bluuebunny/crossref_metadata_2025 huggingface dataset:
A Cross sectional study to determine the prevalence of Diabetes Mellitus and its household awareness in the rural field practice areas of a medical college in Mangalore - A Pilot Study
Authors: D'Souza Agnes Moira Preethi , Kundapur Rashmi , Kiran N. Udaya
Published: April 2020

Introduction: Diabetes mellitus is a major clinical and public health problem accounting for 4.6 million deaths annually world-wide. According to the recent World Health Organization report (WHO), India today leads the world with over 32 million diabetic patients and this number is projected to increase to 79.4 million by the year 2030(2). The recent surveys indicate that Diabetes now affects a large part of the population i.e. 10-16% of urban and 5-8% of rural population in India(1).

Objectives: This study aims at estimating the prevalence of diabetes, the household awareness, the pattern and regularity of health seeking behaviour among the households for diabetes.

Methodology: This cross sectional study was conducted among 40 households of Kuttar and Manjanady village of semi urban Mangalore. Data was collected using a structured questionnaire after pre-testing. Questions on awareness were prioritised, scored and then analysed. Likert scale was used to grade the awareness score.

Results: Community prevalence of diabetes was found to be 7.7%. Out of the total population 8.8% of males and 6.8% of females were diabetics. Among the diabetics male and female distribution was equal i.e. 50%. Among the 7.7% of diabetics 50% of the subjects also had Hypertension. Awareness was average among 35% of the subjects. About 27.5% had poor score and 37.5% had very poor score for the awareness.

Conclusions: Community prevalence was low. Lifestyle modification was not present among Diabetics. Awareness was poor among the households.
Effectiveness of academic stress management programme on academic stress and academic performance among higher secondary students in selected schools of Udupi District
Authors: S. Nikitha , Jose Tessy Treesa , Valsaraj Blessy Prabha
Published: April 2020

Problem statement: “A study to assess the effectiveness of academic stress management programme on academic stress and academic performance among higher secondary students in a selected school of Udupi district, Karnataka, India”

Objective : To evaluate the effectiveness of academic stress management programme on academic stress and academic performance.

Materials and Methods: Study was conducted among 96 subjects. Data were collected using Demographic Proforma and Academic stress Rating Scale. Academic performance was assessed by verifying existing school records of formative evaluation test conducted in the month of January and February 2013. Academic stress management programme was provided one hour per day for three consecutive days.

Result: Data were analysed using t test and Wilcoxon signed rank test. Result showed a significant difference in pretest post test stress level and academic performance.

Conclusion: The findings of the study indicated that academic stress management programme was effective in reducing academic stress but not in improving academic performance.
Extent of awareness regarding periodontal disease in diabetic patients among medical interns
Authors: Chaturvedi Manav , V. Sreelatha S. , Shetty Pushparaja
Published: April 2020

Squamous cell carcinoma is the most common malignant neoplasm of the oral cavity. Betel nut chewing, cigarette smoking and alcohol drinking are thought to be the major environment risk factors responsible for the development of oral squamous cell carcinoma (OSCC).

Reports of OSCC in patients who never used tobacco and alcohol are infrequent.

The aim of this article is to review the current data concerning the possible etiological factors causing OSCC other than tobacco like viral infections, diet, nutrition, chronic irritation, genetic mutations and other. Although it is well known that the incidence of OSCC increases with age, recent trends for a rising incidence particularly relates to cancer in young individuals. Investigations can be routine ranging from simple oral examination, blood test, bone marrow analysis, diet chart analysis as well as molecular analysis through techniques like PCR, ISH (in situ hybridization), DNA sequencing, southern blot and antibody test.

This review critically examines numerous publications devoted to oral cancer in young individuals who never used tobacco and alcohol. Most studies suggest that 4-6% of oral cancer occur in such individuals

Awareness of this possibility is important since it can lead to potentially fatal consequences.Thus providing clinicians a broader vision for diagnosis which will lead to effective treatment and prevention in the future.
Knowledge, awareness and compliance among dental professionals regarding percutaneous exposure incidents as occupational hazard
Authors: Permi Shwethashri R. , Bhandary Rahul , Thomas Biju
Published: April 2020

