| 1. |
- Boxall, A. B. A., et al.
(författare)
-
Pharmaceuticals and Personal Care Products in the Environment: What Are the Big Questions?
- 2012
-
Ingår i: Environmental Health Perspectives. - : Environmental Health Perspectives. - 0091-6765 .- 1552-9924. ; 120:9, s. 1221-1229
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Over the past 10-15 years, a substantial amount of work has been done by the scientific, regulatory, and business communities to elucidate the effects and risks of pharmaceuticals and personal care products (PPCPs) in the environment. OBJECTIVE: This review was undertaken to identify key outstanding issues regarding the effects of PPCPs on human and ecological health in order to ensure that future resources will be focused on the most important areas. DATA SOURCES: To better understand and manage the risks of PPCPs in the environment, we used the "key question" approach to identify the principle issues that need to be addressed. Initially, questions were solicited from academic, government, and business communities around the world. A list of 101 questions was then discussed at an international expert workshop, and a top-20 list was developed. Following the workshop, workshop attendees ranked the 20 questions by importance. DATA SYNTHESIS: The top 20 priority questions fell into seven categories: a) prioritization of substances for assessment, b) pathways of exposure, c) bioavailability and uptake, a effects characterization, e) risk and relative risk, f) antibiotic resistance, and g) risk management. CONCLUSIONS: A large body of information is now available on PPCPs in the environment. This exercise prioritized the most critical questions to aid in development of future research programs on the topic.
|
|
| 2. |
- Fedirko, V., et al.
(författare)
-
Consumption of fish and meats and risk of hepatocellular carcinoma: the European Prospective Investigation into Cancer and Nutrition (EPIC)
- 2013
-
Ingår i: Annals of Oncology. - : Elsevier BV. - 1569-8041 .- 0923-7534. ; 24:8, s. 2166-2173
-
Tidskriftsartikel (refereegranskat)abstract
- While higher intake of fish and lower consumption of red/processed meats have been suggested to play a protective role in the etiology of several cancers, prospective evidence for hepatocellular carcinoma (HCC) is limited, particularly in Western European populations. The associations of fish and meats with HCC risk were analyzed in the EPIC cohort. Between 1992 and 2010, 191 incident HCC were identified among 477 206 participants. Baseline diet was assessed using validated dietary questionnaires. A single 24-h diet recall from a cohort subsample was used for calibration. Multivariable proportional hazard regression was utilized to estimate hazard ratios (HR) and 95% confidence intervals (CI). In a nested case-control subset (HCC = 122), HBV/HCV status and liver function biomarkers were measured. HCC risk was inversely associated with intake of total fish (per 20 g/day increase, HR = 0.83, 95% CI 0.74-0.95 and HR = 0.80, 95% CI 0.69-0.97 before and after calibration, respectively). This inverse association was also suggested after adjusting for HBV/HCV status and liver function score (per 20-g/day increase, RR = 0.86, 95% CI 0.66-1.11 and RR = 0.74, 95% CI 0.50-1.09, respectively) in a nested case-control subset. Intakes of total meats or subgroups of red/processed meats, and poultry were not associated with HCC risk. In this large European cohort, total fish intake is associated with lower HCC risk.
|
|
| 3. |
- Nettleton, Jennifer A., et al.
(författare)
-
Meta-Analysis Investigating Associations Between Healthy Diet and Fasting Glucose and Insulin Levels and Modification by Loci Associated With Glucose Homeostasis in Data From 15 Cohorts
- 2013
-
Ingår i: American Journal of Epidemiology. - : Oxford University Press (OUP). - 0002-9262 .- 1476-6256. ; 177:2, s. 103-115
-
Forskningsöversikt (refereegranskat)abstract
- Whether loci that influence fasting glucose (FG) and fasting insulin (FI) levels, as identified by genome-wide association studies, modify associations of diet with FG or FI is unknown. We utilized data from 15 US and European cohort studies comprising 51,289 persons without diabetes to test whether genotype and diet interact to influence FG or FI concentration. We constructed a diet score using study-specific quartile rankings for intakes of whole grains, fish, fruits, vegetables, and nuts/seeds (favorable) and red/processed meats, sweets, sugared beverages, and fried potatoes (unfavorable). We used linear regression within studies, followed by inverse-variance-weighted meta-analysis, to quantify 1) associations of diet score with FG and FI levels and 2) interactions of diet score with 16 FG-associated loci and 2 FI-associated loci. Diet score (per unit increase) was inversely associated with FG ( 0.004 mmol/L, 95 confidence interval: 0.005, 0.003) and FI ( 0.008 ln-pmol/L, 95 confidence interval: 0.009, 0.007) levels after adjustment for demographic factors, lifestyle, and body mass index. Genotype variation at the studied loci did not modify these associations. Healthier diets were associated with lower FG and FI concentrations regardless of genotype at previously replicated FG- and FI-associated loci. Studies focusing on genomic regions that do not yield highly statistically significant associations from main-effect genome-wide association studies may be more fruitful in identifying diet-gene interactions.
|
|
| 4. |
- Ahmad, Shafqat, et al.
