Initial clinical application of modified Dixon with flexible echo times: hepatic and pancreatic fat assessments in comparison with 1H MRS

Objects

Hepatic and pancreatic fat content become increasingly important for phenotyping of individuals with metabolic diseases. This study aimed to (1) evaluate hepatic fat fractions (HFF) and pancreatic fat fractions (PFF) using ¹H magnetic resonance spectroscopy (MRS) and the recently introduced fast mDixon method, and to examine body fat effects on HFF and PFF, (2) investigate regional differences in HFF and PFF by mDixon.

Materials and methods

HFF and PFF were quantified by mDixon with two flexible echo times and by single voxel ¹H MRS in 24 healthy subjects. The regional differences of PFF within the pancreas were assessed with mDixon. Abdominal visceral and subcutaneous fat was assessed by T1-weighted MRI at 3T.

Results

Both methods correlated well for quantification of HFF (r = 0.98, p < 0.0001) and PFF (r = 0.80, p < 0.0001). However, mDixon showed a higher low limit in HFF and PFF. PFF showed no regional differences using mDixon. In addition, both visceral and subcutaneous fat correlated with pancreatic fat, while only visceral fat correlated with liver fat, employing both ¹H MRS and mDixon.

Conclusion

The novel and fast two-point mDixon exhibits a good correlation with the gold-standard ¹H MRS for assessment of HFF and PFF, with limited sensitivity for assessing lower fat content.     

Effect of Global Warming on Intensity and Frequency Curves of Precipitation, Case Study of Northwestern Iran

Predicting natural phenomena like flood and drought and consequently presenting an appropriate solution for fighting such natural hazards in northwestern Iran is considered in this study through clustering the precipitation regime. To compare the reference period (past) with the simulated data, the statistics of daily precipitation in six stations of Ardebil, Ghazvin, Hamedan, Kermanshah, Sanandaj, and Tabriz, have been provided for a 30-year period (1961–1990) and compared with the simulated data of 2021–2050. The simulated data was generated by general atmosphere circulation model HADCM3, A1scenario and was downscaled using the LARS-WG model. The method for comparing precipitations was done based on clustering in the form of 5 clusters for all the stations and study periods. One of the results of this research is the greater concentration of precipitation for the cold periods of the year (winter and fall) and the increase of annual precipitation by the amount of 20.62 mm for future period. Furthermore, the normality of two coordinates of precipitation and cluster frequency percentage was evaluated. The outputs of this section demonstrate that the precipitations of cluster 3 which have the features of light rain with average intensity, fall on this normal line for most of the stations and study periods. On the other hand, precipitations of cluster 1 indicating very heavy and intense precipitations, have the most distance to the normal line in most cases. Therefore, the precipitations of the third cluster need optimal exploitation management while those of the first cluster need required risk and crisis management.     

Isobutrin from butea monosperma (flame of the forest): a promising new natural sensitizer belonging to chalcone class

In this work, "isobutrin", an ecofriendly sensitizer that is extracted from Butea monosperma (commonly known as "Flame of the Forest") flowers, is introduced. It is a bright yellow pigment belonging to the chalcone class and is examined as a sensitizer for optoelectronic applications. It is observed that chelation of this dye with Ti ions results into a strong dye-TiO(2) charge transfer (DTCT) band in the visible region. This Ti-Isobutrin chelate is stable, irreversible and its formation is studied using Benesi-Hildebrand plot. The locations of HOMO-LUMO states of the Ti-isobutrin chelate and the corresponding band alignment with TiO(2) are obtained. Also, a thermal stability test revealed that isobutrin is stable above 100 °C.     

Sequential Exploration of Complex Surfaces Using Minimum Energy Designs

A new space-filling design, called minimum energy design (MED), is proposed to explore unknown regions of the design space of particular interest to an experimenter. The key ideas involved in constructing the MED are the visualization of each design point as a charged particle inside a box, and minimization of the total potential energy of these particles. It is shown through theoretical arguments and simulations that with a proper choice of the charge function, the MED can asymptotically generate any arbitrary probability density function. A version of the MED, which adaptively updates the design by “learning” about the unknown response surface sequentially, is proposed and implemented. Two potential applications of MED in simulation of complex probability densities and optimization of complex response surfaces are discussed and demonstrated with examples. This article has supplementary material online.     

RK-Energy Efficient Routing Protocol for Wireless Body Area Sensor Networks

Wireless Body Area Sensor Networks are related to the monitoring of human physiological parameters. In these small sized machines called sensors are used to observe the physiological parameters. They are small in size which makes them easy to carry around but on the same time they have a serious problem that they can carry with them a very small sized battery. The sensors deplete their energy while sensing the parameter, communication of the sensed data to the base station and also in processing of the observed data. The sensors cannot be charged on regular intervals because they are attached to human body and charging them may not be an easy option. In this paper an energy efficient routing protocol is presented which uses sensors in WBASN to observe parameter in much efficient way. The concept of multi hopping has been utilized with forwarder node. Forwarder node accepts data from sensor nodes which are far from the sink. After accepting data the forwarder node forwards this data to the sink node. This scheme is compared with an existing scheme with which it has been compared in terms of four parameters which are residual energy, network stability and life time, throughput and path loss.

     

En-Route Filtering Techniques in Wireless Sensor Networks: A Survey

Wireless Personal Communications - Majority of wireless sensor networks (WSNs) are deployed in unattended environments and thus sensor nodes can be compromised easily. A compromised sensor node can...