Search

The multifaceted appearance of soft robots in the form of swimmers, catheters, surgical devices, and drug-carrier vehicles in biomedical and microfluidic applications is ubiquitous today. Jellyfish-inspired soft robotic swimmers (jellyfishbots) have been fabricated and experimentally characterized by several researchers that reported their swimming kinematics and multimodal locomotion. However, the underlying physical mechanisms that govern magnetic-field-induced propulsion are not yet fully understood. Here, we use a robust and efficient computational framework to study the jellyfishbot swimming kinematics and the induced flow field dynamics through numerical simulation. We consider a two-dimensional model jellyfishbot that has flexible lappets, which are symmetric about the jellyfishbot center. These lappets exhibit flexural deformation when subjected to external magnetic fields to displace the surrounding fluid, thereby generating the thrust required for propulsion. We perform a parametric sweep to explore the jellyfishbot kinematic performance for different system parameters—structural, fluidic, and magnetic. In jellyfishbots, the soft magnetic composite elastomeric lappets exhibit temporal and spatial asymmetries when subjected to unsteady external magnetic fields. The average speed is observed to be dependent on both these asymmetries, quantified by the glide magnitude and the net area swept by the lappet tips per swimming cycle, respectively. We observe that a judicious choice of the applied magnetic field and remnant magnetization profile in the jellyfishbot lappets enhances both these asymmetries. Furthermore, the dependence of the jellyfishbot swimming speed upon the net area swept (spatial asymmetry) is twice as high as the dependence of speed on the glide ratio (temporal asymmetry). Finally, functional relationships between the swimming speed and different kinematic parameters and nondimensional numbers are developed. Our results provide guidelines for the design of improved jellyfish-inspired magnetic soft robotic swimmers.

Low˗tech greenhouses (low˗techs) have been used globally to cultivate horticultural crops since many years, but their utilization in Bangladesh is a recent phenomenon. Moreover, information on altered microclimate inside the low˗tech is hardly reported. An investigation has been conducted in the Crop Botany Field Laboratory, Bangladesh Agricultural University (24o72´N, 90o43´E and 18 masl), Mymensingh during the late autumn to winter seasons from mid-October to mid-February of 2015/16, 2016/17 and 2017/18 years to find out the variation in microclimatic parameters between inside and outside of low˗techs and to evaluate the suitability of altered microclimate inside the low˗techs for off˗season production of high value crops in Bangladesh. Three low˗techs were erected in each year using bamboo frame covered with single inflated polyethylene film (thickness = 0.2 mm). Major microclimatic parameters inside and aside outside the low˗techs were measured with standard devices or techniques. Around 30 percent incoming photosynthetically active radiation (PAR) was cut˗off by low˗tech cover during solar noon when the sun’s zenith gets minimum value (around 0o). However, this cut˗off portion of PAR was gradually increased with the sunrise and sunset when zenith is around 90o. During the daytime, low˗tech retains higher air temperature than that found at outside and the differences in air temperature between inside and outside of low˗techs was gradually increased after sunrise with a peak difference of 7 to 9 oC following the solar noon (i.e., 13:00-14:00 hour). No distinct variation in relative humidity was recorded between inside and outside of the low˗tech. Low˗tech cover retains higher soil temperature than that was recorded in outside. The variation of both air and soil temperatures between inside and outside of low˗techs was higher during the daytime but lower at nighttime or even at daytime when the sky remained overcast. The variation in microclimatic parameters under low˗techs not only protect the growing crops from climate vagaries during autumn, winter and spring seasons but also provide suitable warmer environment for growing many high value crops during that seasons and thus crop production in off˗season and/or season extension benefits can easily be achieved by low˗techs.

Soft materials are known for their plethora of biomedical applications, intricate structure–property correlation and nonlinear mechanical response. Multiple length–time scale phenomena and hierarchical structure results in their nonlinearity. Phenomenological and continuum mechanical models have been developed to predict their mechanics, which have mostly been very material-specific with inability to predict the mechanics of different types of soft materials simultaneously. This shortcoming has been addressed in the present work, wherein a generic nonlinear viscoelastic model has been proposed to predict the mechanical response of hydrogels, sponges, and xerogels. A fractal derivative viscoelastic model is proposed considering a fractal Maxwell model in parallel with a nonlinear spring. In particular, this model is chosen to qualitatively mimic the material nonlinearity inherent in soft materials. The fractal dashpot in combination with the nonlinear spring accounts for the power law time-dependent rheology of generic soft materials. These two different aspects in the form of nonlinear stiffness and non-Newtonian rheology account for mechanics of most soft materials. The present model is shown to fit well the existing literature results for mechanical response of a multitude of soft material classes with different test conditions and loading rates, which is one of the salient features of the model, apart from its simplistic mathematical framework. Further, a parametric study is reported on the mechanics of nanocellulose loaded poly(vinyl alcohol) xerogel. The model predictions are observed to be in conjunction with the experimental observations.