(författare)
-
Gene × physical activity interactions in obesity: combined analysis of 111,421 individuals of European ancestry. : combined analysis of 111,421 individuals of European ancestry
- 2013
-
Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 9:7, s. 1003607-1003607
-
Tidskriftsartikel (refereegranskat)abstract
- Numerous obesity loci have been identified using genome-wide association studies. A UK study indicated that physical activity may attenuate the cumulative effect of 12 of these loci, but replication studies are lacking. Therefore, we tested whether the aggregate effect of these loci is diminished in adults of European ancestry reporting high levels of physical activity. Twelve obesity-susceptibility loci were genotyped or imputed in 111,421 participants. A genetic risk score (GRS) was calculated by summing the BMI-associated alleles of each genetic variant. Physical activity was assessed using self-administered questionnaires. Multiplicative interactions between the GRS and physical activity on BMI were tested in linear and logistic regression models in each cohort, with adjustment for age, age(2), sex, study center (for multicenter studies), and the marginal terms for physical activity and the GRS. These results were combined using meta-analysis weighted by cohort sample size. The meta-analysis yielded a statistically significant GRS × physical activity interaction effect estimate (Pinteraction = 0.015). However, a statistically significant interaction effect was only apparent in North American cohorts (n = 39,810, Pinteraction = 0.014 vs. n = 71,611, Pinteraction = 0.275 for Europeans). In secondary analyses, both the FTO rs1121980 (Pinteraction = 0.003) and the SEC16B rs10913469 (Pinteraction = 0.025) variants showed evidence of SNP × physical activity interactions. This meta-analysis of 111,421 individuals provides further support for an interaction between physical activity and a GRS in obesity disposition, although these findings hinge on the inclusion of cohorts from North America, indicating that these results are either population-specific or non-causal.
|
|
| 5. |
- Obón-Santacana, M., et al.
(författare)
-
Dietary intake of acrylamide and endometrial cancer risk in the European Prospective Investigation into Cancer and Nutrition cohort
- 2014
-
Ingår i: British Journal of Cancer. - : Nature Publishing Group. - 0007-0920 .- 1532-1827. ; 111:5, s. 987-997
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Three prospective studies have evaluated the association between dietary acrylamide intake and endometrial cancer (EC) risk with inconsistent results. The objective of this study was to evaluate the association between acrylamide intake and EC risk: for overall EC, for type-I EC, and in never smokers and never users of oral contraceptives (OCs). Smoking is a source of acrylamide, and OC use is a protective factor for EC risk. METHODS: Cox regression was used to estimate hazard ratios (HRs) for the association between acrylamide intake and EC risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Acrylamide intake was estimated from the EU acrylamide monitoring database, which was matched with EPIC questionnaire-based food consumption data. Acrylamide intake was energy adjusted using the residual method. RESULTS: No associations were observed between acrylamide intake and overall EC (n = 1382) or type-I EC risk (n = 627). We observed increasing relative risks for type-I EC with increasing acrylamide intake among women who both never smoked and were non-users of OCs (HRQ5vsQ1: 1.97, 95% CI: 1.08-3.62; likelihood ratio test (LRT) P-value: 0.01, n = 203). CONCLUSIONS: Dietary intake of acrylamide was not associated with overall or type-I EC risk; however, positive associations with type I were observed in women who were both non-users of OCs and never smokers.
|
|
| 6. |
- Obon-Santacana, M., et al.
