Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 50
Filter
1.
Materials (Basel) ; 16(7)2023 Apr 06.
Article in English | MEDLINE | ID: mdl-37049216

ABSTRACT

Liquid organic hydrogen carriers can store hydrogen in a safe and dense form through covalent bonds. Hydrogen uptake and release are realized by catalytic hydrogenation and dehydrogenation, respectively. Indoles have been demonstrated to be interesting candidates for this task. The enthalpy of reaction is a crucial parameter in this regard as it determines not only the heat demand for hydrogen release, but also the reaction equilibrium at given conditions. In this work, a combination of experimental measurements, quantum chemical methods and a group-additivity approach has been applied to obtain a consistent dataset on the enthalpies of formation of different methylated indole derivatives and their hydrogenated counterparts. The results show a namable influence of the number and position of methyl groups on the enthalpy of reaction. The enthalpy of reaction of the overall hydrogenation reaction varies in the range of up to 18.2 kJ·mol-1 (corresponding to 4.6 kJ·mol(H2)-1). The widest range of enthalpy of reaction data for different methyl indoles has been observed for the last step (hydrogenation for the last double bond in the five-membered ring). Here a difference of up to 7.3 kJ·mol(H2)-1 between the highest and the lowest value was found.

2.
Article in English | MEDLINE | ID: mdl-37018556

ABSTRACT

Copy prediction is a renowned category of prediction techniques in video coding where the current block is predicted by copying the samples from a similar block that is present somewhere in the already decoded stream of samples. Motion-compensated prediction, intra block copy, template matching prediction etc. are examples. While the displacement information of the similar block is transmitted to the decoder in the bit-stream in the first two approaches, it is derived at the decoder in the last one by repeating the same search algorithm which was carried out at the encoder. Region-based template matching is a recently developed prediction algorithm that is an advanced form of standard template matching. In this method, the reference area is partitioned into multiple regions and the region to be searched for the similar block(s) is conveyed to the decoder in the bit-stream. Further, its final prediction signal is a linear combination of already decoded similar blocks from the given region. It was demonstrated in previous publications that region-based template matching is capable of achieving coding efficiency improvements for intra as well as inter-picture coding with considerably less decoder complexity than conventional template matching. In this paper, a theoretical justification for region-based template matching prediction subject to experimental data is presented. Additionally, the test results of the aforementioned method on the latest H.266/Versatile Video Coding (VVC) test model (version VTM-14.0) yield an average Bjøntegaard-Delta (BD) bit-rate savings of -0.75% using all intra (AI) configuration with 130% encoder run-time and 104% decoder run-time for a particular parameter selection.

3.
Front Psychiatry ; 13: 958688, 2022.
Article in English | MEDLINE | ID: mdl-36072455

ABSTRACT

Tourette syndrome (TS) is characterized by multiple motor and vocal tics, and high-comorbidity rates with other neuropsychiatric disorders. Obsessive compulsive disorder (OCD), attention deficit hyperactivity disorder (ADHD), autism spectrum disorders (ASDs), major depressive disorder (MDD), and anxiety disorders (AXDs) are among the most prevalent TS comorbidities. To date, studies on TS brain structure and function have been limited in size with efforts mostly fragmented. This leads to low-statistical power, discordant results due to differences in approaches, and hinders the ability to stratify patients according to clinical parameters and investigate comorbidity patterns. Here, we present the scientific premise, perspectives, and key goals that have motivated the establishment of the Enhancing Neuroimaging Genetics through Meta-Analysis for TS (ENIGMA-TS) working group. The ENIGMA-TS working group is an international collaborative effort bringing together a large network of investigators who aim to understand brain structure and function in TS and dissect the underlying neurobiology that leads to observed comorbidity patterns and clinical heterogeneity. Previously collected TS neuroimaging data will be analyzed jointly and integrated with TS genomic data, as well as equivalently large and already existing studies of highly comorbid OCD, ADHD, ASD, MDD, and AXD. Our work highlights the power of collaborative efforts and transdiagnostic approaches, and points to the existence of different TS subtypes. ENIGMA-TS will offer large-scale, high-powered studies that will lead to important insights toward understanding brain structure and function and genetic effects in TS and related disorders, and the identification of biomarkers that could help inform improved clinical practice.

