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1.
Artigo em Inglês | MEDLINE | ID: mdl-38541314

RESUMO

This article reports the results of an investigation into the activity concentration of natural radionuclides in raw building materials for underground parking lots, together with the assessment of the radiation hazard for the public related to exposure to ionizing radiations. To this purpose, high-purity germanium (HPGe) γ-ray spectrometry was employed in order to quantify the average specific activity of 226Ra, 232Th, and 40K natural radioisotopes. With the aim to assess any possible radiological health risk for the population, the absorbed γ-dose rate (D), the annual effective dose equivalent outdoor (AEDEout) and indoor (AEDEin), the activity concentration index (I), and the alpha index (Iα) were also estimated, resulting in values that were lower than the maximum recommended ones for humans. Finally, the extent of the correlations existing between the observed radioactivity and radiological parameters and of these parameters with the analyzed samples was quantified through statistical analyses, including Pearson's correlation, a principal component analysis (PCA), and a hierarchical cluster analysis (HCA). As a result, three clusters of the investigated samples were recognized based on their chemical composition and mineralogical nature. Noteworthily, this paper covers a certain gap in science since its topic does not appear in literature in this form. Thus, the authors underline the importance of this work to global knowledge in the environmental research and public health fields.


Assuntos
Monitoramento de Radiação , Radioatividade , Rádio (Elemento) , Poluentes Radioativos do Solo , Humanos , Monitoramento de Radiação/métodos , Radioisótopos/análise , Saúde Radiológica , Espectrometria gama , Materiais de Construção/análise , Tório/análise , Radioisótopos de Potássio/análise , Rádio (Elemento)/análise , Poluentes Radioativos do Solo/análise
2.
Am J Community Psychol ; 73(3-4): 541-553, 2024 06.
Artigo em Inglês | MEDLINE | ID: mdl-38303603

RESUMO

Neighborhoods are one of the key determinants of health disparities among young people in the United States. While neighborhood deprivation can exacerbate health disparities, amenities such as quality parks and greenspace can support adolescent health. Existing conceptual frameworks of greening-health largely focus on greenspace exposures, rather than greening interventions. In this paper, we develop and propose a Greening Theory of Change that explains how greening initiatives might affect adolescent health in deprived neighborhoods. The theory situates greening activities and possible mechanisms of change in the context of their ability to modify distal social determinants of health factors, stemming from macrostructural and historical processes that lead to resource inequalities, affecting both the social and built environment in which adolescents live and develop. The framework illustrates both short- and long-term health, economic, and security effects of greening. We also describe how the theory informed the development of Project VITAL (Vacant lot Improvement to Transform Adolescent Lives) in Baltimore, MD, which aims to (1) build a citywide sharable database on vacant lot restoration activities, (2) evaluate the impact of greening initiatives on adolescent health outcomes, (3) conduct cost-effectiveness analyses, and (4) develop best practices for greening programs for improved adolescent health.


Assuntos
Saúde do Adolescente , Disparidades nos Níveis de Saúde , Características de Residência , Humanos , Adolescente , Baltimore , Determinantes Sociais da Saúde , Parques Recreativos , Estados Unidos
3.
Eur J Neurol ; 31(1): e16069, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37754769

RESUMO

BACKGROUND AND PURPOSE: Tay-Sachs disease is a rare and often fatal, autosomal recessive, lysosomal storage disease. Deficiency in ß-hexosaminidase leads to accumulation of GM2 ganglioside resulting in neuronal swelling and degeneration. Typical onset is in infancy with developmental regression and early death. Late-onset Tay-Sachs disease (LOTS) is extremely rare, especially in the non-Ashkenazi Jewish population, and is characterized by a more indolent presentation typically encompassing features of cerebellar and anterior horn cell dysfunction in addition to extrapyramidal and neuropsychiatric symptoms. CASES: A case series of four unrelated patients of non-Ashkenazi Jewish origin with a predominantly, and in some cases pure, neuromuscular phenotype with evidence of a motor neuronopathy on electromyography is presented. Cerebellar atrophy, reported to be a ubiquitous feature in LOTS, was absent in all patients. CONCLUSION: This case series provides evidence to support a pure neuromuscular phenotype in LOTS, which should be considered in the differential diagnosis of anterior horn cell disorders.