(författare)
-
Dietary intake of acrylamide and pancreatic cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort
- 2013
-
Ingår i: Annals of Oncology. - : Elsevier BV. - 1569-8041 .- 0923-7534. ; 24:10, s. 2645-2651
-
Tidskriftsartikel (refereegranskat)abstract
- In 1994, acrylamide (AA) was classified as a probable human carcinogen by the International Agency for Research on Cancer. In 2002, AA was discovered at relatively high concentrations in some starchy, plant-based foods cooked at high temperatures. A prospective analysis was conducted to evaluate the association between the dietary intake of AA and ductal adenocarcinoma of the exocrine pancreatic cancer (PC) risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort using Cox regression modeling. EPIC includes > 500 000 men and women aged 35-75 at enrollment from 10 European countries. AA intake was estimated for each participant by combining questionnaire-based food consumption data with a harmonized AA database derived from the EU monitoring database of AA levels in foods, and evaluated in quintiles and continuously. After a mean follow-up of 11 years, 865 first incident adenocarcinomas of the exocrine pancreas were observed and included in the present analysis. At baseline, the mean dietary AA intake in EPIC was 26.22 mu g/day. No overall association was found between continuous or quintiles of dietary AA intake and PC risk in EPIC (HR:0.95, 95%CI:0.89-1.01 per 10 mu g/day). There was no effect measure modification by smoking status, sex, diabetes, alcohol intake or geographic region. However, there was an inverse association (HR: 0.73, 95% CI: 0.61-0.88 per 10 mu g/day) between AA intake and PC risk in obese persons as defined using the body mass index (BMI, >= 30 kg/m(2)), but not when body fatness was defined using waist and hip circumference or their ratio. Dietary intake of AA was not associated with an increased risk of PC in the EPIC cohort.
|
|
| 7. |
- Zamora-Ros, R., et al.
(författare)
-
Flavonoid and lignan intake in relation to bladder cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) study
- 2014
-
Ingår i: British Journal of Cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 111:9, s. 1870-1880
-
Tidskriftsartikel (refereegranskat)abstract
- Background: There is growing evidence of the protective role of dietary intake of flavonoids and lignans on cancer, but the association with bladder cancer has not been thoroughly investigated in epidemiological studies. We evaluated the association between dietary intakes of total and subclasses of flavonoids and lignans and risk of bladder cancer and its main morphological type, urothelial cell carcinoma (UCC), within the European Prospective Investigation into Cancer and Nutrition (EPIC) study. Methods: A cohort of 477 312 men and women mostly aged 35-70 years, were recruited in 10 European countries. At baseline, dietary flavonoid and lignan intakes were estimated using centre-specific validated questionnaires and a food composition database based on the Phenol-Explorer, the UK Food Standards Agency and the US Department of Agriculture databases. Results: During an average of 11 years of follow-up, 1575 new cases of primary bladder cancer were identified, of which 1425 were UCC (classified into aggressive (n = 430) and non-aggressive (n = 413) UCC). No association was found between total flavonoid intake and bladder cancer risk. Among flavonoid subclasses, significant inverse associations with bladder cancer risk were found for intakes of flavonol (hazard ratio comparing fifth with first quintile (HRQ5-Q1) 0.74, 95% confidence interval (CI): 0.61-0.91; P-trend = 0.009) and lignans (HRQ5-Q 10.78, 95% CI: 0.62-0.96; P-trend = 0.046). Similar results were observed for overall UCC and aggressive UCC, but not for non-aggressive UCC. Conclusions: Our study suggests an inverse association between the dietary intakes of flavonols and lignans and risk of bladder cancer, particularly aggressive UCC.
|
|
| 8. |
- Zamora-Ros, R., et al.
(författare)
-
Impact of thearubigins on the estimation of total dietary flavonoids in the European Prospective Investigation into Cancer and Nutrition (EPIC) study
- 2013
-
Ingår i: European Journal of Clinical Nutrition. - : Springer Science and Business Media LLC. - 0954-3007 .- 1476-5640. ; 67:7, s. 779-782
-
Tidskriftsartikel (refereegranskat)abstract
- Thearubigins (TR) are polymeric flavanol-derived compounds formed during the fermentation of tea leaves. Comprising similar to 70% of total polyphenols in black tea, TR may contribute majorly to its beneficial effects on health. To date, there is no appropriate food composition data on TR, although several studies have used data from the US Department of Agriculture (USDA) database to estimate TR intakes. We aimed to estimate dietary TR in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort and assess the impact of including TR or not in the calculation of the total dietary flavonoid intake. Dietary data were collected using a single standardized 24-h dietary recall interviewer-administered to 36 037 subjects aged 35-74 years. TR intakes were calculated using the USDA database. TR intakes ranged from 0.9 mg/day in men from Navarra and San Sebastian in Spain to 532.5 mg/day in men from UK general population. TR contributed <5% to the total flavonoid intake in Greece, Spain and Italy, whereas in the UK general population, TR comprised 48% of the total flavonoids. High heterogeneity in TR intake across the EPIC countries was observed. This study shows that total flavonoid intake may be greatly influenced by TR, particularly in high black tea-consuming countries. Further research on identification and quantification of TR is needed to get more accurate dietary TR estimations.
|
|
| 9. |
- Ahmad, Shafqat, et al.
