Search CORE

171 research outputs found

Enhancing Dental Radiographic Interpretation by Collaborating with AI Systems to Minimise Interpretive Errors

Author: Hegde Shwetha
Publication venue
Publication date: 01/01/2025
Field of study

Interpretive errors in dental radiology pose risks to patient care, often resulting from limitations in human capabilities, including visual detection, pattern recognition and clinical reasoning. Despite the critical role of radiographic assessments, there is a lack of evidence on the prevalence and cause of dental radiographic interpretation, their consequences and the solutions to mitigate them. This PhD thesis addressed this gap by investigating the factors contributing to interpretive errors and evaluating the effectiveness of machine learning (ML) algorithms as cognitive aids in improving diagnostic accuracy. The research involved a systematic review, surveys of Australian dental practitioners and students, and a comparative study assessing cognitive aids (ML algorithms and checklists) for diagnosing caries on bitewing radiographs. Errors of omission were most frequent, leading to undertreatment (72%), increased costs (62%), legal issues (82%) and reputational damage (75.6%). ML algorithms significantly enhanced diagnostic performance, achieving a higher sensitivity (79%) and diagnostic odds ratio (20.3) than the other methods. Participants in the ML group also reported greater confidence in diagnosis. However, concerns regarding accuracy, trust and job displacement remain barriers to AI adoption in dentistry. Beyond caries detection, the potential applications of AI span dentomaxillofacial radiology, implantology and prosthodontics. Additionally, this thesis developed a novel explainability method, enabling clinicians and computer scientists to interpret ML-generated outputs better. In conclusion, ML algorithms serve as valuable assistive cognitive aids, reducing interpretive errors and enhancing clinician confidence in dental radiology. The findings support AI integration as a means to improve diagnostic accuracy and clinical decision making in dentistry

Sydney eScholarship

Investigating the use of autonomic cloudbursts within the MapReduce framework

Author: Hegde Samprita
Publication venue
Publication date: 2011
Field of study

Today MapReduce framework is increasingly becoming a popular programming paradigm for data intensive computing, especially when there is ad-hoc data to be processed. In MapReduce programming paradigm, computation is done in two stages - a map stage and a reduce stage. The users simply have to provide a ‘map’ and a ‘reduce’ function and the underlying framework handles parallelizing and distributing the computation to worker nodes. Currently, the existing MapReduce frameworks work like a batch processing system where the cluster size is assumed to be static. We have developed a new objective-based scheduler which: 1. Provides both deadline and budget based scheduling capability 2. Provides cloudbursting capability where a computation can “burst” out to cloud whenever the existing datacenter is not capable of meeting the objective. Using these features, it is possible to run any MapReduce application subject to a user objective on any existing cluster by leveraging utility cloud resources. In this thesis, we use the Comet coordination engine and the MapReduce framework which is built on top of Comet Engine. The new autonomic scheduler works with the MapReduce Framework and manages the cluster as well as cloud in order to meet computation requirements. We have investigated the use of cloudbursting for MapReduce applications. We found that it is possible to run the application subject to both time and budget based objectives and successfully complete a job by efficiently using datacenter as well as cloud infrastructures.M.S.Includes bibliographical referencesby Samprita Hegd

Rutgers University Community Repository

Applications of Radiomics in Dentistry: A Scoping Review Protocol

Author: Farhana Pethani
Shwetha Hegde
Publication venue
Publication date: 2021
Field of study

This is protocol for a planned scoping review on the applications and impact of radiomics in dentistr

Apoptosis in oral epithelial dysplastic lesions and oral squamous cell carcinoma: A prognostic marker

Author: Veda Hegde
Shwetha Nambiar
Publication venue
Publication date: 2016
Field of study

