Brain HMPAO-SPECT and ocular microangiopathic syndrome in HIV-1-infected patients

OBJECTIVE: The pathogenesis of neurologic and neuropsychologic dysfunction in HIV-1 infection is unclear. The purpose of the study was to determine an association between cerebral perfusion and HIV-1-related ocular microangiopathic syndrome. METHODS: We studied 28 HIV-1-infected patients, seven of whom presented with asymptomatic HIV infection, nine with lymphadenopathy syndrome or AIDS-related complex, and 12 with AIDS. Cerebral perfusion was semi-quantitatively measured by single photon emission computed tomography of the brain using technetium-99 hexamethyl-propylenamine oxime (HMPAO-SPECT). The conjunctival manifestation of HIV-1-related microangiopathic syndrome was measured by a rating scale determining blood-flow sludging and, retinal cotton-wool spots were counted. CD4 count, neopterin, beta 2-microglobulin (beta 2M), haemoglobin, and age were determined as putative confounding variables. RESULTS: Mean conjunctival sludge in patients with normal HMPAO-SPECT findings was 1.3 +/- 0.5 (mean +/- s.e.m.); no cotton-wool spots were present. In patients with slightly impaired HMPAO-SPECT, it was 2.1 +/- 0.6 and mean cotton-wool spot count was 1.1 +/- 0.4. In patients with severely impaired HMPAO-SPECT, mean conjunctival sludge was 4.5 +/- 0.3 and mean cotton-wool spot count was 4.9 +/- 1.1 HMPAO-SPECT findings were closely associated with conjunctival sludge (r = 0.72; P < 0.001) and number of cotton-wool spots (r = 0.78; P < 0.001), whereas only a slight association with staging of HIV disease was found (P = 0.052). Analysis of covariance controlling for CD4 count neopterin, beta 2M, age, and haemoglobin demonstrated a significant difference between the three HMPAO-SPECT groups for both the number of cotton-wool spots (P < 0.001) and the conjunctival sludge rating (P < 0.001). CONCLUSION: There was a close association between severity of HIV-1-related ocular microangiopathic syndrome and severity of cerebral hypoperfusion. Microvascular alterations might contribute to the pathogenesis of neurological and neuropsychological symptoms in patients with HIV-1 disease. Furthermore, the conjunctival sludge rating and the number of cotton-wool spots might be appropriate indicators for severity of microvascular changes of the central nervous system [corrected].     

Applying dual-tree complex discrete wavelet transform and gamma modulating function for simulation of ground motions

The aim of this paper is to develop a stochastic-parametric model for the generation of synthetic ground motions (GMs) which are in accordance with a real GM. In the proposed model, the dual-tree complex discrete wavelet transform (DT-CDWT) is applied to real GMs to decompose them into several frequency bands. Then, the gamma modulating function (GMF) is used to simulate the wavelet coefficients of each level. Consequently, synthetic wavelet coefficients are generated using extracted model parameters and then synthetic GM is extracted by applying the inverse DT-CDWT to synthetic wavelet coefficients. This model simulates the time–frequency distribution of both wide-frequency and narrow-frequency bandwidth GMs. Besides being less time consuming, it simulates several dominant frequency peaks at any moment in the time duration of GM, because each frequency band is separately simulated by the gamma function. Moreover, the inelastic response spectra of synthetic GMs generated by the proposed model are a good estimate of target ones. Using the random sign generator in the proposed model, it is possible to generate any number of synthetic GMs in accordance with a recorded one. Because of these advantages, the proposed model is suitable for using in performance-based earthquake engineering.

     

Proactive task migration with a self-adjusting migration threshold for dynamic thermal management of multi-core processors

Request for more computation power steadily forces designers to provide more powerful processors using more number of cores on a single chip. The increasing complexity of processors leads to higher integration density, power density, and temperature. For avoiding thermal emergencies, various dynamic thermal management techniques have been presented. In this paper, we present a novel online self-adjusting temperature threshold schema for dynamic thermal management to minimize both average and peak temperature with very low performance overhead. Our proposed algorithm adjusts migration threshold according to workload and hardware platforms. The experimental results indicate that our technique can significantly decrease the average and peak temperature compared to Linux standard scheduler, and two well-known thermal management techniques: PDTM and TAS.     

