1,437 research outputs found
Speckle Reduction Using Multiple Tones of Illumination
The occurrence and smoothing of speckle are studied as a function of the line width for a highly collimated illuminating source. A general theory is presented for speckling in the image of a partially diffuse, phase type of object, which has a variable number of random scattering centers per resolution element. Then, an expression is derived for the wavelength spacing required to decouple the speckle patterns arising from two monochromatic tones in an imaging system, thereby establishing that it is feasible to smooth speckle using multicolor illumination. This theory is verified in a series of experiments using both laser illumination and band-limited light from a carbon arc. With highly collimated sources, we show that speckle appears laserlike for an imaged diffuser even up to line widths of 5 Ã…. Then, smoothing of speckle is demonstrated in the imaging of a diffuser and for a section of an optic nerve when the illumination is provided by six narrow lines spread over 1500 Ã…. Since with color-blind, panchromatic viewing the speckle smooths, a direct extension of this method to holographic microscopy, using a multitone laser, should permit one to record and reconstruct holograms of diffraction-limited resolution that are essentially speckle-free
Super-resolution imaging system
The resolution of an imaging system is greatly enhanced by radiating an object with a plane wave field from a coherent source variable in either frequency, angle or distance from the object, detecting the wave field transmitted through, or reflected from, the object at some point on the image of the object, with or without heterodyne detection, and with or without a lens system. The heterodyne detected output of the detector is processed to obtain the Fourier transform as a function of the variable for a direct measurement of the amplitude and surface height structure of the object within a resolution cell centered at the corresponding point on the object. In the case of no heterodyne detection, only intensity data is obtained for a Fourier spectrum
Conformal Structure of Massless Scalar Amplitudes Beyond Tree level
We show that the one-loop on-shell four-point scattering amplitude of
massless scalar field theory in 4D Minkowski space time, when Mellin
transformed to the Celestial sphere at infinity, transforms covariantly under
the global conformal group () on the sphere. The unitarity of the
four-point scalar amplitudes is recast into this Mellin basis. We show that the
same conformal structure also appears for the two-loop Mellin amplitude.
Finally we comment on some universal structure for all loop four-point Mellin
amplitudes specific to this theory.Comment: 15 pages, 4 figures, V2: Reference Adde
A statistical treatment of the loss of stiffness during cyclic loading for short fiber reinforced injection molded composites
Injection molded short fiber reinforced composites (SFRC) have different local fiber orientation distribution (FOD) at every point. SN curves of short fiber reinforced composites are known to depend on the fiber orientation distribution. Such materials also suffer from continuous loss of stiffness during cyclic loading. It is not known whether the loss of stiffness is different for SFRC with different FOD. A statistical analysis of the loss of stiffness curves is presented in this paper. Tension-tension fatigue experiments are performed and loss of stiffness is collected for every data point in the SN curve. A systematic method for comparing the loss of stiffness is developed. It is concluded that the difference in loss of stiffness curves for coupons of SFRC with different FOD is not statistically significant. (C) 2016 Elsevier Ltd. All rights reserved
AflaB2® and osteoarthritis: a multicentric, observational, post-marketing surveillance study in Indian patients suffering from knee osteoarthritis
Background: Osteoarthritis (OA) is one of the most debilitating chronic degenerative joint disorder characterized by pain, inflammation and stiffness of joints with wear and tear of the cartilage. Recent evidences suggest the involvement of the immune pathway in OA development. This study was conducted to evaluate the efficacy and safety of AflaB2® capsules containing Aflapin® and native collagen type II in knee OA patients.Methods: Total 40 knee OA subjects were enrolled at the out-patient department (OPD) of three different sites under supervision of physicians as per the inclusion and exclusion criteria of the study. Subjects were instructed to consume AflaB2® capsules once daily orally for three months. They were informed to visit the respective study center as per the schedule visits to assess and record the efficacy and safety.Results: AflaB2® treatment showed significant reduction in pain and stiffness with improvement in physical functions compared to the baseline. The reduction in pain score was observed from 2nd visit on visual analogue scale (VAS). The VAS score was reduced to 1.63±1.23 (p<0.001) from its baseline score 6.0±1.04 at the end of the treatment. The WOMAC Total Score was reduced to 18.1±6.04 (p<0.001) from its baseline score 74.4±8.07 at the end of the treatment. The improvement was observed in WOMAC pain, stiffness and physical functions score. No significant side-effect was reported with AflaB2® treatment throughout the study.Conclusions: The present study provides the evidence in support of the potential efficacy and excellent tolerability of oral intake of AflaB2® capsules in reducing OA symptoms