Assuntos
Transtornos Mentais , Doença de Tay-Sachs , Humanos , Doença de Tay-Sachs/diagnóstico , Doença de Tay-Sachs/genética , Doença de Tay-Sachs/psicologia , Fenótipo , Cerebelo
4.
Am J Community Psychol ; 72(1-2): 187-202, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37327062

RESUMO

Youth living in areas with high concentrations of vacant properties may be at particular risk for poor health outcomes given the associations between deteriorated vacant properties, poor mental health, and community violence. Vacant lot greening has emerged as a key strategy to mitigate the harms of deteriorated properties. Youth engagement in greening has documented benefits for youth, yet few organizations responsible for managing vacant properties currently engage youth. Further, few researchers have examined the best practices that organizations can employ to effectively engage youth in greening programs. The purpose of this study was to understand how high functioning vacant land management organizations with robust youth engagement capabilities engage youth in their greening work. Based on in-depth interviews with staff from vacant land management organizations, we explored three research questions: (1) what are their identified best practices for youth engagement?; (2) what are the major challenges that impede their youth engagement work?; (3) what solutions are these organizations employing to address these challenges? Findings from this study emphasize the important themes of engaging youth in vacant lot greening in areas of planning, leadership, and decision-making. Youth engagement in vacant lot greening may be a key mechanism for preventing violence through cultivating youth empowerment and development.


Assuntos
Conservação dos Recursos Naturais , Características de Residência , Humanos , Adolescente , Violência/prevenção & controle , Saúde Mental , Liderança
5.
Sensors (Basel) ; 23(5)2023 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-36905012

RESUMO

Owing to the different quantities and processing times of sub-lots, intermingling sub-lots with each other, instead of fixing the production sequence of sub-lots of a lot as in the existing studies, is a more practical approach to lot-streaming flow shops. Hence, a lot-streaming hybrid flow shop scheduling problem with consistent and intermingled sub-lots (LHFSP-CIS) was studied. A mixed integer linear programming (MILP) model was established, and a heuristic-based adaptive iterated greedy algorithm (HAIG) with three modifications was designed to solve the problem. Specifically, a two-layer encoding method was proposed to decouple the sub-lot-based connection. Two heuristics were embedded in the decoding process to reduce the manufacturing cycle. Based on this, a heuristic-based initialization is proposed to improve the performance of the initial solution; an adaptive local search with four specific neighborhoods and an adaptive strategy has been structured to improve the exploration and exploitation ability. Besides, an acceptance criterion of inferior solutions has been improved to promote global optimization ability. The experiment and the non-parametric Kruskal-Wallis test (p = 0) showed the significant advantages of HAIG in effectiveness and robustness compared with five state-of-the-art algorithms. An industrial case study verifies that intermingling sub-lots is an effective technique to enhance the utilization ratio of machines and shorten the manufacturing cycle.