Kasus anak dengan karies gigi anak kelas 1 sampai kelas 3 di Sekolah Dasar (SD) Muhammadiyah 2 Kelurahan Kebon Jayanti Kota Bandung yaitu 69 anak dari 87 anak (79,31 persen) dari total jumlah murid kelas tersebut. Tujuan penelitian ini yaitu systematic review mengenai efektifitas menyikat gigi metode horizontal dan roll terhadap penurunan indeks plak sebagai evidence-based practice (EBP). Metode penelitian menggunakan Critical Appraisal Skills Programme (CASP) Systematic Review yang terdiri dari 11 daftar pertanyaan. Pembuatan rumusan pertanyaan klinis menggunakan format PICOT. Hasil systematic review diperoleh sebanyak 3 bukti dari hasil penelitian. Nilai CASP Systematic Review sebesar 77 persen dan memiliki level of evidence 3, karena penelitian tersebut menggunakan desain studi quasi experiment . Metode horizontal lebih efektif dibandingkan dengan metode roll dalam menurunkan indeks plak pada gigi pada anak usia sekolah dasar. Metode horizontal dapat diaplikasikan untuk menurunkan indeks plak pada siswa kelas 1 sampai 3 di SD Muhammadiyah 2 Kelurahan Kebonjayanti Kota Bandung. Abstract: The case of children with dental caries in grade 1 to 3 at Elementary School (SD) Muhammadiyah 2, Kelurahan Kebonjayanti, Bandung City, namely 69 out of 87 children (79.31 percent) of the total number of students. The objective of this systematic review is to obtain the effectiveness of horizontal and roll brushing methods on the reduction of the teeth plaque index as evidence-based practice (EBP). The research method uses the Critical Appraisal Skills Program (CASP) Systematic Review which consists of 11 lists of questions. Formulation of clinical questions using the PICOT format. The results of the systematic review obtained as much as 3 evidence from the research results. The CASP Systematic Review score is 77 percent and has a level of evidence 3 because this research uses a quasi-experimental study design. The horizontal method is more than the roll method in reducing the plaque index on teeth in children. It can be applied to reduce the plaque index in grade 1 to 3 at SD Muhammadiyah 2, Kelurahan Kebonjayanti, Bandung City.

Light chain (AL) amyloidosis is the result of a clonal plasma cell disorder which causes organ damage by deposition of misfolded light chains. Kidney is a common site of amyloid deposition. Proteinuria, usually in nephrotic range and unexplained renal insufficiency are the main manifestations of renal injury. We report a unique case of renal involvement by AL amyloidosis masquerading as metabolic bone disease. 38 year old male patient presented with progressively increasing diffuse bony pains, low backache and proximal weakness of both lower limbs since two years. On investigation, he was detected to have hypophosphatemic osteomalacia due to renal phosphate loss which was fibroblast growth factor 23 (FGF23)- independent. He also had nephrotic range low molecular weight proteinuria. Renal biopsy to ascertain the aetiology revealed deposition of amyloid fibrils in the glomerular mesangium on electron microscopy. Its characterization by immunofluorescence (IF) was consistent with immunoglobulin light chain (AL) amyloidosis. In the absence of a demonstrable plasma cell clone on bone marrow biopsy, we made a diagnosis of monoclonal gammopathy of renal significance (MGRS). He was treated with chemotherapy following which there was symptomatic improvement and reduction in phosphaturia. This case describes a unique presentation of renal injury due to AL amyloidosis masquerading as hypophosphatemic osteomalacia. The aim of this report is to highlight that hypophosphatemia in adults is usually acquired and treatment of underlying etiology results in cure, unlike in children where genetic counseling and phosphate replacement is the mainstay of treatment.

Soft materials undergo large mechanical deformation prior to failure when subjected to external loads. They exhibit nonlinearity alongside coupled elastic, viscous, and plastic behavior due to their multi-phase material composition, hierarchical structure, and multiple length and time scale effects. It is thus, mandatory to understand the nonlinear behavior of soft materials from a fundamental perspective. In this work, we propose a theoretical framework for the development of a thermodynamically-consistent coupled hyperelastic viscoplastic damage model to study the rate-dependent large deformation mechanical behavior of soft materials, subjected to a wide range of strain rates. A time-integration return-mapping algorithm is used to fit the experimental data previously reported for the human patellar tendons, hydrogels, xerogels, polymers, and sponges. Further, parametric studies are carried out to understand the mechanics of nanocellulose-loaded polyvinyl alcohol xerogels, liver tissues, PVA hydrogels, and skin tissues. It is observed that the proposed model is able to fit and predict the experimental observation with an error of less than 4%.

Esophageal cancer is a complex gastrointestinal malignancy with an extremely poor outcome. Approximately 80% of cases of this malignancy in Asian countries including India are of squamous cell origin, termed Esophageal Squamous Cell Carcinoma (ESCC).The five-year survival rate in ESCC patients is less than 20%. Neo-adjuvant chemo-radiotherapy (NACRT) followed by surgical resection remains the major therapeutic strategy for patients with operable ESCC. However, resistance to NACRT and local recurrence after initial treatment are the leading cause of dismal outcomes in these patients. Therefore, an alternative strategy to promote response to the therapy and reduce the post-operative disease recurrence is highly needed. At the molecular level, wide variations have been observed in tumor characteristics among different populations, nevertheless, several common molecular features have been identified which orchestrate disease progression and clinical outcome in the malignancy. Therefore, determination of candidate molecular pathways for targeted therapy remains the mainstream idea of focus in ESCC research. In this review, we have discussed the key signaling pathways associated with ESCC, i.e., Notch, Wnt, and Nrf2 pathways, and their crosstalk during disease progression. We further discuss the recent developments of novel agents to target these pathways in the context of targeted cancer therapy. In-depth research of the signaling pathways, gene signatures, and a combinatorial approach may help in discovering targeted therapy for ESCC.

