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352. Notes.

Author

Milner, G. W. C., Tylor, C. G., Peach, S. M., Murthy, A. R. Vasudeva, Narayan, V. A., Rao, M. R. A., Tyler, J. F. C., Weston, R. E., and Hayden, K. J.

Published
1956
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353. Studies on Tryptophan-Niacin Metabolism in Streptozotocin Diabetic Rats

Author

Narayan V Shastri and Nilkanth R Akarte

Subjects
Male, Niacinamide, Xanthurenates, medicine.medical_specialty, Endocrinology, Diabetes and Metabolism, Urine, Streptozocin, Eating, chemistry.chemical_compound, Internal medicine, Diabetes Mellitus, Internal Medicine, medicine, Animals, Fluorometry, Xanthurenic acid, Chemistry, Dietary intake, Nicotinic Acids, Tryptophan, nutritional and metabolic diseases, Streptozotocin, Diet, Rats, Endocrinology, Excretory system, Niacin metabolism, Niacin, medicine.drug
Abstract

Streptozotocin diabetic male albino rats were observed to exhibit faulty conversion of tryptophan into niacin. Streptozotocin-injected rats, kept on niacin-deficient diet and given a dose of L-tryptophan (intraperitoneal or oral) excreted comparatively less quantities of niacin and N1-methylnicotinamide in urine than the control nondiabetic rats. Rats continued to show this effect for at least three months after streptozotocin injection. Dietary intake was found to have no influence on the excretory pattern. Streptozotocin diabetic rats were also observed to excrete greater amounts of xanthurenic acid and other tryptophan metabolites on tryptophan administration as compared to the nondiabetic rats.

Published
1974
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354. Cirrhotic portal hypertension: Morbidity of continued alcoholism

Author

Volker F. Eckardt, Robert H. Resnick, William F. H. Yee, Jonathan L. Shurberg, and Narayan V. Pande

Subjects
medicine.medical_specialty, Hepatology, business.industry, Encephalopathy, Portacaval, Gastroenterology, Jaundice, medicine.disease, Group A, Group B, Internal medicine, Ascites, medicine, Portal hypertension, medicine.symptom, business, Varices
Abstract

The morbidity of continued alcoholism was examined among 172 cirrhotic patients participating in controlled trials of portacaval shunts. Of 159 surviving more than 30 days, 76 continued drinking (group A), 68 became abstinent (group B), and 15 (group C) were chronically institutionalized (without potential access to alcohol). The mean number of days in hospital postrandomization and prevalence of bleeding varices, ascites, and encephalopathy were similar for A and B ( P > 0.05 for each comparison). Jaundice at hospital readmission, however, occurred in 50% of group A but in only 28% of group B ( P

Published
1978
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355. Stability of magnetohydrodynamic shock waves

Author

Narayan V. Deshpande and Martin Lessen

Subjects
Physics, Shock wave, symbols.namesake, Shock (fluid dynamics), Mach number, Wave propagation, Normal mode, symbols, Magnetohydrodynamic drive, Mechanics, Magnetohydrodynamics, Condensed Matter Physics, Magnetic field
Abstract

The stability of oblique magnetohycirodynamic shock waves is studied with respect to a disturbance that excites magneto-acoustic waves. The problem is solved numerically by the normal mode analysis and it is shown that slow shocks are unstable in the sense that the disturbance grows exponentially with time. Growth rates are calculated for a particular Mach number and for different values of the magnetic field and obliqueness. The fast shock appears to be stable.

Published
1967
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356. Defective Vascularization of HIF-1α-Null Embryos Is Not Associated with VEGF Deficiency but with Mesenchymal Cell Death

