Frontoparietal Structural Network Disconnections Correlate With Outcome After a Severe Stroke.

Structural disconnectome analyses have provided valuable insights into how a stroke lesion results in widespread network disturbances and how these relate to deficits, recovery patterns, and outcomes. Previous analyses have primarily focused on patients with relatively mild to moderate deficits. However, outcomes vary among survivors of severe strokes, and the mechanisms of recovery remain poorly understood. This study assesses the association between lesion-induced network disconnection and outcome after severe stroke. Thirty-eight ischaemic stroke patients underwent MRI brain imaging early after stroke and longitudinal clinical follow-up. Lesion information was integrated with normative connectome data to infer individual disconnectome profiles on a localized regional and region-to-region pathway level. Ordinal logistic regressions were computed to link disconnectome information to the modified Rankin Scale after 3-6 months. Disconnections of ipsilesional frontal, parietal, and temporal cortical brain areas were significantly associated with a worse motor outcome after a severe stroke, adjusted for the initial deficit, lesion volume, and age. The analysis of the underlying pathways mediating this association revealed location-specific results: For frontal, prefrontal, and temporal brain areas, the association was primarily driven by relatively sparse intrahemispheric disconnections. In contrast, the ipsilesional primary motor cortex, the dorsal premotor cortex, and various parietal brain regions showed a remarkable involvement of either frontoparietal intrahemispheric or additionally interhemispheric disconnections. These results indicate that localized disconnection of multiple regions embedded in the structural frontoparietal network correlates with worse outcomes after severe stroke. Specifically, primary motor and parietal cortices might gain particular importance as they structurally link frontoparietal networks of both hemispheres. These data shed novel light on the significance of distinct brain networks for recovery after a severe stroke.

Cortical microstructure and hemispheric specialization-A diffusion-imaging analysis in younger and older adults.

Characterizing cortical plasticity becomes increasingly important for identifying compensatory mechanisms and structural reserve in the ageing population. While cortical thickness (CT) largely contributed to systems neuroscience, it incompletely informs about the underlying neuroplastic pathophysiology. In turn, microstructural characteristics may correspond to atrophy mechanisms in a more sensitive way. Fractional anisotropy, a diffusion tensor imaging (DTI) measure, is inversely related to cortical histologic complexity. Axial diffusivity and radial diffusivity are assumed to be linked to the density of structures oriented perpendicular and parallel to the cortical surface, respectively. We hypothesized (1) that cortical DTI will reveal microstructural correlates for hemispheric specialization, particularly in the language and motor systems, and (2) that lateralization of cortical DTI parameters will show an age effect, paralleling age-related changes in activation, especially in the prefrontal cortex. We analysed data from healthy younger and older adult participants (N = 91). DTI and CT data were extracted from regions of the Destrieux atlas. Diffusion measures showed lateralization in specialized motor, language, visual, auditory and inferior parietal cortices. Age-dependent increased lateralization for DTI measures was observed in the prefrontal, angular, superior temporal and lateral occipital cortex. CT did not show any age-dependent alterations in lateralization. Our observations argue that cortical DTI can capture microstructural properties associated with functional specialization, resembling findings from histology. Age effects on diffusion measures in the integrative prefrontal and parietal areas may shed novel light on the atrophy-related plasticity in healthy ageing.

Dopaminergic mesolimbic structural reserve is positively linked to better outcome after severe stroke.

The concept of brain reserve capacity has emerged in stroke recovery research in recent years. Imaging-based biomarkers of brain health have helped to better understand outcome variability in clinical cohorts. Still, outcome inferences are far from being satisfactory, particularly in patients with severe initial deficits. Neurorehabilitation after stroke is a complex process, comprising adaption and learning processes, which, on their part, are critically influenced by motivational and reward-related cognitive processes. Amongst others, dopaminergic neurotransmission is a key contributor to these mechanisms. The question arises, whether the amount of structural reserve capacity in the dopaminergic system might inform about outcome variability after severe stroke. For this purpose, this study analysed imaging and clinical data of 42 severely impaired acute stroke patients. Brain volumetry was performed within the first 2 weeks after the event using the Computational Anatomy Toolbox CAT12, grey matter volume estimates were collected for seven key areas of the human dopaminergic system along the mesocortical, mesolimbic and nigrostriatal pathways. Ordinal logistic regression models related regional volumes to the functional outcome, operationalized by the modified Rankin Scale, obtained 3-6 months after stroke. Models were adjusted for age, lesion volume and initial impairment. The main finding was that larger volumes of the amygdala and the nucleus accumbens at baseline were positively associated with a more favourable outcome. These data suggest a link between the structural state of mesolimbic key areas contributing to motor learning, motivational and reward-related brain networks and potentially the success of neurorehabilitation. They might also provide novel evidence to reconsider dopaminergic interventions particularly in severely impaired stroke patients to enhance recovery after stroke.

