A Novel Blind Separation Method in Magnetic Resonance Images

A novel global search algorithm based method is proposed to separate MR images blindly in this paper. The key point of the method is the formulation of the new matrix which forms a generalized permutation of the original mixing matrix. Since the lowest entropy is closely associated with the smooth degree of source images, blind image separation can be formulated to an entropy minimization problem by using the property that most of neighbor pixels are smooth. A new dataset can be obtained by multiplying the mixed matrix by the inverse of the new matrix. Thus, the search technique is used to searching for the lowest entropy values of the new data. Accordingly, the separation weight vector associated with the lowest entropy values can be obtained. Compared with the conventional independent component analysis (ICA), the original signals in the proposed algorithm are not required to be independent. Simulation results on MR images are employed to further show the advantages of the proposed method

State-of-the-Art in Carbides/Carbon Composites for Electromagnetic Wave Absorption

Electromagnetic wave absorbing materials (EWAMs) have made great progress in the past decades, and are playing an increasingly important role in radiation prevention and antiradar detection due to their essential attenuation toward incident EM wave. With the flourish of nanotechnology, the design of high-performance EWAMs is not just dependent on the intrinsic characteristics of single-component medium, but pays more attention to the synergistic effects from different components to generate rich loss mechanisms. Among various candidates, carbides and carbon materials are usually labeled with the features of chemical stability, low density, tunable dielectric property, and diversified morphology/microstructure, and thus the combination of carbides and carbon materials will be a promising way to acquire new EWAMs with good practical application prospects. In this review, we introduce EM loss mechanisms related to dielectric composites, and then highlight the state-of-the-art progress in carbides/carbon composites as high-performance EWAMs, including silicon carbide/carbon, MXene/carbon, molybdenum carbide/carbon, as well as some uncommon carbides/carbon composites and multicomponent composites. The critical information regarding composition optimization, structural engineering, performance reinforcement, and structure-function relationship are discussed in detail. In addition, some challenges and perspectives for the development of carbides/carbon composites are also proposed after comparing the performance of some representative composites

Effect of Ultrasonic Treatment on the Properties of PSE-like Chicken Sarcoplasmic Protein and Myofibrillar Protein Composite Gels

Myofibrillar protein (MP) and sarcoplasmic protein (SP) were extracted from pale, soft and exudative (PSE)-like chicken. The research investigated the differences in the heat-induced gel properties of SP-MP blends at 1:9, 2:8 and 3:7 ratios (m/m) and pure MP in order to select the appropriate SP/MP ratio. Furthermore, the differences in the gel properties, water distribution, intermolecular forces, gel electrophoresis pattern and microstructure of composite gels of SP treated with different ultrasonic powers (0, 300 and 600 W) at 20 kHz and MP were studied. The results showed that compared with the pure MP gel, the gel strength and water retention of the composite gel increased first and then decreased with the increase in SP addition, reaching the highest level at an SP/MP ratio of 2:8. After ultrasonic treatment at 600 W, the gel strength and water retention of the 2:8 composite gel were elevated by 113% and 47%, respectively, compared with those of the control group. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that SP had a certain promotion effect on the aggregation and cross-linking of myosin, but this effect became weaker when the ratio of SP to MP was 3:7. Both hydrophobic interactions and disulfide bond content reached their highest levels and the composite gel formed a denser network structure when the ratio of SP to MP was 2:8, and the ultrasonic power was 600 W. In conclusion, the effect of addition of ultrasonic-treated SP on the gel-forming capacity of PSE-like chicken MP was related to its concentration, and ultrasonic-treated SP favored the formation of MP gel structure, which effectively improved the gel characteristics of PSE-like chicken MP

Suitability Evaluation of River Bank Filtration along the Second Songhua River, China

The Second Songhua River is the biggest river system in Jilin Province, China. In recent years, the rapid economic development in this area has increased the prominence of water resources and water-related environmental problems; these include surface water pollution and the overexploitation of groundwater resources. Bank infiltration on the floodplains of the Second Songhua River is an important process of groundwater-surface water exchange under exploitation conditions. Understanding this process can help in the development of water resource management plans and strategies for the region. In this research, a multi-criteria evaluation index system was developed with which to evaluate the suitability of bank filtration along the Second Songhua River. The system was comprised of main suitability indexes for water quantity, water quality, the interaction intensity between surface water and groundwater, and the exploitation condition of groundwater resources. The index system was integrated into GIS (Geographic Information System) to complete the evaluation of the various indicators. According to the weighted sum of each index, the suitability of river bank filtration (RBF) in the study area was divided into five grades. Although the evaluation index system and evaluation method are applicable only to the Second Songhua River basin, the underlying principle and techniques it embodies can be applied elsewhere. For future generalization of the evaluation index system, the specific evaluation index and its scoring criteria should be modified appropriately based on local conditions