Percutaneous injuries constitute one of the most common occupational health hazards in healthcare profession. Dental professionals are at more risk of acquiring these injuries due to their limited and restricted working area in mouth. This was a cross-sectional study done among dental professionals in Mangalore, Dakshina Kannada, Karnataka state India to access Knowledge awareness and compliance among dental professionals regarding percutaneous exposure incidents. This study concludes that Dental professionals are at a high risk of occupational disease due to accidental exposure to infected blood and body fluids. for which appropriate measures not taken after one such exposure There is a need of clearing the present misconceptions through educational training programs early in the study period and providing facilities for reporting, documenting, supportive and proper guidelines regarding percutaneous injuries in work place for healthy community.
Substance abuse and practices and their consequences among adolescents and young adults in Mangalore
Authors: Prakash Alka , B. Vidya , Suhailah Wan Nur , Mohanan Anjali , Kundapur Rashmi , Badiger Sanjeev ,   Ravi
Published: April 2020

Introduction: Substance abuse is the recent trend among college students. Studies conducted in India shows clear indications of increasing prevalence of substance abuse among adolescents.

Aims and Objectives:To assess the practice prevalence and consequences of drug abuse among adolescent students.

Materials and Methods: This Institution based cross-sectional study conducted in different schools and colleges of Mangalore. Institutions were randomly picked with pen drop method and 5 institution students were selected as study subjects. Totally 487 students between institutions were selected, the age group of 15-25 years were included in the study. The data was collected by means of answering a pretested validated questionnaire with anonymity.

Result: According to our study the results showed that 8.60% have tried some substance of abuse such as marijuana (5.51%), LSD (1.10%), cocaine (1.32%) and others (1.76%). Among the Substance users, 1.54% used it regularly, 1.76% occasionally and 2.20% only once. 33.03% said it has affected their daily activities and academics 21.05% had picked up a quarrel with friends, family or detained by police.

Conclusion: Caffeine consumption in the form coffee is quite common amongst the students as a habit. Marijuana is the most popular drug among the small fraction of students who have tried drugs. Most of them tried it first in college, mainly being influenced by peers.
Fibroma - A misnomer : Case Series
Authors: Verghese Riya , Ramesh Amitha , Bhandary Rahul , Thomas Biju , Philip Nishita L.
Published: April 2020

Objectives: Fibromas are proliferative fibrous lesions of the gingiva and oral mucosa that may cause esthetic and functional problems. Fibrous hyperplasia and Fibro-epithelial hyperplasia are histological variants of these non-neoplasticlesions

Methods: This article addresses the diagnosis, histological features and treatment of two cases of fibroma.

Results: These lesions are a result of trauma/chronic irritation, or arise from cells of periodontium,periodontal ligament, or periosteum.

Conclusion: The cases demonstrate the need for proper diagnosis, role of biopsy and histologic evaluation in management of these lesions
Chondrosarcoma of the anterior chest wall : surgical resection and reconstruction using a two layer polypropylene mesh and bone cement sandwich
Authors: Amonkar Amol , Gopalakrishnan Mundayat , Naik AmithKiran , S. Vishwanath , Sultan Saquib ,   Vimaladhithan
Published: April 2020

Primary malignant tumours of the chest wall are uncommon. Chondrosarcoma is the most common malignancy among them, the current therapy for chondrosarcoma requires adequate surgical excision. A 50 year old male presented with a swelling on the anterior chest wall, trucut biopsy of the swelling was reported as chondrosarcoma. Thorax computed tomography (CT) revealed a large mass nd lesion with the epicentre at the costal cartilage of the right 2 rib extending beyond the chest wall and musculature and protruding internally upto the upper lobe of the right lung, features likely of chondrosarcoma.Inorder to obtain disease free surgical margins, an enst nd rd bloc resection of the tumour along with approximately 4 cms of 1 riband 2 and 3 rib and reconstruction of the anterior chest wall was performed with a 2 layer polypropylene mesh and bone cement sandwich. The post-operative course was uneventful.The chest wall reconstruction with the two layer polypropylene mesh and bone cement provided the essential rigidity and stability to the chest wall.
A Descriptive Study to Assess the Knowledge and Practice Regarding Water, Sanitation and Hygiene among Women in Selected Villages of Udupi District
Authors: Pai Mamatha S. ,   Reshma,   Manjula
Published: April 2020

Background : Safe drinking water and basic sanitation is of crucial importance to the prevention of human heath1. Water can become a vehicle for transmission of feco oral group of infections, because the fecal contamination of water is common and its avoidance and subsequent purification is vigilant2. One of the goal of MDG states - Halve, by 2015, the proportion of people without sustainable access 3 to an improved water source and sanitation3.