4.
Front Chem ; 10: 864663, 2022.
Article in English | MEDLINE | ID: mdl-35392423

ABSTRACT

Deep eutectic solvents (DES) are a new class of green solvents that have shown unique properties in several process applications. This study evaluates nonionic DES containing phenolic alcohols as solvents for carbon dioxide (CO2) capture applications. Potential phenolic alcohols and the molar ratio between DES constituents were preselected for experimental investigations based on the conductor-like screening model for realistic solvation (COSMO-RS). CO2 solubility was experimentally determined in two different DES, namely, L-menthol/thymol in 1:2 molar ratio and thymol/2,6-xylenol in 1:1 molar ratio, at various temperatures and pressures. CO2 solubility in the studied systems was higher than that reported in the literature for ionic DES and ionic liquids. This study demonstrates that nonionic DES containing phenolic alcohols can be excellent, inexpensive, and simple solvents for CO2 capture.

5.
Front Hum Neurosci ; 13: 290, 2019.
Article in English | MEDLINE | ID: mdl-31507395

ABSTRACT

Previous magnetic resonance imaging (MRI) studies revealed structural-functional brain reorganization 12 months after gastric-bypass surgery, encompassing cortical and subcortical regions of all brain lobes as well as the cerebellum. Changes in the mean of cluster-wise gray/white matter density (GMD/WMD) were correlated with the individual loss of body mass index (BMI), rendering the BMI a potential marker of widespread surgery-induced brain plasticity. Here, we investigated voxel-by-voxel associations between surgery-induced changes in adiposity, metabolism and inflammation and markers of functional and structural neural plasticity. We re-visited the data of patients who underwent functional and structural MRI, 6 months (n = 27) and 12 months after surgery (n = 22), and computed voxel-wise regression analyses. Only the surgery-induced weight loss was significantly associated with brain plasticity, and this only for GMD changes. After 6 months, weight loss overlapped with altered GMD in the hypothalamus, the brain's homeostatic control site, the lateral orbitofrontal cortex, assumed to host reward and gustatory processes, as well as abdominal representations in somatosensory cortex. After 12 months, weight loss scaled with GMD changes in right cerebellar lobule VII, involved in language-related/cognitive processes, and, by trend, with the striatum, assumed to underpin (food) reward. These findings suggest time-dependent and weight-loss related gray matter plasticity in brain regions involved in the control of eating, sensory processing and cognitive functioning.

6.
JCI Insight ; 4(19)2019 10 03.
Article in English | MEDLINE | ID: mdl-31465301

ABSTRACT

There is increased interest in whether bariatric surgeries such as Roux-en-Y gastric bypass (RYGB) achieve their profound weight-lowering effects in morbidly obese individuals through the brain. Hypothalamic inflammation is a well-recognized etiologic factor in obesity pathogenesis and so represents a potential target of RYGB, but clinical evidence in support of this is limited. We therefore assessed hypothalamic T2-weighted signal intensities (T2W SI) and fractional anisotropy (FA) values, 2 validated radiologic measures of brain inflammation, in relation to BMI and fat mass, as well as circulating inflammatory (C-reactive protein; CrP) and metabolic markers in a cohort of 27 RYGB patients at baseline and 6 and 12 months after surgery. We found that RYGB progressively increased hypothalamic T2W SI values, while it progressively decreased hypothalamic FA values. Regression analyses further revealed that this could be most strongly linked to plasma CrP levels, which independently predicted hypothalamic FA values when adjusting for age, sex, fat mass, and diabetes diagnosis. These findings suggest that RYGB has a major time-dependent impact on hypothalamic inflammation status, possibly by attenuating peripheral inflammation. They also suggest that hypothalamic FA values may provide a more specific radiologic measure of hypothalamic inflammation than more commonly used T2W SI values.


