Search results for: soft lenses

Authors: Van-Thanh Ho, Hyoungsoon Lee, Jaiyoung Ryu

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Efficient pressure distribution within soft robotic systems, specifically to the pneumatic artificial muscle (PAM) regions, is essential to minimize energy consumption. This optimization involves adjusting reservoir pressure, pipe diameter, and branching network layout to reduce flow speed and pressure drop while enhancing flow efficiency. The outcome of this optimization is a lightweight power source and reduced mechanical impedance, enabling extended wear and movement. To achieve this, a branching network system was created by combining pipe components and intricate cross-sectional area variations, employing the principle of minimal work based on a complete virtual human exosuit. The results indicate that modifying the cross-sectional area of the branching network, gradually decreasing it, reduces velocity and enhances momentum compensation, preventing flow disturbances at separation regions. These optimized designs achieve uniform velocity distribution (uniformity index > 94%) prior to entering the connection pipe, with a pressure drop of less than 5%. The design must also consider the length-to-diameter ratio for fluid dynamic performance and production cost. This approach can be utilized to create a comprehensive PAM system, integrating well-designed tube networks and complex pneumatic models.

Keywords: pneumatic artificial muscles, pipe networks, pressure drop, compressible turbulent flow, uniformity flow, murray's law

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Authors: Thapa Sirjana, Clifton R. Emery

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This paper examines the family order and Informal Social Control (ISC) by the extended families as a protective factor against Child Maltreatment. The findings are discussed using the main effects and the interaction effects of family order and informal social control by the extended families. The findings suggest that IPV mothers are associated with child abuse and child neglect. The children are neglected in the home more and physical abuse occurs in the case, if mothers are abused by their husbands. The mother’s difficulties of being abused may lead them to neglect their children. The findings suggest that ‘family order’ is a significant protective factor against child maltreatment. The results suggest that if the family order is neither too high nor too low than that can play a role as a protective factor. Soft type of ISC is significantly associated with child maltreatment. This study suggests that the soft type of ISC by the extended families is a helpful approach to develop child protection in both the countries. This study is analyzed the data collected from Seoul and Kathmandu families and neighborhood study (SKFNS). Random probability cluster sample of married or partnered women in 20 Kathmandu wards and in Seoul 34 dongs were selected using probability proportional to size (PPS) sampling. Overall, the study is to make a comparative study of Korea and Nepal and examine how the cultural differences and similarities associate with the child maltreatment.

Keywords: child maltreatment, intimate partner violence, informal social control and family order Seoul, Kathmandu

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Authors: Radovan Bures, Madgalena Streckova, Maria Faberova, Pavel Kurek

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Composite material based on Fe3Si micro-particles and Mn-Zn nano-ferrite was prepared using powder metallurgy technology. The sol-gel followed by autocombustion process was used for synthesis of Mn0.8Zn0.2Fe2O4 ferrite. 3 wt.% of mechanically milled ferrite was mixed with Fe3Si powder alloy. Mixed micro-nano powder system was homogenized by the Resonant Acoustic Mixing using ResodynLabRAM Mixer. This non-invasive homogenization technique was used to preserve spherical morphology of Fe3Si powder particles. Uniaxial cold pressing in the closed die at pressure 600 MPa was applied to obtain a compact sample. Microwave sintering of green compact was realized at 800°C, 20 minutes, in air. Density of the powders and composite was measured by Hepycnometry. Impulse excitation method was used to measure elastic properties of sintered composite. Mechanical properties were evaluated by measurement of transverse rupture strength (TRS) and Vickers hardness (HV). Resistivity was measured by 4 point probe method. Ferrite phase distribution in volume of the composite was documented by metallographic analysis. It has been found that nano-ferrite particle distributed among micro- particles of Fe3Si powder alloy led to high relative density (~93%) and suitable mechanical properties (TRS >100 MPa, HV ~1GPa, E-modulus ~140 GPa) of the composite. High electric resistivity (R~6.7 ohm.cm) of prepared composite indicate their potential application as soft magnetic material at medium and high frequencies.

Keywords: micro- and nano-composite, soft magnetic materials, microwave sintering, mechanical and electric properties

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Authors: Shuchi Bharti

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This article intends to analyse the transforming nature of state and corporate sector relationship in the light of evolving regulatory and institutional aspects pertaining to Corporate Social Responsibility (CSR) in India. The focus is on evaluating the accounts of law and decentred discourses, relevant within the changing regulatory and institutional paradigm that substantially goes ahead of formal legal control of state towards corporate actors. At this vantage point, it is important to understand the state’s posture towards a changing scenario particularly as the tone is set by regulatory parameters pertaining to CSR to drive process of engagement with the stakeholders. The tripartite framework of the article intends to focus on finding on the vital interconnected aspects of the CSR provisions (Section 135) of The Companies Act 2013 (The Act), rise of new institutions and the emergence of the decentred regulatory space. Thus is earmarked in a neo-liberal paradigm; state is witnessed to perform a responsive function in engendering enhanced public role for the corporate sector. In this overarching framework the aim is to undertake a causal, exploratory and relational analysis of aspects pertaining law, regulation and institutional transformations. Firstly, focus is drawn on to investigate the relational facets of the advent of law and regulatory framework of CSR. Secondly, in the light of the historical evolution, a causal connection is attempted between globalization, emergence of international soft law framework and the Indian case of CSR. Finally, I look into how the new Companies Act mandates CSR expenditure vis- a -vis multiple parameters and guidelines.

Keywords: corporate social responsibility, stakeholders, soft law, decentred regulation

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Authors: Oualid Walid Ben Ali

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Big Data has become one of the buzzwords today. The recent explosion of digital data has led the organization, either private or public, to a new era towards a more efficient decision making. At some point, business decided to use that concept in order to learn what make their clients tick with phrases like ‘sales funnel’ analysis, ‘actionable insights’, and ‘positive business impact’. So, it stands to reason that Big Data was viewed through green (read: money) colored lenses. Somewhere along the line, however someone realized that collecting and processing data doesn’t have to be for business purpose only, but also could be used for other purposes to assist law enforcement or to improve policing or in road safety. This paper presents briefly, how Big Data have been used in the fields of policing order to improve the decision making process in the daily operation of the police. As example, we present a big-data driven system which is sued to accurately dispatch the patrol cars in a geographic environment. The system is also used to allocate, in real-time, the nearest patrol car to the location of an incident. This system has been implemented and applied in the Emirate of Abu Dhabi in the UAE.

