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1.
Biochem Med (Zagreb) ; 30(2): 020707, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32550815

RESUMO

Introduction: Urine particle analysis is an important diagnostic tool. The aim of this study was to evaluate the quality of urine leukocyte (WBC) and erythrocyte (RBC) counting results obtained with manual and automated methods in Polish laboratories participating in the international external quality assessment (EQA) programme. Materials and methods: 1400 WBC and RBC counting results were obtained from 183 laboratories in EQA surveys organised by Labquality (Helsinki, Finland) from 2017 to 2019. The between-laboratory coefficient of variation (CV), the percentage difference between the laboratories' results and target values (Q-score (%)), as well as modified Youden plots were analysed. Results: For automated method groups, the medians of inter-laboratory CVs varied from 14% to 33% for WBC counting and from 10% to 39% for RBC counting. For manual method groups, the medians of CV varied from 53% to 71% (WBC) and from 55% to 70% (RBC), and they were significantly higher, in comparison to CVs for most automated method groups (P < 0.001). The highest percentage of results outside the target limits (36%) and the highest range of Q-score (%) (from - 93% to 706%) were observed for laboratories which participated in the surveys for the first or second time. The percentage of deviating results and the ranges of Q-score decreased with an increased frequency of laboratories' participation in the surveys. Conclusions: The quality of manual methods of urine WBC and RBC counting is unsatisfactory. There is an urgent need to take actions to improve laboratories' performance and to increase harmonisation of the results.

2.
Life (Basel) ; 10(5)2020 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-32443900

RESUMO

Background: The monogenic defect in familial hypercholesterolemia (FH) is detected in ∼40% of cases. The majority of mutation-negative patients have a polygenic cause of high LDL-cholesterol (LDL-C). We sought to investigate whether the underlying monogenic or polygenic defect is associated with the response to rosuvastatin. METHODS: FH Individuals were tested for mutations in LDLR and APOB genes. A previously established LDL-C-specific polygenic risk score (PRS) was used to examine the possibility of polygenic hypercholesterolemia in mutation-negative patients. All of the patients received rosuvastatin and they were followed for 8 ± 2 months. A propensity score analysis was performed to evaluate the variables associated with the response to treatment. RESULTS: Monogenic subjects had higher mean (±SD) baseline LDL-C when compared to polygenic (7.6 ± 1.5 mmol/L vs. 6.2 ± 1.2 mmol/L; p < 0.001). Adjusted model showed a lower percentage of change in LDL-C after rosuvastatin treatment in monogenic patients vs. polygenic subjects (45.9% vs. 55.4%, p < 0.001). The probability of achieving LDL-C targets in monogenic FH was lower than in polygenic subjects (0.075 vs. 0.245, p = 0.004). Polygenic patients were more likely to achieve LDL-C goals, as compared to those monogenic (OR 3.28; 95% CI: 1.23-8.72). CONCLUSION: Our findings indicate an essentially higher responsiveness to rosuvastatin in FH patients with a polygenic cause, as compared to those carrying monogenic mutations.

3.
Nutrients ; 12(4)2020 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-32325781

RESUMO

Being rich in polyunsaturated fatty acids, flaxseed (Linum usitatissimum L.) is thought to be able to decrease lipid levels and dampen inflammation. In this pilot study, we aimed to determine whether flaxseed supplementation could improve the profiles of lipids and inflammatory mediators in patients with severe hyperlipidemia resistant to conventional lipid-lowering pharmacotherapy and requiring lipoprotein apheresis. To this end, six patients received, blindly-in addition to their normal lipoprotein apheresis regimen-a 10-week dietary supplementation with flaxseed (28 g/d) administered in biscuits. This was followed by a 10-week washed out-period and a 10-week supplementation phase with whole wheat placebo. Blood samples were collected at the end of each phase, before the lipoprotein apheresis session. The primary endpoint was the lipid profile and the secondary endpoints were the concentrations of inflammatory mediators and tolerability. Flaxseed supplementation was well-tolerated and resulted in a consistent and significant decrease in total cholesterol and low-density lipoprotein (LDL) levels. The median (and range) percentage decrease was 11.5% (0-18.8) and 7.3% (4.4-26.6), for cholesterol (p = 0.015) and LDL-C (p = 0.003), respectively. On the other hand, there was no significant effect of flaxseed on lipoprotein(a) (Lp(a)), C-reactive protein (CRP), and interleukin 6 (IL-6) concentrations. These observations indicate that flaxseed can produce a cholesterol- and LDL-lowering effect in patients treated with lipoprotein apheresis. Thus, flaxseed supplementation may help to control cholesterol in this patient population. The flaxseed supplementation protocol applied may be of use for further adequately-powered studies to validate and extend our findings.