1–3 piezocomposites are extensively used for sensor, actuator, naval and aerospace applications owing to their enhanced electromechanical coupling, wider bandwidth and reliability. However, their performance gets adversely affected when they are subjected to combined static and dynamic loads that initiate both creep and fatigue damage, simultaneously. 1–3 piezocomposites undergo damage due to creep–fatigue interactions because of the passive and viscoelastic polymer matrix and inherent domain switching mechanisms. In this work, experiments are conducted to obtain the electromechanical response of 1–3 piezocomposites subjected to electrical fatigue and mechanical compressive creep loads. It is observed that, the electromechanical response degrades with increase in number of electrical fatigue cycles, matrix volume fraction and mechanical compressive pre-stress. A nonlinear phenomenological combined creep–fatigue damage model is developed within a thermodynamic framework to account for the creep–fatigue interactions in 1–3 piezocomposites. The model predictions are found to be in agreement with the experimental observations.

Magnetoelectric core-shell nanocomposites have tremendous applications in biomedical sectors such as targeted and controlled drug delivery for cancer treatment and non-invasive brain stimulation for treatment of Parkinson's disease. The neural activity deep in the brain is triggered with the help of these magnetoelectric nanocomposites by externally applied magnetic fields, since these materials exhibit substantial magneto-mechano-electrical coupling. Also, they posses better connectivity between the ferroelectric and ferromagnetic phases without interface effects. B a T i O 3 (BTO) and C o F e 2 O 4 (CFO) exhibits significant ferroelectric and ferromagnetic properties which are able to induce effective multiferroic properties. Core-shell nanocomposites of C o F e 2 O 4 as core and B a T i O 3 as shell, were synthesized by co-precipitation and sol-gel techniques, respectively. The optimum calcination temperature required to get pure B a T i O 3 phase was observed to be 900 ∘ C . The tetragonal phase of pure B a T i O 3 and the spinal perovskite structure of pure C o F e 2 O 4 was in accordance with the X-ray diffraction patterns. The core-shell type morphology of the synthesized nanocomposites were corroborated using Transmission Electron Microscopic images. The piezoelectric and magnetization response of these magnetoelectric nanocomposites were captured as functions of temperature and volume fractions of individual phases.

Grain size has significant effects on the electromechanical response of piezoceramics. Since the sintering temperature and holding duration affect the grain size and correspondingly their effective piezoelectric response, these issues should be appropriately addressed in order to properly design smart and intelligent systems. In this paper, PMN-PT piezoceramics with different grain sizes are synthesized by using conventional solid state processing and two-stage sintering method. Grain size effects on the hysteresis, fatigue and creep response are analyzed. Dielectric, ferroelectric and piezoelectric material properties of PMN-PT ceramics are investigated. The piezoelectric coefficient and remnant polarization exhibit diverse grain size effects depending on the sintering temperature and holding duration. The relative dielectric permittivity, piezoelectric coupling constant and dielectric constant show maximum values of 4104.2, 559 pC/N 562.291 pC/N and 0.705 for the microstructure with average grain size of 3.8 μm. The myriad effects of grain size on piezoelectric response are reported in details.

1-3 piezocomposites are often subjected to mechanical pre-stress under elevated temperatures in naval and offshore applications, actuators, and so on, where the presence of the ductile epoxy matrix causes considerable creep in the system. This deteriorates the system efficiency and its overall performance. To address this issue, experiments are performed to capture the electromechanical response for thermo-mechanical creep of 1-3 piezocomposites for different fiber volume fractions under various thermal loads, wherein mechanical depolarization is observed. The piezo-coupling coefficient is observed to degrade. Higher thermal loads resulted in an increase in creep strain coupled with a decrease in creep polarization. A Kelvin–Voigt fractal derivative viscoelastic model is used to capture the creep strain. The creep strain is decomposed into ferroelastic and anelastic parts. The evolution of creep polarization is obtained using the ferroelastic component of the creep strain. The model predictions are found to be in agreement with the experimental observations.

Xerogels are porous networks of crosslinked polymers that are useful for biomedical applications such as drug delivery, scaffold engineering, tissue regeneration, cell culture and wound dressing. However, inferior mechanical properties curtail their applications to a considerable extent. Nanocellulose fibers and crystals are often added into the polymer matrix to improve their mechanical strength. Here, nanocellulose in the mass ratios of 7%, 13% and 18% are loaded into polyvinyl alcohol (PVA) matrix followed by thermo-morpho-mechanical characterization. With increase in nanocellulose content, thermal degradation occurs at a lower temperature. It is observed that addition of higher quantity of nanocellulose crystals leads to the formation of weak cellulose-rich regions causing xerogel rupture. This is predominantly observed for xerogel loaded with 18% nanocellulose crystals. Similarly, addition of higher quantity of nanocellulose fibers increase brittleness of the xerogels causing fracture. This is predominantly observed for xerogel loaded with 18% nanocellulose fibers. Creep strain and stress relaxation is observed to decrease with addition of nanocellulose loading owing to molecular chain restriction and polymer chain immobility.

Piezocomposites find extensive use in sensors and actuators, naval applications, etc. owing to their characteristic coupling between electro-mechanical domains. These materials being relatively soft and ductile show a viscoelastic response to applied thermo-mechano-electrical loads. This causes a drift in the system response and creep is observed, which affects system efficiency. During prolonged service periods, self-heating occurs. Often, piezocomposites are subjected to mechanical pre-stresses prior to electrical input. To understand the response of 1–3 piezocomposites under these intricate loading conditions, experiments are performed to study the electro-mechanical response of 1–3 piezocomposites under thermo-mechano-electrical creep loads. Mechanical depolarisation is observed during the creep process. Creep strain is observed to increase with matrix volume fraction, mechanical pre-stress, electric field and temperature. A decrement in creep polarisation is seen with the increase in matrix v...