Keywords: big data, big data analytics, patrol car allocation, dispatching, GIS, intelligent, Abu Dhabi, police, UAE

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Authors: Julia Wimmers Klick

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Interprofessional Education (IPE) is widely recognized as a valuable approach in healthcare education, despite the challenges it presents. This study explores IP surface anatomy lab sessions, with a focus on fostering trust and collaboration among healthcare students. The research is conducted within the context of rural healthcare settings in British Columbia (BC), where a medical school and a physical therapy (PT) program operate under the Faculty of Medicine at the University of British Columbia (UBC). While IPE sessions addressing soft skills have been implemented, the integration of hard skills, such as Anatomy, remains limited. To address this gap, a pilot feasibility study was conducted with a positive outcome, a follow-up study involved these IPE sessions aimed at exploring the influence of bonding and trust between medical and PT students. Data were collected through focus groups comprising participating students and faculty members, and a structured SWOC (Strengths, Weaknesses, Opportunities, and Challenges) analysis was conducted. The IPE sessions, 3 in total, consisted of a 2.5-hour lab on surface anatomy, where PT students took on the teaching role, and medical students were newly exposed to surface anatomy. The focus of the study was on the relationship-building process and trust development between the two student groups, rather than assessing the acquisition of surface anatomy skills. Results indicated that the surface anatomy lab served as a suitable tool for the application and learning of soft skills. Faculty members observed positive outcomes, including productive interaction between students, reversed hierarchy with PT students teaching medical students, practicing active listening skills, and using a mutual language of anatomy. Notably, there was no grade assessment or external pressure to perform. The students also reported an overall positive experience; however, the specific impact on the development of soft skill competencies could not be definitively determined. Participants expressed a sense of feeling respected, welcomed, and included, all of which contributed to feeling safe. Within the small group environment, students experienced becoming a part of a community of healthcare providers that bonded over a shared interest in health professions education. They enjoyed sharing diverse experiences related to learning across their varied contexts, without fear of judgment and reprisal that were often intimidating in single professional contexts. During a joint Christmas party for both cohorts, faculty members observed students mingling, laughing, and forming bonds. This emphasized the importance of early bonding and trust development among healthcare colleagues, particularly in rural settings. In conclusion, the findings emphasize the potential of IPE sessions to enhance trust and collaboration among healthcare students, with implications for their future professional lives in rural settings. Early bonding and trust development are crucial in rural settings, where healthcare professionals often rely on each other. Future research should continue to explore the impact of content-concentrated IPE on the development of soft skill competencies.

Keywords: interprofessional education, rural healthcare settings, trust, surface anatomy

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Authors: El Hatka Hicham, Hafidi Youssef, Saghiri Khalid, Ittobane Najim

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Flexible polyurethane foam (FPUF) is a low-density cellular material generally used as a cushioning material in many applications such as furniture, bedding, packaging, etc. It is commercially produced during a continuous process, where a reactive mixture of foam chemicals is poured onto a moving conveyor. FPUFs are produced by the catalytic balancing of two reactions involved, the blowing reaction (isocyanate-water) and the gelation reaction (isocyanate-polyol). The microstructure of FPUF is generally composed of soft phases (polyol phases) and rigid domains that separate into two domains of different sizes: the rigid polyurea microdomains and the macrodomains (larger aggregates). The morphological features of FPUF are strongly influenced by the phase separation morphology that plays a key role in determining the global FPUF properties. This phase-separated morphology results from a thermodynamic incompatibility between soft segments derived from aliphatic polyether and hard segments derived from the commonly used aromatic isocyanate. In order to improve the properties of FPUF against the different stresses faced by this material during its use, we report in this work a study of the phase separation phenomenon in FPUF that has been examined using SAXS WAXS and FTIR. Indeed, we have studied with these techniques the effect of water, isocyanates, and alkaline chlorides on the phase separation behavior. SAXS was used to study the morphology of the microphase separated, WAXS to examine the nature of the hard segment packing, and FTIR to investigate the hydrogen bonding characteristics of the materials studied. The prepared foams were shown to have different levels of urea phase connectivity; the increase in water content in the FPUF formulation leads to an increase in the amount of urea formed and consequently the increase of the size of urea aggregates formed. Alkali chlorides (NaCl, KCl, and LiCl) incorporated into FPUF formulations show that is the ability to prevent hydrogen bond formation and subsequently alter the rigid domains. FPUFs prepared by different isocyanate structures showed that urea aggregates are difficult to be formed in foams prepared by asymmetric diisocyanate, while are more easily formed in foams prepared by symmetric and aliphatic diisocyanate.

Keywords: flexible polyurethane foam, hard segments, phase separation, soft segments

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Authors: Rajan Goyal, S. Lamba, S. Annapoorni

