Electrical properties of polyvinylidene fluoride/cellulose acetate blend modified by cenosphere

In the present research work we successfully modified the polyvinylidene fluoride (PVDF) and cellulose acetate (CA) blend by cenosphere (CS). We have disclosed the significant effect of cenosphenere on electrical properties of modified polymer blends. The real dielectric constant (Ɛr) decreases and dissipation factor (tan (δ)) increases as a function of cenosphere (wt %). The impedance analysis demonstrates the decrease in bulk resistance as a function of temperature. The inorganic nature of cenosphere increases the AC and DC conductivity and may be covalent ionic contribution of cenosphere. This investigation is highly useful for the structural applications and glass micro balloons fabrication

The Gut Microbiota and Irritable Bowel Syndrome: Friend or Foe?

Progress in the understanding of the pathophysiology of irritable bowel syndrome (IBS), once thought to be a purely psychosomatic disease, has advanced considerably and low-grade inflammation and changes in the gut microbiota now feature as potentially important. The human gut harbours a huge microbial ecosystem, which is equipped to perform a variety of functions such as digestion of food, metabolism of drugs, detoxification of toxic compounds, production of essential vitamins, prevention of attachment of pathogenic bacteria to the gut wall, and maintenance of homeostasis in the gastrointestinal tract. A subset of patients with IBS may have a quantitative increase in bacteria in the small bowel (small intestinal bacterial overgrowth). Qualitative changes in gut microbiota have also been associated with IBS. Targeting the gut microbiota using probiotics and antibiotics has emerged as a potentially effective approach to the treatment of this, hitherto enigmatic, functional bowel disorder. The gut microbiota in health, quantitative and qualitative microbiota changes, and therapeutic manipulations targeting the microbiota in patients with IBS are reviewed in this paper

Modeling of normal force and finishing torque considering shearing and ploughing effects in ultrasonic assisted magnetic abrasive finishing process with sintered magnetic abrasive powder

Ultrasonic assisted magnetic abrasive finishing process (UAMAF) is a precision manufacturing process that results nano-scale level finish in a part. Normal force on a particle helps indenting the particle in the work surface whereas horizontal force provides finishing torque that in-turn helps the particle to perform micro-machining. Better understanding of the effect of these forces on material removal and wear pattern of the work-piece necessitates mathematical modeling of normal force and finishing torque and subsequently its validation with experimental results. In the present study, single particle interaction concept is considered to develop a model which is subsequently applied for all active particles of magnetic abrasive powder (MAP). Separation point theory is applied to consider the effect of ploughing below a critical depth and shearing above that depth. Normal components of shearing and ploughing forces are considered for calculating normal force and horizontal components of shearing and ploughing forces are taken to calculate finishing torque. Johnson-Cook model is applied to calculate shearing strength of the work material during UAMAF. The impact of ultrasonic vibrations is considered while calculating strain rate. Images are taken with the help of scanned electron microscope and atomic force microscope to study the material removal and wear mechanism during UAMAF process. Predicted values of force and torque model are validated with the experimental values

Brain extraction on MRI scans in presence of diffuse glioma: Multi-institutional performance evaluation of deep learning methods and robust modality-agnostic training

Brain extraction, or skull-stripping, is an essential pre-processing step in neuro-imaging that has a direct impact on the quality of all subsequent processing and analyses steps. It is also a key requirement in multi-institutional collaborations to comply with privacy-preserving regulations. Existing automated methods, including Deep Learning (DL) based methods that have obtained state-of-the-art results in recent years, have primarily targeted brain extraction without considering pathologically-affected brains. Accordingly, they perform sub-optimally when applied on magnetic resonance imaging (MRI) brain scans with apparent pathologies such as brain tumors. Furthermore, existing methods focus on using only T1-weighted MRI scans, even though multi-parametric MRI (mpMRI) scans are routinely acquired for patients with suspected brain tumors. In this study, we present a comprehensive performance evaluation of recent deep learning architectures for brain extraction, training models on mpMRI scans of pathologically-affected brains, with a particular focus on seeking a practically-applicable, low computational footprint approach, generalizable across multiple institutions, further facilitating collaborations. We identified a large retrospective multi-institutional dataset of n=3340 mpMRI brain tumor scans, with manually-inspected and approved gold-standard segmentations, acquired during standard clinical practice under varying acquisition protocols, both from private institutional data and public (TCIA) collections. To facilitate optimal utilization of rich mpMRI data, we further introduce and evaluate a novel ‘‘modality-agnostic training’’ technique that can be applied using any available modality, without need for model retraining. Our results indicate that the modality-agnostic approach1 obtains accurate results, providing a generic and practical tool for brain extraction on scans with brain tumors

Efficient Atmospheric and Extra-Atmospheric Interception Through Optimally Biased Proportional Navigation

Starting from a definition of the biased proportional navigation (PN) law and expression of the trajectory parameters, especially the lateral acceleration, in terms of a nondimensional bias parameter, an analytical minimization is made of the integrated (total) control effort with respect to the bias parameter. It is shown that optimum biasing may lead to significantly more control efficient PN guidance in a wide variety of engagement situations, especially those involving higher target maneuvers. The performance of the optimally biased PN is compared with the standard (unbiased) PN law for the general case of a maneuvering target. The optimum bias is expressed through a simple algebraic equation readily solvable in real time even on small on-board processors. For the special (and very useful) case of the effective navigation being equal to 3, the equation reduces to a quadratic leading to an explicit expression for the optimum bias. Specific examples are provided for interception both inside and outside the atmosphere. It is shown that control effort savings upto a factor of 3 can be achieved through optimum biasing under realistic engagement conditions

Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome: A Bridge between Functional Organic Dichotomy

The pathogenesis of irritable bowel syndrome (IBS), once thought to be largely psychogenic in origin, is now understood to be multifactorial. One of the reasons for this paradigm shift is the realization that gut dysbiosis, including small intestinal bacterial overgrowth (SIBO), causes IBS symptoms. Between 4% and 78% of patients with IBS and 1% and 40% of controls have SIBO; such wide variations in prevalence might result from population differences, IBS diagnostic criteria, and, most importantly, methods to diagnose SIBO. Although quantitative jejunal aspirate culture is considered the gold standard for the diagnosis of SIBO, noninvasive hydrogen breath tests have been popular. Although the glucose hydrogen breath test is highly specific, its sensitivity is low; in contrast, the early-peak criteria in the lactulose hydrogen breath test are highly nonspecific. Female gender, older age, diarrhea-predominant IBS, bloating and flatulence, proton pump inhibitor and narcotic intake, and low hemoglobin are associated with SIBO among IBS patients. Several therapeutic trials targeting gut microbes using antibiotics and probiotics have further demonstrated that not all symptoms in patients with IBS originate in the brain but rather in the gut, providing support for the micro-organic basis of IBS. A recent proof-of-concept study showing the high frequency of symptom improvement in patients with IBS with SIBO further supports this hypothesis

The Advantages of Velocity Vector Referencing in Proportional Navigation

Two generic classes of Proportional Navigation (PN) laws exist depending on whether the control acceleration of the pursuer is referenced relative to the pursuer velocity vector or the target-pursuer line-of-sight (LOS). This paper makes a critical comparison of the two types of laws, covering aspects of their implementation, analysis and trajectory behavior. It is shown that the LOS-referenced PN laws possess serious limitations in terms of implementation and trajectory behavior. These include forward acceleration and braking as a part of the control effort, relative inefficiency in terms of control effort requirements, restrictive launch conditions and singularities in acceleration requirements

A Powerful Kinematic Model for Proportional Navigation of Guided Weapons Against Maneuvering Targets

An accurate solution is presented of the nonlinear differential equations describing the pursuer motion under the PN law in the general case when the target is laterally maneuvering. A quasilinearization (QL) approach is used, followed by a perturbation technique to obtain analytical solutions for the trajectory parameters. Explicit expression for the pursuer lateral acceleration is derived and is shown to contain contributions due to initial heading error and target maneuver, with a coupling between the two effects. The solution is shown to be a substantial and consistent generalization of the classical linear solution for maneuvering targets. The generalized QL solution presented here provides very accurate estimates of pursuer lateral acceleration over a much broader range of engagement geometries and target maneuvers than presently available analytical solutions. The analytical solution is of special value for (i) generating accurate insight into PN behavior for maneuvering targets (ii) aiding rapid design calculation involving tradeoff studies (iii) modelling larger systems in which the PN law appears as a building block, and (iv) performing real-time computations of launch envelope, even on modest airborne computers on launching aircraft, to ensure successful intercept

Irritable Bowel Syndrome, Particularly the Constipation-Predominant Form, Involves an Increase in Methanobrevibacter smithii

BACKGROUND/AIMS: Because Methanobrevibacter smithii produces methane, delaying gut transit, we evaluated M. smithii loads in irritable bowel syndrome (IBS) patients and healthy controls (HC). METHODS: Quantitative real-time polymerase chain reaction for M. smithii was performed on the feces of 47 IBS patients (Rome III) and 30 HC. On the lactulose hydrogen breath test (LHBT, done for 25 IBS patients), a fasting methane result ≥10 ppm using 10 g of lactulose defined methane-producers. RESULTS: Of 47, 20 had constipation (IBS-C), 20 had diarrhea (IBS-D) and seven were not sub-typed. The M. smithii copy number was higher among IBS patients than HC (Log(10)5.4, interquartile range [IQR; 3.2 to 6.3] vs 1.9 [0.0 to 3.4], p<0.001), particularly among IBS-C compared to IBS-D patients (Log(10)6.1 [5.5 to 6.6] vs 3.4 [0.6 to 5.7], p=0.001); the copy number negatively correlated with the stool frequency (R=−0.420, p=0.003). The M. smithii copy number was higher among methane-producers than nonproducers (Log(10)6.4, IQR [5.7 to 7.4] vs 4.1 [1.8 to 5.8], p=0.001). Using a receiver operating characteristic curve, the best cutoff for M. smithii among methane producers was Log(10)6.0 (sensitivity, 64%; specificity, 86%; area under curve [AUC], 0.896). The AUC for breath methane correlated with the M. smithii copy number among methane producers (r=0.74, p=0.008). Abdominal bloating was more common among methane producers (n=9/11 [82%] vs 5/14 [36%], p=0.021). CONCLUSIONS: Patients with IBS, particularly IBS-C, had higher copy numbers of M. smithii than HC. On LHBT, breath methane levels correlated with M. smithii loads

Electrical properties of polyvinylidene fluoride/cellulose acetate blend modified by cenosphere

737-742In the present research work we successfully modified the polyvinylidene fluoride (PVDF) and cellulose acetate (CA) blend by cenosphere (CS). We have disclosed the significant effect of cenosphenere on electrical properties of modified polymer blends. The real dielectric constant (Ɛr) decreases and dissipation factor (tan (δ)) increases as a function of cenosphere (wt %). The impedance analysis demonstrates the decrease in bulk resistance as a function of temperature. The inorganic nature of cenosphere increases the AC and DC conductivity and may be covalent ionic contribution of cenosphere. This investigation is highly useful for the structural applications and glass micro balloons fabrication