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In the formulation of efficient drug delivery systems, it is essential to unravel the structural and dynamical aspects of the drug's interaction with biological membranes. This has been done for the anticancer drug-membrane system comprising doxorubicin hydrochloride (DOX), a water-soluble anticancer drug, and the micellar sodium dodecyl sulfate (SDS), the latter serving as a useful mimic for membrane proteins. Using a multimodal NMR approach involving

The commonly used grasp simulators such as GraspIt! and OpenRAVE use wrench space formulations and grasp quality metrics such as ϵ and v to identify stable grasps in dynamic conditions. However, wrench space formulations are derived based on static mechanical equilibrium equations, and the physical attributes of the object such as stiffness and mass are also not considered for grasp analysis. Above all, these grasp analysis frameworks cannot be experimentally validated, thereby resulting in grasps that are not reliable. In this paper, an experimentally validatable Finite Element (FE) based grasp analysis framework is proposed for evaluation of robotic grasps in dynamic conditions. By applying standard solutions of Hertzian contact theory to a few robotic grasps, Finite Element Method (FEM) is validated. A real-world grasp situation is then simulated using FEM, and the FE model is validated based on the contact area measured in real-time using a pressure sensor. By applying dynamic perturbations to the validated FE model, the stability of the grasp is evaluated, and the most stable grasp is identified using the contact area based metric, π. It is observed that FE simulations agree with the analytical solutions and experimental results, with a relative error of not more than 7%.

The COVID-19 outbreak is on the world. While many countries have imposed general lockdown, emergency services are continuing. Healthcare professionals have been infected with the virulent severe acute respiratory syndrome coronavirus-2 (SARS), which spreads by close contact and aerosols. The anesthesiologist is particularly vulnerable to aerosols while performing intubation and other airway related procedures. Regional anesthesia (RA) minimizes the need for airway manipulation and the risks of cross infection to other patients, and the healthcare personnel. In this context, for prioritizing RA over general anesthesia, wherever possible, a structured algorithmic approach is outlined. The role of percentage saturation of hemoglobin with oxygen (oxygen saturation), blood pressure and early use of point-of-care ultrasound in differential diagnosis and specific management is detailed. The perioperative anesthetic implications of multisystem manifestations of COVID-19, anesthetic management options, the scope of RA and considerations for its safe conduct in operating rooms is described. An outline for safe and rapid training of healthcare personnel, with an Entrustable Professional Activity framework for ascertaining the practice readiness among trained residents for RA in COVID-19, is suggested. These are the authors’ experiences gained from the current pandemic and similar SARS, Middle East Respiratory Syndrome and influenza outbreaks in recent past faced by our authors in Singapore, India, Hong Kong and Canada.

Exploring methods to mitigate the effect of COVID-19 pandemic on routine cancer screening activities among women.To investigate the effectiveness of telephone-based outreach as a substitute for physical screening for breast among screened women, during COVID-19 lockdown.Asymptomatic women aged 30-59 years were screened for breast and cervix cancers in the Chennai region, between January 2017 and March 2020 and are due for screening follow-up. A database from the population-based cancer screening program organized by the Cancer Institute during the above period was used for the study. Outcome data were obtained through the period from October 2020 to March 2021.Phone-based breast self-examination awareness, inquiry about breast cancer symptoms, and guiding clinical management.Compliance to BSE protocol after 8-16 weeks, presence of significant symptoms, and incidence of early breast cancer.Among 12,242 screened women, 6716 (56.8%) responded to a phone-based BSE intervention and 53 women had breast-related symptoms. Thirty-two (60.4%) women reported for further evaluation, and five invasive breast cancers were identified.In a low-resource setting where there are no existent screening programs, simple interventions like teaching breast self-examination of women through tele-counseling can result in early detection of breast cancers.

Freshwater aquaculture is the most promising and viable culture method that paves way to develop of new culture techniques for the fulfillment of increasing demand both in terms of quantity and increased nutritional values especially the protein content. In recent days live feed plays an irreplaceable role in aquaculture feed management as the common conventional pellet feed are been replaced by the live feeds. Microalgae are one of the most nutrient rich effective live feeds in freshwater aquaculture. In the present study the microalgae viz; Chlorella vulgaris and Spirulina platensis were used instead of pellet feed for the culture of carp Hypophthalmichthys nobilis. The parameters like growth, performance, feed utilization, biochemical analysis, blood analysis were done in the fish and the water quality parameters were analysed and the results were compared. The analysis showed better results on the sample fishes which was fed with microalgae feed (C. vulgaris and S. platensis,) than the conventional pellet feed. In addition the blood leucocytes oxidative radical production was increased and the counts of Pseudomonas chlorophis was reduced in S. platensis fed fish. Hence, this study affirmed that the microalgae act a suitable live feed whereas S. platensis revealed superior performance among the microalgae given (C. vulgaris and S. platensis) for the culture of H. nobilis.