Author

Lori E. Kotch, Erik Laughner, Gregg L. Semenza, and Narayan V. Iyer

Subjects
Male, Vascular Endothelial Growth Factor A, Apoptosis, Endothelial Growth Factors, Cardiovascular System, Mesoderm, Tissue culture, Mice, 0302 clinical medicine, Genes, Reporter, Cells, Cultured, Mice, Knockout, 0303 health sciences, Lymphokines, Cell Death, Vascular Endothelial Growth Factors, Gene Expression Regulation, Developmental, Nuclear Proteins, Cell Hypoxia, DNA-Binding Proteins, 030220 oncology & carcinogenesis, Female, Hypoxia-Inducible Factor 1, Stem cell, medicine.symptom, Programmed cell death, Biology, Transfection, Vascular Regression, Models, Biological, Andrology, 03 medical and health sciences, Embryonic and Fetal Development, Oxygen Consumption, medicine, Animals, RNA, Messenger, Molecular Biology, Transcription factor, Fetal Death, 030304 developmental biology, Mesenchymal stem cell, Cell Biology, Hypoxia (medical), Hypoxia-Inducible Factor 1, alpha Subunit, Embryonic stem cell, Molecular biology, Oxidative Stress, Glucose, Microscopy, Electron, Scanning, Endothelium, Vascular, Developmental Biology, Transcription Factors
Abstract

Hypoxia-inducible factor 1 (HIF-1) is a dimeric transcription factor composed of HIF-1alpha and HIF-1beta subunits that plays an essential role in mammalian O2 homeostasis. In Hif1a-/- knockout mice, complete deficiency of HIF-1alpha resulted in cardiac and vascular malformations and embryonic lethality at E10.5. Between E8. 75 and E9.25 striking vascular regression and abnormal remodeling occurred in the cephalic region concomitant with marked mesenchymal cell death. Similar vascular defects were observed in HIF-1alpha- and VEGF-deficient embryos and VEGF mRNA expression was not induced by hypoxia in Hif1a-/- embryonic stem cells. Surprisingly, Hif1a-/- embryos demonstrated increased VEGF mRNA expression compared to wild-type embryos. In tissue culture cells, VEGF mRNA expression was induced by glucose deprivation independent of HIF-1alpha, providing a mechanism for increased VEGF mRNA expression in Hif1a-/- embryos, in which absence of adequate tissue perfusion resulted in both O2 and glucose deprivation. Rather than being associated with VEGF deficiency, the vascular defects in Hif1a-/- embryos were spatially correlated with cell death, the onset of which preceded vascular regression.

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358. Synthesizing Optimal Waste Blends

Author

Narayan, V., Diwekar, U. M., and Hoza, M.

Abstract

Vitrification of tank wastes to form glass is a technique that will be used for the disposal of high-level waste at Hanford. Process and storage economics show that minimizing the total number of glass logs produced is the key to keeping cost as low as possible. The amount of glass produced can be reduced by blending of the wastes. The optimal way to combine the tanks to minimize the volume of glass can be determined from a discrete blend calculation. However, this problem results in a combinatorial explosion as the number of tanks increases. Moreover, the property constraints make this problem highly nonconvex where many algorithms get trapped in local minima. In this paper we examine the use of different combinatorial optimization approaches to solve this problem. A two-stage approach using a combination of simulated annealing and nonlinear programming (NLP) is developed. The results of different methods such as the heuristics approach based on human knowledge and judgment, the mixed integer nonlinear programming (MINLP) approach with GAMS, and branch and bound with lower bound derived from the structure of the given blending problem are compared with this coupled simulated annealing and NLP approach.

Published
1996

359. Structures of zinc finger domains from transcription factor Sp1. Insights into sequence-specific protein-DNA recognition.

Author

Narayan, V A, Kriwacki, R W, and Caradonna, J P

Abstract

The carboxyl terminus of transcription factor Sp1 contains three contiguous Cys2-His2 zinc finger domains with the consensus sequence Cys-X2-4-Cys-X12-His-X3-His. We have used standard homonuclear two-dimensional NMR techniques to solve the solution structures of synthetic peptides corresponding to the last two zinc finger domains (Sp1f2 and Sp1f3, respectively) of Sp1. Our studies indicate a classical Cys2-His2 type fold for both the domains differing from each other primarily in the conformation of Cys-X2-Cys (beta-type I turn) and Cys-X4-Cys (beta-type II turn) elements. There are, however, no significant differences in the metal binding properties between the Cys-X4-Cys (Sp1f2) and Cys-X2-Cys (Sp1f3) subclasses of zinc fingers. The free solution structures of Sp1f2 and Sp1f3 are very similar to those of the analogous fingers of Zif268 bound to DNA. There is NMR spectral evidence suggesting that the Arg-Asp buttressing interaction observed in the Zif-268.DNA complex is also preserved in unbound Sp1f2 and Sp1f3. Modeling Sp1-DNA complex by overlaying the Sp1f2 and Sp1f3 structures on Zif268 fingers 1 and 2, respectively, predicts the role of key amino acid residues, the interference/protection data, and supports the model of Sp1-DNA interaction proposed earlier.

