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1.
Opt Express ; 31(4): 5531-5546, 2023 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-36823831

RESUMEN

Tomographic volumetric additive manufacturing (VAM) is an optical 3D printing technique where an object is formed by photopolymerizing resin via tomographic projections. Currently, these projections are calculated using the Radon transform from computed tomography but it ignores two fundamental properties of real optical projection systems: finite etendue and non-telecentricity. In this work, we introduce 3D ray tracing as a new method of computing projections in tomographic VAM and demonstrate high fidelity printing in non-telecentric and higher etendue systems, leading to a 3x increase in vertical build volume than the standard Radon method. The method introduced here expands the possible tomographic VAM printing configurations, enabling faster, cheaper, and higher fidelity printing.

2.
Inj Prev ; 21(e1): e88-92, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24639292

RESUMEN

OBJECTIVE: This study focuses on work-related injuries that required admission to hospital in a population of male workers exposed to occupational noise (≥80 dBA) which some displayed a hearing loss due to their exposure. METHODS: The study population count 46 550 male workers, 1670 (3.6%) of whom incurred at least one work-related injury requiring admission to hospital within a period of 5 years following hearing tests conducted between 1987 and 2005. The noise exposure and hearing loss-related data were gathered during occupational noise-induced hearing loss (NIHL) screening. The hospital data were used to identify all members of the study population who were admitted, and the reason for admission. Finally, access to the death-related data made it possible to identify participants who died during the course of the study. Cox proportional hazards model taking into account hearing status, noise levels, age and cumulative duration of noise exposure at the time of the hearing test established the risk of work-related injuries leading to admission to hospital. RESULTS: For each dB of hearing loss, a statistically significant risk increase was observed (HR=1.01 dB 95% CI 1.006 to 1.01). An association (HR=2.36 95% CI 2.01 to 2.77) was also found between working in an occupational ambient noise ≥100 dBA and the risk of injury. CONCLUSIONS: From a safety perspective, this issue is highly relevant; especially when workers are exposed to intense ambient noise and NIHL.


Asunto(s)
Pérdida Auditiva Provocada por Ruido , Hospitalización/estadística & datos numéricos , Ruido en el Ambiente de Trabajo/efectos adversos , Enfermedades Profesionales , Exposición Profesional/efectos adversos , Traumatismos Ocupacionales/etiología , Adulto , Femenino , Pérdida Auditiva Provocada por Ruido/complicaciones , Pérdida Auditiva Provocada por Ruido/etiología , Humanos , Masculino , Persona de Mediana Edad , Enfermedades Profesionales/complicaciones , Enfermedades Profesionales/etiología , Modelos de Riesgos Proporcionales , Factores de Riesgo , Adulto Joven
3.
Int Arch Occup Environ Health ; 88(1): 123-30, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24792922

RESUMEN

OBJECTIVE: The aim of this study, conducted among retired workers (≥65 years), is to estimate the association between long-term risk of cardiovascular disease (CVD) death and (1) duration of occupational noise exposure in career and (2) noise-induced hearing loss (NIHL), the latter being used as an indicator of adverse effects for long-term exposure to occupational noise. METHODS: Data from screening activities of occupational NIHL were paired to data from death records and were used for this study. A nested case-control analysis was performed. Each case was matched with three controls for length of follow-up and economic sector. A total of 161 CVD deaths occured during an average follow-up of 6.8 years. Conditional logistic regression models were used to estimate the risk (OR) of CVD death by tertiles of duration of noise exposure and of NIHL. RESULTS: Conditional logistic regression models indicated that prolonged duration of noise exposure (≥36.5 years) (3rd tertile) was associated with an increased risk of CVD death (OR 1.70; 95 % CI 1.10-2.62), as compared with shorter duration (<27 years) (first tertile). Moderate NIHL (2nd tertile) (OR 1.64; 95 % CI 1.04-2.6) and severe NIHL (3rd tertile) (OR 1.66; 95 % CI 1.06-2.60) were also associated with an increase in risk of CVD death. CONCLUSIONS: Results are consistent with recent findings on the chronic effects of occupational noise exposure persisting after retirement although it is less than during active working life.


Asunto(s)
Enfermedades Cardiovasculares/mortalidad , Pérdida Auditiva Provocada por Ruido/etiología , Ruido en el Ambiente de Trabajo/efectos adversos , Enfermedades Profesionales/mortalidad , Exposición Profesional/efectos adversos , Anciano , Anciano de 80 o más Años , Enfermedades Cardiovasculares/etiología , Femenino , Humanos , Modelos Logísticos , Masculino , Enfermedades Profesionales/etiología , Jubilación , Factores de Riesgo , Factores de Tiempo
4.
Noise Health ; 17(78): 294-9, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26356371