The interaction of copolymer L61 i.e., (EO)2(PO)32(EO)2 (where EO and PO are ethylene and propylene oxides, respectively) with surfactant SDS (sodium dodecylsulfate) in relation to their self-aggregation, dynamics and microstructures has been physicochemically studied in detail employing the Nuclear Magnetic Resonance (NMR), Electron Paramagnetic Resonance (EPR), Small-Angle Neutron Scattering (SANS), and Freeze-Fracture Transmission Electron Microscopy (FF-TEM) methods. The NMR self-diffusion study indicated a synergistic interaction between SDS and L61 forming L61–SDS mixed complex aggregates, and deuterium (2H) NMR pointed out the nonspherical nature of these aggregates with increasing [L61]. EPR spectral analysis of the motional parameters of 5-doxyl steraric acid (5-DSA) as a spin probe provided information on the microviscosity of the local environment of the L61–SDS complex aggregates. SANS probed the geometrical aspects of the SDS–L61 assemblies as a function of both [L61] and [SDS]. Progressive evolution of the mixed-aggregate geometries from globular to prolate ellipsoids with axial ratios ranging from 2 to 10 with increasing [L61] was found. Such morphological changes were further corroborated with the results of 2H NMR and FF-TEM measurements. The strategy of the measurements, and data analysis for a concerted conclusion have been presented.

Conventionally, a robotic grasp is represented by point contacts with rigid body description for object and gripper. With these assumptions, the contact forces and moments are considered to act at points, and a grasp wrench space is constructed to determine the stability of the grasp. However, wrench space formulations ensure mechanical equilibrium only; it does not guarantee grasp stability. Moreover, the material properties of object and grippers are not taken into account, as a result of which the underlying deformation and the contact pressure are neglected. In this work, the contact pressure maps of robotic grasps, that accounts for deformability occurring at the gripper-object interface, are used for robotic grasp analysis and database generation. Using a conformable pressure sensing sheet, the contact pressure maps of typical household objects such as cans, bottles and cubes, while grasping and perturbation are measured and explored. Apart from these objects, the contact pressure maps of fruits such as apple and orange, while grasping is also studied. The stability of each grasp is determined based on the contact pressure maps, and a contact area-based metric, $$\pi $$ , is used to identify the most stable grasp. These pressure maps are then used to validate the FE framework designed for robotic grasp analysis. $$\pi $$ obtained from experiments is then compared with that of FE simulation outputs, and it is observed that the relative error between them is less than 4%, which, in turn, demonstrates the efficacy of the proposed framework. As the FE framework is not suited for real-time grasp synthesis due to the computational time involved, we show how to exploit the framework for generating an offline grasp experience database, which can then be deployed for grasp synthesis real-time.

Knowledge of prevalence and dynamics of high-risk human papilloma virus (HR HPV) is essential for formulating effective prevention strategies for cervical cancer. A cross-sectional observation study was carried out among sexually active women of rural Tamil Nadu for estimating the cervical HR-HPV prevalence and their persistence using Hybrid Capture 2 technique and Linear Array HPV genotyping method with follow-up at 12 and 36 months. Data related to prevalence, epidemiological determinants, genotype distribution and persistence of infection was analyzed statistically for significance. A total of 193 of 1523 women were tested positive for HR HPV, a prevalence rate of 12.7%. The HR HPV prevalence peaked at 25–29 years (16.4%) and consistent across 30–50 years of age (13%). Socio-demographic, sexual and reproductive characteristics had no association with HPV prevalence. HPV 16 was the predominant type followed by 52, 58, 35 and 18 in order of their prevalence. The prevalence rate of HR-HPV among the positive cases was 23.8%, with 16% type specific persistence at 12 months. Overall, 91.7% women had cleared the infection and 3.2% was detected with new HPV infection in three years. HPV types 16 and 52 were the common persistent genotypes. HPV 16 is the most prevalent and persistent genotype in the Indian population. However, the current vaccine controlled genotype 18 is not among the top five persistent types. More data on diverse population within the country are required to draw conclusive evidence if a tailormade vaccine is the best option towards cervix cancer control.