Removal of iron from milk of lime to produce pure precipitated calcium carbonate

ABSTRACT

Milk of lime (MOL) suspension is widely utilized in many industries; however, in some of the applications, such as the production of precipitated calcium carbonate (PCC), the suspension must be of high purity and quality. In other words, the amounts of iron and magnesium should be so little so that the final PCC product would be of high quality. The effects of initial temperature, quicklime particle size, amount of initial solid present, agitation rate, and time on the recovery of hydrated lime and iron/magnesium reduction efficiency were investigated through a central composite design (CCD) of experiments. The iron reduction efficiency and the weight recovery of hydrated lime were obtained as 91% and 98.5%, respectively. The reduction of magnesium was not significant in this stage. Moreover, approximately the whole existing SiO₂ was eliminated.     

Mechanical and viscoelastic properties of polyethylene-based microfibrillated composites from 100% recycled resources

In this study, recycled polyethylene (rPE) based microfibrillated composites (MFCs) were developed while incorporating recycled poly(ethylene terephthalate) (rPET) and recycled polyamide 6 (rPA) as the reinforcing fibrillar phases at a given weight ratio of 80 wt% (rPE)/20 wt% (rPET or rPA). The blends were first melt processed using a twin-screw extruder. The extrudates were then cold stretched at a drawing ratio of 2.5 to form rPET and rPA fibrillar structures. Next, the pelletized drawn samples were injection molded at the barrel temperatures below the melting temperatures of rPET and rPA. The tensile, three-point bending, impact strength, dynamic thermomechanical, and rheological properties of the fabricated MFCs were analyzed. The effects of injection molding barrel temperature (i.e., 150°C and 190°C) and extrusion melt processing temperature (i.e., 250°C and 275°C) on the generated fibrillar structure and the resultant properties were explored. A strong correlation between the fibrillar morphology and the mechanical properties with the extrusion and injection molding temperatures was observed. Moreover, the ethylene/n-butyl acrylate/glycidyl methacrylate (EnBAGMA) terpolymer and maleic anhydride grafted PE (MAH-g-PE) were, respectively, melt processed with rPE/rPET and rPE/rPA6 blends as compatibilizers. The compatibilizers refined the fibrillar structure and remarkably influenced mechanical properties, specifically the impact strength.     

An integrated semantic-based approach in concept based video retrieval

Multimedia content has been growing quickly and video retrieval is regarded as one of the most famous issues in multimedia research. In order to retrieve a desirable video, users express their needs in terms of queries. Queries can be on object, motion, texture, color, audio, etc. Low-level representations of video are different from the higher level concepts which a user associates with video. Therefore, query based on semantics is more realistic and tangible for end user. Comprehending the semantics of query has opened a new insight in video retrieval and bridging the semantic gap. However, the problem is that the video needs to be manually annotated in order to support queries expressed in terms of semantic concepts. Annotating semantic concepts which appear in video shots is a challenging and time-consuming task. Moreover, it is not possible to provide annotation for every concept in the real world. In this study, an integrated semantic-based approach for similarity computation is proposed with respect to enhance the retrieval effectiveness in concept-based video retrieval. The proposed method is based on the integration of knowledge-based and corpus-based semantic word similarity measures in order to retrieve video shots for concepts whose annotations are not available for the system. The TRECVID 2005 dataset is used for evaluation purpose, and the results of applying proposed method are then compared against the individual knowledge-based and corpus-based semantic word similarity measures which were utilized in previous studies in the same domain. The superiority of integrated similarity method is shown and evaluated in terms of Mean Average Precision (MAP).     

Free vibration analysis of double-viscoelastic nano-composite micro-plates reinforced by FG-SWCNTs based on the third-order shear deformation theory

Microsystem Technologies - In this paper, free vibration analysis of a double viscoelastic nano-composite plate system reinforced by functionally graded single-walled carbon nanotubes (FG-SWCNT)...     

A new localization method in internet of things by improving beetle antenna search algorithm

Wireless Networks - Localization is regarded as one of the important challenges in the internet of things and Wireless Sensor Networks. The failure to localize sensors properly causes data loss and...     

CQARPL: Congestion and QoS-aware RPL for IoT applications under heavy traffic

The Journal of Supercomputing - The Internet of Things (IoT) provides a common platform to connect the heterogeneous devices over the internet. Hence, the number of devices connected via the...