Subject(s)
Gastric Bypass/methods , Hypothalamus/metabolism , Inflammation/metabolism , Obesity, Morbid/surgery , Adipose Tissue , Adult , Biomarkers , Blood Glucose , C-Reactive Protein , Diabetes Mellitus , Female , Humans , Hypothalamus/diagnostic imaging , Inflammation/diagnostic imaging , Insulin/metabolism , Male , Middle Aged , Obesity
7.
Neuroimage ; 199: 680-690, 2019 10 01.
Article in English | MEDLINE | ID: mdl-31173902

ABSTRACT

Acute stress triggers a broad psychophysiological response that is adaptive if rapidly activated and terminated. While the brain controls the stress response, it is strongly affected by it. Previous research of stress effects on brain activation and connectivity has mainly focused on pre-defined brain regions or networks, potentially missing changes in the rest of the brain. We here investigated how both stress reactivity and stress recovery are reflected in whole-brain network topology and how changes in functional connectivity relate to other stress measures. Healthy young males (n = 67) completed the Trier Social Stress Test or a control task. From 60 min before until 105 min after stress onset, blocks of resting-state fMRI were acquired. Subjective, autonomic, and endocrine measures of the stress response were assessed throughout the experiment. Whole-brain network topology was quantified using Eigenvector centrality (EC) mapping, which detects central hubs of a network. Stress influenced subjective affect, autonomic activity, and endocrine measures. EC differences between groups as well as before and after stress exposure were found in the thalamus, due to widespread connectivity changes in the brain. Stress-driven EC increases in the thalamus were significantly correlated with subjective stress ratings and showed non-significant trends for a correlation with heart rate variability and saliva cortisol. Furthermore, increases in thalamic EC and in saliva cortisol persisted until 105 min after stress onset. We conclude that thalamic areas are central for information processing after stress exposure and may provide an interface for the stress response in the rest of the body and in the mind.


Subject(s)
Cerebral Cortex/physiopathology , Connectome , Nerve Net/physiopathology , Stress, Psychological/physiopathology , Thalamus/physiopathology , Adolescent , Adult , Autonomic Nervous System/physiopathology , Cerebral Cortex/diagnostic imaging , Humans , Hydrocortisone/metabolism , Magnetic Resonance Imaging , Male , Nerve Net/diagnostic imaging , Stress, Psychological/diagnostic imaging , Stress, Psychological/metabolism , Thalamus/diagnostic imaging , Young Adult
8.
Neurology ; 92(8): e758-e773, 2019 02 19.
Article in English | MEDLINE | ID: mdl-30674602

ABSTRACT

OBJECTIVE: To test whether elevated blood pressure (BP) relates to gray matter (GM) volume (GMV) changes in young adults who had not previously been diagnosed with hypertension (systolic BP [SBP]/diastolic BP [DBP] ≥140/90 mm Hg). METHODS: We associated BP with GMV from structural 3T T1-weighted MRI of 423 healthy adults between 19 and 40 years of age (mean age 27.7 ± 5.3 years, 177 women, SBP/DBP 123.2/73.4 ± 12.2/8.5 mm Hg). Data originated from 4 previously unpublished cross-sectional studies conducted in Leipzig, Germany. We performed voxel-based morphometry on each study separately and combined results in image-based meta-analyses (IBMA) to assess cumulative effects across studies. Resting BP was assigned to 1 of 4 categories: (1) SBP <120 and DBP <80 mm Hg, (2) SBP 120-129 or DBP 80-84 mm Hg, (3) SBP 130-139 or DBP 85-89 mm Hg, (4) SBP ≥140 or DBP ≥90 mm Hg. RESULTS: IBMA yielded the following results: (1) lower regional GMV was correlated with higher peripheral BP; (2) lower GMV was found with higher BP when comparing individuals in subhypertensive categories 3 and 2, respectively, to those in category 1; (3) lower BP-related GMV was found in regions including hippocampus, amygdala, thalamus, frontal, and parietal structures (e.g., precuneus). CONCLUSION: BP ≥120/80 mm Hg was associated with lower GMV in regions that have previously been related to GM decline in older individuals with manifest hypertension. Our study shows that BP-associated GM alterations emerge continuously across the range of BP and earlier in adulthood than previously assumed. This suggests that treating hypertension or maintaining lower BP in early adulthood might be essential for preventing the pathophysiologic cascade of asymptomatic cerebrovascular disease to symptomatic end-organ damage, such as stroke or dementia.


