Automatic SWI Venography Segmentation Using Conditional Random Fields

Susceptibility-weighted imaging (SWI) venography can produce detailed venous contrast and complement arterial dominated MR angiography (MRA) techniques. However, these dense reversed-contrast SWI venograms pose new segmentation challenges. We present an automatic method for whole-brain venous blood segmentation in SWI using Conditional Random Fields (CRF). The CRF model combines different first and second order potentials. First-order association potentials are modeled as the composite of an appearance potential, a Hessianbased shape potential and a non-linear location potential. Second-order interaction potentials are modeled using an autologistic (smoothing) potential and a data-dependent (edge) potential.

Minimal post-processing is used for excluding voxels outside the brain parenchyma and visualizing the surface vessels. The CRF model is trained and validated using 30 SWI venograms acquired within a population of deep brain stimulation (DBS) patients (age range = 43-73 years). Results demonstrate robust and consistent segmentation in deep and subcortical regions (median kappa = 0.84 and 0.82), as well as in challenging mid-sagittal and surface regions (median kappa = 0.81 and 0.83) regions. Overall, this CRF model produces highquality segmentation of SWI venous vasculature that finds applications in DBS for minimizing hemorrhagic risks and other surgical and non-surgical applications.

Herd Behavior in Technology Adoption: The Role of Adopter and Adopted Characteristics

Herd literature suggests that people tend to discount their own beliefs and imitate others when making adoption decisions. However different people based on their characteristics exhibit different degrees of herd behavior. In the same vein, the characteristics of technology must fit with the requirements of the task that an adopter wants to fulfill Characteristics of individuals and of the technology-to-be-adopted both influence adoption behaviors.

It is important to understand these phenomena because they are strongly related to the staying power of technology. A research model is developed to study the influence adopter characteristics and technology characteristics. An online experiment will be conducted to examine the research model.

Regulation of arterial venous stem cell differentiation on PEG hydrogels using immobilized and soluble developmental signals

Vascular endothelial cells differentiated from pluripotent stem cells have potential in a variety of therapeutic areas such as tissue engineered vascular grafts and revascularization of ischemic tissues. However, there remain limitations in the control of stem cell differentiation into the desired functional phenotypes with current methods. During vascular development, it has been demonstrated that the early arterial-venous cell fate is genetically programmed, with the expression of transmembrane proteins ephrinB2 and EphB4 as the first distinction, prior to hemodynamic cues [1].

Here, we hypothesize that arterial venous differentiation is influenced, not only from the Notch activation pathway, but also from the bidirectional signaling of these transmembrane ligand-receptor proteins. Our results show ephrinB2/EphB4 immobilized signaling in combination with soluble factors can influence arterial venous differentiation in mouse embryonic stem cells (mESCs).

Prediction of the Biomechanical Effects of Compression Therapy by Finite Element Modeling and Ultrasound Elastography

Goal: In the present study, the biomechanical response of soft tissues from the fascia cruris to the skin is studied in the human leg under elastic compression. Methods: The distribution of elastic moduli in these tissues is measured for a volunteer at inactive and active muscle states using transient ultrasound elastography (TUSE). After registering the elasticity maps against magnetic resonance imaging scans of the same volunteer, patient-specific finite element (FE) models are developed for the leg cross section at inactive and active muscle states. Elastic properties obtained with TUSE are assigned at each Gauss point of the models.

The response to 20 mmHg elastic compression is eventually predicted with the models. Results: Results show significantly higher elastic moduli in the fascia cruris tissue and also a significant increase of elastic moduli at active muscle state. Conclusion: This seems to have a marginal impact on pressure maps in the soft tissues of the leg predicted by the FE models. There is still an effect on the reduction of vein diameter induced by elastic compression, which is decreased at active muscle state. Significance: The discussion of this paper highlights the benefits of using elastography to reconstruct patient-specific FE models of soft tissues.

Separating Arterial and Venous-Related Components of Photoplethysmographic Signals for Accurate Extraction of Oxygen Saturation and Respiratory Rate

We propose an algorithm for separating arterial and venous-related signals using second-order statistics of red and infrared signals in a blind source separation technique. The separated arterial signal is used to compute accurate arterial oxygen saturation. We have also introduced an algorithm for extracting the respiratory pattern from the extracted venous-related signal.