Insider Threats: Risk to Organization
Information security is an essential component and assets for any organization, whether it is commercial government or proprietary business. Report after report keeps pointing to the “insider threat†as one of the greatest information security risks within the modern organization. But what exactly is the insider threat and how we can help reduce this risk? This paper analyzes the importance of information security, benefits of it and how the information can be protected by the various threats which are inside the organization, and may leads to information loss. The aim of this paper is to allow businesses, administrators, developers and designers to produce and provide with some methods or techniques to secure such information so that the risk associated with the information loss can be minimized. In this paper we will break down the various attributes of the insider threat, and suggest some methods have been suggested which can help an organization to secure the sensitive and crucial information
Realising the open virtual commissioning of modular automation systems
To address the challenges in the automotive industry posed by the need to rapidly manufacture more
product variants, and the resultant need for more adaptable production systems, radical changes are
now required in the way in which such systems are developed and implemented. In this context, two
enabling approaches for achieving more agile manufacturing, namely modular automation systems
and virtual commissioning, are briefly reviewed in this contribution. Ongoing research conducted at
Loughborough University which aims to provide a modular approach to automation systems design
coupled with a virtual engineering toolset for the (re)configuration of such manufacturing
automation systems is reported. The problems faced in the virtual commissioning of modular
automation systems are outlined. AutomationML - an emerging neutral data format which has
potential to address integration problems is discussed. The paper proposes and illustrates a
collaborative framework in which AutomationML is adopted for the data exchange and data
representation of related models to enable efficient open virtual prototype construction and virtual
commissioning of modular automation systems. A case study is provided to show how to create the
data model based on AutomationML for describing a modular automation system
Positive Allosteric Modulators of Alpha4Beta2 Neuronal Nicotinic Receptors: Synthesis and In vitro Studies
des-Formylflustrabromine (dFBr), isolated from the marine organism Flustra foliacea, is the first selective, positive allosteric modulator (PAM) of α4β2 nicotinic acetylcholine receptors that potentiates the action of the neurotransmitter acetylcholine (ACh). Most agonists for this receptor population are not selective and can activate other nACh receptors. A selective PAM, which activates α4β2 nACh receptors only in the presence of ACh, might find application in the treatment of of various neurological diseases such as Alzheimer’s disease or autism. dFBr was examined and found to produce a biphasic dose-response curve over a wide concentration range (i.e., potentiation at low concentration, but inhibition of the ACh-induced response at high concentrations). Our goal was to examine various structural features of dFBr required for potentiation; a secondary goal was to examine the same for inhibition. To understand the structural requirements of dFBr, a systematic ‘deconstruction reconstruction and elaboration’ approach (see p. 48) was employed to determine the contribution of various structural components of dFBr to its activity at α4β2 nACh receptors. Novel compounds were synthesized and characterized. Human α4β2 nACh receptors were expressed in Xenopus oocytes and the actions of dFBr and its analogs were measured using a two-electrode voltage clamp technique. Dose-response curves were obtained for the compounds in the absence and presence of 100 μM ACh. Structural features of dFBr optimal and/or required for PAM action at 42 nACh receptors were identified. A novel reconstructed analog with all the essential features for PAM action was synthesized and submitted for biological testing. Elaborated analogs of dFBr further helped in identification of various structural features important for PAM action and the inhibition of action of ACh. The ‘deconstruction reconstruction and elaboration’ approach (see p.48) identified important structural features of dFBr that modify its actions as a PAM or an antagonist (NAM? or channel blocker?) at α4β2 nACh receptors. This information should be useful for the subsequent design of novel analogs to evaluate their potential for the treatment of neurological disorders associated with ACh