Background: Apoptotic index (AI) using light microscopy as an indirect measure to assess the significance of apoptosis as a proliferative marker in dysplastic lesions and malignant epithelial lesions of the oral cavity. Aims: (1) To quantify the apoptotic bodies/cells in oral epithelial dysplastic (OED) lesions and oral squamous cell carcinoma (OSCC). (2) To measure AI in OED and OSCC. (3) To compare AI in OED and OSCC. Settings and Design: The proposed laboratory-based retrospective study involved the use of hematoxylin and eosin (H and E)-stained slides of previously diagnosed OED lesions and OSCC from institutional archives. Materials and Methods: This study constituted 50 cases, each of H and E-stained slides of previously diagnosed cases of OED and OSCC. AI was calculated as the number of apoptotic bodies/cells expressed as a percentage of the total number of nonapoptotic tumor/dysplastic cells counted in each case. Statistical Analysis Used: Nonparametric tests such as Kruskal–Wallis test and Mann–Whitney test were used. Results: There was a statistically significant increase in AI from OED to OSCC (P = 0.000). Conclusions: Further studies need to be undertaken to detect and understand the apoptotic mechanisms in the progression from OED to OSCC

Directory of Open Access Journals

Aradhya Pati & Bajantri & Hegde 2023, gen. nov.

Author: Bajantri Parashuram Prabhu
Hegde Gopalkrishna Dattatraya
Pati Sameer Kumar
Publication venue
Publication date: 15/05/2023
Field of study