(författare)
-
Gene x physical activity interactions in obesity : combined analysis of 111,421 individuals of European ancestry
- 2013
-
Ingår i: PLOS Genetics. - : Public Library of Science. - 1553-7390 .- 1553-7404. ; 9:7, s. e1003607-
-
Tidskriftsartikel (refereegranskat)abstract
- Numerous obesity loci have been identified using genome-wide association studies. A UK study indicated that physical activity may attenuate the cumulative effect of 12 of these loci, but replication studies are lacking. Therefore, we tested whether the aggregate effect of these loci is diminished in adults of European ancestry reporting high levels of physical activity. Twelve obesity-susceptibility loci were genotyped or imputed in 111,421 participants. A genetic risk score (GRS) was calculated by summing the BMI-associated alleles of each genetic variant. Physical activity was assessed using self-administered questionnaires. Multiplicative interactions between the GRS and physical activity on BMI were tested in linear and logistic regression models in each cohort, with adjustment for age, age(2), sex, study center (for multicenter studies), and the marginal terms for physical activity and the GRS. These results were combined using meta-analysis weighted by cohort sample size. The meta-analysis yielded a statistically significant GRS x physical activity interaction effect estimate (P-interaction = 0.015). However, a statistically significant interaction effect was only apparent in North American cohorts (n = 39,810, P-interaction = 0.014 vs. n = 71,611, P-interaction = 0.275 for Europeans). In secondary analyses, both the FTO rs1121980 (P-interaction = 0.003) and the SEC16B rs10913469 (P-interaction = 0.025) variants showed evidence of SNP x physical activity interactions. This meta-analysis of 111,421 individuals provides further support for an interaction between physical activity and a GRS in obesity disposition, although these findings hinge on the inclusion of cohorts from North America, indicating that these results are either population-specific or non-causal.
|
|
| 10. |
|
|
| 11. |
- Bauer, Brigitte, 1978, et al.
(författare)
-
Metal nanoparticles amplify photodynamic effect on skin cells in vitro
- 2011
-
Ingår i: Progress in Biomedical Optics and Imaging - Proceedings of SPIE. Optical Interactions with Tissue and Cells XXII; San Francisco, CA; 24-26 January 2011. - : SPIE. - 1605-7422. - 9780819484345 ; 7897
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We report on an investigation aimed to increase the efficiency of photodynamic therapy (PDT) through the influence of localized surface plasmon resonances (LSPR's) in metal nanoparticles. PDT is based on photosensitizers that generate singlet oxygen at the tumour site upon exposure to visible light. Although PDT is a well-established treatment for skin cancer, a major drawback is the low quantum yield for singlet-oxygen production. This motivates the development of novel methods that enhance singlet oxygen generation during treatment. In this context, we study the photodynamic effect on cultured human skin cells in the presence or absence of gold nanoparticles with well established LSPR and field-enhancement properties. The cultured skin cells were exposed to protoporphyrin IX and gold nanoparticles and subsequently illuminated with red light. We investigated the differences in cell viability by tuning different parameters, such as incubation time and light dose. In order to find optimal parameters for specific targeting of tumour cells, we compared normal human epidermal keratinocytes with a human squamous skin cancer cell line. The study indicates significantly enhanced cell death in the presence of nanoparticles and important differences in treatment efficiency between normal and tumour cells. These results are thus promising and clearly motivate further development of nanoparticle enhanced clinical PDT treatment.
|
|
| 12. |
- Hannerz, J, et al.
