Scaling in directed dynamical small-world networks with random responses

A dynamical model of small-world network, with directed links which describe various correlations in social and natural phenomena, is presented. Random responses of every site to the imput message are introduced to simulate real systems. The interplay of these ingredients results in collective dynamical evolution of a spin-like variable S(t) of the whole network. In the present model, global average spreading length \langel L >_s and average spreading time _s are found to scale as p^-\alpha ln N with different exponents. Meanwhile, S behaves in a duple scaling form for N>>N^*: S ~ f(p^-\beta q^\gamma t'_sc), where p and q are rewiring and external parameters, \alpha, \beta, \gamma and f(t'_sc) are scaling exponents and universal functions, respectively. Possible applications of the model are discussed.Comment: 4 pages, 6 Figure

The Application of Diffusion- and Perfusion-Weighted Magnetic Resonance Imaging in the Diagnosis and Therapy of Acute Cerebral Infarction

Diffusion- and perfusion-weighted magnetic resonance imaging (DWI and PWI) was applied for stroke diagnose in 120 acute (< 48 h) ischemic stroke patients. At hyperacute (< 6 h) stage, it is difficult to find out the infarction zone in conventional T1 or T2 image, but it is easy in DWI, apparent diffusion coefficient (ADC) map; when at 3–6-hour stage it is also easy in PWI, cerebral blood flow (CBF) map, cerebral blood volume (CBV) map, and mean transit time (MTT) map; at acute (6–48 h) stage, DWI or PWI is more sensitive than conventional T1 or T2 image too. Combining DWI with ADC, acute and chronic infarction can be distinguished. Besides, penumbra which should be developed in meaning was used as an indication or to evaluate the therapeutic efficacy. There were two cases (< 1.5 h) that broke the model of penumbra because abnormity was found in DWI but not that in PWI, finally they recovered without any sequela

A preliminary study on the monitoring of mixed venous oxygen saturation through the left main bronchus

INTRODUCTION: The study sought to assess the feasibility and accuracy of measuring mixed venous oxygen saturation (SvO(2)) through the left main bronchus (SpO(2trachea)) METHODS: Twenty hybrid pigs of each sex were studied. After anesthesia, a Robertshaw double-lumen tracheal tube with a single-use pediatric pulse oximeter attached to the left lateral surface was introduced toward the left main bronchus of the pig by means of a fibrobronchoscope. Measurements of SpO(2trachea )and oxygen saturation from pulmonary artery samples (SvO(2blood)) were performed with an intracuff pressure of 0 to 60 cmH(2)O. After equilibration, hemorrhagic shock was induced in these pigs by bleeding to a mean arterial blood pressure of 40 mmHg. With the intracuff pressure maintained at 60 cmH(2)O, SpO(2trachea )and SvO(2blood )were obtained respectively during the pre-shock period, immediately after the onset of shock, 15 and 30 minutes after shock, and 15, 30, and 60 minutes after resuscitation. RESULTS: SpO(2trachea )was the same as SvO(2blood )at an intracuff pressure of 10, 20, 40, and 60 cmH(2)O, but was reduced when the intracuff pressure was zero (p < 0.001 compared with SvO(2blood)) in hemodynamically stable states. Changes of SpO(2trachea )and SvO(2blood )corresponded with varieties of cardiac output during the hemorrhagic shock period. There was a significant correlation between the two methods at different time points. CONCLUSION: Measurement of the left main bronchus SpO(2 )is feasible and provides similar readings to SvO(2blood )in hemodynamically stable or in low saturation states. Tracheal oximetry readings are not primarily derived from the tracheal mucosa. The technique merits further evaluation

Sugar-sweetened beverages, artificially sweetened beverages and natural juices and risk of inflammatory bowel disease: a cohort study of 121,490 participants

Background: Inflammatory bowel diseases (IBD) have been related to high-sugar dietary patterns, but the associations of different types of beverages with IBD risk are largely unknown. Aims: To examine the associations of intake of sugar-sweetened beverages, artificially sweetened beverages and natural juices with IBD risk. Methods: This cohort study included 121,490 participants in the UK Biobank who were free of IBD at recruitment. Intake of beverages was obtained from repeated 24-h diet recalls in 2009–2012. Cox proportional hazard models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for associations of beverage intake with IBD risk. Results: During a mean (standard deviation) follow-up of 10.2 (1.5) years, we documented 510 incident IBD cases, (143 Crohn's disease (CD) and 367 ulcerative colitis (UC)). Compared to non-consumers, participants consuming >1 unit per day of sugar-sweetened beverages were at significantly higher risk of IBD (HR 1.51, 95% CI 1.11–2.05), but the trend was non-significant (p-trend = 0.170). This association was significant for CD (HR 2.05, 95% CI 1.22–3.46), but not for UC (HR 1.31, 95% CI 0.89–1.92). We did not observe significant associations for the consumption of artificially sweetened beverages or natural juices. Conclusions: Our findings suggest an association between consumption of sugar-sweetened beverages, rather than artificially sweetened beverages or natural juices, and IBD risk