Aradhya gen. nov. Type species. Aradhya placida sp. nov., by present designation; gender feminine. Diagnosis. Carapace transversely ovate, broader than long (CW/CL = 1.2–1.3), strongly inflated, deep (CH / CW = 0.6–0.7); dorsal surface generally smooth, glabrous, strongly arched; anterolateral margins cristate, lacking distinct serrations; front strongly deflexed, with narrow anterior margin (FW/CW = 0.25); frontal medial triangle incomplete, lateral margins indiscernible; epigastric and postorbital cristae poorly developed; external orbital angle indistinct; epibranchial tooth very low; branchial regions strongly inflated; cervical grooves relatively shallow, not reaching level of postorbital cristae; epistome posterior margin with distinct, triangular medial lobe and strongly sinuous lateral lobes (Figs. 2A, B, 3A, C, E, 4A–C). First, second maxillipeds each with long flagellum on exopod (Fig. 5A). TME lacking flagellum or with relatively short flagellum, reaching about half width of merus (Figs. 3G, 4D, 5B). Chelipeds relatively smooth, unequal in adult males (Figs. 2A, C, 3A–F) and subequal in adult females (Fig. 4A, C). Ambulatory legs slender, long; dactylus (P2–P5) recurved, longer than propodus, distal chitinous part very short or reduced (Figs. 2A, C, 3A–F, 4A–C). Male s2/s3 cristate, not reaching edge of sternum; male s3/s4 deep, broad, reaching edge of sternum (Figs. 2C, 3B, D, F, 5C). Male pleonal locking mechanism with low tubercles on submedial part of s5 (Fig. 5C). Male sternopleonal cavity relatively short, reaching anteriorly to level of mid-length of cheliped coxae (Figs. 2C, 3B, D, F, 5C). Male pleon relatively narrow, triangular; pleonal somite 6 trapezoidal, relatively narrow (proximal width ca. 1.3× medial length), shorter than telson, with gently concave lateral margins (Figs. 2C, 3B, D, F, 5D, 6A). Male telson narrow, elongated (medial length ca. 1.3–1.4× proximal width), with gently concave lateral margins (Figs. 2C, 3B, D, F, 5D, 6A). G1 relatively stout, long, tip reaching pleonal locking structure in situ; flexible zone small; ultimate article relatively stout, conical, relatively short, ca. 0.3× length of penultimate article, gently curved outwards at angle of ca. 15° from longitudinal axis, tip broad, tubular, dorsal flap absent; penultimate article relatively stout, outer margin strongly convex, shelf-like at basal half, inner margin characteristically convex distally (Figs. 3H, 5E, 6B–E). G2 distinctly shorter than G1, ca. 0.6× length of G1; ultimate article very short, ca. 0.2× length of penultimate article (Figs. 3I, 5F, 6F). Female pleon and telson ovate in outline; pleonal somite 6 subequal in length to telson; telson subtriangular, with broad, straight apex (Fig. 4E). Female pleopods 2–5 endopods slender and longer than exopods; pleopods 3–5 exopods conspicuously stouter than endopods (Fig. 4F). Vulvae on s6 close to each other (VD/SW = ca. 0.1), opening inwards, subovate, large, touching s5/s6 (Fig. 4G). Etymology. The genus is named after Miss Aaradhya Bajantri, the only daughter of the second author of the present paper. “ Aradhya ” also means “the first one” in Sanskrit. Crabs of this new genus are the first ones among the Indian gecarcinucid crabs observed to be non-aggressive and quite calm. Gender: feminine. Remarks. Among the Indian gecarcinucid genera, Aradhya gen. nov. most closely resembles Arcithelphusa, Cylindrotelphusa, Rajathelphusa, and Pavizham, because all possess an ovate, relatively narrow (CW/CL = 1.2– 1.4) and deep carapace (CH /CW = 0.5–0.7), with a narrow front (FW/CW = 0.25) and an incomplete frontal median triangle (Figs. 2A, B, 3A, C, E, 4A–C; see Pati et al. 2019: fig. 2A, B, D, E; Bahir & Yeo 2007: fig. 5A, B; Pati et al. 2017: figs. 11a, b, 13a, b; Raj et al. 2021: figs. 3A, B, 7A, C; Raj et al. 2022: figs. 3A, C, 8A, C). Aradhya gen. nov. is nevertheless distinguished from Arcithelphusa, Cylindrotelphusa, Rajathelphusa, and Pavizham mainly by its narrow and elongated male telson, the medial length ca. 1.3–1.4 times the proximal width (Figs. 2C, 3B, D, F, 5D, 6A) (vs. male telson relatively broader and shorter, the medial length ca. 0.9–1.1 times the proximal width; see Pati et al. 2019: fig. 2C, F; Bahir & Yeo 2007: fig. 5C; Pati et al. 2017: figs. 11h, 13h; Raj et al. 2021: figs. 3D, 7E; Raj et al. 2022: figs. 4A, 9C), the relatively stouter ultimate article of the