4.
Cereb Cortex ; 30(8): 4465-4480, 2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-32147725

RESUMO

The ability to detect short gaps in noise is an important tool for assessing the temporal resolution in the auditory cortex. However, the mere existence of responses to temporal gaps bounded by two short broadband markers is surprising, because of the expected short-term suppression that is prevalent in auditory cortex. Here, we used in-vivo intracellular recordings in anesthetized rats to dissect the synaptic mechanisms that underlie gap-related responses. When a gap is bounded by two short markers, a gap termination response was evoked by the onset of the second marker with minimal contribution from the offset of the first marker. Importantly, we show that the gap termination response was driven by a different (potentially partially overlapping) synaptic population than that underlying the onset response to the first marker. This recruitment of additional synaptic resources is a novel mechanism contributing to the important perceptual task of gap detection.

5.
PLoS One ; 15(3): e0221541, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32210448

RESUMO

Stimulus-specific adaptation (SSA) is the reduction in responses to a common stimulus that does not generalize, or only partially generalizes, to other stimuli. SSA has been studied mainly with sounds that bear no behavioral meaning. We hypothesized that the acquisition of behavioral meaning by a sound should modify the amount of SSA evoked by that sound. To test this hypothesis, we used fear conditioning in rats, using two word-like stimuli, derived from the English words "danger" and "safety", as well as pure tones. One stimulus (CS+) was associated with a foot shock whereas the other stimulus (CS-) was presented without a concomitant foot shock. We recorded neural responses to the auditory stimuli telemetrically, using chronically implanted multi-electrode arrays in freely moving animals before and after conditioning. Consistent with our hypothesis, SSA changed in a way that depended on the behavioral role of the sound: the contrast between standard and deviant responses remained the same or decreased for CS+ stimuli but increased for CS- stimuli, showing that SSA is shaped by experience. In most cases the sensory responses underlying these changes in SSA increased following conditioning. Unexpectedly, the responses to CS+ word-like stimuli showed a specific, large decrease, which we interpret as evidence for substantial inhibitory plasticity.


Assuntos
Estimulação Acústica/métodos , Adaptação Fisiológica/fisiologia , Percepção Auditiva/fisiologia , Comportamento Animal/fisiologia , Som , Vigília/fisiologia , Animais , Córtex Auditivo/fisiologia , Escala de Avaliação Comportamental , Condicionamento Clássico/fisiologia , Potenciais Evocados Auditivos/fisiologia , Medo/fisiologia , Feminino , Interneurônios/fisiologia , Ratos
6.
Angew Chem Int Ed Engl ; 59(6): 2323-2327, 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-31765512

RESUMO

Organothiol monolayers on metal substrates (Au, Ag, Cu) and their use in a wide variety of applications have been extensively studied. Here, the growth of layers of organothiols directly onto muscovite mica is demonstrated using a simple procedure. Atomic force microscopy, surface X-ray diffraction, and vibrational sum-frequency generation IR spectroscopy studies revealed that organothiols with various functional endgroups could be self-assembled into (water) stable and adaptable ultra-flat organothiol monolayers over homogenous areas as large as 1 cm2 . The strength of the mica-organothiol interactions could be tuned by exchanging the potassium surface ions for copper ions. Several of these organothiol monolayers were subsequently used as a template for calcite growth.

7.
J Phys Chem Lett ; 10(20): 6324-6330, 2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31539471

RESUMO

We study the structural coherence of a self-assembled overlayer of PbS nanocrystal (NC) superlattice onto an underlying PbS NC monolayer, which acts as a template. We explore the effect of the templating layer on the structure of the overlayer asemblies by varying interfacial strain and determine the impact of new ligands on their superlattice structure. The overlayers and templates are analyzed by grazing-incidence X-ray scattering and microscopy. We find that differences in the lattice parameters of 7.7% between the two layers are tolerated in terms of a "soft epitaxial" assembly into the body-centered tetragonal superstucture and lead to structural registry within the overlayer. Conversely, at the interface, a lattice mismatch of 24.4% is too large for soft epitaxy and invokes a change in the superlattice. Upon ligand treatment, the overlayer superlattices transform their orientation axis and the NCs orient preferentially. These results provide new insights into mitigating defects in layered, heterostructured NC assemblies.

