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1.
Genotoxicity and physicochemical characteristics of traffic-related ambient particulate matter 总被引:1,自引:0,他引:1
de Kok TM Hogervorst JG Briedé JJ van Herwijnen MH Maas LM Moonen EJ Driece HA Kleinjans JC 《Environmental and molecular mutagenesis》2005,46(2):71-80
Exposure to ambient particulate matter (PM) has been linked to several adverse health effects. Since vehicular traffic is a PM source of growing importance, we sampled total suspended particulate (TSP), PM(10), and PM(2.5) at six urban locations with pronounced differences in traffic intensity. The mutagenicity, DNA-adduct formation, and induction of oxidative DNA damage by the samples were studied as genotoxicological parameters, in relation to polycyclic aromatic hydrocarbon (PAH) levels, elemental composition, and radical-generating capacity (RGC) as chemical characteristics. We found pronounced differences in the genotoxicity and chemical characteristics of PM from the various locations, although we could not establish a correlation between traffic intensity and any of these characteristics for any of the PM size fractions. Therefore, the differences between locations may be due to local sources of PM, other than traffic. The concentration of total (carcinogenic) PAHs correlated positively with RGC, direct and S9-mediated mutagenicity, as well as the induction of DNA adducts and oxidative DNA damage. The interaction between total PAHs and transition metals correlated positively with DNA-adduct formation, particularly from the PM(2.5) fraction. RGC was not associated with one specific PM size fraction, but mutagenicity and DNA reactivity after metabolic activation were relatively high in PM(10) and PM(2.5), when compared with TSP. We conclude that the toxicological characteristics of urban PM samples show pronounced differences, even when PM concentrations at the sample sites are comparable. This implies that emission reduction strategies that take chemical and toxicological characteristics of PM into account may be useful for reducing the health risks associated with PM exposure. 相似文献
2.
Rajeesh Kumar Pazhavelikkakath Purushothaman Gijs van Erven Daan S. van Es Lon Rohrbach Augustinus E. Frissen Jacco van Haveren Richard J. A. Gosselink 《RSC advances》2023,13(8):4898
A first systematic approach on the base catalyzed depolymerization (BCD) of five technical lignins derived from various botanical origins (herbaceous, hardwood and softwood) and covering the main three industrial pulping methods (soda, kraft and organosolv) is reported. This study provides a first of its kind in-depth quantification and structural characterization of two main BCD fractions namely lignin oil and lignin residue, describing the influence of the BCD process conditions. Depolymerization is evaluated in terms of lignin conversion, lignin oil yield, phenolic monomer selectivity and the production of lignin residue and char. Lignin oils were extensively characterized by size exclusion chromatography (SEC), GC-MS, GC-FID, 13C-NMR, HSQC NMR and elemental analysis. GC × GC-FID was used to identify and quantify distinct groups of monomeric compounds (methoxy phenols, phenols, dihydroxy-benzenes) in the lignin oil. The lignin oil yields (w/w) ranged from 20–31% with total monomer contents ranging from 48 to 57% w/w. SEC analysis indicated the presence of dimers/oligomers in the lignin oil, which through HSQC NMR analysis were confirmed to contain new, non-native interunit linkages. 13C NMR analyses of the lignin oils suggest the presence of diaryl type linkages (i.e. aryl–aryl, aryl C–O) evidencing deconstruction and recombination of lignin fragments during BCD. Irrespective of the lignin source, a residue, often regarded as ‘unreacted’ residual lignin was the main product of BCD (43 to 70% w/w). Our study highlights that this residue has different structural properties and should not be considered as unreacted lignin, but rather as an alkali soluble condensed aromatic material. HSQC, DEPT-135, 13C, and 31P NMR and SEC analyses confirm that the BCD residues are indeed more condensed, with increased phenolic hydroxyl content and lower molecular weights compared to all feed lignins. Subsequent BCD of solid residual fractions produced only low oil yields (6–9% w/w) with lower phenolic monomer yields (4% w/w) compared to original lignin, confirming the significantly more recalcitrant structure. Our study improves the overall understanding of the BCD process, highlights important feedstock-dependent outcomes and ultimately contributes to the complete valorization of BCD-derived lignin streams.Towards a lignin BCD biorefinery! Overall understanding of the BCD process, feedstock-dependent fractionation results, complete valorization of BCD-derived lignin streams. 相似文献
3.
