentimientos y Disputas , Valor de la Vida , Obligaciones Morales , Comienzo de la Vida Humana
2.
Health Phys ; 123(5): 348-359, 2022 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-35951340

RESUMEN

ABSTRACT: Anecdotal evidence indicates there may be unpublished physical and psychological events associated with the medical treatment of plutonium intakes. A thorough review was conducted of the medical and bioassay records of current and previous Los Alamos National Laboratory (LANL) employees who had experienced plutonium intakes via wound or inhalation. After finding relatively incomplete information in the medical records, the research team interviewed current LANL employees who had undergone chelation therapy and/or surgical excision. Although the dataset is not large enough to reach statistically significant conclusions, it was observed that adverse events associated with treatment appear to be more frequent and more severe than previously reported.


Asunto(s)
Plutonio , Bioensayo , Terapia por Quelación , Humanos , Registros Médicos , Plutonio/efectos adversos , Plutonio/análisis , Estudios Retrospectivos
3.
Fisc Stud ; 43(1): 63-78, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-34538976

RESUMEN

In 2019, the employment rate among 25- to 64-year-olds in the UK reached 80 per cent - the highest on record, and considerably higher than the 76 per cent rate recorded shortly before the Great Recession. In this paper, we investigate the growth in employment between the eve of the Great Recession and the eve of COVID-19 across several dimensions. We analyse which sectors, demographic groups and regions accounted for the rise. We also investigate how job 'quality' - in both financial and non-financial terms - has changed. We find that almost all demographic groups and regions saw a rise in employment, especially those with low pre-existing employment rates and those near the bottom of the income distribution. Hourly pay growth was very weak over the period, with the median actually slightly falling. Other indicators of job quality show a more mixed picture: employees seem to have greater appreciation of their work and firm, but perceive less security and flexibility in their job.

4.
Health Phys ; 119(6): 690-703, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33196522

RESUMEN

The urinary excretion and wound retention data collected after a Pu-contaminated wound were analyzed using Markov Chain Monte Carlo (MCMC) to obtain the posterior distribution of the intakes and doses. An empirical approach was used to model the effects of medical treatments (chelation and excision) on the reduction of doses. It was calculated that DTPA enhanced the urinary excretion, on average, by a factor of 17. The empirical analysis also allowed calculation of the efficacies of the medical treatments-excision and chelation averted approximately 76% and 5.5%, respectively, of the doses that would have been if there were no medical treatment. All bioassay data are provided in the appendix for independent analysis and to facilitate the compartmental modeling approaches being developed by the health physics community.


Asunto(s)
Quelantes/uso terapéutico , Terapia por Quelación/métodos , Plutonio/orina , Traumatismos por Radiación/prevención & control , Heridas Penetrantes/tratamiento farmacológico , Heridas Penetrantes/cirugía , Bioensayo , Humanos , Modelos Biológicos , Plutonio/efectos adversos , Traumatismos por Radiación/diagnóstico , Traumatismos por Radiación/orina , Heridas Penetrantes/etiología
5.
Health Phys ; 119(6): 704-714, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33196523

RESUMEN

The three principal pathways for intakes of plutonium are ingestion, inhalation, and contaminated wounds. In August 2018, a glovebox worker at Los Alamos National Laboratory (LANL) sustained a puncture from a thread of a braided steel cable contaminated with Pu. The puncture produced no pain, no blood, and little or no visible mark. As a result, the potential for a contaminated wound was not immediately recognized, and a wound count was not conducted until elevated urine bioassay results were received 12 d after the incident. This paper discusses the circumstances of the incident, along with the medical response and dose assessment, and a discussion of the risks and benefits of the medical interventions.


Asunto(s)
Bioensayo/métodos , Laboratorios/estadística & datos numéricos , Exposición Profesional/análisis , Plutonio/orina , Punciones/métodos , Traumatismos por Radiación/diagnóstico , Piel/patología , Relación Dosis-Respuesta en la Radiación , Humanos , Exposición Profesional/efectos adversos , Plutonio/efectos adversos , Traumatismos por Radiación/etiología , Traumatismos por Radiación/orina , Monitoreo de Radiación/métodos , Piel/efectos de la radiación
6.
Health Phys ; 119(6): 715-732, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33196524