Subject(s)
Blood Pressure , Gray Matter/diagnostic imaging , Hypertension/epidemiology , Adult , Amygdala/diagnostic imaging , Amygdala/pathology , Cross-Sectional Studies , Female , Frontal Lobe/diagnostic imaging , Frontal Lobe/pathology , Germany/epidemiology , Gray Matter/pathology , Hippocampus/diagnostic imaging , Hippocampus/pathology , Humans , Magnetic Resonance Imaging , Male , Organ Size , Parietal Lobe/diagnostic imaging , Parietal Lobe/pathology , Prehypertension/epidemiology , Thalamus/diagnostic imaging , Thalamus/pathology , Young Adult
9.
Cytokine ; 113: 400-404, 2019 01.
Article in English | MEDLINE | ID: mdl-30539782

ABSTRACT

AIM: Metreleptin treatment in lipodystrophy patients improves eating behavior with increased satiety and reduced hunger. However, no data are available whether effects are maintained beyond 52 weeks of treatment. METHODS: A prospective study with measurements at baseline and at >150 weeks of metreleptin treatment was performed. Five female lipodystrophy patients with indication for metreleptin were included. Behavioral aspects of hunger- and satiety regulation were assessed by validated eating behavior questionnaires and visual analog scales assessing hunger and satiety feelings before and after a standardized meal. RESULTS: Hunger rated on visual analog scales at 120 min after the meal significantly decreased from 46 ±â€¯10 mm at baseline to 17 ±â€¯6 mm at long-term assessment. Furthermore, satiety at 5 and 120 min after the meal significantly increased from baseline to long-term assessment (5 min: 70 ±â€¯7 mm to 87 ±â€¯3 mm; 120 min: 43 ±â€¯10 mm to 79 ±â€¯8 mm). On the Three Factor Eating Questionnaire, the mean value of factor 3 (hunger) significantly decreased from 9.2 ±â€¯0.2 at baseline to 2.6 ±â€¯1.5 at long-term assessment. In the Inventory of Eating Behavior and Weight Problems Questionnaire, mean values for scale 2 (strength and triggering of desire to eat) and scale 7 (cognitive restraint of eating) significantly decreased from baseline (31.6 ±â€¯4.8 and 11.4 ±â€¯2.2, respectively) to long-term assessment (14.0 ±â€¯2.1 and 10.0 ±â€¯1.9). CONCLUSION: First evidence is presented that long-term metreleptin treatment of >150 weeks has sustained effects on eating behavior with increased satiety, as well as reduced hunger and hunger-related measures.


Subject(s)
Feeding Behavior/drug effects , Feeding and Eating Disorders/drug therapy , Hunger/drug effects , Leptin/analogs & derivatives , Lipodystrophy/drug therapy , Surveys and Questionnaires , Adult , Feeding and Eating Disorders/metabolism , Feeding and Eating Disorders/pathology , Feeding and Eating Disorders/physiopathology , Female , Humans , Leptin/administration & dosage , Lipodystrophy/metabolism , Lipodystrophy/pathology , Lipodystrophy/physiopathology , Middle Aged
10.
Front Aging Neurosci ; 10: 47, 2018.
Article in English | MEDLINE | ID: mdl-29559904