Materials and methodology : A descriptive study was undertaken among 300 samples, in adopted villages of MCON Manipal, Udupi District using structured questionnaire. SPSS 16.0 software was used for data analysis.

Results : Findings of the study showed that 42% had average knowledge and majority (75 %) of the subjects followed unsafe practices on water, sanitation and hygiene. Majority (88 %) of the subjects performed unskilled hand washing.

Conclusion: Water pollution is a growing hazard in many developing countries due to human activity. Water is an essential factor in the economic, social and cultural development of community. It can eliminate diseases, and improve quality of life
Anxiety & Coping Patterns Regarding Pubertal Changes among Pre-Adolescent Girls of Udupi Taluk, Karnataka
Authors: F. Sequeira D. , A. D'souza , E. Sanatombi Devi
Published: April 2020

Background: Puberty is a period in the developmental span when the individual changes from an asexual being to a sexual being.

Objectives:The present study was aimed to assess the anxiety and coping pattern regarding pubertal changes among pre-adolescents girls in selected schools of Udupi Taluk, Karnataka.

Materials and methods:The study included 540 pre-adolescent girls of age group (10-12years) from selected schools of Udupi Taluk by cluster random sampling technique. Data was collected using structured questionnaires.

Results:The study showed that out of 231 pre-adolescents who attained menarche (55%) had moderate anxiety and 52.4% had adaptive coping pattern. Among 309 pre-adolescents who did not attain menarche, 62.1% had moderate level of anxiety and 53.4% had adaptive coping pattern regarding pubertal changes. It also showed that there was a negative correlation between anxiety and coping pattern of the pre-adolescent girls, r= -0.754.

Conclusion: The study concluded that pre-adolescent girls have moderate level of anxiety and adaptive coping pattern regarding pubertal changes and it also showed that when anxiety increases coping pattern decreases. Majority of the respondents had moderate level of anxiety and adaptive coping pattern.
Effect of Ionising Radiation on Micro Hardness Property of Restorative Materials
Authors: Hegde Mithra N. , Hegde Nidarsh D. , Kumari Suchetha N. , Sanjeev Ganesh ,   Priya
Published: April 2020

Patients receiving radiation therapy as source of treatment are commonly known to have restorations on their tooth composed of resin or non-resin restorative materials. Any interaction between ionising radiations and these restorative materials can have adverse effects which can be of clinical significance. Hence in this study we investigated the effects of ionising radiation on 3 restorative materials (Impress Direct, Glass Ionomer Gold Label Type 9 and Te- Econom Plus) by testing their microhardness property. All the 3 composite materials showed increased mean micro hardness values among the radiated groups and was found to be statistically significant (P<0.05). The results obtained indicated that restorative materials has undergone increased degree of polymerisation strengthening the bonds sustaining its stability. Hence the above effect will have no adverse effects on the human health, hence these materials are suitable for endodontic treatment among patients undergoing radiotherapy for head and neck cancer.
Aniridia : A window to wilm's tumour
Authors: Shetti Samyakta , Patil Harshavardhan
Published: April 2020

We are reporting a case with aniridia which lead to the diagnosis of Wilm's tumour in a twelve month male child.
Management of Scleral Thinning : An Alternate Approach
Authors: Pai Vijay , Shetty Jayaram , Amin Hrishikesh , Thomas Manu
Published: April 2020

A 5 year old child presented with corneo-scleral tear in his left eye following trauma with knife which was repaired immediately. 1 month later there was thinning of the sclera at the sutured site. An alternate approach was proposed for the management of scleral thinning. An autologous scleral patch graft from the same eye was sutured at the area of thinning. This method was found to be more convenient and easy to perform. Since the graft was stable and the donor site was healthy; this method can be used as an alternative approach for the management of scleral thinning.
Fabrication of a Silicone Auricular Prosthesis – A Case Report
Authors: D. Krishna Prasad , Swaminathan Archana Ashok , D. Anupama Prasad
Published: April 2020

The rehabilitation of a patient with facial defects is a challenging task. An alternative to surgical reconstruction is the creation of a silicone auricular prosthesis. The replacement of anatomical parts is an art and science. These prostheses provide a cost-effective and an acceptable means of camouflage for patients who are disinclined to surgical reconstruction. The process of creating a silicone auricular prosthesis is discussed in this article.
Knowledge regarding Leucorrhoea among women residing in selected urban community of Ludhiana City
Authors: Choudhary Mamta
Published: April 2020

Background: Reproductive tract infections form one of the major burdens of disease in developing countries. Most of the women suffer from leucorrhoea and do not present themselves for seeking medical treatment in early stage as the women has poor understanding regarding leucorrhoea.