The demands placed on global agricultural production arising out of population and income has grown almost tripled. In order to meet the increasing demand, it is mandatory to elevate the production by avoiding the usage of chemical fertilizers that makes the soil barren, unfertile and pollutes the environment as well as harmful to the consumers, where the biofertilizers came in to play. Microalgae can be played a pivotal role in building and maintaining soil fertility, subsequently increasing the growth as well as yield of several agricultural crops. But the reports on production of black gram were found to be scanty and thus this study focuses on its possible role. Algal extracts of varying concentrations were used as foliar sprays treatment and growth parameters; number of root nodules, yield attributes and quality parameters were measured. The implication of green algae as biofertilizer not only increases the yield characters but also improvises the soil physico-chemical properties. In addition, there was a subsequent increase in number of root modules, pigment compositions and yield attributes. Thus, the microalgae benefit the consumers by increasing the proximate composition and a mineral constituent is an added advantage. The results clearly depicted that the treatment of Chlorella vulgaris resulted in the identification of economically feasible, ecofriendly foliar spray treatment for the augmenting the maximum yield in black grams.

Biological fertilizers have ability to supply the main nutrient elements from unavailable form to available ones during biological processes and provide favorable conditions for germination and initial growth. An attempt was made to find out the efficacy of micro algae as biofertilizer of onion plants. The maximum micro/macro nutrient availability, the growth parameters viz., plant height, leaf numbers/plant leaves weight/plant, fresh weight/plant and dry weight were found to be higher in plants treated with cow dung + Spirulina platensis followed by cow dung + Chlorella vulgaris treated plants. The growth and yield of onion including leaf area, neck thickness, bulb length, bulb diameters and bulb weight and pigment contents as well as the Biochemical composition such as total soluble sugars, total phenols free amino acids and total indoles were observed to be maximum in treated plants. Similarly the anti-nutritional factors of onion and mineral analysis of onion were observed in high quantities in algal biofertilizer treated onion plants. Among the tested components the maximum contents were recorded in cow dung + S. platensis and cow dung + C. vulgaris treated onion plants followed by S. platensis, C. vulgaris and cow dung treated onion plants. It is noted that the all the values were higher than the control onion plants. Thus the two marine microalgae mixture treatment exhibited high growth and yield revealed the potential of the marine microalgae as fertilizer in onion cultivation.

We use high-resolution stereo DIC for the first time to study the evolution of strains in copper oligocrystals up to 20% applied tensile strain. Deformation heterogeneity is corroborated with grain-to-grain misorientation angles, Schmid factors, number of active slip systems, grain size and morphology, and geometric constraints from surrounding grains. None of these characteristics can be individually correlated to the resultant deformation, but together they dictate the strain evolution. We observe that the spatial distribution of strains changes substantially through the course of deformation. The steepness of the strain gradient across similar twin boundaries evolves differently through the course of deformation. Similarly, strain localization occurs in different grains at different stages of deformation. At the initial stages, some grains show the highest strains, but with lower strain rates than some neighbouring grains so that these latter grains show more severe strain localization than the former at the later stages of deformation.

Subtle changes in the microstructure and dynamics of the triblock copolymer L121, (ethylene oxide)5 (propylene oxide)68 (ethylene oxide)5i.e., E5P68E5, and sodium dodecylsulfate (SDS) system in aqueous medium were investigated using high-resolution nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) and small-angle neutron scattering (SANS) methods. NMR self-diffusion measurements helped us to understand the nature of binding of SDS with L121, and the formation of their mixed aggregates. These results showed that even at low [SDS] (∼2 mM), the addition of L121 stabilized the dynamics of SDS. Furthermore, the increase in [SDS] resulted in progressive changes in the diffusion behavior of both SDS and L121. 13C chemical shift analysis revealed that preferential binding of L121 occurred on the SDS micelle surface. Deuterium (2H) NMR spin-relaxation data evidenced that the formed mixed aggregates were non-spherical in terms of relaxation rate changes, and slowed the dynamics. The rotational correlation times of mixed aggregates were estimated from EPR analysis. A SANS study indicated the presence of uni- and multi-lamellar vesicles of L121 at low [SDS]. The vesicles transformed to mixed L121-SDS micelles in the presence of a higher [SDS]. This was supported by the measurements of 2H NMR spin-relaxation and EPR rotational correlation times.

Stereo digital image correlation (stereo DIC), a full-field deformation measurement technique, is increasingly being used to resolve strains at µm-length scale by using microscope-like imaging systems. Self calibration of these imaging systems is more cost-effective and convenient than the conventional target-based calibration. Though the use of self-calibrated stereo DIC systems has already been reported, less attention has been paid to improving the accuracy of these systems. In the present work, we improve the accuracy of a self-calibrated stereo DIC system, which is composed of two full-frame DSLR cameras coupled to macro lenses and is used for testing ASTM E8M sub-sized flat dog-bone specimens. First, we collect the images of two of the speckled test specimens that subtend an angle of 12° between them using an f/25 aperture. Our image-collection strategy leads to a convergent imaging configuration with viewpoints that range from −45° to 45° across two perpendicular directions. Next, we process the collected images in a commercial photogrammetric calibration software by using more than nine image points for computing each object point. We validate our findings on a rigid-body motion test and a uniaxial tensile experiment, and we observe an excellent agreement between the stereo-DIC measurements and the ground truth. Using our findings, the reprojection error of self calibration is improved from 0.3 pixel to 0.1 pixel. The error in the stereo-DIC strain measurements is always less than 3.4% with the improvements made to self calibration, whereas it is as large as 7.6% without them.

