21 research outputs found

    A multi-environmental tracer study to determine groundwater residence times and recharge in a structurally complex multi-aquifer system

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    Despite being the main drinking water resource for over 5 million people, the water balance of the Eastern Mountain Aquifer system on the western side of the Dead Sea is poorly understood. The regional aquifer consists of fractured and karstified limestone - aquifers of Cretaceous age, and it can be separated into a Cenomanian aquifer (upper aquifer) and Albian aquifer (lower aquifer). Both aquifers are exposed along the mountain ridge around Jerusalem, which is the main recharge area. From here, the recharged groundwater flows in a highly karstified aquifer system towards the east and discharges in springs in the lower Jordan Valley and Dead Sea region. We investigated the Eastern Mountain Aquifer system for groundwater flow, groundwater age and potential mixtures, and groundwater recharge. We combined 36Cl ∕ Cl, tritium, and the anthropogenic gases SF6, CFC-12 (chlorofluorocarbon) and CFC-11, while using CFC-113 as "dating" tracers to estimate the young water components inside the Eastern Mountain Aquifer system. By application of lumped parameter models, we verified young groundwater components from the last 10 to 30 years and an admixture of a groundwater component older than about 70 years. Concentrations of nitrate, simazine (pesticide), acesulfame K (ACE-K; artificial sweetener) and naproxen (NAP; drug) in the groundwater were further indications of infiltration during the last 30 years. The combination of multiple environmental tracers and lumped parameter modelling helped to understand the groundwater age distribution and to estimate recharge despite scarce data in this very complex hydrogeological setting. Our groundwater recharge rates support groundwater management of this politically difficult area and can be used to inform and calibrate ongoing groundwater flow models.This research has been supported by the Helmholtz Association (grant no. VH-VI527), the Federal Ministry of Education and Research (BMBF; grant no. 02WM0848) and the BMBF-MOST(grant no. YSEP111)

    Modern microwave methods in solid state inorganic materials chemistry: from fundamentals to manufacturing

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    Cerebral perfusion and neuropsychological follow up in mild traumatic brain injury:Acute versus chronic disturbances?

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    In a subgroup of patients with mild traumatic brain injury (TBI) residual symptoms, interfering with outcome and return to work, are found. With neuropsychological assessment cognitive deficits can be demonstrated although the pathological underpinnings of these cognitive deficits are not fully understood. As the admission computed tomography (CT) often is normal, perfusion CT imaging may be a useful indicator of brain dysfunction in the acute phase after injury in these patients. In the present study, directly after admission perfusion CT imaging was performed in mild TBI patients with follow-up neuropsychological assessment in those with complaints and a normal non-contrast CT. Neuropsychological tests comprised the 15 Words test Immediate Recall, Trailmaking test part B, Zoo Map test and the FEEST, which were dichotomized into normal and abnormal. Perfusion CT results of patients with normal neuropsychological test scores were compared to those with abnormal test scores. In total eighteen patients were included. Those with an abnormal score on the Zoo Map test had a significant lower CBV in the right frontal and the bilateral parieto-temporal white matter. Patients with an abnormal score on the FEEST had a significant higher MTT in the bilateral frontal white matter and a significant decreased CBF in the left parieto-temporal grey matter. No significant relation between the perfusion CT parameters and the 15 Words test and the Trailmaking test part B was present. In conclusion, impairments in executive functioning and emotion perception assessed with neuropsychological tests during follow up were related to differences in cerebral perfusion at admission in mild TBI. The pathophysiological concept of these findings is discussed

    GFAP and S100B in the acute phase of mild traumatic brain injury

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    Objective: The biomarkers glial fibrillary acid protein (GFAP) and S100B are increasingly used as prognostic tools in severe traumatic brain injury (TBI). Data for mild TBI are scarce. This study aims to analyze the predictive value of GFAP and S100B for outcome in mild TBI and the relation with imaging. Methods: In 94 patients biomarkers were determined directly after admission. Collected data included injury severity, patient characteristics, admission CT, and MRI 3 months postinjury. Six months postinjury outcome was determined with Glasgow Outcome Scale Extended (GOSE) and return to work (RTW). Results: Mean GFAP was 0.25 mu g/L (SD 1.08) and S100B 0.54 mu g/L (SD 1.18). In 63% GFAP was not discernible. GFAP was increased in patients with an abnormal CT (1.20 mu g/L, SD 2.65) compared to normal CT (0.05 mu g/L, SD 0.17, p <0.05). Also in patients with axonal injury on MRI GFAP was higher (0.65 mu g/L, SD 0.91 vs 0.07 mu g/L, SD 0.2, p <0.05). GFAP was increased in patients with incomplete RTW compared to complete RTW (0.69 mu g/L, SD 2.11 vs 0.12 mu g/L, SD 0.38, p <0.05). S100B was not related to outcome or imaging studies. In multivariate analysis GFAP was not predictive for outcome determined by GOSE and RTW. Conclusions: A relation between GFAP with imaging studies and outcome (determined by RTW) was found in contrast to S100B. As the positive predictive value of GFAP is limited in this category of TBI patients, this biomarker is not suitable for prediction of individual patient outcome. Neurology (R) 2012;78:1428-143

    MR spectroscopy of the brain in Leigh syndrome.

