Nature-derived materials for the fabrication of functional biodevices

Nature provides an incredible source of inspiration, structural concepts, and materials toward applications to improve the lives of people around the world, while preserving ecosystems, and addressing environmental sustainability. In particular, materials derived from animal and plant sources can provide low-cost, renewable building blocks for such applications. Nature-derived materials are of interest for their properties of biodegradability, bioconformability, biorecognition, self-repair, and stimuli response. While long used in tissue engineering and regenerative medicine, their use in functional devices such as (bio)electronics, sensors, and optical systems for healthcare and biomonitoring is finding increasing attention. The objective of this review is to cover the varied nature derived and sourced materials currently used in active biodevices and components that possess electrical or electronic behavior. We discuss materials ranging from proteins and polypeptides such as silk and collagen, polysaccharides including chitin and cellulose, to seaweed derived biomaterials, and DNA. These materials may be used as passive substrates or support architectures and often, as the functional elements either by themselves or as biocomposites. We further discuss natural pigments such as melanin and indigo that serve as active elements in devices. Increasingly, combinations of different biomaterials are being used to address the challenges of fabrication and performance in human monitoring or medicine. Finally, this review gives perspectives on the sourcing, processing, degradation, and biocompatibility of these materials. This rapidly growing multidisciplinary area of research will be advanced by a systematic understanding of nature-inspired materials and design concepts in (bio)electronic devices.

0254 The Effects of Chronic Sleep Restriction on Multiple Object Tracking

Introduction

The ability to simultaneously track numerous moving objects in the presence of irrelevant stimuli is essential for successfully carrying out a variety of tasks. Sleep loss impairs neurocognitive functioning and, as a result, attentional processing capacity is reduced. The objective of the current study was to determine if performance on the multiple object tracking (MOT) task was adversely impacted by a week of chronic sleep restriction (CSR).

Methods

Twelve healthy participants (6 males, 6 females) kept a fixed sleep-wake schedule, with a constant waketime, at home for four weeks (actigraphy confirmed compliance). During weeks one and three, participants maintained 9 hours in bed. During weeks two and four, participants were randomly assigned to 5 and 9 hours of sleep. Following weeks two and four, participants completed a 13-hour laboratory visit under dim light (< 15 lux), where they maintained a constant posture and were provided with hourly isocaloric snacks. MOT was presented at approximately 6 and 8 hours after waking. Participants were required to track four, five, or six moving targets in the presence of identical distractors (always 12 total objects).

Results

Participants slept significantly less when assigned to 5 (M = 4.43 hours, SD = 0.33 hours), compared to 9 hours of sleep (M = 7.42 hours, SD = 0.42 hours; F (1, 22) = 206.89, p = 0.00). The proportion of correct MOT responses was significantly lower following 5 (M = 0.70, SD = 0.15) compared to 9 hours of sleep (M = 0.77, SD = 0.12; F (1, 22) = 10.29, p < .05).

Conclusion

A week of CSR adversely impacted MOT performance compared to a week of sleep satiation. These findings have implications for individuals, such as air traffic controllers and truck drivers, who must visually track multiple moving objects, often while chronically sleep deprived.

Support

Supported by the Force Health Protection Program of the Office of Naval Research (SAA2402925-1, Contract Award no. N0001418IP00050).

0174 Examining Circadian Disadvantages in the National Basketball Association’s Playoffs

Introduction

Prior research on travel in the National Basketball Association’s (NBA) regular season has shown that teams journeying west relative to their home base face circadian disadvantages for evening games, while those traveling east have advantages. The current study extends previous research by examining these effects within the NBA playoffs. We hypothesized that teams would have a greater circadian advantage during eastward compared to westward travel.

Methods

In 2013, the NBA implemented a 7-game series playoff structure, in which teams play an alternating home/away 2-2-1-1-1 format. Data for all 499 postseason games played during the 2013–14 to 2018–2019 seasons were collected from Basketball-Reference and FiveThirtyEight. We investigated the impact of direction of travel based on home base city (same time zone, westward, eastward) and time zones traveled on game outcomes, Elo rating differences (i.e., a team quality metric based on wins and losses), win probability, and team scoring.