8.
Front Neuroanat ; 13: 53, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31213993

RESUMO

The claustrum is a subcortical nucleus that exhibits dense connectivity across the neocortex. Considerable recent progress has been made in establishing its genetic and anatomical characteristics, however, a core, contentious issue that regularly presents in the literature pertains to the rostral extent of its anatomical boundary. The present study addresses this issue in the rat brain. Using a combination of immunohistochemistry and neuroanatomical tract tracing, we have examined the expression profiles of several genes that have previously been identified as exhibiting a differential expression profile in the claustrum relative to the surrounding cortex. The expression profiles of parvalbumin (PV), crystallin mu (Crym), and guanine nucleotide binding protein (G protein), gamma 2 (Gng2) were assessed immunohistochemically alongside, or in combination with cortical anterograde, or retrograde tracer injections. Retrograde tracer injections into various thalamic nuclei were used to further establish the rostral border of the claustrum. Expression of all three markers delineated a nuclear boundary that extended considerably (∼500 µm) beyond the anterior horn of the neostriatum. Cortical retrograde and anterograde tracer injections, respectively, revealed distributions of cortically-projecting claustral neurons and cortical efferent inputs to the claustrum that overlapped with the gene marker-derived claustrum boundary. Finally, retrograde tracer injections into the thalamus revealed insular cortico-thalamic projections encapsulating a claustral area with strongly diminished cell label, that extended rostral to the striatum.

9.
Postepy Kardiol Interwencyjnej ; 15(1): 81-90, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31043989

RESUMO

Introduction: Preclinical, vascular response studies are limited due to lack of underlying disease. The available cholesterol-diet-based and genetic atherosclerotic models are not satisfactory due to long breeding, unpredictable lesion formation, low plaque volume and degree of stenosis. Aim: To evaluate the vascular response to local, intramural delivery of human, highly atherogenic lipids into healthy domestic swine (DS) coronary arteries. Material and methods: A total of 24 coronary artery segments of 10 DS were enrolled. Following balloon injury (plain old balloon angioplasty - POBA), segments were assigned to local delivery of 2 ml of human LDL from apheresis (400 mg/dl, n = 9), 0.9% NaCl (control, n = 7) or to POBA alone. The solutions were infused with a modified, triple micro-needle catheter into the vessel wall. After 28 days, optical coherence tomography (OCT), virtual histology IVUS (VH-IVUS) and near-infra-red spectroscopy (NIRS) were performed. Following euthanasia, vessel segments were harvested for pathological evaluation. Results: At 28 days the % area stenosis in OCT was highest in the LDL group (23.6 ±13 vs. 10.8 ±7 vs. 8.1 ±7%; p = 0.02). The presence of necrotic core (LDL: 55.5%, control: 37.5% and POBA: 42.8%; p = 0.77) and dense calcium (LDL: 33.3%, control: 28.5%, POBA: 37.5%; p = 0.94) in VH-IVUS were comparable between groups. The lipid core burden index in NIRS was negative in all cases. In pathology, the injury was comparable between groups (LDL: 1.6 ±0.4, control: 1.7 ±0.8, POBA: 1.7; p = 0.8) and specimens showed no signs of necrotic or lipid core. The tissue consisted of smooth muscle cells (SMC)/proteoglycan-rich lesions and inflammatory cells. Conclusions: Local delivery of saturated human LDL into the coronary artery wall was feasible and resulted in a higher degree of stenosis caused by intimal thickening. A discrepancy between histopathological findings and virtual histology intravascular ultrasound (VH-IVUS) was also noted.

10.
Cardiol J ; 2019 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-30912576

RESUMO

BACKGROUND: Oxidative stress and dyslipidemia play a critical role in the development of cardiovascular disease. Regular intake of polyphenol-rich diets is associated with a reduced risk of cardiovascular diseases. METHODS: The present study was a pilot study with 24 healthy volunteers and was designed to determine if a 12-week administration of Cistus incanus herbal tea, containing phenolic acids and flavonoids, reduces cardiovascular risk factors including oxidative stress and dyslipidemia in healthy adults. Phenolic compounds profile and antibacterial activity of Cistus incanus infusion were also measured. RESULTS: Herbal infusion led to improvement in lipid profile by increase (D4%, p = 0.033) high-density lipoprotein cholesterol concentration and decrease triglyceride (D14%, p = 0.013) concentrations. In addition, the Cistus incanus diet was associated with decreased serum concentrations of malondialdehyde (D16%, p < 0.01) and advanced oxidation protein products (D18%, p < 0.001). CONCLUSIONS: Cistus incanus administration decreases cardiovascular risk factors including oxidative stress and dyslipidemia and this action supports the idea of using Cistus incanus tea on a daily basis as an effective dietary component for prevention of atherosclerotic cardiovascular disease.