RESUMEN

Noise exposure in the workplace is a common reality in Québec, Canada as it is elsewhere. However, the extent to which noise acts as a causal or contributive factor in industrial work-related accidents has not been studied thoroughly despite its plausibility. This article aims to describe the importance or potential importance, during investigations looking into the specific causes of each work-related fatal accident, of noise as an explanatory factor. The written information contained in the accident reports pertaining to contextual and technical elements were used. The study used multiple case qualitative content analysis. This descriptive study was based on the content analysis of the 788 reports from the Commission de la santé et de la sécurité du travail du Québec [Workers' Compensation Board (WCB)] investigating the fatal work-related accidents between 1990 and 2005. The study was descriptive (number and percentages). Noise was explicitly stated as one of the explanatory factors for the fatal outcome in 2.2% (17/788) of the fatal accidents, particularly when the work involved vehicular movement or the need to communicate between workers. Noise was not typically considered a unique cause in the accident, notably because the investigators considered that the accident would have probably occurred due to other risk factors (for example, disregard of safety rules, shortcomings in work methods, and inadequate training). Noise is an important risk factor when communication is involved in work. Since noise is ubiquitous and may also interfere with vigilance and other risk factors for accidents, it may be a much more important contributing factor to accidents than is currently recognized.


Asunto(s)
Accidentes de Trabajo , Comunicación , Ruido/efectos adversos , Exposición Profesional , Lugar de Trabajo/normas , Accidentes de Trabajo/mortalidad , Accidentes de Trabajo/prevención & control , Accidentes de Trabajo/estadística & datos numéricos , Causalidad , Humanos , Evaluación de Necesidades , Exposición Profesional/efectos adversos , Exposición Profesional/análisis , Exposición Profesional/prevención & control , Quebec , Medición de Riesgo , Factores de Riesgo
5.
Can J Aging ; 33(1): 84-91, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24345605

RESUMEN

This study sought to ascertain whether occupational noise-induced hearing loss (NIHL) increased the risk of falls requiring hospitalization among retired workers. The study population consisted of males (age ≥ 65) with an average occupational noise exposure of 30.6 years and whose mean bilateral hearing loss was 42.2 dB HL at 3, 4, and 6 kHz. Seventy-two retired workers admitted to hospitals after a fall were matched with 216 controls from the same industrial sectors. Conditional logistic regression models were used to estimate the risk (odds ratio; [OR]) of falls leading to hospitalization by NIHL categories. Results showed a relationship between severe NIHL (≥ 52.5 dB HL) and the occurrence of a fall (OR: 1.97, CI95%: 1.001-3.876). Reducing falls among seniors fosters the maintenance of their autonomy. There is a definite need to acquire knowledge about harmful effects of occupational noise to support the prevention of NIHL and ensure healthier workplaces.


Asunto(s)
Accidentes por Caídas , Pérdida Auditiva Provocada por Ruido/etiología , Tiempo de Internación , Ruido en el Ambiente de Trabajo/efectos adversos , Jubilación , Accidentes por Caídas/estadística & datos numéricos , Anciano , Estudios de Casos y Controles , Estudios de Seguimiento , Humanos , Industrias , Tiempo de Internación/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Quebec , Jubilación/estadística & datos numéricos , Medición de Riesgo , Factores de Riesgo
7.
Accid Anal Prev ; 40(5): 1644-52, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18760091

RESUMEN

This retrospective study explores the association between occupational noise exposure at the time of hearing tests, permanent noise-induced hearing loss and work-related accident risk. Log-binomial analysis was used to first ascertain the association between study variables according to activity sector (North American Industry Classification System, NAICS) and accident context while controlling for age. Second part of the paper estimates the overall number of accidents attributable to occupational noise or the associated hearing loss (excess fraction). Study was carried on a sample of 52,982 male workers exposed to a minimum of 80 dBA on a daily basis and whose hearing was examined at least once between 1983 and 1996 by public health authorities of Quebec. These participants evidenced bilateral average hearing threshold levels at 3, 4 and 6 kHz ranging from normal (< or = 15 dB) to hearing loss in excess of 50 dB as a result of chronic occupational noise exposure (subjects otherwise otologically normal). The occupational accident count of these workers was derived from the individual histories registered with the Quebec workers' compensation board for the 1983-1998 period. Results show an association between accident risk and worker's hearing sensitivity. For example, a hearing loss of 20 dB corresponds to a rise of accident risk equal to 1.14 when controlling for age and occupational noise exposure at the time of hearing tests. NAICS economic activity sectors where association is the most noticeable are "Metal Transformation", "Metal Product Manufacturing" and "Transportation Equipment Manufacturing". "Passive accidents" (PR per decibel of hearing loss = 1.008; CI 95 (1.007; 1.010)) and "same-level falls" (1.007; CI 95 (1.003; 1.010)) are the two accidents categories most strongly associated with hearing loss. Overall, 12.2% of accidents considered in this study were attributable to a combination of noise exposure in the workplace (> or = 90 dBA) and noise-induced hearing loss.