G1 (Figs. 3H, 5E, 6B–E) (vs. G1 ultimate article relatively slender; see Pati et al. 2019: fig. 3E, F, J, O; Bahir & Yeo 2007: fig. 4A–C; Pati et al. 2017: figs. 12a–c, 14a–c; Raj et al. 2021: fig. 9B–D, F–H; Raj et al. 2022: figs. 5C–E, 10A–C), and the characteristically convex distal inner margin of the penultimate article of the G1 (Figs. 3H, 5E, 6B, C) (vs. G1 penultimate article with an almost straight distal inner margin; see Pati et al. 2019: fig. 3E, F, J, O; Bahir & Yeo 2007: fig. 4A, C; Pati et al. 2017: figs. 12a, b, 13a, b; Raj et al. 2021: fig. 9B, D, F, H; Raj et al. 2022: figs. 5C, E, 10A, C). Aradhya gen. nov. is morphologically closer to Arcithelphusa than any other Indian genera of gecarcinucid crabs as both genera share several features in common, including a strongly arched and generally smooth dorsal surface of the carapace (Figs. 2A, B, 3A, C, E, 4A–C; see Pati et al. 2019: fig. 2A, B, D, E), the absence of distinct serrations on the anterolateral margins of the carapace (Figs. 2A, 3A, C, E, 4A–C; see Pati et al. 2019: fig. 2A, D), the poorly developed epigastric and postorbital cristae (Figs. 2A, 3A, C, E, 4A–C; see Pati et al. 2019: fig. 2A, D), an indistinct external orbital angle (Figs. 2A, 3A, C, E, 4A–C; see Pati et al. 2019: fig. 2A, D), the relatively shallow and short cervical grooves (Figs. 2A, 3A, C, E, 4A–C; see Pati et al. 2019: fig. 2A, D), the absence of a flagellum or with a relatively short flagellum on the TME (Figs. 3G, 4D, 5B; see Pati et al. 2019: fig. 3B, N), the relatively smooth chelipeds (Figs. 2A, C, 3A–F, 4A–C; see Pati et al. 2019: fig. 2A–F), the relatively shorter male sternopleonal cavity reaching anteriorly to the level of mid-length of the cheliped coxae (Figs. 2C, 3B, D, F, 5C; see Pati et al. 2019: fig. 2C, F), the relatively stout G1 with a relatively shorter ultimate article, ca. 0.3–0.4 times the length of the penultimate article and the strongly convex outer margin of the penultimate article at the basal half (Figs. 3H, 5E, 6B–E; see Pati et al. 2019: fig. 3E, F, J, O), and the relatively shorter G2, ca. 0.6–0.7 times the length of the G1, with a very short ultimate article, ca. 0.2 times the length of the penultimate article (Figs. 3I, 5F, 6F; see Pati et al. 2019: fig. 3H, K, P). In addition to the shorter, elongated male telson and the stouter G1 ultimate article of the new genus, Aradhya gen. nov. is differentiated from Arcithelphusa by the relatively narrow male pleon (Figs. 2C, 3B, D, F, 5D, 6A) (vs. male pleon relatively broad; see Pati et al. 2019: figs. 2C, F, 3D), the relatively narrow male pleonal somite 6, the proximal width ca. 1.3 times the medial length (Figs. 2C, 3B, D, F, 5D, 6A) (vs. male pleonal somite 6 relatively broad, the proximal width ca. 1.7–1.8 times the medial length; see Pati et al. 2019: figs. 2C, F, 3D), the relatively small flexible zone of the G1 (Figs. 3H, 5E, 6B, C) (vs. G1 flexible zone relatively large; see Pati et al. 2019: fig. 3E, J, O), and the gently curved ultimate article of the G1 (Figs. 3H, 5E, 6B, D) (vs. G1 ultimate article strongly bent; see Pati et al. 2019: fig. 3E, F, J, O). Aradhya gen. nov. is found at a lower elevation (629 m) on an isolated mountain, which is surrounded by the Kali and Gangavali rivers, with deep valleys (Fig. 1). The known congeners of Arcithelphusa have been recorded from the Wayanad mountain plateau at slightly higher elevations (709–864 m) (Fig. 1). The Wayanad plateau is some 350 km away from the Bare where Aradhya gen. nov. occurs. The Western Ghats between the Wayanad plateau and the Bare has some mountain peaks and deep valleys (Fig. 1), which form “sky islands” acting as barriers between these two genera. The morphological differences and the geographical isolation between them corroborate the recognition of Aradhya gen. nov. Aradhya gen. nov. is further separated from Cylindrotelphusa and Rajathelphusa by the generally smooth dorsal surface of the carapace (Figs. 2A, 3A, C, E, 4A–C) (vs. carapace dorsal surface relatively rugose; see Bahir & Yeo 2007: fig. 5A; Pati et al. 2017: figs. 11a, 13a; Raj et al. 2021: figs. 3A, 7A; Raj et al. 2022: fig. 8A); the relatively shallow cervical grooves (Figs. 2A, 3A, C, E, 4A–C) (vs. cervical grooves relatively deep; see Bahir & Yeo 2007: fig. 5A; Pati et al. 2017: figs. 11a, 13a; Raj et al. 2021: figs. 3A, 7A; Raj et al. 2022: fig. 8A); the lack of a