11.
Lipids Health Dis ; 18(1): 60, 2019 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-30851738

RESUMO

BACKGROUND: Chronic kidney disease (CKD) associates with complex lipoprotein disturbances resulting in high cardiovascular risk. Apolipoprotein E (APOE) is a polymorphic protein with three common isoforms (E2; E3; E4) that plays a crucial role in lipoprotein metabolism, including hepatic clearance of chylomicrons and very low-density lipoprotein (VLDL) remnants, and reverse cholesterol transport. It demonstrates anti-atherogenic properties but data concerning the link between polymorphism and level of APOE in CKD patients are inconclusive. The aim of our research was to assess the relationship between APOE gene polymorphism and APOE concentration and its redistribution among lipoproteins along with CKD progression. METHODS: 90 non-dialysed CKD patients were included into the study. Real time PCR was used for APOE genotyping. APOE level was measured in serum and in isolated lipoprotein fractions (VLDL; IDL + HDL; HDL). Kidney function was assessed using eGFR CKD-EPI formula. RESULTS: The population was divided into three APOE genotype subgroups: E2(ε2ε3), E3(ε3ε3) and E4(ε3ε4). The highest APOE level was observed for the E2 subgroup (p < 0.001). APOE concentration positively correlated with eGFR value in the E2 subgroup (r = 0.7, p < 0.001) but inversely in the E3 subgroup (r = - 0.29, p = 0.02).). A lower concentration of APOE in the E2 subgroup was associated with its diminished contents in HDL and IDL + LDL particles. In the E3 subgroup, the higher concentration of APOE was related to the increased number of non-HDL lipoproteins. CONCLUSION: In patients with CKD, APOE genotype as well as renal function are associated with the concentration of APOE and its redistribution among lipoprotein classes.


Assuntos
Apolipoproteínas E/sangue , Apolipoproteínas E/genética , Polimorfismo Genético , Insuficiência Renal Crônica/genética , Idoso , Feminino , Taxa de Filtração Glomerular , Humanos , Testes de Função Renal , Lipoproteínas/sangue , Masculino , Pessoa de Meia-Idade , Insuficiência Renal Crônica/fisiopatologia
12.
Int J Mol Sci ; 20(5)2019 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-30857306

RESUMO

In chronic kidney disease (CKD), the level of high-density lipoprotein (HDL) decreases markedly, but there is no strong inverse relationship between HDL-cholesterol (HDL-C) and cardiovascular diseases. This indicates that not only the HDL-C level, but also the other quantitative changes in the HDL particles can influence the protective functionality of these particles, and can play a key role in the increase of cardiovascular risk in CKD patients. The aim of the present study was the evaluation of the parameters that may give additional information about the HDL particles in the course of progressing CKD. For this purpose, we analyzed the concentrations of HDL containing apolipoprotein A-I without apolipoprotein A-II (LpA-I), preß1-HDL, and myeloperoxidase (MPO), and the activity of paraoxonase-1 (PON-1) in 68 patients at various stages of CKD. The concentration of HDL cholesterol, MPO, PON-1, and lecithin-cholesterol acyltransferase (LCAT) activity were similar in all of the analyzed stages of CKD. We did not notice significant changes in the LpA-I concentrations in the following stages of CKD (3a CKD stage: 57 ± 19; 3b CKD stage: 54 ± 15; 4 CKD stage: 52 ± 14; p = 0.49). We found, however, that the preß1-HDL concentration and preß1-HDL/LpA-I ratio increased along with the progress of CKD, and were inversely correlated with the estimated glomerular filtration rate (eGFR), even after adjusting for age, gender, triacylglycerols (TAG), HDL cholesterol, and statin therapy (ß = -0.41, p < 0.001; ß = -0.33, p = 0.001, respectively). Our results support the earlier hypothesis that kidney disease leads to the modification of HDL particles, and show that the preß1-HDL concentration is significantly elevated in non-dialyzed patients with advanced stages of CKD.