6.
Ann Pharm Fr ; 81(1): 64-73, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35803334

RESUMO

OBJECTIVE: A simple and robust head space/gas chromatography with flame ionisation sensor (HS/GC/FIS) approach for the trace evaluation of carcinogenic impurity, methyl chloride, in trimetazidine dihydrochloride (TRD) drug ingredient and its formulation is described. METHOD: This HS/GC/FIS approach was based on separation and analysis of CH3Cl content on DB-624 [75.0m - length, 0.53mm - internal diameter, 3.0µm - film thickness] column using nitrogen as carrier gas flowing through the column at 3mL/min stream rate. Detection of eluted CH3Cl was accomplished with flame ionization sensor at a set temperature of 260̊C. RESULTS: The optimised HS/GC/FIS methodological approach was thoroughly validated, demonstrating that it was linear with range of 5.0ppm to 1508.4ppm, sensitive with detection limit of 1.65ppm and quantification limit of 5.01ppm, reproducible with RSD values of 2.10-2.35%, accurate with recoveries of 81.9-99.0%, robust with percent variation of 7.5-12.22% with respect to changes in oven temperature, injector temperature, detector temperature and practical for regular TRD quality control. CONCLUSION: The findings revealed that with this optimised HS/GC/FIS methodological approach, the trace amounts of carcinogenic impurity (methyl chloride) in TRD drug ingredient and formulation could be successfully measured.


Assuntos
Cloreto de Metila , Trimetazidina , Trimetazidina/análise , Cloreto de Metila/análise , Carcinógenos/análise , Cromatografia Gasosa/métodos , Temperatura , Ionização de Chama
7.
Stud Neotrop Fauna Environ, in press, 2023
Artigo em Inglês | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP | ID: bud-5216

RESUMO

In cities, habitats classified as green areas are especially important for the conservation of species. Therefore, understanding how different biological groups are influenced by differences in the structures of green areas is relevant when planning urban environments. The aim of this study was to evaluate the influence of different types of green areas to the taxonomic and functional diversities of ants and spiders and to discuss the importance of green area management for both groups. We sampled three categories of green areas: forest fragments (40 sample points), vacant lots (20) and gardens/backyards (20), where we evaluated the taxonomic and functional richness and composition of both groups of organisms. At each sample point, we used several techniques, such as: entomological umbrella, Winkler extractors and manual collection. We sampled 149 ant species and 97 spider species. Our results demonstrate that there are differences in the diversity of ants and spiders, as well as in the number of functional groups of ants between the different types of green areas. As expected, forest fragments are the ones that most contribute to the observed diversity, and our findings highlight the importance of evaluating the biotic influence of green areas at a smaller spatial scale.

8.
Sensors (Basel) ; 22(22)2022 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-36433311

RESUMO

Indoor signals are susceptible to NLOS propagation effects, multipath effects, and a dynamic environment, posing more challenges than outdoor signals despite decades of advancements in location services. In modern Wi-Fi networks that support both MIMO and OFDM techniques, Channel State Information (CSI) is now used as an enhanced wireless channel metric replacing the Wi-Fi received signal strength (RSS) fingerprinting method. The indoor multipath effects, however, make it less robust and stable. This study proposes a positive knowledge transfer-based heterogeneous data fusion method for representing the different scenarios of temporal variations in CSI-based fingerprint measurements generated in a complex indoor environment targeting indoor parking lots, while reducing the training calibration overhead. Extensive experiments were performed with real-world scenarios of the indoor parking phenomenon. Results revealed that the proposed algorithm proved to be an efficient algorithm with consistent positioning accuracy across all potential variations. In addition to improving indoor parking location accuracy, the proposed algorithm provides computationally robust and efficient location estimates in dynamic environments. A Cramer-Rao lower bound (CRLB) analysis was also used to estimate the lower bound of the parking lot location error variance under various temporal variation scenarios. Based on analytical derivations, we prove that the lower bound of the variance of the location estimator depends on the (i) angle of the base stations, (ii) number of base stations, (iii) distance between the target and the base station, djr (iv) correlation of the measurements, ρrjai and (v) signal propagation parameters σC and γ.