Published
1997

365. Real‐world experience of immune checkpoint inhibitors in patients with solid tumours in the Top End of the Northern Territory, Australia from 2016 to 2021: a retrospective observational cohort study.

Author

Miller, Abigail R., Balino, Aries, Tun Min, Sandy, Downton, Teesha, Karanth, Narayan V., Backen, Alison, and Charakidis, Michail

Subjects
*THERAPEUTIC use of antineoplastic agents, *RISK assessment, *MORTALITY, *DRUG side effects, *RURAL health, *SCIENTIFIC observation, *RETROSPECTIVE studies, *DESCRIPTIVE statistics, *TREATMENT duration, *SEVERITY of illness index, *IMMUNE checkpoint inhibitors, *LONGITUDINAL method, *MEDICAL records, *ACQUISITION of data, *RURAL conditions, *TUMORS, *CONFIDENCE intervals, *HEALTH equity, *HEALTH of indigenous peoples, *INDIGENOUS Australians, *PATIENTS' attitudes, *URBAN health
Abstract

Background: Use of immune checkpoint inhibitors is growing, but clinical trial data may not apply to Indigenous patients or patients living in remote areas. Aims: To provide real‐world incidence of immune‐related adverse events (irAE) in the Top End of the Northern Territory and compare incidence between demographic subgroups. Methods: This retrospective, observational, cohort study collected data from electronic records of patients living in the Top End with solid organ cancer treated with immunotherapy between January 2016 and December 2021. The primary outcome was cumulative incidence of any‐grade and severe irAE. Secondary outcomes were overall survival, treatment duration and reason for treatment discontinuation. Results: Two hundred and twenty‐six patients received immunotherapy. Forty‐eight (21%) lived in a remote or very remote area, and 36 (16%) were Indigenous. Cumulative incidence of any‐grade irAE was 54% (122/226 patients); incidence of severe irAE was 26% (59/226 patients). Rates were similar between Indigenous and non‐Indigenous patients of any‐grade (42% vs 56%, P = 0.11) and severe (11% vs 18%, P = 0.29) irAE. However, Indigenous patients had shorter treatment duration, more frequently discontinued treatment due to patient preference and appeared to have shorter median overall survival than non‐Indigenous patients (17.1 vs 30.4 months; hazard ratio (HR) = 1.5, 95% confidence interval (CI) = 0.92–2.66). There was no difference in mortality between remote and urban patients (median overall survival 27.5 vs 30.2 months; HR = 1.1, 95% CI = 0.7–1.7). Conclusions: Rates of irAE in our cohort are comparable to those in the published literature. There was no significant difference in any‐grade or severe irAE incidence observed between Indigenous and non‐Indigenous patients. [ABSTRACT FROM AUTHOR]

Published
2024
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366. The molecular characteristics of non‐small cell lung cancer in the Northern Territory's Top End.

Author

Downton, Teesha Dzu Fun, Wing, Kristof, Cosentino, Stevie Brooke, and Karanth, Narayan V

Subjects
*ANAPLASTIC lymphoma kinase, *EPIDERMAL growth factor receptors, *FISHER exact test, *INDIGENOUS Australians, *LUNG cancer
Abstract