The evaluation of bone strength
Bone drilling is a major part of orthopaedic surgery performed during the internal fixation of fractured bones. At present, information related to drilling force, drilling torque, rate of drill bit penetration and drill bit rotational speed is not available to orthopaedic surgeons, clinicians and researchers as bone drilling is performed manually. This research demonstrates that bone drilling force data if recorded in-vivo, during the repair of bone fractures, can provide information about the strength/quality of the bone. Drilling force does not give a direct measure of bone strength; therefore it has been correlated with the shear strength and screw pullout strength to determine the efficacy in estimating the bone strength. Various synthetic bone material densities and animal bones have been tested to demonstrate the use of drilling force data. A novel automated experimental test rig, which enables drilling tests, screw insertion and screw pullout tests to be carried out in a controlled environment, has been developed. Both drilling and screw pullout tests have been carried out in a single setting of the specimen to reduce the experimental errors and increase repeatability of the results. A significantly high value of correlation (r² > 0.99) between drilling force & shear strength and also between drilling force & normalised screw pullout strength in synthetic bone material was found. Furthermore, a high value of correlation (r² = 0.958 for pig bones and r² = 0.901 for lamb bones) between maximum drilling force & normalised screw pullout strength was also found. The result shows that drilling data can be used to predict material strength. Bone screws are extensively used during the internal fixation of fractured bones. The amount of screw been tightened is one of the main factor which affects the bone-screw fixation quality. Over tightening of screw can result into the loss of bone-screw fixation strength, whereas under tightening can result in the screw loosening. Therefore, optimum tightening of the screw is important to achieve the maximum bone-screw fixation strength. At present, optimum tightening of the screw is entirely dependent upon the skill and judgment of the surgeon, which is predominantly based on the feel of the screw tightening torque. Various studies have been reported in the literature to develop an algorithm to set an optimum tightening torque value to be used in surgery. A method which is based on the use of rotation angle of the screw while tightening, rather than using screw insertion/tightening torque, to optimise the bone-screw fixation strength is proposed in this research. The effectiveness of the proposed method has been successfully demonstrated on the synthetic bone material using the designed test rig. The optimum angle for the tested screw was found to be 120° which is equivalent to 33% of the screw pitch.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Bone turnover markers in women can predict low bone mineral density
Background: Morbidity and mortality associated with osteoporosis continues to be high in India due to late diagnosis. This study aims to find the difference in the levels of bone turn over markers in premenopausal and postmenopausal women, in order to assess whether these markers can be used as predictors of low bone mineral density which can develop in later life.Methods: Study was conducted on 350 women aged 30-65 years. Women were classified into premenopausal and postmenopausal groups based on their menstrual history. Serum samples were analyzed for osteocalcin and telopeptide-C. Student’s t-test and logistic regression are used for statistical confirmations.Results: Levels of these markers (ng/ml) were found to be lower in premenopausal women (Osteocalcin = 9.0 ± 1.0; telopeptide-C = 0.270 ± 0.099) than in postmenopausal women (Osteocalcin = 9.8 ± 1.7; telopeptide-C = 0.490 ± 0.135) and this difference was found to be significant (P <0.001) for both the markers. In both the groups, telopeptide-C made significant contribution to prediction of low BMD [(Premenopausal group - odds ratio (OR) = 2.9; 95% confidence interval (95%CI) = 1.3-6.5 and postmenopausal group - OR = 9.6; 95%CI = 6.0-13.23) but osteocalcin could not (premenopausal group - OR = 0.91; 95%CI = 0.58-1.42 and postmenopausal group - OR = 0.87; 95%CI = 0.54-1.4)]. In premenopausal women increase in telopeptide-C by a unit increased chance of developing low BMD by 2.9 times while in postmenopausal women increase in telopeptide-C by a unit increased chance of developing low BMD by 9.6 times.Conclusion: Women with higher levels of telopeptide-C need to be identified at an early stage as it provides with an early warning of the possibility of future development of osteoporosis so that preventive measures can be taken timely.
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