Experimental and theoretical characterization on creep behavior of 1 − 3 piezocomposites subjected to a constant electric field and mechanical pre-stress is carried out. For curved surfaces or systems undergoing large deformations, piezo-ceramics are unsuitable since these are brittle in nature. Hence, piezo-composites are used as replacements. Creep is an important aspect with these systems due to a softer viscoelastic matrix involved. Electrical and electro-mechanical creep are studied for these systems. Electrical creep is observed to be maximum at the coercive field. Also, it is inferred that the volume fraction of fiber in 1 − 3 piezocomposites affects the system performance. The electro-mechanical creep is observed to reduce exponentially with increasing compressive pre-stress. Mechanical depolarization effect is observed during compressive loading. A thermodynamically-consistent macro-mechanical model is proposed to capture the creep behavior of 1 − 3 piezo-composites. It is found that the model predictions are in agreement with the experimental observations.

Piezoelectric materials like bulk PZT are often subjected to mechanical creep loads. But being brittle, these undergo premature failure. Hence, piezocomposites are used instead of bulk PZT. Piezocomposites are viscoelastic in nature owing to the presence of a ductile epoxy matrix. In this paper, mechanical creep is studied for 1–3 piezocomposites of different fiber volume fractions under various levels of compressive prestress. Experiments are performed to understand the difference in their electromechanical response. The creep strain is found to increase with the increase in matrix volume fraction and stress level. The creep polarization is observed to decrease with the decrease in fiber volume fraction and stress level. The degradation in the piezocoupling coefficient is observed to be the maximum for the piezocomposite 35% fiber volume fraction and the least for the bulk PZT. This is attributed to the time-dependent permanent re-orientation of ferroelastic domains by 90 $$^\circ $$ during the mechanical creep phenomenon. Finally, a viscoelastic model comprising of two parallel Kelvin–Voigt elements is proposed to capture the creep strain. The creep strain is decomposed into the ferroelastic strain and anelastic strain. Creep polarization is computed from the ferroelastic strain. The model predictions are found to be in agreement with the experimental results.

Xerogels are attractive candidates for scaffolds in tissue engineering and drug delivery. Polyvinyl alcohol xerogels are extensively used for biomedical applications owing to their ease of synthesis, biocompatibility and biodegradability. However, these materials are challenged in terms of their weak mechanical properties and structural instabilities. This work is aimed to look into the morpho-mechanical response of transversely isotropic freeze-dried PVA xerogels under mechanical compressive loads. Microstructurally aligned PVA xerogels are synthesized using unidirectional freeze-drying technique. Uniaxial compressive tests are performed alongside viscoelastic characterization. The effect of mechanical compressive loads upon the xerogel microstructure is studied. Microbuckling of material fibers, creasing and wrinkling of the bulk xerogels are some of the microstructural and surface instabilities discussed.

This paper develops a method for imposing stress boundary conditions in smoothed particle hydrodynamics (SPH) with and without the need for dummy particles. SPH has been used for simulating phenomena in a number of fields, such as astrophysics and fluid mechanics. More recently, the method has gained traction as a technique for simulation of deformation and fracture in solids, where the meshless property of SPH can be leveraged to represent arbitrary crack paths. Despite this interest, application of boundary conditions within the SPH framework is typically limited to imposed velocity or displacement using fictitious dummy particles to compensate for the lack of particles beyond the boundary interface. While this is enough for a large variety of problems, especially in the case of fluid flow, for problems in solid mechanics there is a clear need to impose stresses upon boundaries. In addition to this, the use of dummy particles to impose a boundary condition is not always suitable or even feasibly, especially for those problems which include internal boundaries. In order to overcome these difficulties, this paper first presents an improved method for applying stress boundary conditions in SPH with dummy particles. This is then followed by a proposal of a formulation which does not require dummy particles. These techniques are then validated against analytical solutions to two common problems in rock mechanics, the Brazilian test and the penny-shaped crack problem both in 2D and 3D. This study highlights the fact that SPH offers a good level of accuracy to solve these problems and that results are reliable. This validation work serves as a foundation for addressing more complex problems involving plasticity and fracture propagation.

In this work, we describe a coupled Drucker–Prager and Grady–Kipp SPH framework in order to simulate mode I, mode II and mixed mode failure under the same formulation. This framework is then applied to study failure in uniaxial compression of gypsum samples containing a single angled flaw. To validate the model, results are compared with the experimental analysis and shows good agreement, where fracture initiation positions and angles are well represented. This trend of agreement continues beyond initiation, through to propagation, and finally post-failure behavior. The methodology and results shown here describe a powerful tool for study of fracture mechanics.