Thermally reduced graphene oxide/carbon nanotube composite films for thermal packaging applications

Thermally reduced graphene oxide/carbon nanotube (rGO/CNT) composite films were successfully prepared by a high-temperature annealing process. Their microstructure, thermal conductivity and mechanical properties were systematically studied at different annealing temperatures. As the annealing temperature increased, more oxygen-containing functional groups were removed from the composite film, and the percentage of graphene continuously increased. When the annealing temperature increased from 1100 to 1400 \ub0C, the thermal conductivity of the composite film also continuously increased from 673.9 to 1052.1 W m-1 K-1. Additionally, the Young\u27s modulus was reduced by 63.6%, and the tensile strength was increased by 81.7%. In addition, the introduction of carbon nanotubes provided through-plane thermal conduction pathways for the composite films, which was beneficial for the improvement of their through-plane thermal conductivity. Furthermore, CNTs apparently improved the mechanical properties of rGO/CNT composite films. Compared with the rGO film, 1 wt% CNTs reduced the Young\u27s modulus by 93.3% and increased the tensile strength of the rGO/CNT composite film by 60.3%, which could greatly improve its flexibility. Therefore, the rGO/CNT composite films show great potential for application as thermal interface materials (TIMs) due to their high in-plane thermal conductivity and good mechanical properties

Is histogram manipulation always beneficial when trying to improve model performance across devices? Experiments using a Meibomian gland segmentation model

Meibomian gland dysfunction (MGD) is caused by abnormalities of the meibomian glands (MG) and is one of the causes of evaporative dry eye (DED). Precise MG segmentation is crucial for MGD-related DED diagnosis because the morphological parameters of MG are of importance. Deep learning has achieved state-of-the-art performance in medical image segmentation tasks, especially when training and test data come from the same distribution. But in practice, MG images can be acquired from different devices or hospitals. When testing image data from different distributions, deep learning models that have been trained on a specific distribution are prone to poor performance. Histogram specification (HS) has been reported as an effective method for contrast enhancement and improving model performance on images of different modalities. Additionally, contrast limited adaptive histogram equalization (CLAHE) will be used as a preprocessing method to enhance the contrast of MG images. In this study, we developed and evaluated the automatic segmentation method of the eyelid area and the MG area based on CNN and automatically calculated MG loss rate. This method is evaluated in the internal and external testing sets from two meibography devices. In addition, to assess whether HS and CLAHE improve segmentation results, we trained the network model using images from one device (internal testing set) and tested on images from another device (external testing set). High DSC (0.84 for MG region, 0.92 for eyelid region) for the internal test set was obtained, while for the external testing set, lower DSC (0.69–0.71 for MG region, 0.89–0.91 for eyelid region) was obtained. Also, HS and CLAHE were reported to have no statistical improvement in the segmentation results of MG in this experiment

Dynamic tear meniscus parameters in complete blinking: insights into dry eye assessment

AIM: To investigate the relationship between dynamic tear meniscus parameters and dry eye using an automated tear meniscus segmentation method. METHODS: The analysis of tear meniscus videos captured within 5s after a complete blink includes data from 38 participates. By processing video data, several key parameters including the average height of the tear meniscus at different lengths, the curvature of the tear meniscus's upper boundary, and the total area of the tear meniscus in each frame were calculated. The effective values of these dynamic parameters were then linearly fitted to explore the relationship between their changing trends and dry eye disease. RESULTS: In 94.74% of the samples, the average height of central tear meniscus increased over time. Moreover, 97.37% of the samples exhibited an increase in the overall tear meniscus height (TMH) and area from the nasal to temporal side. Notably, the central TMH increased at a faster rate compared to the nasal side with the temporal side showing the slowest ascent. Statistical analysis indicates that the upper boundary curvature of the whole tear meniscus as well as the tear meniscus of the nasal side (2, 3, and 4 mm) aid in identifying the presence of dry eye and assessing its severity. CONCLUSION: This study contributes to the understanding of tear meniscus dynamics as potential markers for dry eye, utilizing an automated and non-invasive approach that has implications for clinical assessment