(författare)
-
Orbital phlebography in idiopathic intracranial hypertension and chronic tension-type headache
- 2013
-
Ingår i: Acta radiologica short reports. - : SAGE Publications. - 2047-9816. ; 2:6, s. 2047981613498861-
-
Tidskriftsartikel (refereegranskat)abstract
- Pathologic signs in orbital phlebographies have been reported in various neurological diseases. Purpose To study if pathologic signs in orbital phlebography may be markers of inflammation primarily affecting intracranial capillaries, which would cause intracranial hypertension. Material and Methods Two groups with different intracranial cerebrospinal fluid pressures (Pcsf) were compared as to inflammatory markers in serum and pathologic signs in orbital phlebographies. Nine consecutive patients with idiopathic intracranial hypertension (IIH) with bilateral papilledema and eight consecutive patients with chronic tension-type headache (CTTH) were investigated prospectively with fibrinogen, orosomucoid, haptoglobin in serum, and invasive orbital phlebograms. The angiograms were evaluated by two skilled neuroradiologists, independent of each other and without knowledge of the diagnoses or aim of the study, as to the following pathologic signs: (i) narrowing of superior ophthalmic veins; (ii) caliber changes of intraorbital veins; (iii) collaterals of intraorbital veins; (iv) flow to cavernous sinus; and (v) asymmetric drainage of cavernous sinus. Results Mean body mass index was >30 kg/m2 in both groups. Pcsf was >200 < 250 mm H2O in 50% of the CTTH and >350 mm H2O in all IIH patients. No difference in inflammatory markers in blood was found. The phlebographies of the IIH patients had more pathologic signs and were considered pathologic significantly more often than the ones of the CTTH patients ( P < 0.001). Conclusion The difference as to phlebographic pathologic signs between the IIH and the CTTH patients with different Pcsf supports the hypothesis that such phlebographic signs are markers of inflammation primarily affecting intracranial capillaries, which would disturb cerebrospinal fluid regulation causing intracranial hypertension.
|
|
| 13. |
- Hjelmevoll, Stig Ove, et al.
(författare)
-
Appropriate Time for Test-of-Cure when Diagnosing Gonorrhoea with a Nucleic Acid Amplification Test
- 2012
-
Ingår i: Acta Dermato-Venereologica. - Uppsala : Acta Dermato-Venereologica. - 0001-5555 .- 1651-2057. ; 92:3, s. 316-319
-
Tidskriftsartikel (refereegranskat)abstract
- Culture is commonly regarded as the gold standard for diagnosis of Neisseria gonorrhoeae. However, nucleic acid amplification tests (NAATs) have rapidly replaced culture for diagnostics in many settings. The aim of the present study was to investigate the appropriate time for test-of-cure (TOC) when NAATs are used for diagnosis of gonorrhoea. In total, 30 patients (28 men and 2 women) provided urethral, cervical, rectal or pharyngeal specimens for TOC. All included patients, except one who did not return for second TOC before day 19, tested negative within 2 weeks after treatment with cefixime 400 mg x 1. Antimicrobial susceptibility testing showed that 68% of the culture-positive strains were resistant to ciprofloxacin. Thus, the recommended empirical treatment with ciprofloxacin in Norway should be changed immediately. TOC can be performed 2 weeks after treatment when NAATs are used for diagnosis of gonorrhoea.
|
|
| 14. |
- Johansson, Ulf S., 1970-, et al.
(författare)
-
A complete multilocus species phylogeny of the tits and chickadees (Aves:Paridae)
- 2013
-
Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 69:3, s. 852-860
-
Tidskriftsartikel (refereegranskat)abstract
- The avian family Paridae (tits and chickadees) contains c. 55 species distributed in the Palearctic, Nearctic, Afrotropics and Indomalaya. The group includes some of the most well-known and extensively studied avian species, and the evolutionary history, in particular the post-glacial colonization of the northern latitudes, has been comparably well-studied for several species. Yet a comprehensive phylogeny of the whole clade is lacking. Here, we present the first complete species phylogeny for the group based on sequence data front two nuclear introns and one mitochondrial gene for 67 taxa of parids. Our results strongly support the inclusion of the Fire-capped Tit (Cephalopyrus flammiceps), currently placed in the Remizidae, as the most basal member of the Paridae. The Yellow-browed Tit (Sylviparus modestus) and the Sultan Tit (Melanochlora sultanea) constitute the next two sequential branches whereas the remaining tits fall into two large clades, one of which contains the seed hoarding and nest excavating species. The indicated clades within these two groups are largely congruent with recent classifications, but with several unforeseen relationships, such as non-monophyly of the Sombre Tit (Poecile lugubris) and the Marsh Tit (Poecile palustris), as well as non-monophyly of both the African gray and the African black tits. Further, our results support a close relationship between the White-fronted Tit (Parus semilarvatus) and the varied Tit (Poecile varius) as well as a close relationship between the White-naped Tit (Parus nuchalis) and the Yellow-cheeked and Black-bred tits (Parus spilonotus and P. xanthogenys). Finally, Hume's Ground-tit (Pseudopodoces humilis) is found to be closely related to the Green-backed Tit (Parus monticolus) and the Great Tit (Parus major). We propose a new classification that is in accordance with this phylogeny.
|
|
| 15. |
- Kirejev, Vladimir, 1984, et al.