Digital Image Correlation (DIC) is a popular non-contact image-based full-field deformation measurement tool widely used in mechanics. In spite of its significant advantages, it is still primarily used as a post-processing tool due to its computational cost. In recent years, parallel computing platforms such as multi-core processors and Graphics Processing Units (GPUs) have been used to improve the speed of the DIC algorithm, with GPUs being well-suited for implementing data-parallel operations. Previous works have performed GPU-based DIC wherein each sub-image (i.e. a collection of a few pixels in the local neighborhood of a point of interest) is allocated to a single thread on the GPU, thus achieving parallelism across sub-images. However, this is not the only type of parallelism that is possible: one can also achieve parallelism within a sub-image as well as across whole images. The aim of this work is to efficiently implement 2D-DIC such that parallelism within a sub-image as well as across sub-images leads to considerable reduction in computation time. We use a heterogeneous framework consisting of an Intel Xeon octa-core CPU and an Nvidia Tesla K20C GPU card in this work. The CPU is used to handle image pre-processing, whereas the GPU is used to process four compute-intensive tasks: affine shape function computation, B-Spline interpolation, residual vector calculation and deformation vector update. Parallelization within and across sub-images is achieved in this work by efficient thread handling and use of pre-compiled BLAS libraries. In order to estimate the speedup provided by the GPU, the same four tasks were also evaluated on the octa-core CPU; a speedup of approximately 7 to 5 times was observed for a single sub-image whose size varies from 21×21 to 61×61 respectively. However, it is expected that for a larger number of sub-images, the GPU speedup will be higher and this is indeed the case: when the affine shape function computation and B-Spline interpolation steps were evaluated on 1869 21×21 pixel sub-images, the speedup was around a more impressive 453 times. Further GPU optimization as well as parallelization across image pairs is currently underway and even faster GPU-assisted DIC seems achievable.

Subtle changes in the microstructure and dynamics of the triblock copolymer L121, (ethylene oxide)

The biodegradable nanoparticles of chitosan have received a significance attention as potential drug delivery vehicles in the recent decades. The present study was carried out to extract chitosan nanoparticles from shrimp shell waste and characterized followed by its potential antibacterial activity. Pure chitosan nanoparticles (CNP) and tetracycline coated nanoparticles (TCNP) were prepared by the ionotropic gelation process. The prepared nanoparticles were characterised by UV visible spectrophotometer, SEM, XRD, FTIR, NMR, Nano size - Zeta potential analysis. Antibacterial activity was assessed using CNP and TCNP against 7 different strains of human pathogenic bacteria such as Staphylococcus aureus, Escherichia coli, Vibrio parahaemolyticus, Salmonella typhi, S. paratyphi, Pseudomonas aeruginosa and Bacillus subtilis. In the present study, the CNP and TCNP had exhibited a growth inhibition activity on bacteria at lower concentration and proved as a remarkable drug carrier.

Regulation and production of Fibrinolytic enzymes from bacterial sources especially from Bacillus strains has taken a leading role in the medical sciences for the treatment of cardiovascular disorders as it removes thrombus or clots adding to its significant role in curing human health issues saving millions. Significant progress has been made during the last few years on the studies of fibrinolytic enzymes in identifying, cloning, purification, characterization and overproduction of these for commercialization in medical sciences and in fields like detergents development. Production of fibrinolytic enzyme from Bacillus circulans was done using Nutrient broth medium. In addition, a strong fibrinolytic enzyme was purified from the cultivation media. The purified enzyme was almost homogeneous with other species of same genus, as examined by SDS−PAGE and sephadex G-75 column chromatography. The enzyme had an optimal pH of 7-12, an optimal temperature of 50 °C, for fibrin hydrolysis. The molecular mass estimated by gel filtration was 24 to36 KDa. Further studies for characterization and structural elucidation are necessary for their medicinal applications and molecular biological characteristics.