Polymer Composites with Carbon Fillers Based on Coal Pitch and Petroleum Pitch Cokes: Structure, Electrical, Thermal, and Mechanical Properties.

The effect of particle size and oxidation degree of new carbon microfillers, based on coal pitch (CP) and petroleum pitch (PET) cokes, on the structure as well as thermal, mechanical, and electrical properties of the composites based on ultrahigh molecular weight polyethylene (UHMWPE) was investigated. The composites studied have a segregated structure of filler particle distribution in the UHMWPE matrix. It was found that composite with smaller CP grain fraction has the highest Young's modulus and electrical conductivity compared to the other composites studied, which can be the result of a large contribution of flake-shaped particles. Additionally, conductivity of this composite turned out to be similar to composites with well-known carbon nanofillers, such as graphene, carbon black, and CNTs. Additionally, the relationship between electrical conductivity and Young's modulus values of composites studied was revealed, which indicates that electrical conductivity is very sensitive to the structure of the filler phase in the polymer matrix. In general, it was established that the properties, especially the electrical conductivity, of the composites studied strongly depends on the size, shape, and oxidative treatment of CP and PET filler particles, and that the CP coke of appropriately small particle sizes and flake shape has significant potential as a conductive filler for polymer composites.

Glioblastoma multiforme influence on the elemental homeostasis of the distant organs: the results of inter-comparison study carried out with TXRF method.

Glioblastoma (GBM) is a fast-growing and aggressive brain tumor which invades the nearby brain tissue but generally does not spread to the distant organs. Nonetheless, if untreated, GBM can result in patient death in time even less than few months from the diagnosis. The influence of the tumor progress on organs other than brain is obvious but still not well described. Therefore, we examined the elemental abnormalities appearing in selected body organs (kidney, heart, spleen, lung) in two rat models of GBM. The animals used for the study were subjected to the implantation of human GBM cell lines (U87MG and T98G) characterized by different levels of invasiveness. The elemental analysis of digested organ samples was carried out using the total reflection X-ray fluorescence (TXRF) method, independently, in three European laboratories utilizing various commercially available TXRF spectrometers. The comparison of the data obtained for animals subjected to T98G and U87MG cells implantation showed a number of elemental anomalies in the examined organs. What is more, the abnormalities were found for rats even if neoplastic tumor did not develop in their brains. The most of alterations for both experimental groups were noted in the spleen and lungs, with the direction of the found element changes in these organs being the opposite. The observed disorders of element homeostasis may result from many processes occurring in the animal body as a result of implantation of cancer cells or the development of GBM, including inflammation, anemia of chronic disease or changes in iron metabolism. Tumor induced changes in organ elemental composition detected in cooperating laboratories were usually in a good agreement. In case of elements with higher atomic numbers (Fe, Cu, Zn and Se), 88% of the results were classified as fully compliant. Some discrepancies between the laboratories were found for lighter elements (P, S, K and Ca). However, also in this case, the obtained results fulfilled the requirements of full (the results from three laboratories were in agreement) or partial agreement (the results from two laboratories were in agreement).

High yield and wide lateral size growth of α-Mo2C: exploring the boundaries of CVD growth of bare MXene analogues.