Polyvinylidene fluoride (PVDF) composite films have witnessed widespread applications in biomedical and flexible electronic devices in recent years. These applications require a material that has enhanced electrical properties, mechanical flexibility along with sufficient strength. A lot of research has been carried out to enhance the piezoelectric and dielectric properties of the PVDF composite films. However, the improvements in the mechanical properties of nano filler reinforced PVDF composite films has not received due attention. In this regard, the present work focuses towards enhancing the mechanical strength and load-bearing capability of PVDF, by preparing composites of PVDF films impregnated with Cellulose Nanocrystals (CNC) and Barium Titanate (BTO) nanoparticles. Solution casting method was adapted to fabricate the PVDF/BTO/CNC films. X-ray diffractograms and FTIR (Fourier Transform infrared spectroscopy) corroborate the presence of ferroelectric γ phase in PVDF. Mechanical and viscoelastic measurements have been carried out to examine the influence of CNC and BTO nano fillers in the PVDF matrix. The addition of CNC and BTO in PVDF film has improved the mechanical strength significantly. The stress achieved for PVDF/5% BTO and PVDF/5% BTO with 0.9% of CNC at 5% strain was 17% and 130% higher than the pristine PVDF, respectively. This study can be helpful for the design engineers to meet custom/specific requirements for a myriad of end-user applications such as piezoelectric nanogenerators.

Purpose– The purpose of this paper is to analyse of structures made in rock mass with multiple intersecting discrete discontinuities such as joint, fault, shear plane.Design/methodology/approach– In this study, a numerical method is proposed for analyzing multiple intersecting joints with varying dip angles, spacing and roughness in eXtended Finite Element Method platform. A procedure is also outlined to treat excavated enhanced (jointed) elements for analysing the effect of excavation sequences.Findings– The proposed method is compared with the existing interface element methods (Phase-2 model) by considering the stress and displacement distributions of a multiple intersecting jointed rock sample under uniaxial loading conditions. A circular tunnel in rock mass having intersecting joints is also analyzed for the distribution of mobilised friction angle of joints and results are compared with a derived analytical solution.Research limitations/implications– Nucleation and propagation of cracks should be incorporated into the proposed framework in future studies.Practical implications– The proposed method is a useful tool for rock mechanics and geotechnical engineering problems to analyse strength and deformability of jointed rock masses.Originality/value– The paper enumerates concepts and detail implementation procedures of the proposed method in three-noded triangular elements. The intersection of joints is formulated in such a way that no additional (junction) enrichment is required in model. The method has been improved for inclusion of Dirichlet and Neumann boundary conditions to be applied in the enhanced part of a problem domain.

Background Although primary osteo-arthritis is well known as a benign degenerative condition, the impact of this disease course is becoming terribly disabling day to day in our community possibly because of increasing life expectancy. After lots of search regarding the role of intra-articular hyaluronic acid plus steroid in osteo-arthritis knee it is noted that scarcity of literature regarding conclusive evidence for the above. There is a grey zone regarding the combined role of these two agents in patients with primary osteo-arthritis. This project is a humble sincere attempt to find out the role of high molecular weight hyaluronate plus steroid in osteo-arthritis knee and to compare the effectiveness of this with intra-articular steroid, and intraarticular HMW hyaluronic acid. Methods and Design This is a single blind randomised controlled parallel group study conducted in the department of physical medicine and rehabilitation, IPGME & R, SSKM Hospital, Kolkata for a period of 18 months taking 27 subjects in each group. All patients with primary osteo-arthritis knee with grade two or grade three were included in the study group. And those who did not want to get incorporated in the study, patients with secondary osteo-arthritis knee, grade one or grade four osteo-arthritis knee, with gross knee instability, patients with contra-indications of intra-articular injections or intra-articular injection of steroid or with history of allergy to a viscosupplementation solution and patients received intra-articular injection in knee within last one year were excluded from the study. WOMAC pain, stiffness and functional subscales, VAS pain, ROM of knee joint, 50 feet walk time, Patients global assessment scale, Physicians global assessment scale were the parameters studied. After taking clearance from the institutional ethical committee, patients were selected based on the inclusion and exclusion criteria, and baseline (visit-1) assessment was done on the parameters. The selected patients have been divided into three groups randomly. Written informed consent was taken from all patients before interventions. One group received intra-articular injection of methylprednisolone, second group received intra-articular injection of high molecular weight hyaluronoic acid, and third group received intra-articular injection of high molecular weight hyaluronate plus methylprednisolone in the knee joint. The injections administered under strict aseptic condition. After administering injections, the patients assessed at the interval of 6 weeks (visit-2) and 12 weeks (visit-3) using the parameters mentioned above. The results have been analysed according to the standard statistical methods to fulfill the aims and objectives of the study. Discussion Majority of patients were female and more than 50 years of age with K-L radiological grade of 3. At the baseline visit, the WOMAC pain was comparable in all the three groups. It has been seen that, there was statistically significant improvement in all the parameters at the 2nd visit (6 weeks) from the baseline in all groups, and at the 3rd visit (12 weeks) though there was improvement on all the parameters from the 2nd visit in all groups, it was not statistically significant. Steroid, high molecular weight hyaluronate and steroid plus HMW hyaluronate all are effective in osteo-athritis knee in terms of reduction of pain, reduction of stiffness of knee joint, increase of range of motion of knee joint, reduction of 50 feet walking time, reduction of patients and physicians global assessment score. No treatment regime is statistically significantly better than the other group after 6 and 12 weeks of postinjection. Adverse effects of any treatment regime is negligible.