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The indirect exchange coupled system consists of two ferromagnetic layers separated by non-magnetic spacer layer. The type of exchange coupling may be either ferro or anti-ferro depending on the thickness of the spacer layer. In the present work, the strength of exchange coupling in FePt/Al₂O₃/Fe₃Pt has been investigated by varying the thickness of the spacer layer Al₂O₃. The FePt/Al₂O₃/Fe₃Pt trilayer structure is fabricated on Si <100> single crystal substrate using sputtering technique. The thickness of FePt and Fe₃Pt is fixed at 60 nm and 2 nm respectively. The thickness of spacer layer Al₂O₃ was varied from 0 to 16 nm. The normalized hysteresis loops recorded at room temperature both in the in-plane and out of plane configuration reveals that the orientation of easy axis lies along the plane of the film. It is observed that the hysteresis loop for ts=0 nm does not exhibit any knee around H=0 indicating that the hard FePt layer and soft Fe₃Pt layer are strongly exchange coupled. However, the insertion of Al₂O₃ spacer layer of thickness ts = 0.7 nm results in appearance of a minor knee around H=0 suggesting the weakening of exchange coupling between FePt and Fe₃Pt. The disappearance of knee in hysteresis loop with further increase in thickness of the spacer layer up to 8 nm predicts the co-existence of ferromagnetic (FM) and antiferromagnetic (AFM) exchange interaction between FePt and Fe₃Pt. In addition to this, the out of plane hysteresis loop also shows an asymmetry around H=0. The exchange field Hex = (Hc↑-HC↓)/2, where Hc↑ and Hc↓ are the coercivity estimated from lower and upper branch of hysteresis loop, increases from ~ 150 Oe to ~ 700 Oe respectively. This behavior may be attributed to the uncompensated moments in the hard FePt layer and soft Fe₃Pt layer at the interface. A better insight into the variation in indirect exchange coupling has been investigated using recoil curves. It is observed that the almost closed recoil curves are obtained for ts= 0 nm up to a reverse field of ~ 5 kOe. On the other hand, the appearance of appreciable open recoil curves at lower reverse field ~ 4 kOe for ts = 0.7 nm indicates that uncoupled soft phase undergoes irreversible magnetization reversal at lower reverse field suggesting the weakening of exchange coupling. The openness of recoil curves decreases with increase in thickness of the spacer layer up to 8 nm. This behavior may be attributed to the competition between FM and AFM exchange interactions. The FM exchange coupling between FePt and Fe₃Pt due to porous nature of Al₂O₃ decreases much slower than the weak AFM coupling due to interaction between Fe ions of FePt and Fe₃Pt via O ions of Al₂O₃. The hysteresis loop has been simulated using Monte Carlo based on Metropolis algorithm to investigate the variation in strength of exchange coupling in FePt/Al₂O₃/Fe₃Pt trilayer system.

Keywords: indirect exchange coupling, MH loop, Monte Carlo simulation, recoil curve

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Authors: José Francisco Urrutia Reyes, Judith Espinosa Real

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This paper is meant to re-examine the role of street art in the contemporary world. By studying this form of art in Brussels, it can be explained how murals show the socio-political reality of a given community and influence on its interaction. Through the definitions of street art, murals and street artists, and analysing their role in Brussels, it is possible to understand how this counter culture movement serves as an engine of social development, as it interacts with its surroundings sending a clear message to a wider audience. Street art impacts on its environment because it interacts with the people who occupies the day-to-day public space. This has proven to be effective in the arouse of social consciousness, up to the point of being adopted by the government of Brussels to promote social movements such as the AIDS-HIV campaign along with the Plate-Forme Prévention Sida. It can be concluded that street art has evolved since its vandalic beginnings, to become a form of art that has not lost it counter official status, but now has a critical vision that can promote social awakening. Street art is now a global trend that uses visual inputs to create a positive impact.

Keywords: street art, Brussels, social impact, political perspective

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Authors: Kayode Festus Oyedele, Sunday Oladele, Adaora Chibundu Nduka

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The subsurface of a proposed site for building development in Mowe, Nigeria, using Standard Penetration Test (SPT) and Cone Penetrometer Test (CPT) supplemented with Horizontal Electrical Profiling (HEP) was investigated with the aim of evaluating the suitability of the strata for foundation materials. Four SPT and CPT were implemented using 10 tonnes hammer. HEP utilizing Wenner array were performed with inter-electrode spacing of 10 – 60 m along four traverses coincident with each of the SPT and CPT. The HEP data were processed using DIPRO software and textural filtering of the resulting resistivity sections was implemented to enable delineation of hidden layers. Sandy lateritic clay, silty lateritic clay, clay, clayey sand and sand horizons were delineated. The SPT “N” value defined very soft to soft sandy lateritic (<4), stiff silty lateritic clay (7 – 12), very stiff silty clay (12 - 15), clayey sand (15- 20) and sand (27 – 37). Sandy lateritic clay (5-40 kg/cm2) and silty lateritic clay (25 - 65 kg/cm2) were defined from the CPT response. Sandy lateritic clay (220-750 Ωm), clay (< 50 Ωm) and sand (415-5359 Ωm) were delineated from the resistivity sections with two thin layers of silty lateritic clay and clayey sand defined in the texturally filtered resistivity sections. This study concluded that the presence of incompetent thick clayey materials (18 m) beneath the study area makes it unsuitable for shallow foundation. Deep foundation involving piling through the clayey layers to the competent sand at 20 m depth was recommended.

Keywords: cone penetrometer, foundation, lithologic texture, resistivity section, standard penetration test

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Authors: Gabrielle Holt

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This paper is looking to prove the efficacy of the Schulte Holt IOL Toric Calculator Processor (Schulte Holt ITCP). It has been completed using manually inputted data into the Barrett Toric Calculator and comparing the number of minutes taken to complete the Toric calculations, the number of errors identified during completion, and distractions during completion. It will then compare that data to the number of minutes taken for the Schulte Holt ITCP to complete also, using the Barrett method, as well as the number of errors identified in the Schulte Holt ITCP. The data clearly demonstrate a momentous advantage to the Schulte Holt ITCP and notably reduces time spent doing Toric Calculations, as well as reducing the number of errors. With the ever-growing number of cataract surgeries taking place around the world and the waitlists increasing -the Schulte Holt IOL Toric Calculator Processor may well demonstrate a way forward to increase the availability of ophthalmologists and ophthalmic staff while maintaining patient safety.

Keywords: Toric, toric lenses, ophthalmology, cataract surgery, toric calculations, Barrett

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Authors: John Joseph S. Martis, Rohanchandra R. Gatty, Aaron Jose Fernandes, Rahul P. Nambiar

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Introduction: Surgery for breast cancer is either mastectomy or breast conservation surgery. The most commonly used incision for modified radical mastectomy is the transverse Stewart incision. But this incision may have the disadvantage of causing disparity between the closure lines of superior and inferior skin flaps in mastectomy and can cause overhanging of soft tissue below and behind the axilla. The curvizigzag incision, on principle, may help in this regard and can prevent scar migration beyond the anterior axillary line. This study aims to compare the two incisions in this regard. Methods: 100 patients with cancer of breast were included in the study after satisfying inclusion and exclusion criteria. They underwent surgery at Father Muller Medical College, Mangalore, India, between November 2019 to September 2021. The patients were divided into two groups. Group A patients were subjected to modified radical mastectomy with curvizigzag incision and group B patients with transverse Stewart incision. Results: Seroma on postoperative day1, day 2 was 0% in both the groups. Seroma on postoperative day 30 was present in 14% of patients in group B. 60% of patients in group B had sag of soft tissue below and behind the axilla, and none of the patients in group A had this problem. In 64% of the patients in group B, the incision crossed the anterior axillary fold, 64% of the patients in group B had tension in the incision site while approximation of the skin flaps. Conclusion: Curvizigzag incision is statistically better with lesser complications when compared to the transverse Stewart incision for modified radical mastectomy for carcinoma breast.