Synthesis of Mo2C bare MXenes, without surface terminations groups, via chemical vapor deposition (CVD) on metal foils is scientifically a very intriguing crystal growth process, and there are still challenges and limited fundamental understanding to overcome to obtain high yield and wide crystal size lateral growth. Achieving large area coverage via direct growth is scientifically vital to utilize the full potential of their unique properties in different applications. In this study, we sought to expand the boundaries of the current CVD growth approach for Mo2C MXenes and gain insights into the possibilities and limitations of large area growth, with a particular focus on controlling Mo concentration. We report a facile modification of their typical CVD growth protocol and show its influence on the Mo2C synthesis, with growth times spanning up to 3 h. Specifically, prior to initiating the CVD growth process, we introduced a holding step in temperature at 1095 °C. This proved to be beneficial in increasing the Mo concentration on the liquid Cu growth surface. We achieved an average Mo2C crystals coverage of approximately 50% of the growth substrate area, increased tendency of coalescence and merging of individual flakes, and lateral flake sizes up to 170µm wide. To gain deeper understanding into their CVD growth behavior, we conducted a systematic investigation of the effect of several factors, including (i) a holding step time on Mo diffusion rate through molten Cu, (ii) the Cu foil thickness over the Mo foil, and (iii) the CVD growth time. Phase, chemical and microstructural characterization by x-ray diffraction, x-ray photon spectroscopy, SEM and scanning/transmission electron microscopy revealed that the grown crystals are single phaseα-Mo2C. Furthermore, insights gained from this study sheds light on crucial factors and inherent limitations that are essential to consider and may help guide future research progress in CVD growth of bare MXenes.

Risk factors for cardiovascular diseases: the focus on primary prevention.

Views on the etiopathogenesis of atherosclerosis are subject to evolution. In addition to the classic well-known risk factors, new ones related to mental state, social life and environment are being discovered. Both acute and chronic stress stimulate inflammatory processes. Due to the change in lifestyle and eating habits, the accumulation of risk factors in childhood is an increasing problem. Knowledge of risk factors allows for effective primary prevention of cardiovascular diseases. The effectiveness of prevention increases when the activities cover the largest possible part of the society, and access to a doctor is easy. Therefore, government programs are being implemented offering patients easier access to diagnostics of cardiovascular diseases at the level of primary health care, which enables faster identification of people at the greatest cardiovascular risk. Easier access to primary care and a good doctor-patient relationship improve patient compliance. In this situation, the importance of the family doctor as a key link in the diagnosis, prevention and treatment of cardiovascular diseases is increasing.

Altered microstructure of the contralesional ventral premotor cortex and motor output after stroke.

Cortical thickness analyses have provided valuable insights into changes in cortical brain structure after stroke and their association with recovery. Across studies though, relationships between cortical structure and function show inconsistent results. Recent developments in diffusion-weighted imaging of the cortex have paved the way to uncover hidden aspects of stroke-related alterations in cortical microstructure, going beyond cortical thickness as a surrogate for cortical macrostructure. We re-analysed clinical and imaging data of 42 well-recovered chronic stroke patients from 2 independent cohorts (mean age 64 years, 4 left-handed, 71% male, 16 right-sided strokes) and 33 healthy controls of similar age and gender. Cortical fractional anisotropy and cortical thickness values were obtained for six key sensorimotor areas of the contralesional hemisphere. The regions included the primary motor cortex, dorsal and ventral premotor cortex, supplementary and pre-supplementary motor areas, and primary somatosensory cortex. Linear models were estimated for group comparisons between patients and controls and for correlations between cortical fractional anisotropy and cortical thickness and clinical scores. Compared with controls, stroke patients exhibited a reduction in fractional anisotropy in the contralesional ventral premotor cortex (P = 0.005). Fractional anisotropy of the other regions and cortical thickness did not show a comparable group difference. Higher fractional anisotropy of the ventral premotor cortex, but not cortical thickness, was positively associated with residual grip force in the stroke patients. These data provide novel evidence that the contralesional ventral premotor cortex might constitute a key sensorimotor area particularly susceptible to stroke-related alterations in cortical microstructure as measured by diffusion MRI and they suggest a link between these changes and residual motor output after stroke.

Fourier transform infrared microspectroscopy analysis of ovarian cancerous tissues in paraffin and deparaffinized tissue samples.