RESUMEN

The administration of chelation therapy to treat significant intakes of actinides, such as plutonium, affects the actinide's normal biokinetics. In particular, it enhances the actinide's rate of excretion, such that the standard biokinetic models cannot be applied directly to the chelation-affected bioassay data in order to estimate the intake and assess the radiation dose. The present study proposes a new chelation model that can be applied to the chelation-affected bioassay data after plutonium intake via wound and treatment with DTPA. In the proposed model, chelation is assumed to occur in the blood, liver, and parts of the skeleton. Ten datasets, consisting of measurements of C-DTPA, Pu, and Pu involving humans given radiolabeled DTPA and humans occupationally exposed to plutonium via wound and treated with chelation therapy, were used for model development. The combined dataset consisted of daily and cumulative excretion (urine and feces), wound counts, measurements of excised tissue, blood, and post-mortem tissue analyses of liver and skeleton. The combined data were simultaneously fit using the chelation model linked with a plutonium systemic model, which was linked to an ad hoc wound model. The proposed chelation model was used for dose assessment of the wound cases used in this study.


Asunto(s)
Bioensayo/métodos , Quelantes/uso terapéutico , Exposición Profesional/análisis , Ácido Pentético/uso terapéutico , Plutonio/análisis , Traumatismos por Radiación/prevención & control , Heridas Penetrantes/tratamiento farmacológico , Huesos/metabolismo , Terapia por Quelación/métodos , Interpretación Estadística de Datos , Heces/química , Humanos , Hígado/metabolismo , Masculino , Modelos Biológicos , Exposición Profesional/efectos adversos , Plutonio/efectos adversos , Dosis de Radiación , Traumatismos por Radiación/diagnóstico , Traumatismos por Radiación/orina , Urinálisis , Heridas Penetrantes/etiología
7.
Health Phys ; 118(2): 193-205, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31833972

RESUMEN

Chelating agents are administered to treat significant intakes of radioactive elements such as plutonium, americium, and curium. These drugs may be used as a medical countermeasure after radiological accidents and terrorist acts. The administration of a chelating agent, such as Ca-DTPA or Zn-DTPA, affects the actinide's normal biokinetics. It enhances the actinide's rate of excretion, posing a dose assessment challenge. Thus, the standard biokinetic models cannot be directly applied to the chelation-affected bioassay data in order to assess the radiation dose. The present study reviews the scientific literature, from the early 1970s until the present, on the different studies that focused on developing new chelation models and/or modeling of bioassay data affected by chelation treatment. Although scientific progress has been achieved, there is currently no consensus chelation model available, even after almost 50 y of research. This review acknowledges the efforts made by different research groups, highlighting the different methodology used in some of these studies. Finally, this study puts into perspective where we were, where we are, and where we are heading in regards to chelation modeling.


Asunto(s)
Terapia por Quelación/métodos , Dosis de Radiación , Traumatismos por Radiación/tratamiento farmacológico , Americio/química , Americio/farmacocinética , Animales , Quelantes/uso terapéutico , Humanos , Modelos Animales , Modelos Biológicos , Plutonio/química , Plutonio/farmacocinética
8.
J Radiol Prot ; 39(1): 208-248, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30523984

RESUMEN

The bioassay data collected from several workers involved in 238Pu inhalation incidents have been analysed using the most recent biokinetic models described in the Occupational Intakes of Radionuclides (OIR) series of publications. Although all exposures were thought to be to 238Pu oxides, the observed urinary excretion patterns differed in different inhalation incidents. The urinary excretion from individuals involved in one of the incidents increased steadily with time, peaking around two to three years before decreasing. This pattern is described in Part 4 of the OIR series using the '238PuO2, ceramic' model. This non-monotonic behaviour, explained as being due to fragmentation and dissolution, was not specific to the incident, but observed in other incidents. The urinary excretion data collected from individuals involved in another incident showed dissolution behaviour between Type M and Type S. Finally, the bioassay data from yet another incident showed a pattern that appears to represent behaviour more insoluble than Type S, which is possibly a result of self-heating due to the decay heat from 238Pu. The urinary excretion patterns and corresponding dose coefficients have been calculated and compared.