Keywords: breast cancer, curvizigzag incision, transverse Stewart incision, seroma, modified radical mastectomy

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Authors: Rosaline Govender

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This research study is an exploration of the self-directed professional development of teachers who teach in public schools in an era of democracy and educational change in South Africa. Amidst an ever-changing educational system, the teachers in this study position themselves as self-directed teacher-learners where they adopt particular learning practices which enable change within the broader discourses of public schooling. Life-story interviews were used to enter into the private and public spaces of five teachers which offer glimpses of how particular systems shaped their identities, and how the meanings of self-directed teacher-learner shaped their learning practices. Through the Multidimensional framework of analysis and interpretation the teachers’ stories were analysed through three lenses: restorying the field texts - the self through story; the teacher-learner in relation to social contexts, and practices of self-directed learning.This study shows that as teacher-learners learn for change through self-directed learning practices, they develop their agency as transformative intellectuals, which is necessary for the reworking of South African public schools.

Keywords: professional development, professionality, professionalism, self-directed learning

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Authors: Orod Zarrin, Mohesn Ramezan Shirazi, Hassan Moniri

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The use of pile foundations technique is developed to support structures and buildings on soft soil. The most important dynamic load that can affect the pile structure is earthquake vibrations. Pile foundations during earthquake excitation indicate that piles are subject to damage by affecting the superstructure integrity and serviceability. During an earthquake, two types of stresses can damage the pile head, inertial load that is caused by superstructure and deformation which caused by the surrounding soil. Soil deformation and inertial load are associated with the acceleration developed in an earthquake. The acceleration amplitude at the ground surface depends on the magnitude of earthquakes, soil properties and seismic source distance. According to the investigation, the damage is between the liquefiable and non-liquefiable layers and also soft and stiff layers. This damage crushes the pile head by increasing the inertial load which is applied by the superstructure. On the other hand, the cracks on the piles due to the surrounding soil are directly related to the soil profile and causes cracks from small to large. However, the large cracks reason have been listed such as liquefaction, lateral spreading, and inertial load. In the field of designing, elastic response of piles is always a challenge for designer in liquefaction soil, by allowing deflection at top of piles. Moreover, absence of plastic hinges in piles should be insured, because the damage in the piles is not observed directly. In this study, the performance and behavior of pile foundations during liquefaction and lateral spreading are investigated. In addition, emphasize on the soil behavior in the liquefiable and non-liquefiable layers by different aspect of piles damage such as ranking, location and degree of damage are going to discuss.

Keywords: pile, earthquake, liquefaction, non-liquefiable, damage

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Authors: Varun Kumar, Chandra Shakher

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Micro-optical components such as microlenses and microlens array have numerous engineering and industrial applications for collimation of laser diodes, imaging devices for sensor system (CCD/CMOS, document copier machines etc.), for making beam homogeneous for high power lasers, a critical component in Shack-Hartmann sensor, fiber optic coupling and optical switching in communication technology. Also micro-optical components have become an alternative for applications where miniaturization, reduction of alignment and packaging cost are necessary. The compliance with high-quality standards in the manufacturing of micro-optical components is a precondition to be compatible on worldwide markets. Therefore, high demands are put on quality assurance. For quality assurance of these lenses, an economical measurement technique is needed. For cost and time reason, technique should be fast, simple (for production reason), and robust with high resolution. The technique should provide non contact, non-invasive and full field information about the shape of micro- optical component under test. The interferometric techniques are noncontact type and non invasive and provide full field information about the shape of the optical components. The conventional interferometric technique such as holographic interferometry or Mach-Zehnder interferometry is available for characterization of micro-lenses. However, these techniques need more experimental efforts and are also time consuming. Digital holography (DH) overcomes the above described problems. Digital holographic microscopy (DHM) allows one to extract both the amplitude and phase information of a wavefront transmitted through the transparent object (microlens or microlens array) from a single recorded digital hologram by using numerical methods. Also one can reconstruct the complex object wavefront at different depths due to numerical reconstruction. Digital holography provides axial resolution in nanometer range while lateral resolution is limited by diffraction and the size of the sensor. In this paper, Mach-Zehnder based digital holographic interferometric microscope (DHIM) system is used for the testing of transparent microlenses. The advantage of using the DHIM is that the distortions due to aberrations in the optical system are avoided by the interferometric comparison of reconstructed phase with and without the object (microlens array). In the experiment, first a digital hologram is recorded in the absence of sample (microlens array) as a reference hologram. Second hologram is recorded in the presence of microlens array. The presence of transparent microlens array will induce a phase change in the transmitted laser light. Complex amplitude of object wavefront in presence and absence of microlens array is reconstructed by using Fresnel reconstruction method. From the reconstructed complex amplitude, one can evaluate the phase of object wave in presence and absence of microlens array. Phase difference between the two states of object wave will provide the information about the optical path length change due to the shape of the microlens. By the knowledge of the value of the refractive index of microlens array material and air, the surface profile of microlens array is evaluated. The Sag of microlens and radius of curvature of microlens are evaluated and reported. The sag of microlens agrees well within the experimental limit as provided in the specification by the manufacturer.