Assuntos
Algoritmos , Calibragem
9.
Arch Environ Occup Health ; 77(6): 437-445, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-33999751

RESUMO

Each time a car's brakes are used, asbestos is dispersed in the air. Breathing the air in enclosed parking lots can expose people working in these places to asbestos. This study aimed to evaluate the airborne asbestos dispersion in enclosed parking lots. In this study, 35 air samples were collected from six enclosed parking lots in Tabriz City. The samples were analyzed quantitatively by phase contrast microscopy (PCM) and qualitatively by a scanning electron microscope (SEM) equipped with an energy-dispersive X-ray analyzer. The mean of fiber concentrations was found 0.155 ± 0.069 PCM f/cc. The SEM data demonstrated that the fibers consisted of synthetic fibers (69.57%) and asbestos (30.43%). Fiber concentrations in many enclosed parking lots in the city were higher than the threshold limit value-time weighted average of the American Conference of Governmental Industrial Hygienists and Occupational Exposure Limits of Iran. However, further investigations are needed to clarify asbestos exposure in such places.


Assuntos
Poluentes Ocupacionais do Ar , Amianto , Exposição Ocupacional , Poluentes Ocupacionais do Ar/análise , Monitoramento Ambiental , Humanos , Irã (Geográfico) , Exposição Ocupacional/análise
10.
J Urban Health ; 98(6): 812-821, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34750735

RESUMO

Maintained green space in underserved urban neighborhoods may be an important environmental pathway to improving community health and safety, though effects may vary across population subgroups and by time of day. We examined survey responses from 442 participants (178 men and 264 women), living near vacant lots in a cluster-randomized controlled trial of a cleaning and greening intervention, on perceived safety during the day and at night. At the intervention sites after the intervention, only men reported feeling less unsafe during the day. Women reported more fear, and men reported less fear, after the intervention, although these results and tests for effect modification were not statistically significant. The clean-and-green intervention may have allayed fears for men during the day and supported their ease of movement throughout their neighborhoods. However, at night, it may have had the opposite effect on women. Though our study was under-powered, not designed to test associations stratified by gender, directions and magnitudes of associations differed substantially, indicating a need for further investigations into potential gender differences in the benefits of green space, to inform and better tailor interventions to improve perceived safety for all.


Assuntos
Características de Residência , Violência , Emoções , Medo , Feminino , Humanos , Masculino , Fatores Sexuais
11.
Plants (Basel) ; 10(8)2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34451751

RESUMO

Several outbreaks of pospiviroids have been reported in pepper and tomato crops worldwide. Tracing back the origin of the infections has led to different sources. In some cases, the infections were considered to result from seed transmission. Other outbreaks were related to transmission from ornamental crops and weeds. Pospiviroids, in particular potato spindle tuber viroid, are regulated by many countries because they can be harmful to potatoes and tomatoes. Seed transmission has been considered an important pathway of introduction and spread. However, the importance of this pathway can be questioned. This paper presents data on seed transmission from large-scale grow-out trials of infested pepper and tomato seed lots produced under standard seed-industry conditions. In addition, it presents the results of a systematic review of published data on seed transmission and outbreaks in commercial pepper and tomato crops. Based on the results of the grow-out trials and review of the literature, it was concluded that the role of seed transmission in the spread of pospiviroids in practice is possibly overestimated.

12.
Mol Genet Metab ; 133(4): 386-396, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34226107

RESUMO

OBJECTIVE: Our study aimed to quantify structural changes in relation to metabolic abnormalities in the cerebellum, thalamus, and parietal cortex of patients with late-onset GM2-gangliosidosis (LOGG), which encompasses late-onset Tay-Sachs disease (LOTS) and Sandhoff disease (LOSD). METHODS: We enrolled 10 patients with LOGG (7 LOTS, 3 LOSD) who underwent a neurological assessment battery and 7 age-matched controls. Structural MRI and MRS were performed on a 3 T scanner. Structural volumes were obtained from FreeSurfer and normalized by total intracranial volume. Quantified metabolites included N-acetylaspartate (NAA), choline (Cho), myo-inositol (mI), creatine (Cr), and combined glutamate-glutamine (Glx). Metabolic concentrations were corrected for partial volume effects. RESULTS: Structural analyses revealed significant cerebellar atrophy in the LOGG cohort, which was primarily driven by LOTS patients. NAA was lower and mI higher in LOGG, but this was also significantly driven by the LOTS patients. Clinical ataxia deficits (via the Scale for the Assessment and Rating of Ataxia) were associated with neuronal injury (via NAA), neuroinflammation (via mI), and volumetric atrophy in the cerebellum. INTERPRETATION: The decrease of NAA in the cerebellum suggests that, in addition to cerebellar atrophy, there is ongoing impaired neuronal function and/or loss, while an increase in mI indicates possible neuroinflammation in LOGG (more so within the LOTS subvariant). Quantifying cerebellar atrophy in relation to neurometabolic differences in LOGG may lead to improvements in assessing disease severity, progression, and pharmacological efficacy. Lastly, additional neuroimaging studies in LOGG are required to contrast LOTS and LOSD more accurately.