flagellum or at most with a shorter flagellum on the TME, which is about half the width of the merus (Figs. 3G, 4D, 5B) (vs. flagellum on the TME relatively long, reaching beyond half the width of the merus; see Pati et al. 2017: figs. 11i, 13i; Raj et al. 2021: figs. 3C, 7D; Raj et al. 2022: fig. 9A); the relatively smooth chelipeds (Figs. 2A, C, 3A–F, 4A–C) (vs. chelipeds relatively rugose; see Bahir & Yeo 2007: fig. 5A–C; Pati et al. 2017: figs. 11a, c, d, 13a, c, d; Raj et al. 2021: figs. 3A, 4G, 7A, G; Raj et al. 2022: figs. 8A, 9D); the gently concave lateral margins of the male telson (Figs. 2C, 3B, D, F, 5D, 6A) (vs. male telson with strongly concave lateral margins; see Bahir & Yeo 2007: fig. 5C; Pati et al. 2017: figs. 11h, 13h; Raj et al. 2021: figs. 3D, 7E; Raj et al. 2022: fig. 9C); the relatively stout G1 (Figs. 3H, 5E, 6B, D) (vs. G1 relatively slender; see Bahir & Yeo 2007: fig. 4A, B; Pati et al. 2017: figs. 12a, c, 14a, c; Raj et al. 2021: figs. 9B, F; Raj et al. 2022: fig. 10A); and the relatively stouter penultimate article of the G1, with the outer margin being strongly convex and shelf-like at the basal half (Figs. 3H, 5E, 6B, D) (vs. G1 penultimate article relatively slenderer, with the outer margin straight to relatively less convex at the basal half; see Bahir & Yeo 2007: fig. 4A, B; Pati et al. 2017: figs. 12a, c, 14a, c; Raj et al. 2021: figs. 9B, F; Raj et al. 2022: fig. 10A). The anterolateral margins of the carapace lack distinct serrations (Figs. 2A, 3A, C, E, 4A–C), and the G1 ultimate article is relatively shorter, ca. 0.3 times the length of the penultimate article (Figs. 3H, 5E, 6B) in Aradhya gen. nov.; whereas the anterolateral margins have distinct serrations (see Bahir & Yeo 2007: fig. 5A; Pati et al. 2017: figs. 11a, 13a), and the G1 ultimate article is relatively longer, ca. 0.4–0.6 times the length of the penultimate article (see Bahir & Yeo 2007: fig. 4A; Pati et al. 2017: figs. 12a, 14a) in Cylindrotelphusa. The epigastric and postorbital cristae are poorly developed (Figs. 2A, 3A, C, E, 4A–C), the external orbital angle is indistinct (Figs. 2A, 3A, C, E, 4A–C), and the G2 is relatively shorter, ca. 0.6 times the length of G1, with the ultimate article very short, ca. 0.2 times the length of the penultimate article (Figs. 3I, 5F, 6F) in Aradhya gen. nov.; whereas the epigastric and postorbital cristae are well-developed (see Raj et al. 2021: figs. 3A, 4A, B, 7A, B; Raj et al. 2022: fig. 8A, B), the external orbital angle is distinct (see Raj et al. 2021: figs. 3A, 4A, B, 7A, B; Raj et al. 2022: fig. 8A, B), and the G2 is relatively longer, ca. 1.0 times the length of G1, with the ultimate article long, ca. 0.5 times the length of the penultimate article (see Raj et al. 2021: fig. 9E, I; Raj et al. 2022: fig. 10D) in Rajathelphusa. Cylindrotelphusa is known to dwell in both lower and higher elevations (3–980 m), but it is restricted to the southern Indian states of Kerala and Tamil Nadu (Fig. 1). Cylindrotelphusa is probably not known beyond these two states, and this fact along with the morphological differences between Cylindrotelphusa and Aradhya gen. nov. support their generic separation. On the other hand, Rajathelphusa occurs at high mountains (750–1623 m altitude) of the Southern Western Ghats and is geographically clearly isolated from Aradhya gen. nov. of the Central Western Ghats mainly by the Palghat gap (Fig. 1). The superficial resemblance of Aradhya gen. nov. with Pavizham notwithstanding, the new genus is distinct from the latter genus mainly by the elongated male telson and the stouter G1 ultimate article. Other important differences between them are as follows: the carapace is deeper and strongly arched dorsally, CH /CW = 0.6–0.7 (Figs. 2A, B, 3A, C, E, 4A–C) in Aradhya gen. nov. (vs. carapace less deep and gently arched dorsally, CH /CW = 0.5 in Pavizham; see Raj et al. 2022: fig. 3A, C); the flagellum on the TME is missing or with a shorter flagellum, which reaches about half the width of the merus (Figs. 3G, 4D, 5B) in Aradhya gen. nov. (vs. flagellum on the TME almost as long as the width of the merus in Pavizham; see Raj et al. 2022: fig. 5A); the chelipeds are relatively smooth (Figs. 2A, C, 3A–F, 4A–C) in Aradhya gen. nov. (vs. chelipeds relatively rugose in Pavizham; see Raj et al. 2022: figs. 3A, 4D); the male s2/s3 does not reach the edges of the sternum (Figs. 2C, 