Ovarian cancer is one of the deadliest cancers occurring in women. This is typically due to late diagnosis of the disease and difficult treatment. Infrared microspectroscopy is a complementary research method that can be helpful in the diagnosis of this disease, because it allows for the analysis of the tissues biomolecular composition. In this study, archival paraffin-embedded preparations of ovarian tissues, tumours and control, were used. However, the paraffin present in such specimens is a strong absorber of infrared radiation, which makes it impossible to reliably analyse the biomolecular composition of the sample. The solution to this problem is to deparaffinize the tissue before the analysis. However, the extend to which the paraffinization and deparaffinization processes influence the biomolecular composition of the tissues is unclear. Analysed tissues in the form of cores were placed in a paraffin micromatrix and FTIR measurements were performed. Then the samples were deparaffinized and the measurements were taken again. For both sets of samples (embedded in paraffin and deparaffinized) ratios of integrated peaks and massifs within the obtained spectra were calculated. The obtained ratios were compared for different types of diseased and healthy, control tissues. The Kruskal-Wallis test revealed statistically significant differences of the calculated ratios between most of the types of tissues. Random Forest models clearly showed that both samples in paraffin and deparaffinized retain enough information to classify the tissues reliably. The feature analysis revealed the most important feature for distinguishing between different types of samples, i.e. 1080 cm-1/1240 cm-1 ratio and lipid saturation for the samples embedded in paraffin and deparaffinized respectively. The study showed that the deparaffinization process leads to changes in the biomolecular composition of the analysed tissues. Despite this, classification of the tissues based on FTIR measurements remains possible.

A combined X-ray fluorescence and infrared microspectroscopy study for new insights into elemental-biomolecular obesity-induced changes in rat brain structures.

The objective of our research was to determine the brain changes at the molecular and elemental levels typical of early-stage obesity. Therefore a combined approach using Fourier transform infrared micro-spectroscopy (FTIR-MS) and synchrotron radiation induced X-ray fluorescence (SRXRF) was introduced to evaluate some brain macromolecular and elemental parameters in high-calorie diet (HCD)- induced obese rats (OB, n = 6) and in their lean counterparts (L, n = 6). A HCD was found to alter the lipid- and protein- related structure and elemental composition of the certain brain areas important for energy homeostasis. The increased lipid unsaturation in the frontal cortex and ventral tegmental area, the increased fatty acyl chain length in the lateral hypothalamus and substantia nigra as well as the decreased both protein α helix to protein ß- sheet ratio and the percentage fraction of ß-turns and ß-sheets in the nucleus accumbens were revealed in the OB group reflecting obesity-related brain biomolecular aberrations. In addition, the certain brain elements including P, K and Ca were found to differentiate the lean and obese groups at the best extent. We can conclude that HCD-induced obesity triggers lipid- and protein- related structural changes as well as elemental redistribution within various brain structures important for energy homeostasis. In addition, an approach applying combined X-ray and infrared spectroscopy was shown to be a reliable tool for identifying elemental-biomolecular rat brain changes for better understanding the interplay between the chemical and structural processes involved in appetite control.

Combined spectroscopic, biochemical and chemometric approach toward finding of biochemical markers of obesity.

BACKGROUND: Early-stage detection of subclinical obesity-driven systemic changes is a challenging area of medical diagnostics, where the most popular existing measures - such as body mass index - BMI - often fall short of providing a realistic estimate of adiposity and, therefore, of ongoing pathologies at the systemic, tissue and cellular level. In the quest for identifying new more robust diagnostic markers, whole-organ analysis of chemical elements is a promising approach for identifying candidate proxies of obesity status in the system. METHODS: Total Reflection X-ray fluorescence (TXRF) coupled with biochemical assays, chemometrics and statistical validation was used as a new integrated pipeline for marker identification in external ear samples of obese animals. The specimens were taken from obese animals fed a high calorie diet as well as from lean intact animals fed a standard diet. RESULTS: The most significant differences in the content of K, Fe, Br, and Rb between the studied groups of the animals were identified. However, with the methodology applied Rb was found the most robust biochemical discriminator of early-stage obesity effects, as validated by the logistic regression model. We observed no relationship between the levels of the elements consumed by the animals and their apparent content in the earlobe tissue samples. CONCLUSIONS: Our preliminary study confirms that obesity alters tissue trace metal metabolism and shows the proposed new approach as an accurate and reliable methodology for detecting tissue elemental obesity-related alterations. GENERAL SIGNIFICANCE: This result can be of practical significance for designing new point-of-care systems for obesity screening tests, taking advantage of direct/indirect Rb measurements.