Assuntos
Gangliosidoses GM2/diagnóstico por imagem , Gangliosidoses GM2/fisiopatologia , Transtornos de Início Tardio/diagnóstico por imagem , Transtornos de Início Tardio/fisiopatologia , Imageamento por Ressonância Magnética/métodos , Análise Espectral/métodos , Adulto , Cerebelo/diagnóstico por imagem , Cerebelo/patologia , Estudos de Coortes , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Lobo Parietal/diagnóstico por imagem , Lobo Parietal/patologia , Doença de Sandhoff/diagnóstico por imagem , Doença de Sandhoff/fisiopatologia , Doença de Tay-Sachs/diagnóstico por imagem , Doença de Tay-Sachs/fisiopatologia , Tálamo/diagnóstico por imagem , Tálamo/patologia , Adulto Jovem
13.
Ambio ; 50(3): 695-705, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32948986

RESUMO

Urban greening increases vegetation and can restore ecological functions to urban systems. It has ties to restoration ecology, which aims to return degraded land to diverse, functional ecosystems. Both practices can be applied to maximizing ecosystem services and habitat in vacant lots, which are abundant in post-industrial cities, including Chicago, Illinois (USA), where our study took place. We tested four methods for increasing native plant diversity in vacant lots, ranging from low input to resource-intensive: seed bombing, broadcast seeding, planting plugs, and gardening. After three growing seasons, we assessed the growth of eight target native species and all non-target species. We expected that intensive treatments would have more target species stems and flowers and fewer non-target species, but we found that less-intensive options often produce equal or better results. From this, we recommend broadcast seeding as a viable, low-cost method for improving habitat and biodiversity in vacant lots.


Assuntos
Ecossistema , Plantas , Biodiversidade , Cidades , Estações do Ano
14.
J Safety Res ; 70: 201-206, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31847996

RESUMO

INTRODUCTION: Pedestrian injuries are a significant pediatric public health concern worldwide. Younger children are at particular risk for pedestrian injuries in parking lots, but there is limited research regarding children's pedestrian behaviors in parking lots. METHOD: This study examined children's behaviors and safety risks in parking lots through unobtrusive and unannounced observation of 124 children ages 2-10 years and their adult supervisors as they crossed a parking lot from their parked vehicle into a community recreation center. RESULTS: Adult supervision was inadequate: over 67% of children 10 years of age and younger were unsupervised in the parking lot at some point between the vehicle parking and the child entering into the building. Approximately 90% of all children were outside of arm's length of the accompanying adult at some point while in the parking lot. Additionally, children exited the vehicle prior to the adult in over 50% of observations. Age was associated with safety risk, with older children being unsupervised more often than younger ones. CONCLUSIONS: Adult supervision of children in a parking lot setting was poor, creating significant safety risks. In addition, many children failed to follow basic pedestrian safety practices themselves, such as looking for moving cars. Injury prevention strategies should be implemented. Practical applications: As researchers gain better understanding about the safety risks for children in parking lots, interventions could target adult and child behaviors through improved supervision, altered perception of risk, and mandated behavioral guidelines for child behavior, such as how and when children exit vehicles in parking lots.