125 Background: Approximately 20% of cervical cancer deaths worldwide occur in India, most notably in rural areas. The key to addressing the cervical cancer epidemic is early detection and treatment of precancerous cervical lesions. Many studies that assess barriers to cervical cancer care in India focus on individual level factors, such as awareness and education. Given the disparities in cervical cancer in India, particularly between rural and urban settings, a comprehensive, multi-level approach to evaluating barriers and facilitators to care is needed. Methods: In December 2018, we used semi-structured interviews and direct observation of 15 community health workers, medical officers and gynecologic oncologists to explore the multi-level barriers and facilitators to cervical cancer care in rural Tamil Nadu. Data collection occurred within an existing organized cervical cancer screening program and was guided by the social-ecological model. Results: Barriers and facilitators to cervical cancer screening and treatment of precancerous lesions were identified at all levels of the social-ecological model. Barriers included fear of and travel distance to urban centers for treatment (individual), limited social support (interpersonal), lack of rural clinical facilities that provide treatment (organizational), competing community health initiatives (community), and lack of cohesive national screening and treatment guidelines (policy). Facilitators included travel distance to local screening services (individual), access to community health workers (interpersonal), institutional initiatives to increase screening access (organizational), mass awareness campaigns (community), and Tamil Nadu State priorities to improve cervical cancer care (policy). Conclusions: This assessment underscores the gap between cervical cancer screening and treatment in rural Tamil Nadu. This data will inform the development of a multi-faceted intervention, targeting all levels of the social-ecological model, to improve the linkage between cervical cancer screening and treatment for precancerous cervical lesions to decrease the burden of disease and mortality in India.

The primary output from several full-field deformation measurement techniques, e.g., Digital Image Correlation (DIC), is the displacement vector at a dense grid of points covering the area of interest. Since such displacement data inherently contain noise, they are usually smoothed first and then differentiated to obtain strains. Another common approach is to use finite-element shape functions for the strains and compute them by treating the measured displacements as nodal displacements. In this paper, we propose a novel method for strain calculation from full-field data, based on the multivariate analysis technique of Principal Component Analysis (PCA) using which we first obtain the singular values and singular vectors for each component of the displacement field. By choosing only the dominant singular values and their corresponding singular vectors, we show that the dimensionality of the displacement data is sharply reduced and a significant portion of the noise is eliminated. Moreover, the shapes of the dominant singular vectors offer physical insight into dominant deformation patterns. We demonstrate the accuracy of the proposed technique by applying it to two cases each of homogeneous and inhomogeneous strain fields and show that in all cases the proposed method yields excellent results. � 2013 Society for Experimental Mechanics.

Polycrystalline powder samples of rare earth doped Zinc borates were synthesized by high temperature solid state diffusion technique. Dosimetric characteristics of the phosphor like thermoluminescence glow curve, TL emission spectra, dose–response, fading studies, reproducibility and reusability studies were carried out on the synthesized phosphors. Among the different rare earth doped phosphors, thulium doped zinc borate was found to have a higher sensitivity. Hence detailed dosimetric characteristics of this phosphor were carried out. It is observed that the dose–response is linear from 10 mGy to 103 Gy in this phosphor. EPR measurements were carried out on unirradiated, gamma irradiated and annealed phosphors to identify the defect centers responsible for thermoluminescence. A TL model is proposed based on the EPR studies in these materials. Kinetic parameters were evaluated for the dosimetric peaks using various methods. The experimental results show that this phosphor can have potential applications in radiation dosimetry applications.

Introduction Currently, there is a lack of studies focusing on professional doctoral students’ and graduates’ perceptions of their learning environment, in particular, using a qualitative approach to elicit in-depth information. This article aims to contribute to the existing body of knowledge by systematically exploring, critically analysing and getting a deeper understanding of professional doctorate dental students’ and graduates’ insights into effective and ineffective clinical and physical learning environment characteristics. Methods The study included a total of 20 participants. Participants included 16 final-year Doctor of Clinical Dentistry (DClinDent) students and four dental specialists (graduates of the DClinDent programme). Semi-structured, individual interviews were used. Participants were asked to reflect upon and describe in detail their effective and ineffective learning environment experiences. The critical incident technique was used to guide the data collection. Data were analysed using a general inductive qualitative approach. Results Learning environment characteristics which participants associated with effective learning included the following: sufficient opportunities for comprehensive treatment planning; introduction to a number of patient treatment philosophies; a sufficient number of complex cases; clinically oriented research and assignment topics; a focus on clinical training in the programme generally; a research topic of a realistic depth and breadth, suitable for their ‘specialist training’ degree; and a well-resourced and updated physical infrastructure. On the other hand, most participants indicated that the absence of an adequate number of clinical cases, an overemphasis on research (as opposed to clinical practice) in the DClinDent programme and an ‘outdated’ physical infrastructure in the dental school clinics could hamper effective clinical learning. Conclusion These findings contribute to the meaningful advancement of the literature on learning environment strategies through the exploration of (and in-depth qualitative insights into) what facilitated effective learning by New Zealand professional doctorate candidates and graduates. These findings provide a starting point for reflection by international academic directors, educational developers, curriculum planners, programme managers and clinical teachers in respect of the further development of the learning environment. Although the findings from this study may not be directly transferable to all international contexts, they have the potential to contribute to the further development of theory in this area.