ABSTRACT

Objective: Recently, the characteristic longitudinal distribution pattern of the underlying phosphorylated TDP-43 (pTDP-43) pathology in the behavioral variant of frontotemporal dementia (bvFTD) excluding Pick's disease (PiD) across specific brain regions was described. The aim of the present study was to investigate whether in vivo investigations of bvFTD patients by use of diffusion tensor imaging (DTI) were consistent with these proposed patterns of progression. Methods: Sixty-two bvFTD patients and 47 controls underwent DTI in a multicenter study design. Of these, 49 bvFTD patients and 34 controls had a follow-up scan after ~12 months. Cross-sectional and longitudinal alterations were assessed by a two-fold analysis, i.e., voxelwise comparison of fractional anisotropy (FA) maps and a tract of interest-based (TOI) approach, which identifies tract structures that could be assigned to brain regions associated with disease progression. Results: Whole brain-based spatial statistics showed white matter alterations predominantly in the frontal lobes cross-sectionally and longitudinally. The TOIs of bvFTD neuroimaging stages 1 and 2 (uncinate fascicle-bvFTD pattern I; corticostriatal pathway-bvFTD pattern II) showed highly significant differences between bvFTD patients and controls. The corticospinal tract-associated TOI (bvFTD pattern III) did not differ between groups, whereas the differences in the optic radiation (bvFTD pattern IV) reached significance. The findings in the corticospinal tract were due to a "dichotomous" behavior of FA changes there. Conclusion: Longitudinal TOI analysis demonstrated a pattern of white matter pathways alterations consistent with patterns of pTDP-43 pathology.

11.
AIDS Res Hum Retroviruses ; 34(4): 365-374, 2018 04.
Article in English | MEDLINE | ID: mdl-29262692

ABSTRACT

The analysis of patient derived HIV neutralizing antibodies (nAbs) and their target epitopes in the viral envelope (Env) protein provides important basic information for vaccine design. In this study we optimized an epitope, EC26-2A4, that is targeted by neutralizing antibodies from an elite controller (EC26) and localizes in the membrane-proximal external region from the gp41 transmembrane protein. Due to its overlap with the epitope of the first generation broadly neutralizing monoclonal Ab (mAb) 2F5 associated with autoreactivity, we first defined the minimal core epitope reacting with antibodies from EC26 plasma, but not with mAb 2F5. The optimized minimal epitope, EC26-2A4ΔM, was able to induce neutralizing antibodies in vaccinated mice. We further analyzed the frequency of antibodies against the EC26-2A4ΔM peptide in HIV-positive patient sera from a treated cohort and an untreated long-term nonprogressor (LTNP) cohort. Interestingly, 27% of the LTNP sera reacted with the peptide, whereas only 9% showed reactivity in the treated cohort. Although there was no association between the presence of antibodies against the EC26-2A4ΔM epitope and viral load or CD4 count in these patients, the CD4 nadir in the treated cohort was higher in patients positive for EC26-2A4ΔM antibodies, in particular in patients having such antibodies at an early and a late timepoint after infection.


Subject(s)
Antibodies, Neutralizing/immunology , Epitopes/immunology , HIV Antibodies/immunology , HIV Envelope Protein gp41/immunology , HIV Infections/immunology , HIV-1/immunology , AIDS Vaccines/administration & dosage , AIDS Vaccines/immunology , Animals , Anti-HIV Agents/therapeutic use , Antibodies, Monoclonal/immunology , Broadly Neutralizing Antibodies , CD4 Lymphocyte Count , Epitopes/chemistry , HIV Envelope Protein gp41/chemistry , HIV Infections/drug therapy , HIV Long-Term Survivors , Humans , Mice , Peptides/immunology
12.
Neuroimage ; 172: 853-863, 2018 05 15.
Article in English | MEDLINE | ID: mdl-29107772