Results

Teams had lower win probabilities following 3-hour westward than same time zone and all eastward travel, while 3-hour eastward travel related to higher probabilities of winning compared to same time and all westward travel (p < .001, d > .95). Teams travelling westward with 2-hour time changes lost significantly more games than those experiencing 1-hour westward (p = .04, OR = 2.45), 1-hour eastward (p = .05, OR = 2.34), and 3-hour eastward changes (p = .02, OR = 4.68). Scoring was significantly higher following eastward travel compared to both westward (p = .001, d = 0.60) and same time zone travel (p = .003, d = 0.44). There were no differences in team quality based on direction of travel or number of time zones traveled, and game outcomes based on overall direction of travel (p > .05).

Conclusion

Direction and magnitude of travel were related to win probability, team scoring, and game outcomes, whereby teams travelling eastward and within the same time zone gained an advantage over those travelling westward. Adjustment to travel and time changes appear to influence in-game performances and outcomes in the NBA playoffs.

Support

None

Multi-drug Resistant and Extended Spectrum β-lactamase Producing Salmonella Species Isolated from Fresh Chicken Liver Samples

Background Ductus arteriosus is a vascular structure which connects the roof of main pulmonary artery near the origin of the left branch pulmonary artery to the proximal descending aorta. Patent ductus arteriosus (PDA) closure is indicated for any patient who is symptomatic from left to right shunting. Objective To investigate the hospital outcomes of surgical closure of patent ductus arteriosus over last 19 years starting from the very first case of our center. Method This is a retrospective analysis of all patent ductus arteriosus treated surgically from August 2001 to July 2019. Patients who underwent isolated surgical closure of patent ductus arteriosus were included. Data have been presented in three different eras (Era 1: 2001-2007, Era 2: 2008-2013, and Era 3: 2014-2019) to see the trend of evolution of this surgery. Result A total of 901 patients aged 8.67±8.76 years under went patent ductus arteriosus surgical closure over last 19 years. Patients in the initial era 2001-2007 were significantly older compared with other 2 eras (p=0.000). Males accounted for 35.5% of all cases. Twenty percent had severe pulmonary artery hypertension.Duration of mechanical ventilation was 3.57±9.64 hours with ICU stay of 1.55±1.53 days, and hospital stay of 3.9±2.3 days. Overall in hospital mortality was 0.8%; for isolated patent ductus arteriosus diagnosis, mortality was 0.2%. Chylothorax was noted in 0.4%. Conclusion This is the first report to analyze surgical outcomes of patent ductus arteriosus ligation in our center. We have discussed the evolution of patent ductus arteriosus surgery in our center, and have shown favorable outcomes in terms of morbidity and mortality.

Primary surgical repair of coarctation of the aorta in adolescents and adults: intermediate results and consequences of hypertension

OBJECTIVES

Coarctation of the aorta is known to present with hypertension in older patients; we reviewed our experience and assessed the outcome of hypertension following surgical correction.

METHODS

From April 2004 to date, 43 patients above the age of 12 underwent coarctation of the aorta repair. The mean age was 20.4 + 9.7 years (maximum 56 years); 21 (48.8%) were older than 18 years and 28 (65.1%) were men. Thirty (69.8%) patients had hypertension. Fourteen (32.6%) had a bicuspid aortic valve; 11 (25.6%) had patent ductus arteriosus; 6 (14%) had myxomatous mitral valve; 4 (9.3%) had ascending aortic aneurysms; and 2 (4.7%) had descending aneurysms.

RESULTS

Surgical correction included resection and interposition of a tube graft in 31 (72.1%), an end-to-end anastomosis in 6 (14%) and patch aortoplasty in 3 (7%). Three (7%) patients required an extra-anatomical bypass: 1 had a long segment coarctation of the aorta, and 2 had a Bentall procedure with an ascending-to-descending aortic bypass. Staged procedures were done for concomitant disease in 4 (9.3%). There was 1 death: a 56-year-old woman died of refractory ventricular fibrillation during surgery. Thirty (69.8%) patients were discharged with antihypertensive medication. At a follow-up of 2.8 ± 2.2 years (maximum 9.2 years), the number of hypertensive patients decreased (17/36; 47.2%) (P = 0.042). Univariable predictors for persistence of hypertension revealed the use of an interpositional tube graft for repair (odds ratio 13.855, confidence interval 0.000-0.001; P = 0.001) as an indicator, whereas there were no independent predictors for persistence of hypertension.

