Because nanomaterials have been increasingly developed and used in many technology and industry sectors over the last 20 years, an increasing number of workers is likely to be exposed to airborne nanoparticles. In addition, the question of the nanomaterial characteristics that should be assessed in epidemiological studies remains open. Thus, assessing occupational exposure to airborne nanoparticles will not only rely on mass concentration and chemical composition. Rather, key parameters, such as particle size, have to be included in measurement strategies.
We previously proposed a methodology to estimate the Count Median Diameter (CMD) of an aerosol based on the simultaneous size-integrated measurement of two particle concentrations, lung-deposited surface area, and number, thanks to field-portable, commercially available aerosol instruments (Nanoparticle Surface Area Monitor/Condensation Particle Counter combination).
In addition to previous work, this study investigates the case of various polydisperse metal oxides, organic oil, and salt particles with CMDs ranging from 16–410 nm. Once corrected, the CMDs derived from the NSAM/CPC agree within ±20% with regard to the reference electrical mobility equivalent diameter, regardless of aerosol composition, morphology, or geometric standard deviation (GSD).
Furthermore, the field-applicability of the method was tested through 6 sets of experimental data stemming from workplace measurement campaigns where different materials were produced and handled (TiO2, SiO2, Ag, Multi-Walled Carbon Nanotubes—MWCNT), covering a range of CMDs between 40 and 190 nm. All situations considered, the approach based on the combination of a NSAM and a CPC leads to a satisfying estimation of particle CMD, within ±20% compared to reference CMD. 相似文献
Primary scarring alopecia (PSA) is caused by irreversible damage to the hair epithelial stem cells that reside in hair follicles. There is limited published work regarding PSA amongst the Asian population. The aim of this study was to evaluate the clinical features and to characterize the subtypes of PSA in southern Taiwan. In this retrospective case series, we reviewed 89 patients with pathology‐confirmed PSA. The data was collected from National Cheng Kung University Hospital between 1988 through 2016. The clinical and histological data were reviewed, and the patients were characterized into different subtypes of PSA based on the clinical features and histological findings. We noted seven different subtypes of PSA. The most common type was dissecting cellulitis (DC) (30.3%), followed by lichen planopilaris (LPP) (23.5%), central centrifugal cicatricial alopecia (CCCA) (12.4%) and acne keloidalis nuchae (AKN) (12.4%). The other subtypes include folliculitis decalvans (FD), discoid lupus erythematosus (DLE) and pseudopelade of Brocq (PPB). Interestingly, FD, DC and AKN were more common in males, while CCCA, LPP, DLE and PPB had a female predominance. The mean age of patients with DLE, DC and AKN were younger, while patients with CCCA, LPP, PPB and FD tend to be older. The pattern of hair loss was more likely to be unifocal‐ragged border in CCCA and DLE, multifocal‐interconnected in LPP and FD, and multifocal‐separated in DC. The pathogenesis of PSA may be influenced by sex, age and genetic background. It is important to identify the hair loss pattern to differentiate the subtypes of PSA. 相似文献
Attention-deficit/hyperactivity disorder (ADHD) affects approximately 5 % of school-aged children and 2.5 % of adults. Genetic studies in ADHD have pointed to genes in different neurobiological systems, with relatively small individual effects. The mineralocorticoid receptor is the main receptor involved in the initial triggering of stress response. Therefore, its encoding gene (NR3C2) is a candidate for psychiatric disorder studies, including ADHD, and behavioral phenotypes. There is evidence that the Val allele of the MRI180V polymorphism (rs5522) increases the risk of depression, attention and cognitive deficits. We investigated the possible role of the mineralocorticoid receptor gene in the symptom dimensions and susceptibility to persistent ADHD. We compared genotype and allele frequencies in 478 adult patients with ADHD and 597 controls and symptom dimensions in 449 patients and 132 controls. Diagnoses were based on the DSM-IV criteria. ADHD symptom dimensions were investigated with SNAP-IV for ADHD severity and Barkley scales for severity and impairment. Carriers of the Val allele presented higher inattention, hyperactivity/impulsivity and impairment scores, while genotype and allele frequencies did not differ between patients and controls. These results are consistent with a possible link between genetic variations in the HPA axis and inattention and hyperactivity measures. 相似文献
Overweight and obesity prevalence is rapidly rising in developing countries. The reading and understanding of nutrition information on food packages has been shown to improve food choices and instill healthy eating habits in individuals.
Objective
The aim of this study was to describe the prevalence of food label usage and understanding among urban and rural adults in Zimbabwe and its association with demographic and socio economic factors.
Methods
A cross sectional study was conducted on 320 adults (147 urban and 173 rural) using a validated questionnaire adapted from previous similar studies. Data were analysed using SPSS-17 statistical software.
Results
A high proportion (77.2%) of the respondents read food labels. Food label reading differed significantly by educational status (p<0.05), employment status (p<0.05) and locality (p<0.05). Only 40.9% of food label readers mostly understood the information on the food labels. More urban shoppers (86.1%) read food labels than their rural counterparts (66.7%). A significant number of participants (80.6%) indicated they would like to be educated on the meaning of food labels and 80.3% preferred the nutrition information on food labels to be simplified.
Conclusion
The study found above average reported reading of nutrition information on food labels with partial understanding. Efforts should be made to determine how all consumers could be made to understand the nutrition information on food labels and use it effectively in decision making. 相似文献
A number of studies have demonstrated that stress is involved in all aspects of smoking behavior, including initiation, maintenance and relapse. The mineralocorticoid (MR) and glucocorticoid (GR) receptors are expressed in several brain areas and play a key role in negative feedback of the hypothalamic–pituitary–adrenal (HPA) axis. As nicotine increases the activation of the HPA axis, we wondered if functional SNPs (single nucleotide polymorphisms) in MR and GR coding genes (NR3C2 rs5522 and NR3C1 rs6198, respectively) may be involved in smoking susceptibility. The sample included 627 volunteers, of which 514 were never-smokers and 113 lifetime smokers. We report an interaction effect between rs5522 and rs6198 SNPs. The odds ratio (OR) for the presence of the NR3C2 rs5522 Val allele in NR3C1 rs6198 G carriers was 0.18 (P = 0.007), while in rs6198 G noncarriers the OR was 1.83 (P = 0.027). We also found main effects of the NR3C1 rs6198 G allele on number of cigarettes smoked per day (P = 0.027) and in total score of the Fagerström Test for Nicotine Dependence (P = 0.007). These findings are consistent with a possible link between NR3C2 and NR3C1 polymorphisms and smoking behavior and provide a first partial replication for a nominally significant GWAS finding between NR3C2 and tobacco smoking. 相似文献