Assuntos
Acidentes de Trânsito/prevenção & controle , Automóveis , Comportamento Infantil , Cuidado da Criança , Saúde da Criança , Pedestres , Segurança , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Ferimentos e Lesões/prevenção & controle
15.
Landsc Urban Plan ; 1902019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32831442

RESUMO

Predictions of airborne allergenic pollen concentrations at fine spatial scales require information on source plant location and pollen production. Such data are lacking at the urban scale, largely because manually mapping allergenic pollen producing plants across large areas is infeasible. However, modest-sized field surveys paired with allometric equations, remote sensing, and habitat distribution models can predict where these plants occur and how much pollen they produce. In this study, common ragweed (Ambrosia artemisiifolia) was mapped in a field survey in Detroit, MI, USA. The relationship between ragweed presence and habitat-related variables derived from aerial imagery, LiDAR, and municipal data were used to create a habitat distribution model, which was then used to predict ragweed presence across the study area (392 km2). The relationship between inflorescence length and pollen production was used to predict pollen production in the city. Ragweed occurs in 1.7% of Detroit and total pollen production is 312 × 1012 pollen grains annually, but ragweed presence was highly heterogeneous across the city. Ragweed was predominantly found in in vacant lots (75%) and near demolished structures (48%), and had varying associations with land cover types (e.g., sparse vegetation, trees, pavement) detected by remote sensing. These findings also suggest several management strategies that could help reduce levels of allergenic pollen, including appropriate post-demolition management practices. Spatially-resolved predictions for pollen production will allow mechanistic modeling of airborne allergenic pollen and improved exposure estimates for use in epidemiological and other applications.

16.
Transp Policy (Oxf) ; 74: 15-23, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38283107

RESUMO

The efficiency of park and ride (PnR) lots has not been investigated in serious depth in prior literature. This study examines the effect of various factors on the utilization rate of PnR lots with panel Tobit models. The examined factors consist of land use features, roadway design features, transit ridership, sociodemographic attributes, travel characteristics, policy tools, gasoline prices, and weather conditions. The data is drawn from PnR lots in King County, Washington. Results show that: (1) degree of mixed land use, road density, employment density, percentages of people aged between 18 and 34 and people over 65, the percentage of white people, the percentage of poor people, and transit ridership are positively associated with the utilization rate of PnR lots; (2) the percentage of drive lanes in total roadway miles, the percentage of males, and the mode share percentage of driving are negatively correlated with the utilization rate of PnR lots; (3) various policy interventions, including countermeasures for preserving transit after the economic recession, congestion reduction charge, and bus-rail integration, are all positively correlated with the utilization rate of PnR lots. Contextualized to US cities, PnR is a practical way to attract bus riders, especially young adults, senior citizens, and low-income people to public transit. Dense urban development is encouraged for the full utilization of PnR lots. Additionally, the integration between bus and rail appears to be an effective policy tool to promote PnR utilization.

17.
Food Chem ; 257: 83-89, 2018 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-29622234

RESUMO

Given the increasing consumers demand for novelty, tea companies have been presenting new added value products such as reserve lots of aromatic plants. Herein, infusions from different lots of three aromatic plants were assessed in terms of phenolic composition (HPLC-DAD-ESI/MS) and antioxidant properties (reducing power, free radical scavenging and lipid peroxidation inhibition capacity). Cymbopogon citratus (C. citratus; main compound 5-O-caffeoylquinic acid) and Aloysia citrodora (A. citrodora; prevalence of verbascoside) reserve lots revealed higher phenolic compounds concentration than the respective standard lots. Thymus × citriodorus (T. citriodorus; main compound rosmarinic acid) standard lot presented higher amounts of phenolic acids than the reserve lot, nonetheless, total flavonoids and phenolic compounds were not significantly different. The differences between both lots antioxidant activity were more noticeable in C. citratus, with the reserve lot presenting the highest activity. This study provides evidence of the differences between these plants chemical composition and bioactivity depending on the harvesting conditions.