ABSTRACT

Bariatric surgery has become the gold standard for the treatment of morbid obesity (body mass index (BMI) ≥ 40 kg/m2), but only few studies investigated its plastic influences on the obese brain. In this longitudinal study, we combined structural and functional magnetic resonance brain imaging (MRI) in 27 patients (BMI 47.8 ± 5.5 kg/m2) undergoing gastric-bypass surgery and 14 non-obese matched controls (BMI 24.7 ± 3.4 kg/m2). Over the first year after surgery, patients presented widespread changes in white matter density (WMD) as well as gray matter density (GMD) in the cerebral cortex of all lobes, subcortical structures, the brainstem as well as the cerebellum, but no changes in white matter water diffusivity throughout the brain. Voxel-by-voxel regression analyses revealed that all GMD and WMD changes were well associated with elevated regional homogeneity of spontaneous neural activity (ReHo) in blood-oxygenation level-dependent signals. Spatial-temporal integration of structural and functional MRI suggests that gastric-bypass surgery induces widespread plastic changes in brain structure that concurrently homogenizes the functional profile of the cortex, subcortical regions as well as white matter structures.


Subject(s)
Brain , Gastric Bypass , Neuronal Plasticity/physiology , Obesity/surgery , Female , Humans , Longitudinal Studies , Magnetic Resonance Imaging , Male , Middle Aged , Neuroimaging
13.
Diabetes ; 65(8): 2179-86, 2016 08.
Article in English | MEDLINE | ID: mdl-27207511

ABSTRACT

Lipodystrophy (LD) is a rare disease with a paucity of subcutaneous adipocytes and leptin deficiency. Patients often develop severe diabetes and, additionally, show a disturbed eating behavior with reduced satiety. The disturbed eating behavior can be restored by substitution with the leptin analog metreleptin. Long-term effects of metreleptin on resting state brain connectivity in treatment-naive patients with LD have not been assessed. In this study, resting state functional MRI scans and extensive behavioral testing assessing changes in hunger/satiety regulation were performed during the first 52 weeks of metreleptin treatment in nine patients with LD. Resting state connectivity significantly increased over the course of metreleptin treatment in three brain areas (i.e., hypothalamus, insula/superior temporal gyrus, medial prefrontal cortex). Behavioral tests demonstrated that perceived hunger, importance of eating, eating frequencies, and liking ratings of food pictures significantly decreased during metreleptin therapy. Taken together, leptin substitution was accompanied by long-term changes of hedonic and homeostatic central nervous networks regulating eating behavior as well as decreased hunger feelings and diminished incentive value of food. Future studies need to assess whether metreleptin treatment in LD restores physiological processes important for the development of satiety.


Subject(s)
Feeding Behavior/drug effects , Leptin/pharmacology , Leptin/therapeutic use , Lipodystrophy/drug therapy , Adult , Brain/drug effects , Brain/metabolism , Female , Humans , Hunger/drug effects , Leptin/analogs & derivatives , Lipodystrophy/pathology , Magnetic Resonance Imaging , Male , Satiation/drug effects
14.
Isotopes Environ Health Stud ; 50(2): 277-84, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24620719

ABSTRACT

The accurate ultra-trace analysis of six fluorobenzoic acids (FBAs) via isotope dilution gas chromatography mass spectrometry through their deuterated analogues is described. North Sea reservoir and ground water samples were spiked with six deuterated FBAs (dFBAs), enriched using solid-phase extraction (SPE) and analysed using GC/MS after derivatisation with BF 3· MeOH. All FBAs were enriched and determined simultaneously. SPE allowed a 250-fold enrichment of the acids if 100 mL of sample volume was used. The method enables the determination of FBAs down to the range of 8-37 ng L (-1) with recoveries between 66 % and 85 %. It uses low amounts of chemicals and is adaptable to larger and smaller sample volumes.