Asunto(s)
Modelos Biológicos , Exposición Profesional/análisis , Plutonio/farmacocinética , Bioensayo , Humanos , Urinálisis
9.
Health Phys ; 115(3): 397-401, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-30045124

RESUMEN

Investigations into possible actinide intakes, as well as the intakes themselves, may result in significant psychological harm that should be mitigated by the internal dosimetrist. Many aspects of this psychological impact are unique to actinide intakes and have not been discussed in the literature. This paper discusses some of these unique considerations and describes how the Internal Dosimetry Team at Los Alamos National Laboratory (LANL) has, with input and guidance from LANL psychologists, tried to address them. We feel that much of the psychological harm can be mitigated by educating employees specifically about internal dosimetry and internal doses, and by improving communication with radiation workers.


Asunto(s)
Elementos de Series Actinoides/metabolismo , Elementos de Series Actinoides/toxicidad , Exposición Profesional , Estrés Psicológico/etiología , Estrés Psicológico/prevención & control , Humanos , Dosis de Radiación , Protección Radiológica , Riesgo
10.
Health Phys ; 114(3): 307-318, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-29360709

RESUMEN

After a plutonium-contaminated wound, the role of an internal dosimetrist is to inform the patient and the physician of the dosimetric considerations. The doses averted due to medical treatments (excision or chelation) are higher if the treatments are administered early; therefore, the internal dosimetrist needs to rely on limited information on wound counts and process knowledge for advising the physician. Several wound cases in the literature were reviewed to obtain estimates of the efficacies of surgical excision and chelation treatment after plutonium-contaminated wounds. The dose coefficients calculated by coupling the NCRP 156 wound model with the systemic model were used to derive the decision guidelines that may indicate medical treatment based on 1) the concept of saved doses proposed by the NCRP 156 wound model, 2) the limits recommended by the CEC/DOE guidebook, and 3) the Clinical Decision Guidelines proposed in NCRP Report No. 161. These guidelines by themselves, however, are of limited use for several reasons, including 1) large uncertainties associated with wound measurements, 2) exposure to forms of radionuclides that cannot be assigned to a single category in the NCRP 156 framework, 3) inability of the NCRP 156 model to explain some of the wound cases in the literature, 4) neglect of the local doses to the wound site and the pathophysiological response of the tissue, 5) poorly understood relationship between effective doses and risks of late health effects, and 6) disregard of the psychological aspects of radionuclide intake.


Asunto(s)
Quelantes/uso terapéutico , Plutonio/efectos adversos , Traumatismos por Radiación/prevención & control , Heridas y Lesiones/tratamiento farmacológico , Heridas y Lesiones/cirugía , Simulación por Computador , Humanos , Modelos Biológicos , Heridas y Lesiones/etiología
11.
Health Phys ; 115(6): 712-726, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33289996

RESUMEN

The main concern of operational internal dosimetry is to detect intakes and estimate doses to the worker from a series of bioassay measurements. Although several methods are available, the inverse problem of internal dosimetry-i.e., determination of time, amount, and types of intake given a set of bioassay data-is well suited to a Bayesian approach. This paper summarizes the Bayesian methodology used at Los Alamos National Laboratory to detect intakes and estimate doses from plutonium bioassay measurements. Some advantages and disadvantages of the method are also discussed. The successful application of Bayesian methods for several years at Los Alamos National Laboratory, which monitors thousands of workers annually for plutonium, indicates that the methods can be extended to other facilities.

12.
Radiat Prot Dosimetry ; 178(2): 170-178, 2018 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-28985423

RESUMEN

The National Council on Radiation Protection (NCRP)-156 Report proposes seven different biokinetic models for wound cases depending on the physicochemistry of the contaminant. Because the models were heavily based on experimental animal data, the authors of the report encouraged application and validation of the models using bioassay data from actual human exposures. Each of the wound models was applied to three plutonium-contaminated wounds, and the models resulted in a good agreement to only one of the cases. We then applied a simpler biokinetic model structure to the bioassay data and showed that fitting the transfer rates from this model structure yielded better agreement with the data than does the best-fitting NCRP-156 model. Because the biokinetics of radioactive material in each wound is different, it is impractical to propose a discrete set of model parameters to describe the biokinetics of radionuclides in all wounds, and thus each wound should be treated empirically.