The New Markers of Early Obesity-Related Organ and Metabolic Abnormalities.

The objective of our study was to identify new markers related to excessive body adiposity and its early consequences. For this purpose we determined serum FGF-19 and FGF-21 concentrations in obese rats, whose role in the pathogenesis of obesity is not yet established. In addition, a total reflection X-ray fluorescence technique was applied to determine the elemental chemistry of certain tissues affected by obesity. Next, the new biochemical and molecular parameters were correlated with well-known obesity-related markers of metabolic abnormalities. Our obese rats were characterized by increased calorie consumption and body adiposity, hypercholesterolemia, elevated levels of liver enzymes and FGF-21, while the level of FGF-19 was reduced. Strong relationships between new hormones and established metabolic parameters were observed. Furthermore, we demonstrated that obesity had the greatest effect on elemental composition in the adipose tissue and liver and that rubidium (Rb) had the highest importance in distinguishing the studied groups of animals. Tissue Rb strongly correlated with both well-known and new markers of obesity. In conclusion, we confirmed serum FGF-19 and FGF-21 as useful new markers of obesity-related metabolic alternations and we robustly propose Rb as a novel indicator of excessive body adiposity and its early consequences. However, further investigations are encouraged to address this clinical issue.

Elemental Composition of Skeletal Muscle Fibres Studied with Synchrotron Radiation X-ray Fluorescence (SR-XRF).

Diseases of the muscle tissue, particularly those disorders which result from the pathology of individual muscle cells, are often called myopathies. The diversity of the content of individual cells is of interest with regard to their role in both biochemical mechanisms and the structure of muscle tissue itself. These studies focus on the preliminary analysis of the differences that may occur between diseased tissues and tissues that have been recognised as a reference group. To do so, 13 samples of biopsied human muscle tissues were studied: 3 diagnosed as dystrophies, 6 as (non-dystrophic) myopathy and 4 regarded as references. From these sets of muscle biopsies, 135 completely measured muscle fibres were separated altogether, which were subjected to investigations using synchrotron radiation X-ray fluorescence (SR-XRF). Muscle fibres were analysed in terms of the composition of elements such as Br, Ca, Cl, Cr, Cu, Fe, K, Mn, P, S and Zn. The performed statistical tests indicate that all three groups (dystrophies-D; myopathies-M; references-R) show statistically significant differences in their elemental compositions, and the greatest impact, according to the multivariate discriminate analysis (MDA), comes from elements such as Ca, Cu, K, Cl and S.

Evaluation of the impact of pH of the reaction mixture, type of the stirring, and the reagents' concentration in the wet precipitation method on physicochemical properties of hydroxyapatite so as to enhance its biomedical application potential.

Hydroxyapatite (HAp) constitutes a significant inorganic compound which due to its osteoinductivity, osteoconductivity as well as the ability to promote bone growth and regeneration is widely applied in development of biomaterials designed for bone tissue engineering. In this work, various synthesis methodologies of HAp based on the wet precipitation technique were applied, and the impact of pH of the reaction mixture, the concentration of individual reagents as well as the type of stirring applied (mechanical/magnetic) on the properties of final powders was discussed. Spectroscopic methods (Fourier transform infrared, Raman) and X-ray diffraction allowed to verify the synthesis parameters leading to obtaining calcium phosphate with 96% HAp in phase which indicated higher homogeneity of obtained powder (93.4%) than commercial HAp. Powders' morphology was evaluated using microscopic techniques while specific surface area was determined via Brunauer-Emmett-Teller analysis. Particle size distribution, porosity of powders, and stability of HAp suspensions were also characterized. It was proved that synthesis at pH = 11.0 using mechanical stirring resulted in calcium phosphate with a high phase homogeneity and homogeneous pore size distribution (6-20 nm). Moreover, obtained HAp powder showed 71.8% more specific surface area than commercial material-that is, 110 m3 /g for synthetic HAp and 64 m3 /g in the case of commercial powder-which, in turn, is significant in terms of its potential application as carrier of active substances. Thus it was demonstrated that by applying appropriate conditions of HAp synthesis it is possible to obtain powder with properties enhancing its application potential for medical purposes.

