202 research outputs found
A schlieren method for ultra-low angle light scattering measurements
We describe a self calibrating optical technique that allows to perform
absolute measurements of scattering cross sections for the light scattered at
extremely small angles. Very good performances are obtained by using a very
simple optical layout similar to that used for the schlieren method, a
technique traditionally used for mapping local refraction index changes. The
scattered intensity distribution is recovered by a statistical analysis of the
random interference of the light scattered in a half-plane of the scattering
wave vectors and the main transmitted beam. High quality data can be obtained
by proper statistical accumulation of scattered intensity frames, and the
static stray light contributions can be eliminated rigorously. The
potentialities of the method are tested in a scattering experiment from non
equilibrium fluctuations during a free diffusion experiment. Contributions of
light scattered from length scales as long as Lambda=1 mm can be accurately
determined.Comment: 7 pages, 3 figure
High resolution computed tomography quantitation of emphysema is correlated with selected lung function values in stable COPD.
BACKGROUND:
The literature shows conflicting results when high-resolution computed tomography (HRCT) scores of emphysema were correlated with different indices of airflow obstruction.
OBJECTIVES:
We correlated HRCT scores of emphysema with different indices of airflow obstruction.
METHODS:
We performed HRCT of the chest in 59 patients, all smokers or ex-smokers, with stable chronic obstructive pulmonary disease of different severity [GOLD stages I-IV; mean age \ub1 SD 67.8 \ub1 7.3 years; pack/years 51.0 \ub1 34.6; percent predicted forced expiratory volume in 1 s (FEV(1)% predicted) 52.3 \ub1 17.6; post-bronchodilator FEV(1)% predicted 56.5 \ub1 19.1; FEV(1)/forced vital capacity (FVC) ratio 50.8 \ub1 10.2; post-bronchodilator FEV(1)/FVC ratio 51.6 \ub1 11.0; percent diffusion lung capacity for carbon monoxide (DLCO%) 59.2 \ub1 21.1; DLCO/percent alveolar volume (VA%) 54.5 \ub1 18.2; percent residual volume 163.0 \ub1 35.6; percent total lung capacity (TLC%) 113.2 \ub1 15; residual volume/TLC 1.44 \ub1 0.2]. All patients were in stable phase.
RESULTS:
The mean \ub1 SD visual emphysema score in all patients was 25.6 \ub1 25.4%. There was a weak but significant correlation between the percentage of pulmonary emphysema and numbers of pack/years (R = +0.31, p = 0.024). The percentage of emphysema was inversely correlated with the FEV(1)/FVC ratio before and after bronchodilator use (R = -0.44, p = 0.002, and R = -0.39, p = 0.005), DLCO% (R = -0.64, p = 0.0003) and DLCO/VA% (R = -0.68, p < 0.0001). A weak positive correlation was also found with TLC% (R = +0.28, p = 0.048). When patients with documented emphysema were considered separately, the best significant correlation observed was between DLCO/VA% and HRCT scan score (p = 0.007).
CONCLUSIONS:
These data suggest that in patients with stable chronic obstructive pulmonary disease of varying severity, the presence of pulmonary emphysema is best represented by the impaired gas exchange capability of the respiratory system
Math Skills: a New Look from Functional Data Analysis
: Mental calculations involve various areas of the brain. The frontal, parietal and temporal lobes of the left hemisphere have a principal role in the completion of this typology of tasks. Their level of activation varies based on the mathematical competence and attentiveness of the subject under examination and the perceived difficulty of the task. Recent literature often investigates patterns of cerebral activity through fMRI, which is an expensive technique. In this scenario, EEGs represent a more straightforward and cheaper way to collect information regarding brain activity. In this work, we propose an EEG based method to detect differences in the cerebral activation level of people characterized by different abilities in carrying out the same arithmetical task. Our approach consists in the extraction of the activation level of a given region starting from the EEG acquired during resting state and during the completion of a subtraction task. We then analyze these data through Functional Data Analysis, a statistical technique that allows operating on biomedical signals as if they were functions. The application of this technique allowed for the detection of distinct cerebral patterns among the two groups and, more specifically, highlighted the presence of higher levels of activation in the parietal lobe in the population characterized by a lower performance
Porous dipeptide crystals as volatile-drug vessels
Anesthetic vapors find temporary hospitality in porous dipeptide crystals, which behave as biologically friendly hosts and carriers
Diaphragmatic, thoracic and abdominal breathing for sport: The effect on vagal activity, a case report