CD200-CD200R dysfunction exacerbates microglial activation and dopaminergic neurodegeneration in a rat model of Parkinson's disease

<p>Abstract</p> <p>Background</p> <p>Increasing evidence suggests that microglial activation may participate in the aetiology and pathogenesis of Parkinson's disease (PD). CD200-CD200R signalling has been shown to be critical for restraining microglial activation. We have previously shown that expression of CD200R in monocyte-derived macrophages, induced by various stimuli, is impaired in PD patients, implying an intrinsic abnormality of CD200-CD200R signalling in PD brain. Thus, further in vivo evidence is needed to elucidate the role of malfunction of CD200-CD200R signalling in the pathogenesis of PD.</p> <p>Methods</p> <p>6-hydroxydopamine (6-OHDA)-lesioned rats were used as an animal model of PD. CD200R-blocking antibody (BAb) was injected into striatum to block the engagement of CD200 and CD200R. The animals were divided into three groups, which were treated with 6-OHDA/Veh (PBS), 6-OHDA/CAb (isotype control antibody) or 6-OHDA/BAb, respectively. Rotational tests and immunohistochemistry were employed to evaluate motor deficits and dopaminergic neurodegeneration in animals from each group. HPLC analysis was used to measure monoamine levels in striatum. Morphological analysis and quantification of CD11b- (or MHC II-) immunoreactive cells were performed to investigate microglial activation and possible neuroinflammation in the substantia nigra (SN). Finally, ELISA was employed to assay protein levels of proinflammatory cytokines.</p> <p>Results</p> <p>Compared with 6-OHDA/CAb or 6-OHDA/Veh groups, rats treated with 6-OHDA/BAb showed a significant increase in counts of contralateral rotation and a significant decrease in TH-immunoreactive (TH-ir) neurons in SN. A marked decrease in monoamine levels was also detected in 6-OHDA/BAb-treated rats, in comparison to 6-OHDA/Veh-treated ones. Furthermore, remarkably increased activation of microglia as well as up-regulation of proinflammatory cytokines was found concomitant with dopaminergic neurodegeneration in 6-OHDA/BAb-treated rats.</p> <p>Conclusions</p> <p>This study shows that deficits in the CD200-CD200R system exacerbate microglial activation and dopaminergic neurodegeneration in a 6-OHDA-induced rat model of PD. Our results suggest that dysfunction of CD200-CD200R signalling may be involved in the aetiopathogenesis of PD.</p

Randomized controlled trial to treat migraine with acupuncture: design and protocol

<p>Abstract</p> <p>Background and motivation</p> <p>The effectiveness of using acupuncture to treat migraine is rarely and even suspectedly reported in the literature. In this article, we report the design and the protocol of a randomized controlled large-scale trial to treat migraine using acupuncture, aiming at testifying it is effective to use acupuncture to treat migraine. We demonstrate also that the effectiveness of the treatment may vary due to using acupoints of different meridians or different acupoints of one meridian.</p> <p>Methods and design</p> <p>A multi-center randomized controlled trial is currently undergoing, with three acupoints treatment groups and one non-acupoints control group. The acupuncture treatment consists of 20 sessions per patient with a observation period of 20 weeks. In total, 480 patients with Migraine are registered in this study within 8 hospitals in China from March 2008 to June 2009. These patients are randomly assigned to receive one of the following four acupoints treatment groups, i.e. 1) specific acupoints of Shaoyang meridians (120 patients), 2) non-specific acupoints of Shaoyang meridians (120 patients), 3) acupoints of other meridians (120 patients); or 4) non-acupoints control group (120 patients). The main outcome measurement in this trial is the effect comparison achieved among these four groups in terms of number of days with migraine and intensity of migraine during and after the baseline phase, i.e. the first 4 weeks before randomization and 4, 8 and 16 weeks after randomization. The intensity of headache including Headache intensity grade (0–3) and visual analogue scale (VAS) score will also be used in this study. In addition, the differences of Migraine-Specific Quality-of-Life Questionnaire (MSQ) and Transcranial Doppler Sonography (TCD) before and after randomization are also used as the secondary outcome measurement.</p> <p>Discussion</p> <p>The result of this trial (which will be available in 2009) will demonstrate the efficacy of using acupuncture to treat migraine, and verify whether the specific effect of acupoints exists and whether this specific effect of acupoints is related to meridian and a collection of meridian Qi.</p> <p>Trials registration</p> <p>Clinical Trials.gov NCT00599586</p