3B, D, F, 5C) in Aradhya gen. nov. (vs. male s2/s3 reaching the edges of the sternum in Pavizham; see Raj et al. 2022: figs. 3D, 4B, 5B); the male sternopleonal cavity is relatively shorter, reaching anteriorly to the level of mid-length of the cheliped coxae (Figs. 2C, 3B, D, F, 5C) in Aradhya gen. nov. (vs. male sternopleonal cavity relatively longer, reaching anteriorly to the level of the anterior margin of the cheliped coxae in Pavizham; see Raj et al. 2022: figs. 3D, 4B); the male pleon is relatively narrow, with the pleonal somite 6 being relatively narrow, the proximal width ca. 1.3 times the medial length (Figs. 2C, 3B, D, F, 5D, 6A) in Aradhya gen. nov. (vs. male pleon relatively broad, with relatively broad pleonal somite 6, the proximal width ca. 1.7 times the medial length in Pavizham; see Raj et al. 2022: figs. 3D, 4A); the outer margin of the G1 penultimate article is strongly convex and shelf-like at the basal half (Figs. 3H, 5E, 6B, C) in Aradhya gen. nov. (vs. G1 penultimate article with a less convex outer margin at the basal half in Pavizham; see Raj et al. 2022: fig. 5C–E); and the G2 is short, ca. 0.6 times the length of G1, with the ultimate article very short, ca. 0.2 times the length of the penultimate article (Figs. 3I, 5F, 6F) in Aradhya gen. nov. (vs. G2 long, ca. 1.4 times the length of G1, with the ultimate article long, ca. 0.6 times the length of the penultimate article in Pavizham; see Raj et al. 2022: fig. 5F). Aradhya gen. nov. is also separated from Pavizham geographically as both genera are apart from each other by a distance of about 650 km with several mountain peaks and deep valleys, including the prominent Palghat gap between the Central- and Southern Western Ghats (Fig. 1). Crabs of the following genera are likely to coexist with Aradhya gen. nov.: Barusa Pati & Yeo, 2022; Barytelphusa Alcock, 1909; Ghatiana Pati & Sharma, 2014; Vanni Bahir & Yeo, 2007; and Vela Bahir & Yeo, 2007 (cf. Pati & Thackeray 2021; Pati & Yeo 2022; Pati et al. 2022a, 2023; unpublished data). Aradhya gen. nov. need not be confused with those genera because its carapace is relatively deep, with the front relatively narrow (Fig. 2B) (vs. carapace relatively low, with the front relatively wider; see Bahir & Yeo 2007: fig. 32B; Pati & Thackeray 2021: fig. 4C; Pati & Yeo 2022: figs. 1B, 10B; Pati et al. 2022a: fig. 3B; Pati et al. 2023: fig. 2B). In Aradhya gen. nov., the epigastric and postorbital cristae are poorly developed (Fig. 2A) (vs. epigastric and postorbital cristae well developed in Barusa and Barytelphusa; see Pati & Yeo 2022: figs. 1A, 10A), the external orbital angle is indistinct (Fig. 2A) (vs. external orbital angle distinct in Barusa and Barytelphusa; see Pati & Yeo 2022: figs. 1A, 10A), the flagellum on the TME is absent or relatively short (Figs. 3G, 4D, 5B) (vs. flagellum on the TME relatively long in Barusa and Barytelphusa; see Pati & Yeo 2022: fig. 1D), the male s3/s4 is distinct (Fig. 5C) (vs. male s3/s4 indiscernible in Barusa and Barytelphusa; see Pati & Yeo 2022: figs. 1F, 10C), and the G1 ultimate article is relatively stout and short, ca. 0.3 times the length of the penultimate article (Fig. 6B) (vs. G1 ultimate article relatively slender and long, ca. 0.6–0.8 times the length of the penultimate article in Barusa and Barytelphusa; see Pati & Yeo 2022: figs. 3A, 7I). The G2 is shorter than the G1, with the ultimate article very short, ca. 0.2 times the length of the penultimate article in Aradhya gen. nov. (Fig. 6B, F); whereas the G2 is as long as or longer than the G1, with the ultimate article relatively long, ca. 0.3–0.5 times the length of the penultimate article in Vanni and Vela (see Bahir & Yeo 2007: fig. 31C, G; Pati et al. 2023: fig. 4E, I). Aradhya gen. nov. is further separated from Ghatiana by the distinct male s2/s3 and s3/s4 (Fig. 5C) (vs. male s2/s3 and s3/s4 indistinct in Ghatiana; see Pati & Thackeray 2021: fig. 5C; Pati et al. 2022a: fig. 3C); the relatively short male sternopleonal cavity, which reaches anteriorly to the level of mid-length of the cheliped coxae (Fig. 5C) (vs. male sternopleonal cavity relatively long, reaching anteriorly beyond the level of the bases of the third maxillipeds in Ghatiana; see Pati & Thackeray 2021: fig. 5C; Pati et al. 2022a: fig. 3C); and the relatively stouter ultimate article of the G1 (Fig. 6B) (vs. G1 ultimate article relatively slender in <