Aim: Indigenous Australians with lung cancer have poorer survival than non‐Indigenous Australians. The reasons for the disparity are not fully understood and this study hypothesized that there may be a difference in the molecular profiles of tumors. The aim of this study, therefore, was to describe and compare the characteristics of non‐small cell lung cancer (NSCLC) in the Northern Territory's Top End, between Indigenous and non‐Indigenous patients, and describe the molecular profile of tumors in the two groups. Methods: A retrospective review was conducted of all adults with a new diagnosis of NSCLC in the Top End from 2017 to 2019. Patient characteristics assessed were Indigenous status, age, sex, smoking status, disease stage, and performance status. Molecular characteristics assessed were epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), v‐raf murine sarcoma viral oncogene homolog B (BRAF), ROS proto‐oncogene 1 (ROS1), Kirsten rat sarcoma viral oncogene homolog (KRAS), mesenchymal‐epithelial transition (MET), human epidermal growth factor receptor 2 (HER2), and programmed death‐ligand 1 (PD‐L1). Student's t‐test and Fisher's Exact Test were used in the statistical analysis. Results: There were 152 patients diagnosed with NSCLC in the Top End from 2017–2019. Thirty (19.7%) were Indigenous and 122 (80.3%) were non‐Indigenous. Indigenous patients compared to non‐Indigenous patients were younger at diagnosis (median age 60.7 years versus 67.1 years, p = 0.00036) but were otherwise similar in demographics. PD‐L1 expression was similar between Indigenous and non‐Indigenous patients (p = 0.91). The only mutations identified among stage IV non‐squamous NSCLC patients were EGFR and KRAS but testing rates and overall numbers were too small to draw conclusions about differences in prevalence between Indigenous and non‐Indigenous patients. Conclusion: This is the first study to investigate the molecular characteristics of NSCLC in the Top End. [ABSTRACT FROM AUTHOR]

Published
2024
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367. Significance of lung nodules detected on chest CT among adult Aboriginal Australians – a retrospective descriptive study.

Author

Ng, Lai Yun, Howarth, Timothy P., Doss, Arockia X., Charakidis, Michail, Karanth, Narayan V., Mo, Lin, and Heraganahally, Subash S.

Subjects
*PULMONARY nodules, *ABORIGINAL Australians, *COMPUTED tomography, *PULMONARY function tests, *LUNG cancer
Abstract

Introduction: There are limited data on chest computed tomography (CT) findings in the assessment of lung nodules among adult Aboriginal Australians. In this retrospective study, we assessed lung nodules among a group of adult Aboriginal Australians in the Northern Territory of Australia. Methods: Patients who underwent at least two chest CT scans between 2012 and 2020 among those referred to undergo lung function testing (spirometry) were included. Chest CT scans were assessed for the number, location, size and morphological characteristics of lung nodules. Results: Of the 402 chest CTs assessed, 75 patients (18.7%) had lung nodules, and 57 patients were included in the final analysis with at least two CT scans available for assessment over a median follow‐up of 87 weeks. Most patients (68%) were women, with a median age of 58 years and smoking history in 83%. The majority recorded only a single nodule 43 (74%). Six patients (10%) were diagnosed with malignancy, five with primary lung cancer and one with metastatic thyroid cancer. Of the 51 (90%) patients assessed to be benign, 64 nodules were identified, of which 25 (39%) resolved, 38 (59%) remained stable and one (1.8%) enlarged on follow‐up. Nodules among patients with malignancy were typically initially larger and enlarged over time, had spiculated margins and were solid, showing no specific lobar predilection. Conclusions: Most lung nodules in Aboriginal Australians are likely to be benign. However, a proportion could be malignant. Further prospective studies are required for prognostication and monitoring of lung nodules in this population. [ABSTRACT FROM AUTHOR]

Published
2024
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368. Autonomous systems: Indoor drone navigation.

Author

Ashwin, Iyer, Rajagopal, Manojkumar, Naren, M., Narayan, V. Santosh, and Murugan, Bala

Subjects
*AERONAUTICAL navigation, *NAVIGATION
Abstract

In this research work, we present an advanced autonomous indoor navigation system for drones, leveraging the Nav2 navigation system framework and SLAM Toolbox in ROS (Robot Operating System) within the Gazebo simulation environment. Unlike previous implementations which primarily focused on terrestrial robots and land vehicles, our system introduces significant innovations in the context of UAVs (Unmanned Aerial Vehicles). The proposed solution addresses the critical challenge of precise localization and mapping in complex indoor settings, where GPS signals are unavailable. This research contributes to the field by showcasing a simulated quadcopter's capability to autonomously navigate and traverse obstacles in an indoor environment. Distinctly, our approach extends the functionalities of the Nav2 framework, previously validated in ground vehicles, to UAVs, demonstrating its adaptability and potential for broader applications. This innovation represents a substantial leap over existing systems, offering a novel use case for indoor UAV navigation, which is critical for tasks such as emergency rescue operations, inspection, and surveillance in GPS-denied environments. [ABSTRACT FROM AUTHOR]