Asunto(s)
Bioensayo/métodos , Exposición Profesional/análisis , Plutonio/análisis , Plutonio/orina , Traumatismos por Radiación/orina , Humanos , Estados Unidos
13.
Eur J Mass Spectrom (Chichester) ; 24(1): 43-48, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29233003

RESUMEN

Two gas-phase catalytic cycles involving C-F bond activation of trifluoroethanol and trifluoroacetic acid were detected by multistage mass spectrometry experiments. A binuclear dimolybdate centre [Mo2O6(F)]- acts as the catalyst in each cycle. The first cycle, entered via the reaction of [Mo2O6(OH)]- with trifluoroethanol and elimination of water to form [Mo2O6(OCH2CF3)]-, proceeds via four steps: (1) oxidation of the alkoxo ligand and its elimination as aldehyde; (2) reaction of [Mo2O5(OH)]- with trifluoroethanol and elimination of water to form [Mo2O5(OCH2CF3)]; (3) decomposition of the alkoxo ligand via loss of 1,1 difluoroethene; and (4) reaction of [Mo2O6(F)]- with a second equivalent of trifluoroethanol to regenerate Mo2O6(OCH2CF3)]-. Steps (2) and (3) do not occur at room temperature and require collisional activation to proceed. The second cycle is entered via the reaction of [Mo2O6(OH)]- with trifluoroacetic acid and elimination of water to form [Mo2O6(O2CCF3)]- and involves two steps only: (1) fluoride transfer to a molybdenum centre to form [Mo2O6(F)]-; (2) reaction of [Mo2O6(F)]- with trifluoroacetic acid and loss of water to regenerate [Mo2O6(O2CCF3)]-. Comparisons are made with the chemistry of [Mo2O6(OH)]- reacting with acetic acid.

14.
Health Phys ; 113(4): 315-323, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28846588

RESUMEN

Complying with regulations for bioassay monitoring of radionuclide intakes is significantly more complex for mixtures than it is for pure radionuclides. Different constituents will naturally have different dose coefficients, be detectable at significantly different levels, and may require very different amounts of effort to bioassay. The ability to use certain constituents as surrogates for others will depend on how well characterized the mixture is, as well as whether the employee is also working with other radionuclides. This is further compounded by the fact that the composition of a mixture (or even of a pure radionuclide) is likely to change over time. Internal dosimetrists must decide how best to monitor employees who work with radionuclide mixtures. In particular, they must decide which constituents should be monitored routinely, which constituents only need to be monitored in the case of an intake, and how to estimate doses based on intakes of monitored and unmonitored constituents.


Asunto(s)
Bioensayo/métodos , Monitoreo de Radiación/métodos , Radioisótopos/análisis , Humanos , Dosímetros de Radiación , Exposición a la Radiación/análisis
15.
Health Phys ; 113(3): 209-219, 2017 09.
Artículo en Inglés | MEDLINE | ID: mdl-28749811

RESUMEN

The NCRP 156 wound model was heavily based on data from animal experiments. The authors of the report acknowledged this limitation and encouraged validation of the models using data from human wound exposures. The objective of this paper was to apply the NCRP 156 wound models to the bioassay data from four plutonium-contaminated wound cases reported in the literature. Because a wide variety of forms of plutonium can be expected at a nuclear facility, a combination of the wound models-rather than a single model-was used to successfully explain both the urinary excretion data and wound retention data in three cases. The data for the fourth case could not be explained by any combination of the default wound models. While this may possibly be attributed to the existence of a category of plutonium whose solubility and chemistry are different than those described by the NCRP 156 default categories, the differences may also be the result of differences in systemic biokinetics. The concept of using a combination of biokinetic models may be extended to inhalation exposures as well, where more than one form of radionuclide-particles of different solubility or different sizes-may exist in a workplace.


Asunto(s)
Bioensayo , Modelos Biológicos , Plutonio/efectos adversos , Traumatismos por Radiación/etiología , Cinética
16.
Health Phys ; 113(1): 30-40, 2017 07.
Artículo en Inglés | MEDLINE | ID: mdl-28542009

RESUMEN

After a chelation treatment, assessment of intake and doses is the primary concern of an internal dosimetrist. Using the urinary excretion data from two actual wound cases encountered at Los Alamos National Laboratory (LANL), this paper discusses several methods that can be used to interpret intakes from the urinary data collected after one or multiple chelation treatments. One of the methods uses only the data assumed to be unaffected by chelation (data collected beyond 100 d after the last treatment). This method, used by many facilities for official dose records, was implemented by employing maximum likelihood analysis and Bayesian analysis methods. The impacts of an improper assumption about the physicochemical behavior of a radioactive material and the importance of the use of a facility-specific biokinetic model when available have also been demonstrated. Another method analyzed both the affected and unaffected urinary data using an empirical urinary excretion model. This method, although case-specific, was useful in determining the actual intakes and the doses averted or the reduction in body burdens due to chelation treatments. This approach was important in determining the enhancement factors, the behavior of the chelate, and other observations that may be pertinent to several DTPA compartmental modeling approaches being conducted by the health physics community.