ZENODO

Apoptosis detection modalities: A brief review

Author: K. Shwetha Nambiar
Veda Hegde
Publication venue
Publication date: 01/01/2016
Field of study

Crossref

Design and Properties of SWCNT-Polyetherimide Nanocomposites

Author: Hegde M.
Hegde M. (author)
Publication venue
Publication date: 28/01/2014
Field of study

The main objective of the research presented in the thesis is to explore non-functionalized single-walled carbon nanotubes (SWCNTs) as reinforcing nanofiller in all-aromatic thermoplastic poly(etherimide)s. The role of polymer geometry and how this affects the morphological and thermo-mechanical properties of the SWCNT-PEI nanocomposites were investigated. The inclusion of SWCNTs in aBPDA-P3, an amorphous non-linear polyetherimide matrix had no effect on the morphology and thermo-mechanical properties of the matrix. In ODPA-P3, a more linear amorphous polyetherimide matrix, the SWCNTs act as a nucleating agent with the polymer crystallinity increasing linearly with SWCNT content to 45% (at 2.4 vol.% SWCNT). TEM measurements showed that the SWCNTs become embedded within the crystal lattice of the polymer matrix. The result is a significant increase in thermo-mechanical properties; the storage modulus (E’) above Tg increased by a factor 105 GPa and the elastic modulus from stress-strain measurements increased with a reinforcement efficiency (dY/dVf) of 170 GPa. Our findings show that the polyetherimide backbone geometry determines whether the polymer is good host for SWCNTs. To investigate the role of polymer morphology on the final nanocomposite properties, we compared SWCNT nanocomposites based on amorphous ODPA-P3 with that of a semi-crystalline BPDA-P3. In semi-crystalline BPDA-P3, the SWCNTs were found to exist within the amorphous domains of the BPDA-P3 matrix. Using the Halpin-Tsai equation, the effective SWCNT modulus was found to be ~100 GPa which is significantly lower than the 640 GPa obtained for ODPA-P3 SWCNT. By application of an isothermal step above the Tm of the nanocomposites during imidization, the conversion of the crystalline ordering around the CNT to an amorphous morphology in ODPA-P3 results in a significant reduction in the reinforcement efficiency, i.e. from 170 GPa to 30 GPa. The reinforcement efficiency for semi-crystalline and amorphous BPDA-P3 nanocomposites remains constant at 30 GPa. By comparing reinforcement efficiencies of ODPA-P3 with SWCNTs residing in contrasting morphologies, we have shown that having a crystalline-SWCNT interface is critical in obtaining nanocomposites with improved thermo-mechanical performance over the neat polymer. We have also compared ODPA-P3 nanocomposites based on 0-D fullerenes (C60) with 1-D SWCNTs. The inclusion of C60 in ODPA-P3 induces crystallization (40% at 0.6 vol.%) of the polymer matrix. At 40% crystallinity, the E’ above Tg in ODPA-P3 C60 is a mere 0.01 GPa, which is substantially lower than the 1.2 GPa observed in the ODPA-P3 SWCNT nanocomposite. By comparing mechanical property improvements as a function of crystal content in the matrix, the elastic modulus of nanocomposites with 100% crystal content could be calculated and was found to be 5.8 GPa for ODPA-P3 C60 and 10.4 GPa for ODPA-P3 SWCNT. The presence of the cylindrical crystalline coating around the CNT was found to aid in stress-transfer from the matrix to the SWCNTs.Novel Aerospace MaterialsAerospace Engineerin