Keywords: micro-optics, microlens array, phase map, digital holographic interferometric microscopy

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Authors: Sanjay K. Behera, Debasish Saha, Paramesh Gadige, Ranjini Bandyopadhyay

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The zero shear viscosity (η₀) of a suspension of hard sphere colloids characterized by a significant polydispersity (≈10%) increases with increase in volume fraction (ϕ) and shows a dramatic increase at ϕ=ϕg with the system entering a colloidal glassy state. Fragility which is the measure of the rapidity of approach of these suspensions towards the glassy state is sensitive to its size polydispersity and stiffness of the particles. Soft poly(N-isopropylacrylamide) (PNIPAM) particles deform in the presence of neighboring particles at volume fraction above the random close packing volume fraction of undeformed monodisperse spheres. Softness, therefore, enhances the packing efficiency of these particles. In this study PNIPAM particles of a nearly constant swelling ratio and with polydispersities varying over a wide range (7.4%-48.9%) are synthesized to study the effects of polydispersity on the dynamics of suspensions of soft PNIPAM colloidal particles. The size and polydispersity of these particles are characterized using dynamic light scattering (DLS) and scanning electron microscopy (SEM). As these particles are deformable, their packing in aqueous suspensions is quantified in terms of effective volume fraction (ϕeff). The zero shear viscosity (η₀) data of these colloidal suspensions, estimated from rheometric experiments as a function of the effective volume fraction ϕeff of the suspensions, increases with increase in ϕeff and shows a dramatic increase at ϕeff = ϕ₀. The data for η₀ as a function of ϕeff fits well to the Vogel-Fulcher-Tammann equation. It is observed that increasing polydispersity results in increasingly fragile supercooled liquid-like behavior, with the parameter ϕ₀, extracted from the fits to the VFT equation shifting towards higher ϕeff. The observed increase in fragility is attributed to the prevalence of dynamical heterogeneities (DHs) in these polydisperse suspensions, while the simultaneous shift in ϕ₀ is ascribed to the decoupling of the dynamics of the smallest and largest particles. Finally, it is observed that the intrinsic nonlinearity of these suspensions, estimated at the third harmonic near ϕ₀ in Fourier transform oscillatory rheological experiments, increases with increase in polydispersity. These results are in agreement with theoretical predictions and simulation results for polydisperse hard sphere colloidal glasses and clearly demonstrate that jammed suspensions of polydisperse colloidal particles can be effectively fluidized with increasing polydispersity. Suspensions of these particles are therefore excellent candidates for detailed experimental studies of the effects of polydispersity on the dynamics of glass formation.

Keywords: dynamical heterogeneity, effective volume fraction, fragility, intrinsic nonlinearity

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Authors: Alaa Fezai, Anuj Sharma, Wolfgang Mueller-Hirsch, André Zimmermann

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Viscoelastic materials have been widely used in the automotive industry over the last few decades with different functionalities. Besides their main application as a simple and efficient surface damping treatment, they may ensure optimal operating conditions for on-board electronics as thermal interface or sealing layers. The dynamic behavior of viscoelastic materials is generally dependent on many environmental factors, the most important being temperature and strain rate or frequency. Prior to the reliability analysis of systems including viscoelastic layers, it is, therefore, crucial to accurately predict the dynamic and lifetime behavior of these materials. This includes the identification of the dynamic material parameters under critical temperature and frequency conditions along with a precise damage localization and identification methodology. The goal of this work is twofold. The first part aims at applying an inverse viscoelastic material-characterization approach for a wide frequency range and under different temperature conditions. For this sake, dynamic measurements are carried on a single lap joint specimen using an electrodynamic shaker and an environmental chamber. The specimen consists of aluminum beams assembled to adapter plates through a viscoelastic adhesive layer. The experimental setup is reproduced in finite element (FE) simulations, and frequency response functions (FRF) are calculated. The parameters of both the generalized Maxwell model and the fractional derivatives model are identified through an optimization algorithm minimizing the difference between the simulated and the measured FRFs. The second goal of the current work is to guarantee an on-line detection of the damage, i.e., delamination in the viscoelastic bonding of the described specimen during frequency monitored end-of-life testing. For this purpose, an inverse technique, which determines the damage location and size based on the modal frequency shift and on the change of the mode shapes, is presented. This includes a preliminary FE model-based study correlating the delamination location and size to the change in the modal parameters and a subsequent experimental validation achieved through dynamic measurements of specimen with different, pre-generated crack scenarios and comparing it to the virgin specimen. The main advantage of the inverse characterization approach presented in the first part resides in the ability of adequately identifying the material damping and stiffness behavior of soft viscoelastic materials over a wide frequency range and under critical temperature conditions. Classic forward characterization techniques such as dynamic mechanical analysis are usually linked to limitations under critical temperature and frequency conditions due to the material behavior of soft viscoelastic materials. Furthermore, the inverse damage detection described in the second part guarantees an accurate prediction of not only the damage size but also its location using a simple test setup and outlines; therefore, the significance of inverse numerical-experimental approaches in predicting the dynamic behavior of soft bonding layers applied in automotive electronics.

Keywords: damage detection, dynamic characterization, inverse approaches, vibration testing, viscoelastic layers

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Authors: Adila Shaukat, Hussam Al Soub, Muna Al Maslamani, Abdullatif Al Khal

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Background: The aim of this study was to assess clinical presentation and antimicrobial susceptibility of Streptococcus (S.) anginosus group infections in Hamad General Hospital, a tertiary care hospital in the state of Qatar, which is a multinational community. The S. anginosus group is a subgroup of viridans streptococci that consist of 3 different species: S. anginosus, S. constellatus, and S. intermedius. Although a part of the human bacteria flora, they have potential to cause suppurative infections. Method: We studied a total of 101 patients with S. anginosus group infections from January 2006 until March 2012 by reviewing medical records and identification of organisms by VITEK 2 and MALDI-TOF. Results: The most common sites of infection were skin and soft tissue, intra-abdominal, and bacteremia (28.7%, 24.8%, and 22.7%, respectively). Abscess formation was seen in approximately 30% of patients. Streptococcus constellatus was the most common isolated species (40%) followed by S. anginosus(30%) and S. intermedius(7%). In 23% of specimens, the species was unidentified. The most common type of specimen for organism isolation was blood followed by pus and tissue (50%, 22%, and 8%, respectively). Streptococcus constellatus was more frequently associated with abdominal and skin and soft tissue infections than the other 2 species, whereas S. anginosus was isolated more frequently from blood. All isolates were susceptible to penicillin, ceftriaxone, and vancomycin. Susceptibility to erythromycin and clindamycin was also good, reaching 91% and 95%, respectively. Forty percent of patients needed surgical drainage along with antibiotic therapy. Conclusions: Identification of S. anginosus group to species level is helpful in clinical practice because different species exhibit different pathogenic potentials.