Subject(s)
Benzoates/analysis , Water Pollutants, Chemical/analysis , Benzoates/chemistry , Deuterium/chemistry , Gas Chromatography-Mass Spectrometry , Groundwater/analysis , Isotope Labeling , North Sea , Petroleum , Water Pollutants, Chemical/chemistry
15.
NMR Biomed ; 27(5): 594-609, 2014 May.
Article in English | MEDLINE | ID: mdl-24610794

ABSTRACT

The arterial transit time (δa ) is a potentially important physiological parameter which may provide valuable information for the characterization of cerebrovascular diseases. The present study shows that δa can be measured by arterial spin labeling (ASL) applied quasi-continuously in an amplitude-modulated fashion at the human neck. Imaging was performed using short repetition times and excitation flip angles of 90°, which resulted in the selection of an ASL signal of mostly intravascular origin. Model-independent estimates of δa were obtained directly from the temporal shift of the ASL time series. An extended two-compartment perfusion model was developed in order to simulate the basic features of the proposed method and to validate the evaluation procedure. Vascular structures found in human δa maps, such as the circle of Willis or cerebral border zones, hint at the sensitivity of the method to most sizes of arterial vessels. Group-averaged values of δa measured from the carotid bifurcation to the tissue of interest in selected regions of the human brain ranged from 925 ms in the insular cortex to 2000 ms in the thalamic region.


Subject(s)
Carotid Arteries/physiology , Signal Processing, Computer-Assisted , Adult , Female , Humans , Male , Spin Labels , Time Factors
16.
ChemSusChem ; 7(4): 1133-9, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24616303

ABSTRACT

Carbon dioxide can be used in various ways as a cheap C1 source. However, the utilization of CO2 requires energy or energy-rich reagents, which leads to further emissions, and therefore, diminishes the CO2-saving potential. Therefore, life cycle assessment (LCA) is required for each process that uses CO2 to provide valid data for CO2 savings. Carbon dioxide can be incorporated into epoxidized fatty acid esters to provide the corresponding carbonates. A robust catalytic process was developed based on simple halide salts in combination with a phase-transfer catalyst. The CO2-saving potential was determined by comparing the carbonates as a plasticizer with an established phthalate-based plasticizer. Although CO2 savings of up to 80 % were achieved, most of the savings arose from indirect effects and not from CO2 utilization. Furthermore, other categories have been analyzed in the LCA. The use of biobased material has a variety of impacts on categories such as eutrophication and marine toxicity. Therefore, the benefits of biobased materials have to be evaluated carefully for each case. Finally, interesting properties as plasticizers were obtained with the carbonates. The volatility and water extraction could be improved relative to the epoxidized system.


Subject(s)
Carbon Dioxide/chemistry , Carbonates/chemistry , Fatty Acids/chemistry , Fatty Acids/chemical synthesis , Catalysis , Chemistry Techniques, Synthetic , Esters
17.
Isotopes Environ Health Stud ; 50(1): 88-93, 2014.
Article in English | MEDLINE | ID: mdl-24499142

ABSTRACT

A method for the deuterium labelling of fluorobenzoic acids (FBAs) via acidic H/D exchange of the aromatic hydrogen atoms in concentrated D2SO4 is described. The synthesis is shown to be easy, fast, low-priced and without the use of catalysts or further purification. The use of at least double-deuterated FBAs as internal standards in organic isotope dilution mass spectrometry allows the determination of FBAs in complex matrices with highest possible accuracy in combination with a simplified analytical evaluation.


Subject(s)
Deuterium/chemistry , Hydrocarbons, Fluorinated/chemical synthesis , Isotope Labeling/methods , Mass Spectrometry/methods , Mass Spectrometry/standards , Chemistry Techniques, Synthetic , Gas Chromatography-Mass Spectrometry/methods
18.
Eur J Neurosci ; 38(7): 3099-105, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23859464