Assuntos
Lipoproteínas de Alta Densidade Pré-beta/sangue , Insuficiência Renal Crônica/sangue , Idoso , Progressão da Doença , Feminino , Taxa de Filtração Glomerular , Humanos , Rim/patologia , Masculino , Pessoa de Meia-Idade , Diálise Renal , Insuficiência Renal Crônica/patologia , Insuficiência Renal Crônica/terapia
13.
Data Brief ; 21: 1451-1457, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30456270

RESUMO

The primary data are the impulse responses that were recorded in an echoic environment, using a set of twelve loudspeakers and a microphone. They were used as a part of an acoustic calibration process of large environments, as presented by Kazakov and Nelken (DOI: 10.1016/j.jneumeth.2018.08.025; Kazakov and Nelken, 2018). The impulse responses can be also used to localize the microphone in 3D (multi-lateration). The required audio files and the MATLAB code allows a complete reproduction of the experiment.

14.
PLoS One ; 13(6): e0197678, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29874246

RESUMO

Deviance sensitivity is the specific response to a surprising stimulus, one that violates expectations set by the past stimulation stream. In audition, deviance sensitivity is often conflated with stimulus-specific adaptation (SSA), the decrease in responses to a common stimulus that only partially generalizes to other, rare stimuli. SSA is usually measured using oddball sequences, where a common (standard) tone and a rare (deviant) tone are randomly intermixed. However, the larger responses to a tone when deviant does not necessarily represent deviance sensitivity. Deviance sensitivity is commonly tested using a control sequence in which many different tones serve as the standard, eliminating the expectations set by the standard ('deviant among many standards'). When the response to a tone when deviant (against a single standard) is larger than the responses to the same tone in the control sequence, it is concluded that true deviance sensitivity occurs. In primary auditory cortex of anesthetized rats, responses to deviants and to the same tones in the control condition are comparable in size. We recorded local field potentials and multiunit activity from the auditory cortex of awake, freely moving rats, implanted with 32-channel drivable microelectrode arrays and using telemetry. We observed highly significant SSA in the awake state. Moreover, the responses to a tone when deviant were significantly larger than the responses to the same tone in the control condition. These results establish the presence of true deviance sensitivity in primary auditory cortex in awake rats.


Assuntos
Adaptação Fisiológica , Córtex Auditivo/fisiopatologia , Vigília/fisiologia , Estimulação Acústica , Animais , Percepção Auditiva/fisiologia , Potenciais Evocados Auditivos , Ratos
15.
Kidney Blood Press Res ; 43(3): 970-978, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29913451

RESUMO

BACKGROUND/AIMS: Hypertriglyceridaemia (HTG) and reduction and dysfunction of high density lipoprotein (HDL) are common lipid disturbances in chronic kidney disease (CKD). HTG in CKD is caused mainly by the decreased efficiency of lipoprotein lipase (LPL)-mediated very low density lipoprotein triglyceride (VLDL-TG) lipolysis. It has not been clarified whether HDL dysfunction in CKD contributes directly to HTG development; thus, the aim of this study was to assess the impact of CKD progression on the ability of HDL to enhance LPL-mediated VLDL-TG lipolysis efficiency. METHODS: VLDL was isolated from non-dialysis patients in CKD stages 3 and 4 and from non-CKD patients. The VLDL was incubated with LPL at the constant LPL:VLDL-TG ratio, in the absence or presence of HDL. After incubation, the VLDL was separated and the percentage (%) of hydrolyzed TG was calculated. RESULTS: HDL presence increased the lipolysis efficiency of VLDL isolated from CKD and non-CKD patients, for the VLDL-TG> 50 mg/dl. Its effect was dependent on the VLDL-TG and HDL-cholesterol concentrations in the reaction mixtures: the higher the concentrations of VLDL-TG and HDL-cholesterol, the greater the effect. The positive impact of HDL on VLDL lipolysis was modified by CKD progression: the percentage of lipolyzed VLDL-TG in the presence of HDL decreased with a reduction in eGFR (r=0.43, p=0.009), and for patients with stage 4 CKD, no positive impact of HDL on lipolysis was observed. The percentage of lipolyzed TG correlated negatively with apoE and apoCs content in VLDL, and positively with HDL-apoCII, as well as with VLDL and HDL apoCII/ apoCIII ratios. The progression of CKD was associated with unfavourable changes in VLDL and HDL composition; apoE and apoCs levels increased in VLDL with a decrease in eGFR whereas the HDL-cholesterol level decreased. CONCLUSION: The progression of CKD affects lipoprotein composition and properties, and modulates the positive impact of HDL on VLDL lipolysis efficiency. In CKD patients, HDL deficiency and dysfunction can directly affect hypertriglyceridaemia development.