R.J. van de Peppel M.T. van der Beek L.G. Visser M.G.J. de Boer J. Wallinga 《International journal of antimicrobial agents》2019,53(3):284-293
Objectives
Triazole resistance in Aspergillus spp. is emerging and complicates prophylaxis and treatment of invasive aspergillosis (IA) worldwide. New polymerase chain reaction (PCR) tests on broncho-alveolar lavage (BAL) fluid allow for detection of triazole resistance at a genetic level, which has opened up new possibilities for targeted therapy. In the absence of clinical trials, a modelling study delivers estimates of the added value of resistance detection with PCR, and which empiric therapy would be optimal when local resistance rates are known.Design
A decision-analytic modelling study was performed based on epidemiological data of IA, extended with estimated dynamics of resistance rates and treatment effectiveness. Six clinical strategies were compared that differ in use of PCR diagnostics (used vs not used) and in empiric therapeutic choice in case of unknown triazole susceptibility: voriconazole, liposomal amphotericin B (LAmB) or both. Outcome measures were proportion of correct treatment, survival and serious adverse events.Results
Implementing aspergillus PCR tests was projected to result in residual treatment-susceptibility mismatches of <5% for a triazole resistance rate up to 20% (using voriconazole). Empiric LAmB outperformed voriconazole at resistance rates >5–20%, depending on PCR use and estimated survival benefits of voriconazole over LAmB. Combination therapy of voriconazole and LAmB performed best at all resistance rates, but the advantage over the other strategies should be weighed against the expected increased number of drug-related serious adverse events. The advantage of combination therapy over LAmB monotherapy became smaller at higher triazole resistance rates.Conclusions
Introduction of current aspergillus PCR tests on BAL fluid is an effective way to increase the proportion of patients that receive targeted therapy for IA. The results indicate that close monitoring of background resistance rates and adverse drug events are important to attain the potential benefits of LAmB. The choice of strategy ultimately depends on the probability of triazole resistance, the availability of PCR and individual patient characteristics. 相似文献4.
Peter van Gelderen Jacco A. de Zwart Jongho Lee Pascal Sati Daniel S. Reich Jeff H. Duyn 《Magnetic resonance in medicine》2012,67(1):110-117
Visualizing myelin in human brain may help the study of diseases such as multiple sclerosis. Previous studies based on T1 and T2 relaxation contrast have suggested the presence of a distinct water pool that may report directly on local myelin content. Recent work indicates that T2* contrast may offer particular advantages over T1 and T2 contrast, especially at high field. However, the complex mechanism underlying T2* relaxation may render interpretation difficult. To address this issue, T2* relaxation behavior in human brain was studied at 3 and 7 T. Multiple gradient echoes covering most of the decay curve were analyzed for deviations from mono‐exponential behavior. The data confirm the previous finding of a distinct rapidly relaxing signal component (T2* ~ 6 ms), tentatively attributed to myelin water. However, in extension to previous findings, this rapidly relaxing component displayed a substantial resonance frequency shift, reaching 36 Hz in the corpus callosum at 7 T. The component's fractional amplitude and frequency shift appeared to depend on both field strength and fiber orientation, consistent with a mechanism originating from magnetic susceptibility effects. The findings suggest that T2* contrast at high field may be uniquely sensitive to tissue myelin content and that proper interpretation will require modeling of susceptibility‐induced resonance frequency shifts. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc. 相似文献
5.
6.