Quantifying and Examining Reserve in Symptomatic Former National Football League Players.

BACKGROUND: Repetitive head impacts (RHI) from contact sports have been associated with cognitive and neuropsychiatric disorders. However, not all individuals exposed to RHI develop such disorders. This may be explained by the reserve hypothesis. It remains unclear if the reserve hypothesis accounts for the heterogenous symptom presentation in RHI-exposed individuals. Moreover, optimal measurement of reserve in this population is unclear and likely unique from non-athlete populations. OBJECTIVE: We examined the association between metrics of reserve and cognitive and neuropsychiatric functioning in 89 symptomatic former National Football League players. METHODS: Individual-level proxies (e.g., education) defined reserve. We additionally quantified reserve as remaining residual variance in 1) episodic memory and 2) executive functioning performance, after accounting for demographics and brain pathology. Associations between reserve metrics and cognitive and neuropsychiatric functioning were examined. RESULTS: Higher reading ability was associated with better attention/information processing (ß=0.25; 95% CI, 0.05-0.46), episodic memory (ß=0.27; 95% CI, 0.06-0.48), semantic and phonemic fluency (ß=0.24; 95% CI, 0.02-0.46; ß=0.38; 95% CI, 0.17-0.59), and behavioral regulation (ß=-0.26; 95% CI, -0.48, -0.03) performance. There were no effects for other individual-level proxies. Residual episodic memory variance was associated with better attention/information processing (ß=0.45; 95% CI, 0.25, 0.65), executive functioning (ß=0.36; 95% CI, 0.15, 0.57), and semantic fluency (ß=0.38; 95% CI, 0.17, 0.59) performance. Residual executive functioning variance was associated with better attention/information processing (ß=0.44; 95% CI, 0.24, 0.64) and episodic memory (ß=0.37; 95% CI, 0.16, 0.58) performance. CONCLUSION: Traditional reserve proxies (e.g., years of education, occupational attainment) have limitations and may be unsuitable for use in elite athlete samples. Alternative approaches of reserve quantification may prove more suitable for this population.

Application of Factorisation Methods to Analysis of Elemental Distribution Maps Acquired with a Full-Field XRF Imaging Spectrometer.

The goal of the work was to investigate the possible application of factor analysis methods for processing X-ray Fluorescence (XRF) data acquired with a full-field XRF spectrometer employing a position-sensitive and energy-dispersive Gas Electron Multiplier (GEM) detector, which provides only limited energy resolution at a level of 18% Full Width at Half Maximum (FWHM) at 5.9 keV. In this article, we present the design and performance of the full-field imaging spectrometer and the results of case studies performed using the developed instrument. The XRF imaging data collected for two historical paintings are presented along with the procedures applied to data calibration and analysis. The maps of elemental distributions were built using three different analysis methods: Region of Interest (ROI), Non-Negative Matrix Factorisation (NMF), and Principal Component Analysis (PCA). The results obtained for these paintings show that the factor analysis methods NMF and PCA provide significant enhancement of selectivity of the elemental analysis in case of limited energy resolution of the spectrometer.

Physicochemical Characteristics of Chitosan-Based Hydrogels Containing Albumin Particles and Aloe vera Juice as Transdermal Systems Functionalized in the Viewpoint of Potential Biomedical Applications.

In recent years, many investigations on the development of innovative dressing materials with potential applications, e.g., for cytostatics delivery, have been performed. One of the most promising carriers is albumin, which tends to accumulate near cancer cells. Here, chitosan-based hydrogels containing albumin spheres and Aloe vera juice, designed for the treatment of skin cancers or burn wounds resulting from radiotherapy, were developed. The presence of albumin in hydrogel matrices was confirmed via Fourier transform infrared (FT-IR) and Raman spectroscopy. Albumin spheres were clearly visible in microscopic images. It was proved that the introduction of albumin into hydrogels resulted in their increased resistance to the tensile load, i.e., approximately 30% more force was needed to break such materials. Modified hydrogels showed approximately 10% more swelling ability. All hydrogels were characterized by hydrophilicity (contact angles were <90°) which may support the regeneration of epithelial cells and non-cytotoxicity towards murine fibroblasts L929 and released Aloe vera juice more effectively in an acidic environment than in a neutral one wherein spheres introduced into the hydrogel matrix extended the release time. Thus, the developed materials, due to their chemical composition and physicochemical properties, constitute promising materials with great application potential for biomedical purposes.