Introduction Research suggests that students' perceptions should be considered in any discussion of their education. However, to date, there has been no systematic examination of New Zealand postgraduate dental students' learning processes in both the research and clinical settings. This study aimed to obtain in-depth qualitative insights into student and graduate perspectives of effective and ineffective learning experiences during their postgraduate dental education. Methods Data were collected in 2010 using semi-structured individual interviews. Participants included 2010 final-year students and 2009 graduates of the University of Otago Doctor of Clinical Dentistry programme. Using the Critical Incident Technique, participants were asked to describe at least one effective and one ineffective learning experience in detail. Interview transcripts were analysed using a general inductive approach. Results Broad themes which emerged included supervisory approaches, characteristics of the learning process and characteristics of the physical learning environment. The focus of this article is to report and discuss the learning processes that participants identified as promoting and precluding effective learning experiences in the clinical and research settings. Students and graduates in the study had largely similar perspectives of learning processes likely to result in effective clinical and research learning. These included self-directed and collaborative learning; timely, constructive and detailed feedback with directions for further improvement; and discreet clinical feedback. Learning processes that precluded effective learning included unsupported and isolated learning, delayed and overly critical/destructive feedback and open criticism in the clinical context. Conclusion The in-depth findings of this study contribute to the scientific literature that identifies learning process characteristics which facilitate effective learning from New Zealand postgraduate students' and graduates' perspectives. Additional cross-sectional and longitudinal studies (both qualitative and quantitative) would lead to a better understanding of what constitutes effective teaching in postgraduate dental education.

Although much published school and higher education research have established a strong conceptual foundation for eliciting student feedback, this element is relatively poorly developed in dental education research. This paper examines 'student voice' as a conceptual/theoretical framework and justification for attending to students' perspectives in dental education. The aims of this review paper were: to explore the concept of student voice, including some pragmatic considerations and key critiques of listening to student feedback; to critically analyse key debates about the importance of a research focus on student perceptions using themes from the seminal and contemporary educational literature on student voice from the school, higher and dental educational sectors; to identify gaps in the dental education literature in relation to students' perceptions of their learning, and highlight some practical implications drawn from the 'student voice' literature for dental education; and to assist dental educational researchers in developing a strong rationale for listening to student voice in dental educational institutions. This paper is intended to assist dental educational researchers in justifying future research projects which require eliciting dental student feedback/perceptions.

Introduction: Research suggests that students’ perceptions should be considered in any discussion of their education, but there has been no systematic examination of New Zealand postgraduate dental students’ learning experiences. This study aimed to obtain in-depth qualitative insights into student and graduate perceptions of effective and ineffective learning in postgraduate dental education. Methods: Data were collected in 2010 using semi-structured individual interviews. Participants included final-year students and graduates of the University of Otago Doctor of Clinical Dentistry programme. Using the Critical Incident Technique, participants were asked to describe atleast one effective and one ineffective learning experience in detail. Interview transcripts were analysed using a general inductive approach. Results: Broad themes which emerged included supervisory approaches, characteristics of the learning process, and the physical learning environment. This paper considers students’ and graduates’ perceptions of postgraduate supervision in dentistry as it promotes or precludes effective learning. Effective learning was associated by participants with approachable and supportive supervisory practices, and technique demonstrations accompanied by explicit explanations. Ineffective learning was associated with minimal supervisor demonstrations and guidance (particularly when beginning postgraduate study), and aggressive, discriminatory and/or culturally insensitive supervisory approaches. Conclusion: Participants’ responses provided rich, in-depth insights into their reflections and understandings of effective and ineffective approaches to supervision as it influenced their learning in the clinical and research settings. These findings provide a starting point for the development of curriculum and supervisory practices, enhancement of supervisory and mentoring approaches, and the design of continuing education programmes for supervisors at an institutional level. Additionally, these findings might also stimulate topics for reflection and discussion amongst dental educators and administrators more broadly.