The influence of riverbank filtration on regional water resources: a case study in the Second Songhua River catchment, China

Abstract Riverbank filtration (RBF) of river water recharging a groundwater system has been identified as a source of water supply that guarantees the quantity of abstracted water and reduces the cost of water treatment. This paper evaluates the safe yield of groundwater in suitable areas using a numerical model of groundwater flow and discusses the influence of RBF on the temporal variation of regional hydraulic heads, groundwater flow, river flow, and groundwater–surface water interaction (GSI) under different precipitation frequencies from 20% to 95% along the Second Songhua River in Northeast China. This study shows that the potential of RBF is enormous and that the total safe yield of groundwater abstraction was 29.56 × 104 m3/day under the precipitation frequency of 95%. The direction of regional groundwater flow was not obviously changed except within the local groundwater flow field under the maximum safe yield pumping conditions. When the precipitation frequencies are higher than 75%, the direction of the GSI might be changed, and the rate of river recharge of groundwater is enhanced. The water quantity that would be captured from the river does not threaten the safety of the river ecology. It is concluded that there were no obvious adverse impacts of the large scale of RBF on regional water resources in the Second Songhua River area.</jats:p

In vitro and in vivo assessment of biocompatibility of AZ31 alloy as biliary stents: a preclinical approach

IntroductionBiomaterial technology due to its lack of or minimal side effects in tissues has great potential. Traditionally biomaterials used were cobalt-chromium, stainless steel and nitinol alloys. Biomaterials such as magnesium (Mg) and zinc (Zn) have good biocompatibility and consequently can be a potential material for medical implants. To date, the effects of AZ31 alloy stent on cell apoptosis are still unclear. The current investigation was designed to determine the effect of AZ31 alloy stent on necrosis and apoptosis of common bile duct (CBD) epithelial cells.Material and methodsWe experimented with application of different concentrations of AZ31 alloy stent to primary mouse extrahepatic bile epithelial cells (MEBECs) and estimated the effect on apoptosis and necrotic cells. Apoptosis and pro-apoptosis expression were estimated through real-time PCR. For in vivo protocol, we used rabbits, implanted the AZ31 bile stent, and estimated its effect on the CBD. AZ31 (40%) concentration showed an effect on the apoptotic and necrotic cells.ResultsReal-time PCR revealed that AZ31 (40%) concentration increased the apoptotic genes such as NF-κB, caspase-3, Bax and Bax/Bcl-2 ratio as compared to the control group. In the in vivo experiment, AZ31 alloy stents were implanted into the CBD and showed an effect on the alteration the hema¬tological, hepatic and non-hepatic parameters.ConclusionsTo conclude, it can be stated that AZ31 induces apoptosis via alteration in genes including nuclear factor kappa-B (NF-κB), caspase-3, Bax and Bax/Bcl-2 ratio and improved the hematological, hepatic and non-hepatic parameters.</jats:sec

The creation of functioning gastrojejunostomy following magnetic compression

AbstractBackgroundMagnetic compression for creating gastrojejunostomy has many advantages according to previous studies. However, following mechanical device release after healing, the anastomotic stenosis becomes the pivotal point.MethodsRectangle-shaped magnets were used for magnetic compression in rabbits. Both paclitaxel-loaded magnets and a strategy of pyloric ligation were chosen to improve the gastrojejunostomy. Based on these choices, the half-capsule was applied to occlude the pylorus after anastomotic formation. The size and patency of the anastomoses were analyzed to evaluate the efficacy of these approaches. A histological examination was also performed.ResultsThe positive effect of ligating the pylorus on gastrojejunostomy was significantly greater than that achieved using paclitaxel-loaded magnets during either short- or long-term follow-up. There were fewer scar tissue and collagen fibers at the anastomotic site in the treatment group than in the control group. The anastomotic aperture was of great interest at 9 months after the ligation of the pylorus following magnetic compression. In the view of the jejunum, although the aperture was barely visible, gastric juice was continuously spilling through it like a spring, and the aperture was clearly visible from the stomach side. All half-capsules failed to block the pylorus.ConclusionThe effect of paclitaxel on maintaining gastrojejunostomy patency was temporary. The ligation of the pylorus ensured the long-term patency of gastrojejunostomy, and the aperture was comparable to the pylorus which could play an anti-reflux role. Further studies for the sort of gastrointestinal aperture are being planned.</jats:sec