Asunto(s)
Modelos Biológicos , Ácido Pentético/uso terapéutico , Plutonio/orina , Traumatismos por Radiación/prevención & control , Traumatismos por Radiación/orina , Micción , Terapia por Quelación/métodos , Simulación por Computador , Humanos , Masculino , Tasa de Depuración Metabólica , Plutonio/farmacocinética , Dosis de Radiación , Monitoreo de Radiación/métodos , Resultado del Tratamiento , Heridas Penetrantes/metabolismo , Heridas Penetrantes/terapia
17.
Health Phys ; 112(5): 465-469, 2017 05.
Artículo en Inglés | MEDLINE | ID: mdl-28350701

RESUMEN

For radionuclides such as plutonium and americium, detection of removable activity in the nose (i.e., nasal swab measurements) are frequently used to determine whether follow-up bioassay measurements are warranted following a potential intake. For this paper, the authors analyzed 429 nasal swab measurements taken following incidents or suspicious circumstances (such as an air monitor alarming) at Los Alamos National Laboratory (LANL) for which the dose was later evaluated using in vitro bioassay. Nasal swab measurements were found to be very poor predictors of dose and should not be used as such in the field. However, nasal swab measurements can be indicative of whether a reliably detectable committed effective dose (CED) occurred. About 14% of nasal swab measurements between 1.25 and 16.7 Bq corresponded to CEDs greater than 1 mSv, so in general, positive nasal swabs always indicate that follow-up bioassay should be performed (positive nasal swabs less than 1.25 Bq are considered separately). This probability increased significantly for nasal swabs greater than 16.7 Bq. Only about 3% of nasal swabs with no detectable activity (NDA) corresponded to reliably detectable CEDs. A nasal swab with NDA is therefore necessary, but not sufficient, to negate the need for a follow-up bioassay if it was collected following other workplace indicators of a potential intake.


Asunto(s)
Aerosoles/análisis , Contaminantes Radiactivos del Aire/análisis , Americio/análisis , Bioensayo/métodos , Mucosa Nasal/química , Plutonio/análisis , Monitoreo de Radiación/métodos , Humanos , Dosis de Radiación , Exposición a la Radiación/análisis , Liberación de Radiactividad Peligrosa , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
18.
J Phys Chem A ; 117(6): 1124-35, 2013 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-22889366

RESUMEN

The gas-phase reactivity of the vanadium hydroxides [VO(2)(OH)(2)](-) and [V(2)O(5)(OH)](-) toward methanol was examined using a combination of ion-molecule reactions (IMRs) and collision-induced dissociation (CID) in a quadrupole ion trap mass spectrometer. Isotope-labeling experiments with CD(3)OH, (13)CH(3)OH, and CH(3)(18)OH were used to confirm the stoichiometry of ions and the observed sequence of reactions. The experimental data were interpreted with the aid of density functional theory calculations, carried out at the B3LYP/SDD6-311++G** level of theory. While [VO(2)(OH)(2)](-) is unreactive, [V(2)O(5)(OH)](-) undergoes a metathesis reaction to yield [V(2)O(5)(OCH(3))](-). The DFT calculations reveal that the metathesis reaction of methanol with [VO(2)(OH)(2)](-) suffers from a barrier of +0.52 eV (relative to separated reactants) but that the reaction of [V(2)O(5)(OH)](-) with methanol readily proceeds via addition/elimination reactions with both transition states being below the energy of the separated reactants. CID of [V(2)O(5)(OCH(3))](-) (m/z 213) yields three ions arising from activation of the methoxo ligand: [V(2), O(6), C, H](-) (m/z 211); [V(2), O(5), H](-) (m/z 183); and [V(2), O(4), H](-) (m/z 167). Additional experiments and DFT calculations suggest that these ions arise from losses of H(2), formaldehyde and the sequential losses of H(2) and CO(2), respectively. The use of an (18)O-labeled methoxo ligand in [V(2)O(5)((18)OCH(3))](-) (m/z 215) showed the competing losses of H(2)C(16)O and H(2)C(18)O and [H(2) and C(16)O(18)O] and [H(2) and C(16)O(2)], highlighting that (16)O/(18)O exchange between the methoxo ligand and the vanadium oxide occurs prior to the subsequent fragmentation of the ligand. DFT calculations reveal that a key step involves hydrogen atom transfer from the methoxo ligand to the oxo ligand of the same vanadium center, producing the intermediate [V(2)O(4)(OH)(OCH(2))](-) containing a ketyl radical ligand and a hydroxo ligand. This intermediate can either undergo CH(2)O loss, or the ketyl radical can couple with an oxo ligand of the adjacent vanadium center, producing [V(2)O(3)(µ(2)-O(2)CH(2))](-), which is a key intermediate in the (16)O/(18)O scrambling and in the H(2) loss channel.