The lap-shear test is frequently used in the microelectronics industry to obtain mechanical properties of solder joints. In these tests, solder joints formed between slender metallic substrates are pulled apart in a simple shear configuration. Although it is known that calculation of stress-strain curves from lap shear tests is not straightforward due to rotation of the joints and strain inhomogeneity within the joint, these tests still find widespread use due to their simplicity and apparent ease of use. Chawla and co-workers [1, 2] show that the state of strain near the solder-substrate interfaces is significantly different from that in the interior of the joint and that this effect is only minimized for large joints. In the present work, we offer experimental evidence for these conclusions by presenting full-field strain measurements on solder joints in double-lap shear configuration, obtained using Digital Image Correlation (DIC). While confirming that significant strain gradients exist within the joint, the present work also indicates that a simple calculation of shear strain as axial displacement of the joint divided by joint thickness is misleading due to the presence of a significant gradient of the transverse displacement along the loading direction. This gradient persists through the course of the deformation and results in the actual average shear strain in the joint being smaller than that computed from the axial displacement alone.

Mannich aminomethylation reactions involving M(aa)2, where M = Cu, Ni and aa = glycine(gly), dl -alanine( dl -ala), l -alanine( l -ala), with formaldehyde and diethylmalonate have been carried out, resulting in carboxylate appended systems in high yield. All the compounds have been characterized by UV-Vis spectroscopy, infrared spectroscopy and elemental analysis. One of the synthesized complexes, (5,5-dicarboxyethyl-3,7-diazanonanedioato)copper(II) monohydrate, has been characterized by single crystal XRD and has been used as catalyst in the hydrogen peroxide-induced degradation of pyrocatechol violet (PCV) dye. The variations in the rate of degradation of the dye with respect to change in concentration of hydrogen peroxide, dye, catalyst and pH have been studied. Effect of addition of NaCl has been studied and a suitable mechanism based on the formation of free radical species during the degradation process has been proposed.

Mannich aminomethylation products have been prepared from one-pot template condensation of bis(glycinato)metal(II) complexes, M(gly)2, with formaldehyde and nitromethane. The synthesized compounds were characterized by suitable spectroscopic and analytical methods such as UV–Vis, infrared spectroscopy, elemental analysis, FAB mass, ESR, cyclic voltammetry, TGA and NMR. One of the synthesized products has been used as catalyst in the hydrogen peroxide induced degradation of pyrocatechol violet (PCV) dye.

The influence of the water soluble non-ionic tri-block copolymer PEO-PPO-PEO [poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)] i.e., E2P16E2 (L31) on the microstructure and self-aggregation dynamics of the anionic surfactant sodium dodecylsulfate (SDS) in aqueous solution was investigated using cloud point (CP), isothermal titration calorimetry (ITC), high resolution nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), and small-angle neutron scattering (SANS) measurements. CP provided the thermodynamic information on the Gibbs free energy, enthalpy, entropy and heat capacity changes pertaining to the phase separation of the system at elevated temperature. The ITC and NMR self-diffusion measurements helped to understand the nature of the binding isotherms of SDS in the presence of L31 in terms of the formation of mixed aggregates and free SDS micelles in solution. EPR analysis provided the micro-viscosity of the spin probe 5-DSA in terms of rotational correlation time. The SANS study indicated the presence of prolate ellipsoidal mixed aggregates, whose size increased with the increasing addition of L31. At a large [L31], SANS also revealed the progressive decreasing size of the ellipsoidal mixed aggregates of SDS-L31 into nearly globular forms with the increasing SDS addition. Wrapping of the spherical SDS micelles by L31 was also corroborated from (13)C NMR and SANS measurements.

The dinucleating ligand, tpbpd (tetrapyridyl biphenylenediamine) forms a dicopper complex with practically no electronic coupling between the two copper (II) centres. The EPR spectrum of the complex is consistent with coordination of each copper ion to two nitrogens of the binuclear ligand. Cyclic voltammogram of the complex also reveals that the two copper (II) centres have identical ligating environment. This dimeric copper (II) complex is found to be a very efficient catalyst for the cleavage of plasmid DNA in the absence of any added cofactor. The amount of conversion of supercoiled form (Form I) of plasmid to the open circular form (Form II) depends on the concentration of the complex as well as the duration of incubation of the complex with DNA. The maximum rate of conversion of the supercoiled form to the nicked circular form at pH 7.5 in the presence of 150 microM of the complex is found to be 1.8 x 10(-3) s(-1).