Age at First Exposure to Tackle Football is Associated with Cortical Thickness in Former Professional American Football Players.

Younger age at first exposure (AFE) to repetitive head impacts while playing American football increases the risk for later-life neuropsychological symptoms and brain alterations. However, it is not known whether AFE is associated with cortical thickness in American football players. Sixty-three former professional National Football League players (55.5 ± 7.7 years) with cognitive, behavioral, and mood symptoms underwent neuroimaging and neuropsychological testing. First, the association between cortical thickness and AFE was tested. Second, the relationship between clusters of decreased cortical thickness and verbal and visual memory, and composite measures of mood/behavior and attention/psychomotor speed was assessed. AFE was positively correlated with cortical thickness in the right superior frontal cortex (cluster-wise P value [CWP] = 0.0006), the left parietal cortex (CWP = 0.0003), and the occipital cortices (right: CWP = 0.0023; left: CWP = 0.0008). A positive correlation was found between cortical thickness of the right superior frontal cortex and verbal memory (R = 0.333, P = 0.019), and the right occipital cortex and visual memory (R = 0.360, P = 0.012). In conclusion, our results suggest an association between younger AFE and decreased cortical thickness, which in turn is associated with worse neuropsychological performance. Furthermore, an association between younger AFE and signs of neurodegeneration later in life in symptomatic former American football players seems likely.

Facile production of ultra-fine silicon nanoparticles.

A facile procedure for the synthesis of ultra-fine silicon nanoparticles without the need for a Schlenk vacuum line is presented. The process consists of the production of a (HSiO1.5) n sol-gel precursor based on the polycondensation of low-cost trichlorosilane (HSiCl3), followed by its annealing and etching. The obtained materials were thoroughly characterized after each preparation step by electron microscopy, Fourier transform and Raman spectroscopy, X-ray dispersion spectroscopy, diffraction methods and photoluminescence spectroscopy. The data confirm the formation of ultra-fine silicon nanoparticles with controllable average diameters between 1 and 5 nm depending on the etching time.

Investigation of the role and chemical form of iron in the ovarian carcinogenesis process.

BACKGROUND: Ovarian cancer is one of the most frequent types of gynaecological malignancy among women. Despite the advances in diagnostic techniques, ovarian tumours are still detected at a late stage, thus the survival rate is very low. Iron is an essential metal in the human body, yet its potential role in ovarian carcinogenesis is yet to be determined. The aim of this study was to check if iron oxidation state in tissue and cystic fluid can be treated as an indicator of the malignancy of the ovarian tumours. Another aspect of this study was to investigate the role of iron in carcinogenesis mechanism in ovarian tumour transformation. METHODS: Synchrotron radiation X-ray absorption near edge structure (SR-XANES) spectroscopy was used to analyze the human ovarian tumour tissues and cystic fluids of different types and grades of malignancy. Fresh, non-fixed, frozen samples were used to analyze the state of iron oxidation in all the biological materials. The samples were obtained from patients requiring surgical intervention. The High Energy X-ray Absorption Spectroscopy (XANES) measurements were performed at the beamline P65 at Petra III Extension, DESY - Deutsches Elektronen - Synchrotron. RESULTS: Fe XANES spectra were collected at selected points of a few different regions of the samples. For each specimen, an average of these points was probed. Having been measured, the spectra were compared with organic and inorganic reference materials. Also, the position of the absorption edge was calculated using the integration method. In all specimens, iron occurred in the oxidation states, Fe2+ and Fe3+, although the fraction of iron in the third oxidation state was substantial, especially in malignant cases. The results also show differences in the chemical form of iron in the tissue and cystic fluids of the same patient. CONCLUSIONS: The cryo-XANES measurement carried out for ovarian cancer tissues and cystic fluids showed changes in the chemical form of iron between non-malignant and malignant tumours. For both types of sample can be observed that they contain iron on second and iron on third oxidation state. Moreover, the tendency was observed that malignant tumours of the ovary contain a larger fraction of iron in the second oxidation state compared to non-malignant ones.