The paper presents a methodology in the SPH framework to analyze physical phenomena those occur in detonation process of an explosive. It mainly investigates the dynamic failure mechanism in surrounding brittle rock media under blast-induced stress wave and expansion of high pressure product gases. A program burn model is implemented along with JWL equation of state to simulate the reaction zone in between unreacted explosive and product gas. Numerical examples of detonation of one- and two-dimensional explosive slab have been carried out to investigate the effect of reaction zone in detonation process and outward dispersion of gaseous product. The results are compared with those obtained from existing solutions. A procedure is also developed in SPH framework to apply continuity conditions between gas and rock interface boundaries. The modified Grady–Kipp damage model for the onset of tensile yielding and Drucker–Prager model for shear failure are implemented for elasto-plastic analysis of rock medium. The results show that high compressive stress causes high crack density in the vicinity of blast hole. The major principal stress (tensile) is responsible for forming radial cracks from the blast hole. Spalling zones are also developed due to stress waves reflected from the free surfaces.

Summary A methodology is developed in SPH framework to analyze the behavior of preexisting multiple intersecting discontinuities or joints in rock material. The procedure does not require any additional unknowns to represent discontinuities and to capture velocity jump across them. Instead, a discontinuity is represented by a set of joint particles placed along the discontinuity plane, in which relative velocity and traction vector is evaluated, obeying the Mohr–Coulomb friction law with zero tension constrain. For failure of continuous rock material, the Drucker–Prager yield criterion with tensile cracking is employed in the elastic-plastic constitutive model. Free-sip, no-slip, and symmetric boundary conditions are also implemented in SPH framework for proper representation of physical system. The paper analyzes behavior of a rock sample having a discontinuity plane under uniaxial loading and compares velocity and stress with a theoretical solution derived considering effective vertical stiffness of the joint planes. The efficacy of the proposed method is successfully demonstrated by solving another two problems of jointed rock mass under uniaxial and gravitational loading conditions.Copyright © 2014 John Wiley & Sons, Ltd.

Integration of makhana (Euryale ferox Salisb.)-cum-fish culture including sole system as sub-plot on the nutritional quality under wetland ecosystem reveal that seed yield as well as nutritional value of makhana seeds (starch, sugar, protein and minerals) vary significantly by different integrated nutrient management (INM) packages applied on the crop and fishes. The result exhibited highest value (75.04, 2.37, 9.45 and 0.52%) with N4 treatment (plants and fishes both received a well-balanced organic and inorganic sources of plant nutrients along with fish-feed including zinc spray). The combined effect of different farming system and INM on the nutritional status of makhana seeds was not significant. These important food ingredients as fresh as well as its different value-added products have great importance for small and cottage industries, particularly poor and marginal section of rural people as well. DOI: http://dx.doi.org/10.3329/bjsir.v48i4.11501 Bangladesh J. Sci. Ind. Res. 48(4), 281-286, 2013

Introduction Over the years NCS has been used to diagnose and monitor the patients with CTS though USG has several advantages as diagnostic tool. This study has been done to find out the diagnostic accuracy of USG in CTS and to compare the efficacy of USG with standard NCS in CTS. Prospective cross-sectional analytical study was conducted at Dept. of PM&R, IPGME&R, Kolkata from 1st March, 2012 to 31st August 2012 (6 months). Patient with clinical diagnosis of CTS of age >18 year of both sexes were included in this study and on the other hand patient with previous wrist surgery /injury, wrist deformity, diabetes mellitus, anatomical variants of median nerve on ultrasound were excluded from the study. Methodology After getting institutional ethical committee clearance, all patients who fulfil the above criteria were included in the study and further diagnostic conformation done by the standard diagnostic criteria of NCS. The same group of patients have been also screened by ultrasonography (USG). Results At the end of the study, data analysis showed that sensitivity and specificity were 92.3 and 70.0% respectively. Predictive value of +test, predictive value of -test were 88.9 and 77.8% respectively. Kappa value was 0.64 (between 0.5 and 0.7). It signifies that there is good correlation between NCS and USG as diagnostic tool of CTS. The comparison of the numerical values of median latency, amplitude and CSA USG within the groups with the help of ANOVA followed by Tukey's test showed that there was good correlation between latency and amplitude in mild, moderate, severe and profound CTS but unfortunately it was not correlated with the CSA measured by USG. Conclusion USG can be used for screening large population of patients as it is simple, easily available, non-invasive test and has relatively low cost and useful in evaluating and excluding local causes of nerve compression.

Polyvinyl alcohol (PVA) hydrogels have recently emerged as suitable bio-mimetic materials for various applications such as scaffold engineering, controlled drug delivery and cell culture. In this paper, PVA hydrogels with different concentrations of PVA have been synthesized using uni-directional freeze-drying technique. Unidirectional freeze-dried hydrogels exhibit transverse isotropy. The microstructurally aligned porous architecture of the hydrogels has been confirmed from Scanning Electron Microscope (SEM) images. Experiments have been conducted to characterize their transversely isotropic and viscoplastic behavior. These materials have been observed to behave non-linearly when subjected to compressive mechanical loads. Theoretical models are proposed to predict the mechanical behavior of the transversely isotropic microstructurally aligned hydrogels. The first model is a visco-elasto-plastic model that incorporates the effect of non-Newtonian behavior effectively using a fractal dashpot. The second model is an anisotropic finite viscoplastic model. The predictions of both the models are found to be in close agreement with the experimental results.