Asunto(s)
Accidentes de Trabajo/estadística & datos numéricos , Pérdida Auditiva Provocada por Ruido/epidemiología , Ruido , Exposición Profesional , Adulto , Pérdida Auditiva de Alta Frecuencia/epidemiología , Humanos , Masculino , Persona de Mediana Edad , Quebec/epidemiología , Estudios Retrospectivos , Lugar de Trabajo , Adulto Joven
8.
Traffic Inj Prev ; 9(5): 489-99, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18836961

RESUMEN

OBJECTIVE: A study was conducted to verify if there is an association between occupational noise exposure, noise-induced hearing loss and driving safety expanding on previous findings by Picard, et al. (2008) that the two factors did increase accident risk in the workplace. METHODS: This study was made possible when driving records of all Quebec drivers were made available by the Societe de l'assurance automobile du Quebec (SAAQ is the state monopoly responsible for the provision of motor vehicle insurance and the compensation of victims of traffic accidents). These records were linked with personal records maintained by the Quebec National Institute of Public Health as part of its mission to prevent noise induced hearing loss in the workplace. Individualized information on occupational noise exposure and hearing sensitivity was available for 46,030 male workers employed in noisy industries who also held a valid driver's permit. The observation period is of five years duration, starting with the most recent audiometric examination. The associations between occupational noise exposure levels, hearing status, and personal driving record were examined by log-binomial regression on data adjusted for age and duration of exposure. Daily noise exposures and bilateral average hearing threshold levels at 3, 4, and 6 kHz were used as independent variables while the dependent variables were 1) the number of motor vehicle accidents experienced by participants during the study period and 2) participants' records of registered traffic violations of the highway safety code. The findings are reported as prevalence ratios (PRs) with their 95% confidence intervals (CIs). Attributable numbers of events were computed with the relevant PRs, lesser-noise, exposed workers and those with normal hearing levels making the group of reference. RESULTS: Adjusting for age confirmed that experienced workers had fewer traffic accidents. The data show that occupational noise exposure and hearing loss have the same effect on driving safety record than that reported on the risk of accident in noisy industrial settings. Specifically, the risk of traffic accident (PR = 1.07 (CI 95% [1.01; 1.15]) is significantly associated with the daily occupational noise exposures >or= 100 dBA. For participants having a bilateral average hearing loss ranging from 16 to 30 dB, the PR of traffic accident is 1.06 (CI 95% [1.01; 1.11]) and reaches 1.31 (CI 95% [1.2; 1.42]) when the hearing loss exceeds of 50 dB. A reduction in the number of speeding violations occurred among workers occupationally exposed to noise levels >or= 90 dBA and those with noise-induced hearing loss >or=16 dB. By contrast, the same individuals had an increase in other violations of the Highway safety code. This suggests that noise-exposed workers might be less vigilant to other traffic hazards. CONCLUSION: Daily occupational noise exposures >or= 100 dBA and noise-induced hearing losses-even when just barely noticeable-may interfere with the safe operation of motor vehicles.


Asunto(s)
Prevención de Accidentes/métodos , Accidentes de Tránsito/estadística & datos numéricos , Conducción de Automóvil , Pérdida Auditiva Provocada por Ruido/epidemiología , Ruido en el Ambiente de Trabajo/efectos adversos , Accidentes de Tránsito/prevención & control , Adolescente , Adulto , Distribución por Edad , Intervalos de Confianza , Bases de Datos Factuales , Femenino , Pérdida Auditiva Provocada por Ruido/prevención & control , Humanos , Masculino , Persona de Mediana Edad , Ruido en el Ambiente de Trabajo/prevención & control , Prevalencia , Probabilidad , Quebec , Estudios Retrospectivos , Medición de Riesgo , Distribución por Sexo , Adulto Joven
9.
Br J Nutr ; 90(6): 1023-9, 2003 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-14641961

RESUMEN

Chicken muscle ribosomal protein S6 kinase (S6K1) has been recently characterised and its enzymic activity is regulated by the nutritional and hormonal (insulin) status in vivo. The regulation of S6K1 is still unknown in neonatal chicks. The present study aimed to compare the activation of S6K1 in early-feeding (EF) and 48 h-delayed-feeding (DF) chicks from hatching to 4 d of age. During post-hatching starvation, S6K1 activity remained at the basal level measured in the control-hatched chicks. The maximum S6K1 activity was recorded on the first day of feeding with an increase of about 2.5-fold in the EF and DF chicks (P<0.01). S6K1 activity was correlated with plasma insulin level, suggesting a probable insulin-dependent S6K1 activation. The feeding-induced increase in S6K1 activity was related to its Thr389 residue phosphorylation. A similar pattern for protein kinase B phosphorylation was observed, upstream from S6K1. The S6K1 pathway was stimulated to the same extent in the EF and DF chicks, which indicates that post-hatching starvation did not increase S6K1 activation. It is concluded that muscle S6K1 is activated as soon as food is available without improvement in the response of the S6K1 pathway after post-hatching starvation.


Asunto(s)
Pollos/metabolismo , Músculo Esquelético/enzimología , Proteínas Serina-Treonina Quinasas , Proteínas Quinasas S6 Ribosómicas 70-kDa/metabolismo , Inanición/metabolismo , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Animales Recién Nacidos , Glucemia/metabolismo , Dieta/veterinaria , Ingestión de Alimentos/fisiología , Activación Enzimática/fisiología , Insulina/sangre , Fosforilación , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Proto-Oncogénicas c-akt
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