Published
2024
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370. Fluid Mechanics of Bubble Growth and Collapse in a Thermal Ink Jet Printhead

Author

Narayan V. Deshpande

Subjects
Physics::Fluid Dynamics, Physics, Bubble, Cavitation, Thermal, Microfluidics, Collapse (topology), Fluid mechanics, Mechanics, Computing systems
Abstract

A three-dimensional fluid mechanics analysis of a bubble growth and collapse has been carried out for some thermal ink jet printhead geometries. For that purpose, a computer code has been developed which can handle multi-valued free surfaces that arise in such geometries. This paper presents sample results which show how the bubble grows and collapses, and how it differs with geometrical changes.

Published
1989
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371. Studies on niacin biosynthesis from 3-hydroxyanthranilic acid in streptozotocin diabetic rats in vivo and in vitro

Author

Nilkanth R Akarte and Narayan V Shastri

Subjects
Male, medicine.medical_specialty, 3-Hydroxyanthranilic Acid, Medicine (miscellaneous), Streptozocin, chemistry.chemical_compound, Biosynthesis, In vivo, Internal medicine, medicine, Diabetes Mellitus, Animals, ortho-Aminobenzoates, 3-Hydroxyanthranilic acid, Nutrition and Dietetics, Nicotinic Acids, nutritional and metabolic diseases, Streptozotocin, In vitro, Pyruvate carboxylase, Rats, Quinolinic Acids, Endocrinology, chemistry, Liver, Niacin, Quinolinic acid, medicine.drug
Abstract

Biosynthesis of niacin from 3-hydroxyanthranilic acid (3-OHAA) in normal and streptozotocin diabetic rats was studied in vivo and in vitro. Streptozotocin (SZ) diabetic rats were found to excrete lesser quantities of 3-OHAA, quinolinic acid, niacin and N1-methylnicotinamide (nmn) in their urines following 3-OHAA administration than corresponding normal rats. In vitro studies indicated that SZ diabetic livers form less quinolinic acid from 3-OHAA than normal livers. It appears that this may be due to elevated picolinic carboxylase activity in the livers of SZ diabetic rats.

Published
1976

372. Bibliography of Infrared Spectroscopy through 1960. Part 1.

Author

NATIONAL STANDARD REFERENCE DATA SYSTEM, Rao, C N R, Dikshit, S K, Kudchadker, S A, Gupta, D S, Narayan, V A, NATIONAL STANDARD REFERENCE DATA SYSTEM, Rao, C N R, Dikshit, S K, Kudchadker, S A, Gupta, D S, and Narayan, V A

Abstract

This bibliography is based on a systematic search of the literature on infrared spectroscopy up to the end of 1960. It covers, directly or through abstract journals, 121 periodicals. As a general rule, any paper of interest in the field of infrared spectroscopy is included. Substance coverage is provided in four sections: organic compounds, inorganic compounds, polymeric compounds, and minerals and ores. Information provided includes: empirical formula, compound name, range of wavelengths reported, state of material, type of data presented in paper, and literature reference. Issued in three parts. (Author), See also Part 2, AD-D095 382.

Published
1976

373. Bibliography of Infrared Spectroscopy through 1960. Part 2.

Author

NATIONAL STANDARD REFERENCE DATA SYSTEM, Rao, C N R, Dikshit, S K, Kudchadker, S A, Gupta, D S, Narayan, V A, NATIONAL STANDARD REFERENCE DATA SYSTEM, Rao, C N R, Dikshit, S K, Kudchadker, S A, Gupta, D S, and Narayan, V A

Abstract

This infrared bibliography is based on a systematic search of the literature on infrared spectroscopy up to the end of 1960. The literature search has been made by going through journals as well as through Chemical Abstracts. As a general rule, any paper of interest in the field of infrared spectroscopy is included: Examples of fringe areas include microwave spectra where rotational constants are given, papers on preparation of chemical compounds where infrared spectra are used for identification, papers on Beer's law, references to mathematical treatments such as group theory and statistical mechanics and so on. Papers on Raman spectroscopy have, however, not been included. The bibliography has been divided into four sections: I, Organic Compounds; II, Inorganic Compounds (a, of non-metals; b, of metals); III, Polymeric compounds; and IV, Minerals and Ores., See also Part 3, AD-D095 383.