ABSTRACT

Helmholtz himself speculated about a role of the cochlea in the perception of musical dissonance. Here we indirectly investigated this issue, assessing the valence judgment of musical stimuli with variable consonance/dissonance and presented diotically (exactly the same dissonant signal was presented to both ears) or dichotically (a consonant signal was presented to each ear--both consonant signals were rhythmically identical but differed by a semitone in pitch). Differences in brain organisation underlying inter-subject differences in the percept of dichotically presented dissonance were determined with voxel-based morphometry. Behavioral results showed that diotic dissonant stimuli were perceived as more unpleasant than dichotically presented dissonance, indicating that interactions within the cochlea modulated the valence percept during dissonance. However, the behavioral data also suggested that the dissonance percept did not depend crucially on the cochlea, but also occurred as a result of binaural integration when listening to dichotic dissonance. These results also showed substantial between-participant variations in the valence response to dichotic dissonance. These differences were in a voxel-based morphometry analysis related to differences in gray matter density in the inferior colliculus, which strongly substantiated a key role of the inferior colliculus in consonance/dissonance representation in humans.


Subject(s)
Auditory Perception , Inferior Colliculi/anatomy & histology , Music , Acoustic Stimulation , Adult , Female , Humans , Imaging, Three-Dimensional , Magnetic Resonance Imaging , Male , Young Adult
19.
IEEE Trans Image Process ; 22(9): 3366-78, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23715605

ABSTRACT

This paper describes an extension of the high efficiency video coding (HEVC) standard for coding of multi-view video and depth data. In addition to the known concept of disparity-compensated prediction, inter-view motion parameter, and inter-view residual prediction for coding of the dependent video views are developed and integrated. Furthermore, for depth coding, new intra coding modes, a modified motion compensation and motion vector coding as well as the concept of motion parameter inheritance are part of the HEVC extension. A novel encoder control uses view synthesis optimization, which guarantees that high quality intermediate views can be generated based on the decoded data. The bitstream format supports the extraction of partial bitstreams, so that conventional 2D video, stereo video, and the full multi-view video plus depth format can be decoded from a single bitstream. Objective and subjective results are presented, demonstrating that the proposed approach provides 50% bit rate savings in comparison with HEVC simulcast and 20% in comparison with a straightforward multi-view extension of HEVC without the newly developed coding tools.

20.
PLoS One ; 8(2): e55415, 2013.
Article in English | MEDLINE | ID: mdl-23451025

ABSTRACT

Positron emission tomography with [18F] fluorodeoxyglucose (FDG-PET) plays a well-established role in assisting early detection of frontotemporal lobar degeneration (FTLD). Here, we examined the impact of intensity normalization to different reference areas on accuracy of FDG-PET to discriminate between patients with mild FTLD and healthy elderly subjects. FDG-PET was conducted at two centers using different acquisition protocols: 41 FTLD patients and 42 controls were studied at center 1, 11 FTLD patients and 13 controls were studied at center 2. All PET images were intensity normalized to the cerebellum, primary sensorimotor cortex (SMC), cerebral global mean (CGM), and a reference cluster with most preserved FDG uptake in the aforementioned patients group of center 1. Metabolic deficits in the patient group at center 1 appeared 1.5, 3.6, and 4.6 times greater in spatial extent, when tracer uptake was normalized to the reference cluster rather than to the cerebellum, SMC, and CGM, respectively. Logistic regression analyses based on normalized values from FTLD-typical regions showed that at center 1, cerebellar, SMC, CGM, and cluster normalizations differentiated patients from controls with accuracies of 86%, 76%, 75% and 90%, respectively. A similar order of effects was found at center 2. Cluster normalization leads to a significant increase of statistical power in detecting early FTLD-associated metabolic deficits. The established FTLD-specific cluster can be used to improve detection of FTLD on a single case basis at independent centers - a decisive step towards early diagnosis and prediction of FTLD syndromes enabling specific therapies in the future.


Subject(s)
Fluorodeoxyglucose F18 , Frontotemporal Lobar Degeneration/diagnosis , Positron-Emission Tomography/methods , Adult , Female , Humans , Male
SELECTION OF CITATIONS
SEARCH DETAIL
...