Arjen Kolk Nienke Wolterbeek Kiem Gie Auw Yang Jacco A. C. Zijl Ronald N. Wessel 《International orthopaedics》2016,40(2):323-329
Purpose
Disease-specific instruments of quality of life (QOL) are more sensitive to disease-specific changes. The purpose of this study is to identify prognostic factors for disease-specific QOL after all-arthroscopic rotator cuff (RC) repair using the Western Ontario Rotator Cuff Index (WORC).Methods
A total of 140 patients were evaluated after an RC repair with a mean follow-up of 22?±?6.7 months. Evaluations included the WORC, EQ-5D and anchor questions. Preoperative patient demographics and radiologic characteristics were assessed to identify predictors of disease-specific QOL.Results
Most patients (81.4 %) were satisfied with their surgical result. Minor tear retraction (odds ratio [OR] 2.97, p?=?0.030), male gender (OR 3.67, p?=?0.003), no social benefits (OR 3.67, p?=?0.042) and pre-surgical complaints for more than six months (OR 3.03, p?=?0.021) were independent predictors for superior postoperative WORC score in multivariable analysis. None of these factors were predictive for a higher EQ-5D score.Conclusion
These findings highlight the important impact of retraction on QOL after RC repair and underline the utility of disease-specific instruments. Future studies should focus on how these significant predictors can be used to improve decision making and to develop new treatment approaches.7.
8.
Frenk Peeters Jacco Ronner Lonneke Bodar Jim van Os Richel Lousberg 《International journal of psychophysiology》2014
It is claimed that neurofeedback (NF) is an effective treatment for a variety of psychiatric disorders. NF, within an operant conditioning framework, helps individuals to regulate cortical electroencephalographic (EEG) activity while receiving feedback from a visual or acoustic signal. For example, changing asymmetry between left and right frontal brain alpha activity by NF, is claimed to be an efficacious treatment for major depressive disorder. However, the specificity of this intervention in occasioning electrophysiological changes at target locations and target wave-frequencies, and its relation to changes in mood, has not been established. During a single session of NF, it was tested if the balance between left and right frontal alpha-activity could be changed, regardless of direction, in 40 healthy females. Furthermore, we investigated whether this intervention was electrophysiologically specific and if it was associated with changes in mood. Participants were able to decrease or increase frontal alpha-asymmetry during the intervention. However, no changes in mood were observed. Changes in EEG activity were specific in terms of location and wave-frequency. 相似文献
9.
Frits van der Klis Linda Gootjes Noud Hendrik Verstijnen Jacco van Haveren Daniël Stephan van Es Johannes Hendrik Bitter 《RSC advances》2022,12(15):8918
This paper describes the base-free gold-catalysed oxidation of four different carbohydrates in a packed bed plug flow reactor. The influence of the carbohydrate structure on the catalytic activity and selectivity was investigated by comparing two neutral sugars (glucose (Glc) and galactose (Gal), both with primary alcohols at C6), with their sugar-acid analogues (glucuronic acid (GlcA) and galacturonic acid (GalA), both with carboxylic acids at C6). The orientation of OH-groups at the C4-position (equatorial in Glc/GlcA and axial in Glc/GlcA), and the C6-functionality (primary alcohols in Gal/Glc and carboxylic acids in GalA/GlcA) has a profound influence on the catalytic activity. When the OH-groups are in an axial position their reactivity was higher compared to the OH-groups in the equatorial position for both the sugars and the sugar acids. In addition the reactivity of carbohydrates over Au-catalysts under base-free conditions is different compared to alkaline conditions, and is more in line with a Pt-catalysed dehydrogenation mechanism.Gold mimicking Platinum in base-free catalytic carbohydrate oxidations. 相似文献
10.
Kedrin D van Rheenen J Hernandez L Condeelis J Segall JE 《Journal of mammary gland biology and neoplasia》2007,12(2-3):143-152
Cell motility and chemotaxis can make important contributions to the metastatic cascade. Cell migration pathways in general
play significant roles in a variety of physiological processes that can be “hijacked” by cancer cells. Both growth factors
and chemokines provide important chemotactic signals in development and metastasis. Receptor activation, following binding
of a growth factor or a chemokine, leads to dynamic morphological changes in the actin cytoskeleton network via a variety
of distinct and interconnected pathways, resulting in translocation of the cell up a chemoattractant gradient. Such gradients
may be produced by stromal cells in the local microenvironment, including macrophages and fibroblasts. A better understanding
of the mechanisms of cell motility and cytoskeletal regulation may provide novel therapeutic strategies that would block metastatic
progression, reducing dissemination of tumor cells and increasing patient survival. 相似文献