Breathing is important for any sport, particularly in aquatic sports. The autonomous response to diving is characterized by bradycardia mediated by the vagus nerve. Specific breathing techniques, particularly those involving deep and slow respiration tasks, could phasically and tonically stimulate the vagus nerve. This case report aimed to measure the effects of different breathing techniques (thoracic, diaphragmatic and spontaneous breathing) on autonomic vagal activity through simultaneous monitoring of ECG and ventilatory and thoraco-Abdominal patterns. An elite male apneist was enrolled (50 years old, 186 cm, 80 kg) during spontaneous breathing (SB), diaphragmatic breathing (DB); thoracic breathing (TB) and diaphragmatic breathing combined with transverse abdominis activation (DTB) following a visual and acoustic timer to uniform the respiratory frequency at 6 breaths/minute. Compared to baseline, breathing exercises involving diaphragmatic recruitment (DB and DTB) increased the total power (index of overall autonomic activity and the plasticity of the cardiovascular system) by fourfold, while maintaining the mean heart rate nearly unchanged. However, the end-expiratory abdominal volume reduced during DB and DTB indicating a strong recruitment of the abdominal muscles. These results suggest that slow, deep and abdominal (and not just diaphragmatic) breathing enhanced vagal activity, independently of respiratory rate. We can speculate that a possible vagal stimulation occurs even when the diaphragm is stretched passively by the abdominal muscles. This mechanism would explain the vagal-related beneficial effects during exercise even in the absence of a direct increased diaphragmatic contribution. This hypothesis needs to be confirmed in a wider population
Thymus Extracellular Matrix-Derived Scaffolds Support Graft-Resident Thymopoiesis and Long-Term In Vitro Culture of Adult Thymic Epithelial Cells
The thymus provides the physiological microenvironment critical for the development of T lymphocytes, the cells that orchestrate the adaptive immune system to generate an antigen-specific response. A diverse population of stroma cells provides surface-bound and soluble molecules that orchestrate the intrathymic maturation and selection of developing T cells. Forming an intricate 3D architecture, thymic epithelial cells (TEC) represent the most abundant and important constituent of the thymic stroma. Effective models for in and ex vivo use of adult TEC are still wanting, limiting the engineering of functional thymic organoids and the understanding of the development of a competent immune system. Here a 3D scaffold is developed based on decellularized thymic tissue capable of supporting in vitro and in vivo thymopoiesis by both fetal and adult TEC. For the first time, direct evidences of feasibility for sustained graft-resident T-cell development using adult TEC as input are provided. Moreover, the scaffold supports prolonged in vitro culture of adult TEC, with a retained expression of the master regulator Foxn1. The success of engineering a thymic scaffold that sustains adult TEC function provides unprecedented opportunities to investigate thymus development and physiology and to design and implement novel strategies for thymus replacement therapies
Blunted cardiac autonomic dynamics to active standing test in postmenopausal women
Introduction: Although both aging and menopause influence cardiovascular autonomic control, the effect of menopause per se remains unclear. The current study was undertaken to test the hypothesis that post-menopausal women (PMW) have a blunted cardiovascular autonomic adjustment to active standing compared to pre-menopausal women. Thus, we compared the heart rate variability (HRV) indexes from supine (SUP) to orthostatic (ORT) positions among young women (YW), young men (YM), older men (OM), and PMW. Methods: The participants rested for 10 min in SUP and then stood up and remained for 5 min in ORT. ECG was continuously recorded, and R-R time series of about 300 beats were analyzed using linear (spectral analysis) and non-linear (symbolic analysis) methods. The variation from SUP to ORT was calculated (Δ = ORT-SUP) for each HRV index. Results: In SUP, no difference was found for any HRV index among groups. However, Δ0V% and ΔLFn (cardiac sympathetic modulation) were reduced in PWM compared to all groups (OM, YW, and YM), while Δ2UV% and ΔHFn (cardiac vagal modulation) were reduced in PMW than the younger group (YW and YM). No differences were found among the male groups (OM and YM). Discussion: In light of our results, the cardiac autonomic dynamic response to orthostatic stress is blunted in post-menopausal women compared to younger women and older men, a finding that might be influenced not only by aging
A coumaroyl-ester-3-hydroxylase insertion mutant reveals the existence of nonredundant meta-hydroxylation pathways and essential roles for phenolic precursors in cell expansion and plant growth