Keywords: abscess, bacterial infection, bacteremia, Streptococcus anginosus

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Authors: Albert Suryaprawira

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The Nasion-Sella Line (NSL) has been used for several years as a reference line in longitudinal growth study. Therefore this line is considered to be stable not only to evaluate treatment outcome and to predict relapse possibility but also to manage prognosis. This is a radiographic superimposition of an adult male aged 19 years who complained of difficulty in aesthetic, talking and chewing. Patient has a midface hypoplasia profile (concave). He was diagnosed to have a severe Skeletal Class III with Class III malocclusion, increased lower vertical height, and an anterior open bite. A pre-treatment cephalometric radiograph was taken to analyse the skeletal problem and to measure the amount of bone movement and the prediction soft tissue response. A panoramic radiograph was also taken to analyse bone quality, bone abnormality, third molar impaction, etc. Before the surgery, a pre-surgical cephalometric radiograph was taken to re-evaluate the plan and to settle the final amount of bone cut. After the surgery, a post-surgical cephalometric radiograph was taken to confirm the result with the plan. The superimposition using NSL as a reference line between those radiographs was performed to analyse the outcome. It is important to describe the amount of hard and soft tissue movement and to predict the possibility of relapse after the surgery. The patient also needs to understand all the surgical plan, outcome and relapse prevention. The surgical management included maxillary impaction and advancement of Le Fort I osteotomy. The evaluation using NSL as a reference was a very useful method in determining the outcome and prognosis.

Keywords: Nasion-Sella Line, midface hypoplasia, Le Fort 1, maxillary advancement

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Authors: David Ryan, Martin Breugst, Turlough Downes, Peter A. Byrne, Gerard P. McGlacken

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An ambident nucleophile is a nucleophile that possesses two or more distinct nucleophilic sites that are linked through resonance and are effectively “in competition” for reaction with an electrophile. Examples include enolates, pyridone anions, and nitrite anions, among many others. Reactions of ambident nucleophiles and electrophiles are extremely prevalent at all levels of organic synthesis. The principle of hard and soft acids and bases (the “HSAB principle”) is most commonly cited in the explanation of selectivities in such reactions. Although this rationale is pervasive in any discussion on ambident reactivity, the HSAB principle has received considerable criticism. As a result, the principle’s supplantation has become an area of active interest in recent years. This project focuses on developing a model for rationalizing ambident reactivity. Presented here is an approach that incorporates computational calculations and experimental kinetic data to construct Gibbs energy profile diagrams. The preferred site of alkylation of nitrite anion with a range of ‘hard’ and ‘soft’ alkylating agents was established by ¹H NMR spectroscopy. Pseudo-first-order rate constants were measured directly by ¹H NMR reaction monitoring, and the corresponding second-order constants and Gibbs energies of activation were derived. These, in combination with computationally derived standard Gibbs energies of reaction, were sufficient to construct Gibbs energy wells. By representing the ambident system as a series of overlapping Gibbs energy wells, a more intuitive picture of ambident reactivity emerges. Here, previously unexplained switches in reactivity in reactions involving closely related electrophiles are elucidated.

Keywords: ambident, Gibbs, nucleophile, rates

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Authors: Sarah Kinyanjui, Mahnaaz Mohamed

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The child justice system in Kenya is organically departing from a managerial and retributive model to one that espouses restorative justice. Notably, the Children Act 2001, and the most recent, Children Act 2022, signalled an aspiration to facilitate meaningful interventions as opposed to ‘processing’ children through the justice system. In this vein, the Children Act 2022 formally recognises diversion and provides modalities for its implementation. This paper interrogates the diversion promise and reflects on the implementation of diversion as envisaged by the 2022 Act. Using restorative justice, labelling and differential association theories as well as the value of care lenses, the paper discusses diversion as a meaningful response to child offending. It further argues that while diversion presents a strong platform for the realisation of the restorative and rehabilitative ideals, in the absence of a well-planned, coordinated, and resourced framework, diversion may remain a mere alternative ‘conveyor belt’. Strategic multi-agency planning, capacity building and cooperation are highlighted as essential minimums for the realisation of the goals of diversion.

Keywords: diversion for child offenders, restorative justice, responsive criminal justice system, children act 2022 kenya

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Authors: Seyedeh Mehri Hamidi, Nasrin Asgari, Foozieh Sohrabi, Mohammad Ali Ansari

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New neuro plasmonic sensor based on one dimensional plasmonic nano-grating has been prepared. To record neural activity, the sample has been exposed under different infrared laser and then has been calculated by ellipsometry parameters. Our results show that we have efficient sensitivity to different laser excitation.

Keywords: neural activity, Plasmonic sensor, Nanograting, Gold thin film

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Authors: Yau-Luen Ng, Nathan Banka, Santosh Devasia

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In this paper, a method based on soft artificial cilia is introduced to separate particles based on size and mass. In nature, cilia are used for fluid propulsion in the mammalian circulatory system, as well as for swimming and size-selective particle entrainment for feeding in microorganisms. Inspired by biological cilia, an array of artificial cilia was fabricated using Polydimethylsiloxane (PDMS) to simulate the actual motion. A row of four individually-controlled magnetic artificial cilia in a semi-circular channel are actuated by the magnetic fields from four permanent magnets. Each cilium is a slender rectangular cantilever approximately 13mm long made from a composite of PDMS and carbonyl iron particles. A time-varying magnetic force is achieved by periodically varying the out-of-plane distance from the permanent magnets to the cilia, resulting in large-amplitude deflections of the cilia that can be used to drive fluid motion. Previous results have shown that this system of individually-controlled magnetic cilia can generate effective mixing flows; the purpose of the present work is to apply the individual cilia control to a particle separation task. Based on the observed beating patterns of cilia arrays in nature, the experimental beating patterns were selected as a metachronal wave, in which a fixed phase lead or lag is imposed between adjacent cilia. Additionally, the beating frequency was varied. For each set of experimental parameters, the channel was filled with water and polyethylene microspheres introduced at the center of the cilia array. Two types of particles were used: large red microspheres with density 0.9971 g/cm³ and 850-1000 μm avg. diameter, and small blue microspheres with density 1.06 g/cm³ and diameter 30 μm. At low beating frequencies, all particles were propelled in the mean flow direction. However, the large particles were observed to reverse directions above about 4.8 Hz, whereas reversal of the small particle transport direction did not occur until 6 Hz. Between these two transition frequencies, the large and small particles can be separated as they move in opposite directions. The experimental results show that selecting an appropriate cilia beating pattern can lead to selective transport of neutrally-buoyant particles based on their size. Importantly, the separation threshold can be chosen dynamically by adjusting the actuation frequency. However, further study is required to determine the range of particle sizes that can be effectively separated for a given system geometry.