CONCLUSIONS

Surgical intervention is warranted irrespective of age and helps correct and control hypertension better; however, significant numbers of patients still require antihypertensive medication and regular monitoring. Intervention using an interposition tube graft may affect the prevalence of hypertension.

Factors Affecting the Uptake of Institutional Delivery, Antenatal and Postnatal Care in Nawalparasi District, Nepal

Background Maternal deaths and complications are highly preventable with good antenatal, postnatal and skilled care during childbirth. Inadequate information on the factors affecting these services could be barrier to a reduction of maternal deaths in lowincome countries. Objective To assess the uptake of antenatal, postnatal and skilled care during childbirth. Method A cross-sectional study was conducted in eight villages of Nawalparasi district in southern Nepal. A total of 447 women who had given birth within the preceding 24 months were recruited using multistage random sampling. Data were collected using a pre-tested semi-structured questionnaire. Chi-square tests were used to assess association between variables. Result Over 70% of women had gone for at least four antenatal care check-ups while only 14.3% had at least three postnatal check-ups in their last pregnancies. The proportion of institution delivery was 54%. Women's literacy was associated with the uptake of antenatal services (p=< 0.001), postnatal care (p=0.04) and institutional delivery (p=< 0.001). Knowledge of antenatal (p=< 0.001) and postnatal care was also associated with uptake of respective services (p=< 0.001). Conclusion The uptake and knowledge of antenatal care was much better than of postnatal care. Home delivery rates were still very high. A scaling-up of education and awarenessraising interventions in this community could help improve the uptake of maternal health services.

Comprehensive case management of malaria: Operational research informing policy

In 2013, the Odisha state Vector Borne Disease Control Programme led a five year operational research project, under programmatic conditions, in close collaboration with several partners. This Comprehensive Case Management Project covered a population of 900,000 across paired control and intervention blocks in four districts, each with different transmission intensities. Key gaps in access to malaria services were identified through household surveys and a detailed situation analysis. The interventions included ensuring adequate stocks of rapid diagnostic tests and antimalarial drugs at the village level, the capacity building of health workers and ASHAs, setting up microscopy centres at the primary health care level, and conducting mass screening and treatment in poorly accessible areas. The programme strengthened the routine health system, and improved malaria surveillance as well as the access to and quality of care. Initially, the programme led to increased case reporting due to improved detection, followed by a decline in malaria incidence. Lessons from the project were then scaled up statewide in the form of a new initiative-Durgama Anchalare Malaria Nirakaran (DAMaN).

Monte Carlo Study of Unflattened Photon Beams Shaped by Multileaf Collimator

INTRODUCTION

This study investigates basic dosimetric properties of unflattened 6 MV photon beam shaped by multileaf collimator and compares them with those of flattened beams.

MATERIALS AND METHODS

Monte Carlo simulation model using BEAM code was developed for a 6MV photon beam based on Varian Clinic 600 unique performance linac operated with and without a flattening filter in beam line. Dosimetric features including lateral profiles, central axis depth dose, photon and electron spectra were calculated for flattened and unflattened cases, separately.

RESULTS

An increase in absolute depth dose with a factor of more than 2.4 was observed for unflattened beam which was dependent on depth. PDDs values were found to be lower for unflattened beam for all field sizes. Significant decrease in calculated mlc leakage was observed when the flattening filter was removed from the beam line. The total scatter factor, S_CP was found to show less variation with field sizes for unflattened beam indicating a decrease in head scatter. The beam profiles for unflattened case are found to have lower relative dose value in comparison with flattened beam near the field edge, and it falls off faster with distance.

CONCLUSION

Our study showed that increase in the dose rate and lower peripheral dose could be considered as realistic advantages for unflattened 6MV photon beams.