Background Gemcitabine with platinum is regarded as the standard of care in patients with unresectable and/or metastatic disease with good performance status (PS). There is no standard of care for poor PS patients. A report from M.D.A.C.C. stated a median OS of only one month in GBC patients with poor PS. Erlotinib and capecitabine, both have shown efficacy in metastatic GBC. There has been no RCT to date in GBC patients with poor PS. With limited data showing the activity of erlotinib and capecitabine, we conducted this RCT to evaluate the efficacy and toxicity of these drugs in this patient cohort. Methods This is an ongoing open-label, phase II/III RCT (phase II part of the study is complete).The primary objective is to determine if erlotinib (150 mg/d PO )+ BSC or capecitabine (625 mg/m2 BD PO) + BSC has an OS benefit compared to BSC alone in patients with unresectable/metastatic GBC with ECOG PS III. A total of 51 patients with histopathologically confirmed GBC, age >/=18 years, with adequate organ functions (S. bilirubin 50 ml/min/1.73m2) were randomised. Patients were followed up q2wk in first month and q4wk thereafter. Toxicity was assessed using CTCAE v4.1. Radiological response evaluation (as per RECIST v1.1) was done at 8-10 weeks/earlier if clinically indicated, QoL assessment (using EORTC QLQ-C30 BIL21 ) was done at baseline and at 6-8 weeks. Intervention was continued until progression/unacceptable toxicity. Serial evaluation for OS in all three arms was done. Initially the study was started as a phase II RCT, an interim pre-planned analysis was done after completion of phase II. Results The median OS in capecitabine +BSC arm (n = 19) was 209 days, relotinib +BSC arm(n = 14) was 105 days and BSC alone arm was 71 days (p value 0.022). Only 2 patients had grade III diarrhea with erlotinib. There were no drug-related SAEs. Conclusions There is a statistically significant OS benefit of capecitabine+BSC or erlotinib+BSC over BSC alone in unresectable/metastatic GBC patients with ECOG PS III. Results will be updated upon completion of phase III. Clinical trial identification CTRI/2019/04/018860. Legal entity responsible for the study The authors. Funding All India Institute of Academic Sciences. Disclosure All authors have declared no conflicts of interest.

1-3 piezocomposites are excellent candidate materials for sensor, actuator and transducer applications owing to their remarkable dielectric properties, enhanced piezoelectric coupling constants and improved hydrostatic performance along with tunable acoustic impedance, high bandwidth and reliability. These materials find extensive use in aerospace, naval and biomedical sectors. 1-3 piezocomposites show a linear response when subjected to low electric fields and/or mechanical stresses. In such cases, linear models are sufficient for predicting their linear response. But, when high electro-mechanical loads are applied to these materials, they show nonlinearity owing to the presence of a passive and viscoelastic polymer matrix phase and inherent hysteretic damping in the piezoceramic fibers. This is when it becomes mandatory to understand both their linear and nonlinear behavior under different magnitudes of thermo-electro-mechanical static and dynamic loads. Linear response is modeled using linear piezoelectric constitutive equations. Nonlinearities in the form of hysteresis, depolarization, fatigue and creep occurs in 1-3 piezocomposites, which drastically affects their accuracy, precision and efficiency. In order to understand these nonlinearities, analytical and numerical methods have been proposed by several researchers in the past. An endeavor has been undertaken to review some of the attempts made earlier in these directions. Effective properties of these inhomogeneous media are evaluated through different hypotheses and assumptions. Most often, experimental routes are undertaken to predict material properties of 1-3 piezocomposites; nevertheless, the experimental evaluation of a few material properties is quite difficult and sometimes impossible, even with the best state-of-the-art experimental facilities. This motivates researchers to develop theoretical models to predict these material properties. Nonlinearities in 1-3 piezocomposites have been studied by researchers earlier with different theoretical modeling approaches and experimental techniques. This review paper is an endeavor to discuss the progress regarding the study of effective properties and nonlinearities in 1-3 piezocomposites in a coherent and holistic manner.

Hydrogels are soft materials which comprise of trapped solvent within entangled polymeric chains. Although these materials are highly compliant, they are prone to structural and surface instabilities. Buckling, rupture, wrinkling and fracture are some consequences of these instabilities. Under the influence of self-weight and external axial loads, slender hydrogels show viscoelastic buckling. In this paper, the time-dependent response of hydrogels under these conditions has been modelled by considering the energy on account of bending, the work done due to self-weight and external loads, and the viscous damping effects. A Prony series has been used to characterize the compliance and capture the viscoelastic nature of the hydrogels. The parameters of the Prony series were calculated by assuming the hydrogel to be a 3–3 composite. The governing differential equations have been derived using a variational technique. Components of the model have been verified using recorded experimental findings. The model predictions have been reported and a parametric study has been carried out to understand the effect of different system parameters such as the axial load, density and compliance on the viscoelastic response of slender hydrogels.

This paper presents a numerical procedure based on smoothed particle hydrodynamics (SPH) to analyze the failure process of a rock medium by predicting the initiation of microcracks. The subsequent propagation of cracks has also been analyzed without any special treatment or assumption regarding fracturing process. The procedure for implementing softening elastoplastic model has been discussed in the SPH framework. For failure of a rock specimen under uniaxial compression, the Drucker-Prager yield criterion is used in the elastic-plastic constitutive model by considering associative and nonassociative plastic flow rules. The Rankine maximum tensile failure criterion is implemented to model the tensile failure of a circular rock specimen. The results obtained from this study have been compared with laboratory tests and existing analytical solutions. It is found that the developed procedure has the potential to provide useful information to understand the key physical phenomena that occur in the fail...