Cytochromes P450 monooxygenases from the CYP98 family catalyze the meta-hydroxylation step in the phenylpropanoid biosynthetic pathway. The ref8 Arabidopsis (Arabidopsis thaliana) mutant, with a point mutation in the CYP98A3 gene, was previously described to show developmental defects, changes in lignin composition, and lack of soluble sinapoyl esters. We isolated a T-DNA insertion mutant in CYP98A3 and show that this mutation leads to a more drastic inhibition of plant development and inhibition of cell growth. Similar to the ref8 mutant, the insertion mutant has reduced lignin content, with stem lignin essentially made of p-hydroxyphenyl units and trace amounts of guaiacyl and syringyl units. However, its roots display an ectopic lignification and a substantial proportion of guaiacyl and syringyl units, suggesting the occurrence of an alternative CYP98A3-independent meta-hydroxylation mechanism active mainly in the roots. Relative to the control, mutant plantlets produce very low amounts of sinapoyl esters, but accumulate flavonol glycosides. Reduced cell growth seems correlated with alterations in the abundance of cell wall polysaccharides, in particular decrease in crystalline cellulose, and profound modifications in gene expression and homeostasis reminiscent of a stress response. CYP98A3 thus constitutes a critical bottleneck in the phenylpropanoid pathway and in the synthesis of compounds controlling plant development. CYP98A3 cosuppressed lines show a gradation of developmental defects and changes in lignin content (40% reduction) and structure (prominent frequency of p-hydroxyphenyl units), but content in foliar sinapoyl esters is similar to the control. The purple coloration of their leaves is correlated to the accumulation of sinapoylated anthocyanins
Maximizing the Products Display for Purchaser Lucidity and Alleviation in Circulation to Augment the Sale of Supermarket: Milieu of Bangladesh
The purpose of this study is to appraise the accessible products display for the purchaser lucidity which may maximizes offers and actions of business with the alleviation in circulation to augment the random sale in the arena of supermarket. The study scrutinizes a fundamental research on the context of Bangladesh and especially for the Dhaka zone. A supermarket, a large form of the traditional grocery store, is a self-service shop offering a wide variety of food and household products, organized into aisles. It is larger in size and has a wider selection than a traditional grocery store, but is smaller and more limited in the range of merchandise than a hypermarket or big-box market. The traditional supermarket occupies a large amount of floor space, usually on a single level. It is usually situated near a residential area in order to be convenient to consumers. The basic appeal is the availability of a broad selection of goods under a single roof, at relatively low prices. Other advantages include ease of parking and frequently the convenience of shopping hours that extend far into the evening or even 24 hours a day. Key words: Circulation, Supermarket, Alleviation, Sale, Products, Variation, Lucidit
Large cryptic genomic rearrangements with apparently normal karyotypes detected by array-CGH.
Background: Conventional karyotyping (550 bands resolution) is able to identify chromosomal aberrations >5-10 Mb,
which represent a known cause of intellectual disability/developmental delay (ID/DD) and/or multiple congenital
anomalies (MCA). Array-Comparative Genomic Hybridization (array-CGH) has increased the diagnostic yield of 15-20%.
Results: In a cohort of 700 ID/DD cases with or without MCA, including 15 prenatal diagnoses, we identified a
subgroup of seven patients with a normal karyotype and a large complex rearrangement detected by array-CGH
(at least 6, and up to 18 Mb). FISH analysis could be performed on six cases and showed that rearrangements
were translocation derivatives, indistinguishable from a normal karyotype as they involved a similar band pattern
and size. Five were inherited from a parent with a balanced translocation, whereas two were apparently de novo.
Genes spanning the rearrangements could be associated with some phenotypic features in three cases (case 3:
DOCK8; case 4: GATA3, AKR1C4; case 6: AS/PWS deletion, CHRNA7), and in two, likely disease genes were present
(case 5: NR2F2, TP63, IGF1R; case 7: CDON). Three of our cases were prenatal diagnoses with an apparently normal
karyotype.
Conclusions: Large complex rearrangements of up to 18 Mb, involving chromosomal regions with similar size
and band appearance may be overlooked by conventional karyotyping. Array-CGH allows a precise chromosomal
diagnosis and recurrence risk definition, further confirming this analysis as a first tier approach to clarify molecular
bases of ID/DD and/or MCA. In prenatal tests, array-CGH is confirmed as an important tool to avoid false negative
results due to karyotype intrinsic limit of detection
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