Submitral Aneurysm: An Unusual Aneurysm of the Left Ventricle

We report a case of a 42-year-old man with a submitral aneurysm who presented to the emergency room in circulatory collapse, with left ventricular obstruction and severe mitral valve stenosis and regurgitation secondary to the aneurysm. Resection of the aneurysm and mitral valve replacement were performed through a median sternotomy without any complication and with good results.

Retrospective study on outcome of macular hole surgery

INTRODUCTION

Macular hole is a common and treatable cause of central visual loss. Classic macular hole surgery consists of vitrectomy, posterior vitreous cortex removal and intraocular gas tamponade, but during the past decade focus has especially been on internal limiting membrane (ILM) peeling as adjuvant therapy for increasing closure rates.

OBJECTIVE

To determine and evaluate anatomical and visual outcome of macular hole surgery.

MATERIALS AND METHODS

Retrospective analysis of all cases of macular hole surgery done by single surgeon between 2014 -2015.

RESULTS

16 eyes were analysed with follow up of 3 months. Macular hole closure after vitrectomy was 75% with visual improvement of two or more line in 62.5%.Post surgical complication included cataract 18.8%, Increased IOP 12.5% and retinal detachment 6.2%.

CONCLUSION

Vitrectomy along with ILM peeling and Gas Tamponade with effective positioning improves in visual acuity and achieve hole closure in people with macular hole.

Phytostimulatory effect of silver nanoparticles (AgNPs) on rice seedling growth: An insight from antioxidative enzyme activities and gene expression patterns

The knowledge on the mode of action, biocompatibility and ecological tolerance of silver nanoparticles (AgNPs) is gradually accumulating over the years with contradictory findings. Most of the studies indicated the toxic impact of AgNPs on plant growth and development, where induction of oxidative stress was considered to be one of the causal factors. The present study demonstrates the phytostimulatory effect of bio-synthesized silver nanoparticles (AgNPs) during seed germination and seedling growth of rice (Oryza sativa L., cv. Swarna) under in vitro condition. All the tested concentrations of AgNPs (10, 20, 40 ppm) promote both the shoot and root growth which was evident from the increased length and biomass of the seedlings. Exposure to AgNPs also significantly increased the chlorophyll a and carotenoid contents. The content and the pattern of distribution of phenolic metabolites among the different treatments are indicative of non-toxic impact of AgNP mimicking mild or no stress to the seedlings. Growth stimulation of rice seedlings by AgNPs was further supported by a low level of reactive oxygen species (ROS) concomitant with decreased amount of lipid peroxidation and H₂O₂ content, compared to control. In order to unravel the stimulatory impact of AgNPs on rice seedling growth, the present study also describes the AgNPs induced changes in antioxidative enzyme activity and related gene expression levels. Elevated levels of catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) activities were recorded in all the AgNPs treated seedlings with improved growth. The activity of superoxide dismutase (SOD) was not significantly altered at low concentration of AgNPs. It appears that enzymes of ascorbate cycle, APX and GR are more active in ensuring protection against oxidative damage than SOD. There was significant up-regulation of CAT and APX gene expressions in seedlings exposed to AgNPs, whereas the expression level of CuZnSOD gene was decreased gradually with an increase in the concentration of AgNPs. The antioxidant enzyme activities and gene expression patterns coupled with the levels of H₂O₂ and lipid peroxidation indicates that the efficiency of redox reactions was increased in the presence of AgNPs and that accelerates the seedling growth.

Spin-Resolved Spectroscopy of the Yu-Shiba-Rusinov States of Individual Atoms

A magnetic atom in a superconducting host induces so-called Yu-Shiba-Rusinov (YSR) bound states inside the superconducting energy gap. By combining spin-resolved scanning tunneling spectroscopy with simulations we demonstrate that the pair of peaks associated with the YSR states of an individual Fe atom coupled to an oxygen-reconstructed Ta surface gets spin polarized in an external magnetic field. As theoretically predicted, the electron and hole parts of the YSR states have opposite signs of spin polarizations which keep their spin character when crossing the Fermi level through the quantum phase transition. The simulation of a YSR state right at the Fermi level reveals zero spin polarization which can be used to distinguish such states from Majorana zero modes in chains of YSR atoms.