Asunto(s)
Hidróxidos/química , Metanol/química , Teoría Cuántica , Compuestos de Vanadio/química , Gases/química
19.
Chemistry ; 17(27): 7454-9, 2011 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-21633980

RESUMEN

The combination of Cu(NO(3))(2), potassium hydrogen saccharate (KC(6)H(9)O(8)) and 1,10-phenanthroline (phen) yields a pair of chiral cluster compounds, each with composition Cu(21)(C(6)H(5)O(8))(6)(phen)(12)(NO(3))(12) ⋅solvate. One of the compounds forms as orthorhombic crystals, while the other forms cubic crystals. Each of the clusters has D(3) or approximate D(3) symmetry, but the arrangement of the saccharate ion in the clusters is quite different in the two cases. The clusters in the cubic form interact with neighbouring clusters through face-to-face π interactions involving the phen ligands, an association that leads to the generation of very large solvent-filled spaces in the crystal structure. In contrast the clusters in the orthorhombic form are much more densely packed. At the centre of each cluster that crystallises in the orthorhombic form is a nitrate anion that binds to six Cu(II) centres. ESI mass spectral studies indicate that the Cu(21) clusters exist in solution. Solid-state magnetic studies of the cubic form of Cu(21) show that antiferromagnetic coupling occurs to leave a non-zero-spin ground state, and comparisons are made to the magnetic data for other large Cu(II) clusters.


Asunto(s)
Cobre/química , Compuestos Organometálicos/síntesis química , Aniones/química , Ligandos , Modelos Moleculares , Conformación Molecular , Compuestos Organometálicos/química
20.
Health Phys ; 99(4): 532-8, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20838095

RESUMEN

Chelation treatments with dosages of 1 g of either Ca-DTPA (Trisodium calcium diethylenetriaminepentaacetate) or Zn-DTPA (Trisodium zinc diethylenetriaminepentaacetate) were undertaken at Los Alamos Occupational Medicine in three recent cases of wounds contaminated with metallic forms of Pu. All cases were finger punctures, and each chelation injection contained the same dosage of DTPA. One subject was treated only once, while the other two received multiple injections. Additional measurements of wound, urine, and excised tissues were taken for one of the cases. These additional measurements served to improve the estimate of the efficacy of the chelation treatment. The efficacy of the chelation treatments was compared for the three cases. Results were interpreted using models, and useful heuristics for estimating the intake amount and final committed doses were presented. In spite of significant differences in the treatments and in the estimated intake amounts and doses amongst the three cases, a difference of four orders of magnitude was observed between the highest excretion data point and the values observed at about 100 d for all cases. Differences between efficacies of Zn-DTPA and Ca-DTPA could not be observed in this study. An efficacy factor of about 50 was observed for a chelation treatment, which was administered at about 1.5 y after the incident, though the corresponding averted dose was very small (LA-UR 09-02934).


Asunto(s)
Quelantes/farmacología , Laboratorios , Física Nuclear , Exposición Profesional/análisis , Ácido Pentético/farmacología , Plutonio/farmacocinética , Carga Corporal (Radioterapia) , Calibración , Quelantes/administración & dosificación , Simulación por Computador , Descontaminación , Humanos , New Mexico , Ácido Pentético/administración & dosificación , Plutonio/aislamiento & purificación , Plutonio/orina , Traumatismos por Radiación/metabolismo , Traumatismos por Radiación/prevención & control , Protectores contra Radiación/administración & dosificación , Protectores contra Radiación/farmacología , Efectividad Biológica Relativa , Factores de Tiempo
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