In addition to real-time monitoring, respiratory rate is also extracted. Our experimental results from multiple subjects show that the proposed separation technique is extremely useful for extracting accurate arterial oxygen saturation and respiratory rate. Specifically, the breathing rate is extracted with average root mean square deviation of 1.89 and average mean difference of $-$0.69.

An approach to automated thesaurus construction using clusterization-based dictionary analysis

In the paper an automated approach for construction of the terminological thesaurus for a specific domain is proposed. It uses an explanatory dictionary as the initial text corpus and a controlled vocabulary related to the target lexicon to initiate extraction of the terms for the thesaurus. Subdivision of the terms into semantic clusters is based on the CLOPE clustering algorithm.

The approach diminishes the cost of the thesaurus creation by involving the expert only once during the whole construction process, and only for analysis of a small subset of the initial dictionary. To validate the performance of the proposed approach the authors successfully constructed a thesaurus in the cardiology domain.

Polarization domain information on insect wing chitin using the scanning pyroelectric microscope (SPEM)

Scanning Pyroelectric Microscopy (SPEM) at micrometer resolutions has been employed to study permanent polarity and its spatial organization in various insect wings containing chitin, one of the most abundant biopolymers.

Both measurements on wings of houseflies and wasps revealed a well defined pyroelectric response, showing a multidomain polarization pattern at several length scales, from millimeter sized domains in the wing veins, to 20 micrometer sized domains in the membranes. The size of the smaller domains correlates well with the average chitin fiber length of 18 micrometers.

Fine-Wire Electromyography Response to Neuromuscular Electrical Stimulation in the Triceps Surae

Neuromuscular electrical stimulation (NMES) has previously been used to enhance venous return from the lower leg. By artificially activating lower leg muscles, venous blood may be effectively ejected from the muscle and adjacent veins. It could easily be assumed that combined NMES of the gastrocnemius and soleus would be the most effective single-channel application in this regard, as these muscles represent the largest muscular bulk in the lower leg.However, we have previously reported that soleus stimulation in isolation is substantially more effective.To understand why this is the case, we recorded fine-wire electromyography during NMES of the gastrocnemius and soleus muscles.

We found that gastrocnemius and soleus stimulation are effective in eliciting selective stimulation of these muscles. However, combined stimulation of these muscles using a single set of electrodes was only capable in generating ~ 50% of the response in each muscle, insufficient to generate their theoretical maximum venous return.

Biometrics security system: A review of multimodal biometrics based techniques for generating crypto-key

In today’s world the life is very fast we want to do everything so quickly and easily without putting much physical and mental effort. With the advancement of technology we are provided with higher level of knowledge through the invention of different devices. However each technological innovation has its pros and cons. One of the emerging devise for biometric security system is Smartphone’s we are using today. Today we cannot think of living without smart phones as they have become the part of our life.

We depend on our phone for our so man day to day activities like paying bills connecting with friends and office, making money transaction. But using the traditional security features we cannot get appropriate security as anyone who knows the password to unlock my phone can get access to my phone. Using biometrics traits like fingerprint, voice, face, and iris one cannot get access to the device. In this paper we focus on how biometrics help in making the device more secure and fool proof and what were the lacking in the traditional methods of security system which give birth to the implementation of biometric security system.

Enhancing security of one-time password using Elliptic Curve Cryptography with biometrics for e-commerce applications

Security of one-time password (OTP) is essential because nowadays most of the e-commerce transactions are performed with the help of this mechanism. OTP is used to counter replay attack/eavesdropping. Replay attack or eavesdropping is one type of attacks on network-connected computing environment or isolated computing environment. For achieving 112 bits of security level, Rivest Shamir and Adleman (RSA) algorithm needs key size of 2048 bits, while Elliptic Curve Cryptography (ECC) needs key size of 224-255 bits. Another issue with most of the existing implementation of security models is storage of secret keys. Cryptographic keys are often kept in en-secured way that can either be guessed/social-engineered or obtained through brute force attacks.

This becomes a weak link and leads integrity issues of sensitive data in a security model. To overcome the above problem, biometrics is combined with cryptography for developing strong security model. This paper suggests an enhanced security model of OTP system using ECC with palm-vein biometrie. This model also suggests better security with lesser key size than other prevalent public key crypto-model. The cryptographic keys are also not required to memorize or keep anywhere, these keys are generated as and when needed.