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    Contains fulltext : 69088.pdf (publisher's version ) (Closed access)Brain magnetic resonance spectroscopy in two patients with Leigh syndrome revealed the presence of lactate in gray and white matter brain tissue and relatively high choline levels in the white matter. The latter observation, most probably related to an ongoing demyelination process, underlines specific involvement of white matter metabolism in Leigh syndrome even in cases without involvement of the white matter as visualized on MRI. Magnetic resonance spectroscopy might thus be of help in differentiating Leigh syndrome from a range of other mitochondrial diseases, such as ophthalmoplegia and Kearns-Sayre syndrome, showing lack of lactate in brain tissues appearing normal on MRI

    Implementation of quality control methods in conjunction with chemometrics toward authentication of dairy products

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    The implementation of novel and accurate quality and safety control methods in conjunction with chemometrics in various fields of science, particularly in food science, showed that this combination stands for a very powerful tool for detecting food authenticity. The latter reflects both geographic origin and variety Dairy products, in particular have repeatedly worried the public authorities in terms of authentication regarding origin and in view of the many illnesses occasionally due to products of specific origin. Therefore, the development of a robust and reliable system endowed with this discriminatory power (varietal and/or geographic) is of great importance, both in terms of public health and consumer protection

    FDG-PET and detection of distant metastases and simultaneous tumors in head and neck squamous cell carcinoma: A comparison with chest radiography and chest CT

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    Detection of distant metastases and second primary tumors inpatients with head and neck squamous cell carcinoma (HNSCC) is of importance because of the impact on treatment and prognosis. The aim of this study was to assess the value of whole-body fluorodeoxyglucose-positron emission tomography (FDG-PET) in detecting distant metastases and second primary tumors below clavicular level in HNSCC compared to chest CT and chest radiography (CXR). Patient records of 149 consecutive patients with a primary HNSCC in whom a whole-body FDG-PET for initial staging was performed were reviewed. FDG-PET showed a sensitivity and specificity for detecting distant disease of 92% and 93%, respectively. Chest CT (n = 82) showed a sensitivity and a specificity of 74% and 61% respectively. CXR (n = 106) showed a sensitivity and a specificity of 41% and 91%, respectively. FDG-PET was shown to be able to detect distant metastases and second primary tumors in HNSCC with a high sensitivity and specificity. The higher sensitivity of PET compared to chest CT is mainly due to the detection of extrapulmonary malignancy. Sensitivity of PET and CT were similar in detecting intrapulmonary malignancy, but PET specificity was significantly higher. FDG-PET helps to determine the nature of pulmonary lesions and might be considered as a first diagnostic modality for detecting distant disease in advanced HNSCC. (C) 2008 Elsevier Ltd. All rights reserved

    Acute Cerebral Perfusion CT Abnormalities Associated with Posttraumatic Amnesia in Mild Head Injury

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    Posttraumatic amnesia (PTA) is a common symptom following traumatic brain injury. Although this transient memory deficit implies specific impairment of higher brain function, the actual pathophysiology of PTA is not well understood. The aim of this study was to assess regional cerebral hemodynamics with perfusion computed tomography (CT) in patients during PTA following mild head injury compared to patients with resolved PTA. A total of 74 patients with mild head injury without structural abnormalities on a non-contrast CT scan were included and compared to 25 healthy controls. Two patient groups were defined: (1) a PTA group that was scanned during the episode of PTA (n = 34), and (2) a post-PTA group scanned after resolution of PTA (n = 40). The PTA group had significantly reduced cerebral blood flow (CBF) in the frontal grey matter (41.78 [SD 7.4] versus 44.44 [SD 6.2] mL . 100 g(-1) . min(-1), p = 0.023), and caudate nucleus (44.59 [SD 6.2] versus 47.85 [SD 7.7] mL . 100 g(-1) . min(-1), p = 0.021), compared to the post-PTA group. Thus in patients with mild head injury, PTA is associated with cerebral perfusion abnormalities in specific cortical and subcortical regions
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