(författare)
-
Photophysics and ex vivo biodistribution of beta-cyclodextrin-meso-tetra(m-hydroxyphenyl)-porphyrin conjugate for biomedical applications
- 2014
-
Ingår i: Photochemical & Photobiological Sciences. - : Springer Science and Business Media LLC. - 1474-905X .- 1474-9092. ; 13:8, s. 1185-1191
-
Tidskriftsartikel (refereegranskat)abstract
- Low aqueous solubility of porphyrin-based photosensitizers hampers their clinical use in photodynamic therapy because of complex delivery. In this study, we explore meso-tetra(m-hydroxyphenyl)-21,23H-porphyrin (mTHPP), a potent photosensitizer, covalently attached to beta-cyclodextrin (CD-mTHPP) with a focus on topical delivery and cellular uptake. The photophysical properties of CD-mTHPP were examined using steady-state fluorescence and lifetime measurements verifying increased aqueous solubility. Confocal and fluorescence lifetime imaging microscopy on human squamous carcinoma cells (A431) evidenced a cytoplasmic uptake of CD-mTHPP in predominantly monomeric form. CD-mTHPP was also delivered to human skin ex vivo and the skin penetration was assessed using two-photon fluorescence microscopy. The results indicated that CD-mTHPP exhibits improved skin distribution compared to mTHPP alone using aqueous vehicles. Thus the CD-mTHPP conjugate demonstrates improved biodistribution ex vivo compared to mTHPP and is a promising multimodal system for photodynamic therapy.
|
|
| 16. |
|
|
| 17. |
- Rago, Gianluca, et al.
(författare)
-
Uptake of gold nanoparticles in healthy and tumor cells visualized by nonlinear optical microscopy
- 2011
-
Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 115:17, s. 5008-16
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding the mechanism underlying the interactions between inorganic nanostructures and biological systems is crucial for several rapidly growing fields that rely on nano-bio interactions. In particular, the further development of cell-targeted drug delivery using metallic nanoparticles (NP) requires new tools for understanding the mechanisms triggered by the contact of NPs with membranes in different cells at the subcellular level. Here we present a novel concept of multimodal microscopy, enabling three-dimensional imaging of the distribution of gold NPs in living, unlabeled cells. Our approach combines multiphoton induced luminescence (MIL) with coherent anti-Stokes Raman scattering (CARS) microscopy. Comparison with transmission electron microscopy (TEM) reveals in vivo sensitivity down to the single nanostructure. By monitoring the incorporation of NPs in human healthy epidermal keratinocytes and squamous carcinoma cells (SCC), we address the feasibility of noninvasive delivery of NPs for therapeutic purposes. While neutralizing PEG coating was confirmed to prevent NP integration in SCCs, an unexpectedly efficient integration of NPs into keratinocytes was observed. These results, independently validated using TEM, demonstrate the need for advanced surface modification protocols to obtain tumor selectivity for NP delivery. The CARS/MIL microscopy platform presented here is thus a promising tool for noninvasive study of the interaction between NPs and cell.
|
|
| 18. |
- Scragg, Jonathan J., et al.
(författare)
-
Effects of Back Contact Instability on Cu2ZnSnS4 Devices and Processes
- 2013
-
Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 25:15, s. 3162-3171
-
Tidskriftsartikel (refereegranskat)abstract
- Cu2ZnSnS4 (CZTS) is a promising material for thin film solar cells based on sustainable resources. This paper explores some consequences of the chemical instability between CZTS and the standard Mo “back contact” layer used in the solar cell. Chemical passivation of the back contact interface using titanium nitride (TiN) diffusion barriers, combined with variations in the CZTS annealing process, enables us to isolate the effects of back contact chemistry on the electrical properties of the CZTS layer that result from the synthesis, as determined by measurements on completed solar cells. It is found that instability in the back contact is responsible for large current losses in the finished solar cell, which can be distinguished from other losses that arise from instabilities in the surface of the CZTS layer during annealing. The TiN-passivated back contact is an effective barrier to sulfur atoms and therefore prevents reactions between CZTS and Mo. However, it also results in a high series resistance and thus a reduced fill factor in the solar cell. The need for high chalcogen pressure during CZTS annealing can be linked to suppression of the back contact reactions and could potentially be avoided if better inert back contacts were to be developed.
|
|