This paper presents a numerical simulation for predicting fracture and failure growth of geomaterial using smoothed-particle hydrodynamics (SPH). The first example deals with slope stability analysis of a chromite mine having friable chromite as the ore body. The ultimate pit may reach up to 144 m below the surface with an ultimate pit angle of 30° for 19 benches. It is require to forecast the stability of the ultimate pit slope for a given material and pit geometry. This paper analyses the stability of this slope by considering Drucker–Prager rock mass medium using the SPH procedure. The second example comprises the fracture growth of a circular rock specimen under diametrically opposite concentrated angular loads. In order to determine the plastic regime of the specimen for a given tensile strength, the Rankine maximum tensile failure criterion is implemented in the SPH framework.

A better understanding of failure in heterogeneous rock materials can benefit a wide range of areas, from earthquake engineering to petroleum engineering. Study of such failure is of particular interest in the field of hydraulic fracturing. The prediction of this breakage phenomenon is a big challenge for the scientific community. Traditional continuum modeling techniques have the advantage of using classical nonlinear material models, however they often fail to accurately capture the complexity of the fractured geometry and path of multiple intersecting fractures. In particular, mesh dependence of the fracture path, 3D representation of natural fractures and their intersections, closing of an opened fracture, or shear in fractures, are difficult to accurately capture using these techniques. The use of the smoothed particle hydrodynamics (SPH) method for simulation of fracture in solids is relatively recent, where mesh free methods like SPH have the potential to overcome the previously mentioned limitations of mesh based methods. Simulation of the initiation and propagation of pressure-driven fractures in brittle rocks is presented in this study. By exploiting techniques commonly used in traditional continuum methods, we have implemented an elasto-plastic SPH model, which is based on the Drucker-Prager yield criterion, and the Grady-Kipp damage model. Results show that SPH is able to correctly predict the evolution of fracture in brittle rocks. The SPH method has been applied to the solution of crack propagation in a variety of test cases, including a pressurized borehole, 2D line crack, and 3D penny shaped crack. The influence of initial in-situ stresses was also accounted for. Comparison of SPH results for these cases to analytical solutions shows that SPH may be applied to accurately simulate the evolution of fluid-driven fractures in brittle rocks. Such model is a vital tool in correctly predicting fracture propagation in highly heterogeneous formations, for instance, shale formations.

Objective To study the functional outcomes in different groups of meningoencephalitis patients after rehabilitation approach in addition to standard medical therapy. Study period From January 2007 to January 2009. Study Design Prospective longitudinal analytical study. Study Area Departmentof Physical Medicine & Rehabilitation, Department of Paediatric Medicine in North Bengal Medical College, Sushrutanagar, Darjeeling, India. Study population 108 patients. Material and methods After taking consent and institutional ethical committee clearance the sample size were assessed. After stabilisation of the affected children with medical therapies, rehabilitation regimen was added. Outcome measures Percentage of total Wee FIM score. Follow up 0, 2weeks, 6 weeks. Results Data analysed by McNamara's chi Square test showed disability rate is much higher than other aetiology. Best prognosis is seen in patients with viral infections. Discussion In developing countries children in lower socioeconomic group from rural areas are the most victim of tuberculous meningoencephalitis who responded reasonably with rehabilitation regimen. Conclusion Rehabilitation regimen is best helpful in viral infection. Tuberculous infection, relatively commoner in India does not respond very well.

The magnetic field effect (MFE) on the photoinduced electron transfer (PET) reaction between the [Cu(phen)2]2+ complex and DNA has been studied in homogeneous buffer medium and in reverse micelles. The copper complex on photoexcitation can oxidize DNA in a deoxygenated environment. A prominent MFE is found even in a homogeneous aqueous medium for the triplet born radicals. The process of partial intercalation of [Cu(phen)2]2+ complex within DNA is responsible for such a rare observation. In reverse micelles, the MFE is not very much prominent because of the large separation distance between the component radicals of the geminate radical ion pairs generated through PET.

Arjunolic acid, the major extractable constituent of the heavy wood ofTerminalia Arjuna, has the potential to be used as a rigid and functional molecular framework for the construction of nanosized supramolecular architectures and nanomaterials. The nanosized triterpenoid, arjunolic acid, showed efficient gelation of various organic solvents at low concentrations. The low molecular mass gelator molecules self-assembled in the solvents to form fibers of nanometer diameters. The movement of the solvent molecules was hindered inside the fibrous network leading to the formation of a gel

Arjunolic acid, a functionally rich chiral triterpenoid with a rigid pentacyclic backbone, has the potential to be used as a structural framework for the design of molecular receptors and supramolecular architectures. The design and synthesis of the first arjunolic acid-derived 18-crown-6 and its binding studies with metal and tert-butylammonium ions are reported.

SummaryThe effects of exudates from strawberry roots on the growth of strawberries in hydroponic culture were investigated. Vegetative and reproductive growth in nutrient solution without activated charcoal (–AC) was lower than with AC (+AC). The root exudates adsorbed by the AC were extracted and analysed in a gas chromatograph coupled to mass spectrometer (GC-MS). The compounds identified included lactic, benzoic, succinic, adipic and p-hydroxybenzoic acids. The allelopathic potential of these compounds were evaluated on strawberry plantlets. The results indicated that benzoic acid significantly inhibited the fresh weights of shoots, the dry weights of shoots and roots, and the maximum root length, at all concentrations tested. These results suggest that root exudates from strawberry plants may cause growth inhibition, and that the greatest inhibition was caused by benzoic acid.