Published
1976

374. Bibliography of Infrared Spectroscopy through 1960. Part 3.

Author

NATIONAL STANDARD REFERENCE DATA SYSTEM, Rao, C N R, Dikshit, S K, Kudchadker, S A, Gupta, D S, Narayan, V A, NATIONAL STANDARD REFERENCE DATA SYSTEM, Rao, C N R, Dikshit, S K, Kudchadker, S A, Gupta, D S, and Narayan, V A

Abstract

This infrared bibliography is based on a systematic search of the literature on infrared spectroscopy up to the end of 1960. The literature search has been made by going through journals as well as through Chemical Abstracts. As a general rule, any paper of interest in the field of infrared spectroscopy is included. Examples of fringe areas include microwave spectra where rotational constants are given, papers on preparation of chemical compounds where infrared spectra are used for identification, papers on Beer's law, references to mathematical treatments such as group theory and statistical mechanics and so on. The bibliography has been divided into four sections: I, Organic compounds; II, Inorganic Compounds (a, of non-metals; b, of metals); III, Polymeric Compounds; and IV, Minerals and Ores., See also Part 1, AD-D095 381.

Published
1976

375. Verrucous Carcinoma of Buccal Mucosa in Female: A Rare Case Report of Traumatic Tooth Origin

Author

Keerthi Narayan, V.

Abstract

Verrucous carcinoma or Ackermann’s tumor is considered a low-grade variant of squamous cell carcinoma frequently presenting at the oral mucosa and skin. Oral verrucous carcinoma clinically presents as a proliferative or cauliflower-like lesion or as ulceroproliferative lesion on the buccal mucosa followed by other sites such as the gingiva, tongue, and hard palate. Tobacco in both smoking and smokeless form, alcohol, and opportunist viral infections are the most associated etiologies in most of the reported literature cases. Here, in this paper, we discuss a rare case scenario of a 52-year-old female diagnosed with verrucous carcinoma of the left buccal mucosa with constant traumatic irritation caused by tooth as etiology for the occurrence of lesion, though verrucous carcinoma is described as a benign lesion with minimum aggressive potential but long-standing cases have shown transformation into squamous cell carcinoma. Therefore, early diagnosis and surgical excision of the lesion are the most appropriate treatment modality of verrucous carcinoma.

Published
2021
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376. The effect of acute autonomic denervation on pulmonary vascular resistance

Author

Thomas J. E. O'neill and Narayan V. Nimbkar

Subjects
Pulmonary and Respiratory Medicine, Male, medicine.medical_specialty, Pulmonary Circulation, Blood Pressure, Autonomic Nervous System, Autonomic Denervation, Systemic circulation, Transplantation, Autologous, law.invention, Dogs, law, Internal medicine, medicine, Cardiopulmonary bypass, Pulmonary blood flow, Animals, Transplantation, Homologous, Lung, Denervation, business.industry, Carbon Dioxide, Hydrogen-Ion Concentration, Transplantation, Oxygen, medicine.anatomical_structure, Regional Blood Flow, Anesthesia, Cardiology, Vascular resistance, Surgery, Female, Vascular Resistance, Cardiology and Cardiovascular Medicine, business, Lung Transplantation
Abstract

Experiments were performed on 13 dogs to study the effects of acute denervation on pulmonary vascular resistance. Limited systemic circulation was maintained by cardiopulmonary bypass. Pulmonary blood flow rate was altered serially and pressure measurements were made to compute pulmonary vascular resistance. Other variables of systemic and pulmonary circulation were held constant. Denervation seemed to produce either no change or a reduction in pulmonary vascular resistance. These data, along with previous work, absolve denervation as an etiological factor for higher vascular resistance in pulmonary transplantation.