This paper addresses the growth of a void in a nonlinearly creeping material in the presence of the void-surface energy effect and void-surface diffusion driven by surface curvature gradients. Large strain finite element analysis of the coupled problem indicates that microstructural variables (porosity and void aspect ratio), as well as macroscopic deformation rates are strongly affected by the relative strength of the void-surface energy effect and the void-surface diffusion process vis-a-vis the rate of creep deformation in the bulk of the solid. The phenomenon is characterized by two-dimensionless groups, one measuring the strength of the surface diffusion process with respect to the nonlinear creep deformation in the interior of the solid, and the other the magnitude of the surface energy of the void in relation to the applied load and the size of the void. The computations reveal a rich variety of solutions that reflect a wide range of external load, material, and geometric parameters. Classical void growth studies that ignore both surface diffusion and surface energy effects are shown to recover only one case of this family of solutions. The computations also serve to quantitatively evaluate recent constitutive theories for porous nonlinear materials that account for continuously evolving microstructure, but do not include surface diffusion or surface energy effects.

[Cr(naphen)(H 2 O) 2 ] + , where naphen is 1,2-bis(naphthylideneamino)ethane having the basic salen moiety, has been characterized structurally. [Cr(naphen)(H 2 O) 2 ] + , which has an extended aromatic system and binds with calf thymus DNA (CT DNA) intercalatively, has been found to promote DNA cleavage in the presence of biological reductant such as ascorbate and oxidant like hydrogen peroxide. Results of electron paramagnetic resonance (EPR) experiments suggest involvement of hydroxyl radicals in the oxidative cleavage of DNA in the presence of the Cr(III) complex and hydrogen peroxide. The cell viability study on nicked DNA by [Cr(naphen)(H 2 O) 2 ] + has shown that the damage brought about to DNA could be repaired by Escherichia coli DNA repair enzymes.

In this paper, the issue of the identification of constitutive parameters of the Anand visco-plastic model is addressed using the Virtual Fields Method (VFM) in an infinitesimal deformation framework. By using VFM, one can take advantage of heterogeneous strain fields obtained by full-field experimental techniques, such as Digital Image Correlation (DIC). Since a wide range of strains and strain rates are sampled in a typical heterogeneous strain field, the number of experiments required to reliably estimate constitutive parameters, especially of rate-dependent materials, is significantly smaller than that needed if conventional experiments (such as uniaxial tension or pure shear configurations) leading to nominally homogeneous strain states were used. However, for such an approach to be successful, the test configuration and loading program should be such that all the constitutive parameters play a significant role (are 'activated') in the resulting strain fields. An analysis of the Anand constitutive model shows that 4 of the 8 parameters can only be found to within a multiplicative constant from full-field kinematic data. Therefore, one of these 4 constants is arbitrarily chosen and the activation of the remaining 7 material parameters is investigated by performing a series of one-element models. Detailed sensitivities of the VFM cost function to these material parameters are derived for a variety of normal stress to shear stress ratios and loading rates. Two main conclusions are drawn based on this one-element study: (i) the VFM cost function sensitivities to the material parameters do not vary significantly with loading ratios or rates, and (ii) 2 of the 7 material parameters are not activated for any of the loading ratios or rates considered. Based on the results of the finite-element study, a modified single lap-shear test configuration is designed to yield heterogeneous strains in the joint. Deformation data from a finite-element analysis of this experiment are used as inputs to a VFM routine to compute the Anand material parameters. Our results highlight that non-uniqueness of the identified parameters is a significant issue. The effect of the choice of the cost function and the loading profile on the inverse technique is also thoroughly investigated. � 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

A macroscopic constitutive potential has been developed for the deformation of a powder compact of cylindrical particles during pressure sintering. The derivation is based on finite-element simulations of the densification process that proceeds under the synergistic action of power-law creep deformation in the particles, evolution of the nonlinearly developing contact area between the particles, and interparticle and pore free-surface diffusional mass transport. Solution to this initial/boundary-value problem as deformation proceeds with time provides all necessary information for the calculation of the constitutive potential. The associated constitutive law predicts the densification rate of the powder compact at a given temperature and pressure in terms of material parameters, such as creep constants and diffusion coefficients, and reflects the role played in the densification process by various micromechanical features at the microscale such as the pore surface curvature. The model predictions are compared with the existing analytical models for plane strain densification and experimental data from sintering of copper wires by grain boundary and curvature-driven pore surface diffusion.

In this paper a micromechanical model of the interaction between densification mechanisms in powder compaction is presented. It accounts for elastic and power-law creep deformation of the bulk material along with stress-driven diffusion along the interparticle contact areas and curvature-driven diffusion on the pore surfaces. The finite element method is used to obtain the time-dependent deformation of the powder aggregate under plane strain deformation conditions. To reduce the number of case calculations needed to analyze the process, important dimensionless parameters that measure the relative magnitude of the densification mechanisms are identified. The calculated densification rates of the compact are compared with those predicted by analytical models, and conclusions are drawn on the significance of including the interaction between the densifying mechanisms in powder compaction models.