Assuntos
Cymbopogon/química , Fenóis/análise , Thymus (Planta)/química , Verbenaceae/química , Antioxidantes/análise , Antioxidantes/química , Fenóis/química
19.
J Biopharm Stat ; 27(2): 213-219, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27906604

RESUMO

In the evaluation of the analytical similarity data, an equivalence testing approach for most critical and quantitative quality attributes, which are assigned to Tier 1 in their proposed three-tier approach, was proposed. The Food and Drug Administration (FDA) has recommended the proposed equivalence testing approach to sponsors through meeting comments for Pre-Investigational New Drug Applications (PINDs) and Investigational New Drug Applications (INDs) since 2014. The FDA has received some feedback on the statistical issues of potentially correlated reference lot values subjected to equivalence testing since independent and identical observations (lot values) from the proposed biosimilar product and the reference product are assumed. In this article, we describe one method for correcting the estimation bias of the reference variability so as to increase the equivalence margin and its modified versions for increasing the equivalence margin and correcting the standard errors in the confidence intervals, assuming that the lot values are correlated under a few known correlation matrices. Our comparisons between these correcting methods and no correction for bias in the reference variability under several assumed correlation structures indicate that all correcting methods would increase the type I error rate dramatically but only improve the power slightly for most of the simulated scenarios. For some particular simulated cases, the type I error rate can be extremely large (e.g., 59%) if the guessed correlation is larger than the assumed correlation. Since the source of a reference drug product lot is unknown in nature, correlation between lots is a design issue. Hence, to obtain independent reference lot values by purchasing the reference lots at a wide time window often is a design remedy for correlated reference lot values.


Assuntos
Medicamentos Biossimilares/normas , Interpretação Estatística de Dados , Projetos de Pesquisa , Humanos , Estados Unidos , United States Food and Drug Administration
20.
Artigo em Inglês | MEDLINE | ID: mdl-27901640

RESUMO

The advantage of using naphthenic acid (NA) mixtures for the determination of total NA lies in their chemical characteristics and identification of retention times distinct from isobaric interferences. However, the differing homolog profiles and unknown chemical structures of NA mixtures do not allow them to be considered a traceable reference material. The current study provides a new tool for the comparative assessment of different NA mixtures by direct reference to a single, well-defined and traceable compound, decanoic-d19 acid. The method employed an established liquid chromatography time-of-flight mass spectrometry (LC/QToF) procedure that was applicable both to the classic O2 NA species dominating commercial mixtures and additionally to the O4 species known to be present in acid extractable organics (AEOs) derived from oil sands process water (OSPW). Four different commercial NA mixtures and one OSPW-derived AEOs mixture were comparatively assessed. Results showed significant difference among Merichem Technical, Aldrich, Acros, and Kodak commercial NA mixtures with respect to "equivalent to decanoic-d19 acid" concentration ratios to nominal. Furthermore, different lot numbers of single commercial NA mixtures were found to be inconsistent with respect to their homolog content by percent response. Differences in the observed homolog content varied significantly, particularly at the lower (n = 9-14) and higher (n = 20-23) carbon number ranges. Results highlighted the problem between using NA mixtures from different sources and different lot numbers but offered a solution to the problem from a concentration perspective. It is anticipated that this tool may be utilized in review of historical data in addition to future studies, such as the study of OSPW derived acid extractable organics (AEOs) and fractions employed during toxicological studies.


Assuntos
Ácidos Carboxílicos/toxicidade , Resíduos Industriais , Campos de Petróleo e Gás , Poluentes Químicos da Água/toxicidade , Cromatografia Líquida , Humanos , Limite de Detecção , Espectrometria de Massas , Valores de Referência
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