Published
1973

382. Enhanced thermoelectric properties of flexible aerosol-jet printed carbon nanotube-based nanocomposites

Author

Ou, C, Sangle, AL, Chalklen, T, Jing, Q, Narayan, V, and Kar-Narayan, S

Subjects
7 Affordable and Clean Energy, 7. Clean energy, 4016 Materials Engineering, 40 Engineering
Abstract

Aerosol-jet printing allows functional materials to be printed from inks with a wide range of viscosities and constituent particle sizes onto various substrates, including the printing of organic thermoelectric materials on flexible substrates for low-grade thermal energy harvesting. However, these materials typically suffer from relatively poor thermoelectric performance, compared to traditional inorganic counterparts, due to their low Seebeck coefficient, S, and electrical conductivity, σ. Here, we demonstrate a modified aerosol-jet printing technique that can simultaneously incorporate well dispersed high S Sb2Te3 nanoflakes, and high-σ multi-walled carbon nanotubes (MWCNTs) providing good inter-particle connectivity, to significantly enhance the thermoelectric performance of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) structures on flexible polyimide substrates. A nominal loading fraction of 85 wt.% yielded a power factor of ~41 µW/mK2, which is among the highest for printed organic-based structures. Rigorous flexing and fatigue tests were performed to confirm the robustness and stability of these aerosol-jet printed MWCNT-based thermoelectric nanocomposites.

383. Compositionally Graded Organic–Inorganic Nanocomposites for Enhanced Thermoelectric Performance

Author

Ou, C, Zhang, L, Jing, Q, Narayan, V, and Kar-Narayan, S

Subjects
thermal energy harvesting, aerosol-jet printing, nanocomposites, 7. Clean energy, thermoelectrics
Abstract

Thermoelectric generators (TEGs) operate in the presence of a temperature gradient, where the constituent thermoelectric (TE) material converts heat into electricity via the Seebeck effect. However, TE materials are characterised by a thermoelectric figure of merit (ZT) and/or power factor (PF), which often has a strong dependence on temperature. Thus, a single TE material spanning a given temperature range is unlikely to have an optimal ZT or PF across the entire range, leading to inefficient TEG performance. Here, we demonstrate compositionally graded organic-inorganic nanocomposites, where the composition of the TE nanocomposite is systematically tuned along the length of the TEG, in order to optimise the PF along the applied temperature gradient. The nanocomposite composition can be dynamically tuned by an aerosol-jet printing method with controlled in-situ mixing capability, thus enabling the realisation of such compositionally graded thermoelectric composites (CG-TECs). We show how CG-TECs can be realised by varying the loading weight percentage of Bi2Te3 nanoparticles or Sb2Te3 nanoflakes within an organic conducting matrix using bespoke solution-processable inks. The enhanced energy harvesting capability of these CG-TECs from low-grade waste heat (

388. PJTEL Editorial 2022-2024

Author

Cochrane, T, Narayan, V, Sissons, H, Cochrane, T, Narayan, V, and Sissons, H

Abstract

In this second editorial for the Pacific Journal of Technology Enhanced Learning, PJTEL, the lead editors reflect upon the first five years of the journal leading to indexing in EBSCO and explore the impact statistics of the journal to date. We also explore future directions and themes for the journal particularly considering the impact of Generative AI on education.

389. CMALT cMOOC

Author

Cochrane, T, Narayan, V, Cochrane, T, and Narayan, V

Abstract

This paper outlines the design stage of a project that reimagines lecturer professional development around a network of communities of practice scaffolded by a cMOOC (connectivist Massive Open Online Course), where sustained collaborative engagement with innovative teaching practice is recognised via established international peer-based professional accreditation pathways such as CMALT (Certified Member of the Association for Learning Technology). Informed by a design based research methodology, the CMALT cMOOC leverages a network of national and international collaboration and innovative teaching expertise, providing an agile and scalable framework to support the development of participants’ CMALT portfolios as evidence of critical engagement with new modes of practice and enhanced student outcomes.

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