Assuntos
Hipertrigliceridemia/etiologia , Lipólise/efeitos dos fármacos , Lipase Lipoproteica/metabolismo , Lipoproteínas HDL/farmacologia , Lipoproteínas VLDL/metabolismo , Insuficiência Renal Crônica/patologia , Triglicerídeos/metabolismo , Idoso , HDL-Colesterol/metabolismo , Progressão da Doença , Feminino , Humanos , Lipoproteínas HDL/deficiência , Masculino , Pessoa de Meia-Idade
17.
Brain Res ; 1677: 101-117, 2017 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-28947380

RESUMO

The functions of the claustrum are not well understood. Few studies explore its electrophysiological properties in awake animals. Here, we address this lacuna by recording spontaneous local field potential (LFP) activity in the anterior claustrum of rats freely exploring open field environments under differing conditions (light; dark; with, without an object present). We found three peaks in the LFP power spectral density (PSD) at 1-4Hz, 4-7Hz and 8-12Hz. Two of those peaks, in the 1-4Hz and 8-12Hz bands, were present in almost all recordings and dominated the power spectrum. The power or frequency of detected peaks in some cases changed depending on the environmental context. The power of detected frequency bands of spontaneous LFPs showed varied patterns of distribution across the experimental arena. The 8-12Hz band was predominantly found at running speeds of up to 6cm/s. We suggest that spontaneous LFP activity in the anterior claustrum depends on the environmental context and running speed of the animal.


Assuntos
Gânglios da Base/fisiologia , Comportamento Exploratório/fisiologia , Atividade Motora/fisiologia , Percepção Espacial/fisiologia , Animais , Eletrodos Implantados , Meio Ambiente , Masculino , Células de Lugar/fisiologia , Ratos , Corrida/fisiologia
18.
J Synchrotron Radiat ; 24(Pt 5): 1082-1085, 2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28862632

RESUMO

A simple experiment to characterize the gating properties of X-ray area detectors using pulsed X-ray sources is presented. For a number of time-resolved experiments the gating uniformity of area detectors is important. Relative gating delays between individual modules and readout chips of PILATUS2 series area X-ray detectors have been observed. For three modules of a PILATUS 300K-W unit the maximum gating offset between the modules is found to be as large as 30 ns. On average, the first photosensor module is found to be triggered 15 ns and 30 ns later than the second and the third modules, respectively.

19.
Ultramicroscopy ; 182: 233-242, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28734230

RESUMO

A combined X-ray and scanning tunneling microscopy (STM) instrument is presented that enables the local detection of X-ray absorption on surfaces in a gas environment. To suppress the collection of ion currents generated in the gas phase, coaxially shielded STM tips were used. The conductive outer shield of the coaxial tips can be biased to deflect ions away from the tip core. When tunneling, the X-ray-induced current is separated from the regular, 'topographic' tunneling current using a novel high-speed separation scheme. We demonstrate the capabilities of the instrument by measuring the local X-ray-induced current on Au(1 1 1) in 800 mbar Ar.

20.
Dev Period Med ; 21(1): 69-73, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28551695

RESUMO

Down syndrome (DS) is the most common chromosomal aberration and genetically determined cause of intellectual disability. DS patients often present with some congenital defects and chronic diseases, including early onset dementia, which affects 70% of DS patients over 55 years of age and has a clinical presentation similar to Alzheimer disease (AD). The symptoms of DS originate from excessive genetic material within the "critical region" of the 21st chromosome. The "critical region" encompasses genes potentially associated with increase risk of dementia, e.g. the APP gene (amyloid beta precursor protein) which leads to excessive amyloid beta production. Post-mortem studies of DS patients' brains revealed diffuse deposition of the insoluble form of amyloid beta (Aß), which is a characteristic feature of AD. Moreover, those changes were commonly observed in subjects > 31 years old. The pathomechanisms of AD have not been fully elucidated and scientists are still searching for new risk factors that may contribute to the development of this common illness. Recent research proved that lipid disturbance, especially disorders in the metabolism of HDL (high density lipoprotein) may play a crucial role in this pathogenic process. There are many studies examining lipid and lipoprotein concentration in the DS population, but up to now there are insufficient studies comparing these parameters with memory impairment, which may be a useful model for better understanding of the dementia pathomechanism.


Assuntos
Demência/fisiopatologia , Síndrome de Down/fisiopatologia , Metabolismo dos Lipídeos , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Demência/etiologia , Síndrome de Down/complicações , Síndrome de Down/metabolismo , Humanos , Pessoa de Meia-Idade , Adulto Jovem
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