TU Delft Repository

The Efficacy Of Dental Imaging In Crack Teeth Diagnosis, A Systematic Review

Author: ATIEH SADR
XIaoyan Zhou
Shwetha Hegde
Publication venue
Publication date: 2025
Field of study

This systematic review aims to consolidate the existing evidence using a hierarchical model to analyse the demonstrated levels of diagnostic efficacy of dental imaging in a cracked tooth

Author response

Author: Ramanujan S Hegde
Eszter Zavodszky
Publication venue
Publication date: 16/05/2019
Field of study

Crossref

A Metric to Quantify the Hazard Avoidance Capability of Vehicles

Author: Hegde Anoosh (author)
Publication venue
Publication date: 28/08/2019
Field of study

Safety is an important parameter considered during the design of Advanced Driver Assistance Systems and fully autonomous vehicles.One of the ways to assess the road vehicle's safety is by estimating the likelihood with which the vehicle can react to prevent the danger. In the presence of an impending collision (hazard), the trajectory planning module in the autonomous vehicle would generate few escape trajectories to avoid the collision.The escape trajectory is chosen such that it maximises the safety of the vehicle based on certain criteria.One of these criteria is the vehicle's avoidance capability throughout the trajectory.This thesis presents an avoidance metric that is constructed using a computational procedure to quantify the avoidance capability of the vehicle in both pure longitudinal (1-D) and, combination of both lateral and longitudinal (2-D) scenario.The key idea is (a) Propagate forward in time the current state of the host (and the world) using a vehicle model to estimate the host's reachable set of states.(b) Carefully select a set of samples from the reachable set and repeat the propagation.(c) At every step, the trajectories that lead to collisions are eliminated.The ratio of the size of the region spanned by the remaining trajectories to the size of the region spanned by all the trajectories (including those that lead to collision) then constitute the estimate of the host's avoidance capability.Through simulations on specific use-cases, for a pure longitudinal motion, on comparison with Brake Threat Number (BTN), it was observed that the metric (from the proposed computational procedure) performs very similar to BTN and also takes a low computational time of 380 [ms] for a time horizon of 2.5 [s].However, in the presence of dynamic obstacles, major differences in performance (such as discontinuities, step-like variation), were observed between the metric and BTN.In the case of the combination of both lateral and longitudinal motion, the computation time for the proposed procedure was found to be independent of the number of obstacles.To reason about the accuracy of the approximation of the reachable set for a double integrator model obtained from the proposed procedure, it was compared with the nodes obtained from Rapidly-exploring Random Trees (RRT), an under-approximation, and found that the nodes lie either very close or well within the boundary of the approximation.However, the computation time for the proposed procedure took around 10.87 [s] which comes as a major drawback.Mechanical Engineerin

TU Delft Repository