Keywords: magnetic cilia, particle separation, tunable separation, soft actutors

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Authors: M. L. Burnwal, P. Raychowdhury

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Earthquake leads to adverse effects on buildings resting on soft soils. Mitigating the response of shallow foundations on soft soil with different methods reduces settlement and provides foundation stability. Few methods such as the rocking foundation (used in Performance-based design), deep foundation, prefabricated drain, grouting, and Vibro-compaction are used to control the pore pressure and enhance the strength of the loose soils. One of the problems with these methods is that the settlement is uncontrollable, leading to differential settlement of the footings, further leading to the collapse of buildings. The present study investigates the utility of geosynthetics as a potential improvement of the subsoil to reduce the earthquake-induced settlement of structures. A steel moment-resisting frame building resting on loose liquefiable dry soil, subjected to Uttarkashi 1991 and Chamba 1995 earthquakes, is used for the soil-structure interaction (SSI) analysis. The continuum model can simultaneously simulate structure, soil, interfaces, and geogrids in the OpenSees framework. Soil is modeled with PressureDependentMultiYield (PDMY) material models with Quad element that provides stress-strain at gauss points and is calibrated to predict the behavior of Ganga sand. The model analyzed with a tied degree of freedom contact reveals that the system responses align with the shake table experimental results. An attempt is made to study the responses of footing structure and geosynthetics with unreinforced and reinforced bases with varying parameters. The result shows that geogrid reinforces shallow foundation effectively reduces the settlement by 60%.

Keywords: settlement, shallow foundation, SSI, continuum FEM

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Authors: Alexander Machikhin, Olga Polschikova, Vitold Pozhar, Alina Ramazanova

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White-light quantitative phase imaging is an effective technique for achieving sub-nanometer phase sensitivity. Highly stable interferometers based on common-path geometry have been developed in recent years to solve this task. Some of these methods also apply multispectral approach. The purpose of this research is to suggest a simple and effective interferometer for such systems. We developed a three-lens common-path interferometer, which can be used for quantitative phase imaging with or without multispectral modality. The lens system consists of two components, the first one of which is a compound lens, consisting of two lenses. A pinhole is placed between the components. The lens-in-lens approach enables effective light transmission and high stability of the interferometer. The multispectrality is easily implemented by placing a tunable filter in front of the interferometer. In our work, we used an acousto-optical tunable filter. Some design considerations are discussed and multispectral quantitative phase retrieval is demonstrated.

Keywords: acousto-optical tunable filter, common-path interferometry, digital holography, multispectral quantitative phase imaging

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Authors: Paria Baharvand, Mohammad Reza Abbasi, Soha Namazi

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Introduction: Uremic pruritus (UP) is one of the major complaints in hemodialysis patients. The aim of this randomized clinical trial study was the evaluation of the anti-pruritus effect of Melatonin on hemodialysis patients with UP. Methods: This multi-centered double, blinded randomized clinical trial study was conducted on hemodialysis patients with UP that referred to the dialysis department of Imam Khomeini Hospital, Labbafinezhad Hospital and Ghiasi Hospital in Tehran, Iran, in 2018. Forty participants were enrolled and block randomization was performed by using a randomized list and divided into 2 groups of twenty patients. Evaluation of the 12-Item Pruritus Severity Scale (12-PSS), Visual analog scale (VAS), and Calculation of the affected body surface area for pruritus extent (BSA %) was performed every week. The Melatonin group received a 10 mg soft gel capsule, and the placebo group received a soft gel capsule placebo after dinner. For statistical analysis used by SPSS version 21(IRCT20180714040462N1). Results: 38 hemodialysis patients enrolled in this study. The mean age in the placebo group and in the Melatonin group was 55.88 ± 11.70 and 54.52 ± 13.00 years (p> 0.05). Also, 46% of all participants were female. Aspartate transaminase, alanine transaminase and C-reactive protein have significant differences between the two groups (p< 0.05). VAS score reduction in the two groups had a statistically significant (CI 95% = -1.71, P= 0.015(.The results of BSA% showed Melatonin had a significant effect on the decrease of the pruritus extent compared to placebo (CI 95% = -22.82, P= 0.001(. Conclusion: According to the results of this study and the preliminary effects of Melatonin on uremic pruritus, we suggest performing advanced clinical trials studies.

Keywords: Melatonin, Uremic Pruritus, hemodialysis, anti-pruritus

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Authors: Hayden R Schott, John M Felder III

Abstract:

Introduction: Chronic lower extremity wounds in the diabetic and vasculopathic populations are associated with a high degree of morbidity.When wounds require more extensive treatment than can be offered by wound care centers, more aggressive solutions involve local tissue transfer and microsurgical free tissue transfer for achieving definitive soft tissue coverage. These procedures of autologous tissue transfer (ATT) offer resilient, soft tissue coverage of limb-threatening wounds and confer promising limb salvage rates. However, chronic osteomyelitis and recalcitrant soft tissue infections are common in severe diabetic foot wounds and serve to significantly complicate ATT procedures. Stimulan is a resorbable calcium sulfate antibiotic carrier. The use of stimulan antibiotic beads to treat chronic osteomyelitis is well established in the orthopedic and plastic surgery literature. In these procedures, the beads are placed beneath the skin flap to directly deliver antibiotics to the infection site. The purpose of this study was to quantify the success of Stimulan antibiotic beads in treating recalcitrant infections in patients with diabetic foot wounds receiving ATT. Methods: A retrospective review of clinical and demographic information was performed on patients who underwent ATT with the placement of Stimulan antibiotic beads for attempted limb salvage from 2018-21. Patients were analyzed for preoperative wound characteristics, demographics, infection recurrence, and adverse outcomes as a result of product use. The primary endpoint was 90 day infection recurrence, with secondary endpoints including 90 day complications. Outcomes were compared using basic statistics and Fisher’s exact tests. Results: In this time span, 14 patients were identified. At the time of surgery, all patients exhibited clinical signs of active infection, including positive cultures and erythema. 57% of patients (n=8) exhibited chronic osteomyelitis prior to surgery, and 71% (n=10) had exposed bone at the wound base. In 57% of patients (n=8), Stimulan beads were placed beneath a free tissue flap and beneath a pedicle tissue flap in 42% of patients (n=6). In all patients, Stimulan beads were only applied once. Recurrent infections were observed in 28% of patients (n=4) at 90 days post-op, and flap nonadherence was observed in 7% (n=1). These were the only Stimulan related complications observed. Ultimately, lower limb salvage was successful in 85% of patients (n=12). Notably, there was no significant association between the preoperative presence of osteomyelitis and recurrent infections. Conclusions: The use of Stimulanantiobiotic beads to treat recalcitrant infections in patients receiving definitive skin coverage of diabetic foot wounds does not appear to demonstrate unnecessary risk. Furthermore, the lack of significance between the preoperative presence of osteomyelitis and recurrent infections indicates the successful use of Stimulan to dampen infection in patients with osteomyelitis, as is consistent with the literature. Further research is needed to identify Stimulan as the significant contributor to infection treatment using future cohort and case control studies with more patients. Nonetheless, the use of Stimulan antibiotic beads in patients with diabetic foot wounds demonstrates successful infection suppression and maintenance of definitive soft tissue coverage.

Keywords: wound care, stimulan antibiotic beads, free tissue transfer, plastic surgery, wound, infection

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Authors: Leila M. Carvalho, Maria Erica S. Oliveira, Arnoud C. Neto, Elza I. Ida, Massami Shimokomaki, Marta S. Madruga

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The quality of broiler breast meat is changing as a result of the continuing emphasis on genetic selection for a more efficient meat production. Breast meat has been classified as PSE (pale, soft, exudative), DFD (dark, firm, dry) and normal color meat, and recently a third group has emerged: the so-called PFN (pale, firm, non-exudative) meat. This classification was based on pH, color and functional properties. The aim of this work was to confirm the existence of PFN and PSE meat by biochemical characterization and functional properties. Twenty four hours of refrigerated fillet, Pectoralis major, m. samples (n= 838) were taken from Cobb flocks 42-48 days old, obtained in Northeastern Brazil tropical region, the Northeastern, considered to have only dry and wet seasons. Color (L*), pH, water holding capacity (WHC), values were evaluated and compared with PSE group samples. These samples were classified as Normal (465.8), PSE meat (L*≥53; pH<5.8) and PFN (L*≥53; pH>5.8). The occurrence of control meat, PSE and PFN was 69.09%, 11.10% and 19.81%, respectively. Samples from PFN presented 4.0-5.0% higher WHC in relation to PSE meat and similar to control group. These results are explained by the fact that PSE meat syndrome occurs because of higher protein denaturation as the consequence of a simultaneous lower pH values under warm carcass sooner after slaughtering impairing the myofibril proteins functional properties. Conversely, PFN samples follow normal glycolysis rate maintaining the normal proteins activities. In conclusion, the results reported herein confirm the existence of this emerging broiler meat group with similar properties as control group and it should be considered as normal breast meat group.

Keywords: broiler breast meat, funcional properties, PFN, PSE

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Authors: Muhammad Hamza

Abstract:

This study attempts to analyze the social media reports regarding Covid-19 that impacted the psyche of Pakistanis. This Study is delimited to hashtags from Tweets on a social media platform. During Covid-19, it has been observed that it affected the psychological conditions of Pakistanis. With the application of the three-dimensional model presented by Fairclough, together with a data analytic software “FireAnt” i.e., social media and data analysis toolkit, which is used to filter, identify, report and export data from social media accurately. A detailed and explicit exploration of the various hashtags by users from different fields was conducted. This study conducted a quantitative as well as qualitative methods of analysis. The study examined the perspectives of the Pakistanis behind the use of various hashtags with the lenses of Critical Discourse Analysis (CDA). While conducting this research, CDA was helpful to reveal the connection between the psyche of the people and the Covid-19 pandemic. It was found that how different Pakistanis used social media and how Covid-19 impacted their psyche. After collecting and analyzing the hashtags from twitter it was concluded that majority of people received negative impact from social media reports, while, some people used their hashtags positively and were found positive during Covid-19, and some people were found neutral.

Keywords: Covid, Covid-19, psyche, Covid Pakistan

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Authors: Duvert A. Puentes T., Javier A. Maldonado E., Ivan Quintero., Diego F. Villegas

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Mechanical Computation is a great tool to study the performance of complex models. An example of it is the study of the human body structure. This paper took advantage of different types of software to make a 3D model of the glenohumeral joint and apply a finite element analysis. The main objective was to study the change in the biomechanical properties of the joint when it presents an injury. Specifically, a BANKART lesion, which consists in the detachment of the anteroinferior labrum from the glenoid. Stress and strain distribution of the soft tissues were the focus of this study. First, a 3D model was made of a joint without any pathology, as a control sample, using segmentation software for the bones with the support of medical imagery and a cadaveric model to represent the soft tissue. The joint was built to simulate a compression and external rotation test using CAD to prepare the model in the adequate position. When the healthy model was finished, it was submitted to a finite element analysis and the results were validated with experimental model data. With the validated model, it was sensitized to obtain the best mesh measurement. Finally, the geometry of the 3D model was changed to imitate a BANKART lesion. Then, the contact zone of the glenoid with the labrum was slightly separated simulating a tissue detachment. With this new geometry, the finite element analysis was applied again, and the results were compared with the control sample created initially. With the data gathered, this study can be used to improve understanding of the labrum tears. Nevertheless, it is important to remember that the computational analysis are approximations and the initial data was taken from an in vitro assay.

Keywords: biomechanics, computational model, finite elements, glenohumeral joint, bankart lesion, labrum

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