Objectives: To assess the knowledge of females regarding leucorrhoea.

Study Design: Cross- sectional study.

Materials and Methods: The study involved collection of information regarding knowledge of females about leucorrhoeausingmultiple-choice questionnaire. Two hundred and fifty females residing in Model Town, Ludhiana were recruited in the study by using convenient sampling.

Results: The result revealed that only 20% of subjects had good level of knowledge, and 80% subject had poor level of knowledge regarding leucorrhoea. The mean knowledge score regarding leucorrhoea among subjects was 19 with a standard deviation of 3.94. The highest mean knowledge score of 19.5 + 4.69 was in the age group of >35 years.
Effectiveness of planned teaching programme on knowledge regarding pubertal changes among adolescent boys in selected high school of Udupi District
Authors: Shetty Ajith Kumar , Georg Alphoni P. , J. Beena K. , Kabiraj Tandra , Paul Blenita , A. Anil Raj , Alex Soumya
Published: April 2020

Adolescent is a challenging crossroad between childhood and the adulthood. It is considered as vital because of the physical, physiological and psychological changes take place during this period. These changes occur in puberty may bring about a feeling of fear and apprehension in adolescent boys. Proper knowledge and timely guidance and information can enable them to enjoy the adolescent period. Objectives of the study were to assess the knowledge regarding pubertal changes among adolescent boys, by using a structured knowledge questionnaire and evaluate the effectiveness of planned teaching programme. Pre experimental one group pretest post- test design was used among adolescents in selected high school of Udupi District. The study participants (100) were assessed through a questionnaire and selected by purposive sampling. Data shows that mean knowledge score of the group before intervention was 16.96 ± 3.816. After intervention (the planned teaching program), the mean knowledge score was 24.05 ± 3.036 which indicates the significant difference in mean pre-test and post-test knowledge scores, and paired t-test showed the statistical significance for the effectiveness of planned teaching programme (“t”=14.352 and P<0.05). The study concluded that planned teaching was found to be effective in improving the knowledge regarding pubertal changes among adolescent boys and it would be beneficial to manage the physical and psychological problem related to puberty.
Incidence and Pattern of Bacterial Growth in Propofol Vial - An In vitro Study
Authors: Raveendra U. S. , Soori Rashmi , Karnekar Vimal Kumar , Nayak Swathi N. , Bangera Anand
Published: April 2020

Introduction- Propofol vials are often used in parts or are opened and left unattended. This has lead to blood stream infections, surgical site infections and acute febrile episodes. A prospective observational study was undertaken to know the incidence and pattern of bacterial growth in samples of Propofol in tropical climate.

Materials and methods- Samples were collected from vials of propofol of different brands, both with and without edetate at different time intervals with relation to room temperature. Each sample of 1ml were inoculated in Brain Heart Infusion (BHI) and incubated for 48hours. Presence of bacterial growth and their pattern were studied.

Statistical analysis used- Paired t test for categorical variables and for non categorical variables Levine's test and Pearson correlation. Results- Overall 42.26% of samples showed bacterial growth. The incidence was more in samples of propofol without edetate (43.75%) compared to samples with edetate (41.97 %). Most common organism was Staphylococcus aureus, followed by Enterococcus, Acinetobacter, Bacillus species, Pseudomonas and Staphylococcus citrus.

Conclusion- Propofol vial once opened favours bacterial colonisation and growth. Adding edetate to propofol has not shown much benefit in decreasing the incidence.
Quantitative evaluation of DNA from the tooth pulp exposed to varying temperatures
Authors: Ibrahim Aisha N. , Bhat Vinaya , Shenoy Shilpa M. , Shetty Veena A.
Published: April 2020

Context: During natural calamities like fire accidents, many times the human body gets charred beyond recognition. Tooth, being the hardest structure in the human body protects the pulp within from such accidents. Forensic identification through the pulpal DNA could be avery useful tool in such situations.

Aim: This study was designed to evaluate the quantity of DNA obtained from the pulp when exposed to varying temperatures.

Methods and Material: Extracted teeth were subjected to the following temperatures:-80°C,37°C,100°C, 200°C, 300°C, 500°C and 1000°C. Pulp from these teeth were retrieved by horizontally sectioning the teeth using a fine needle diamond point in a high speed air rotor, followed by extraction of DNA with the HipuraA™ Forensic Genomic DNA purification spink it. The samples were quantified using personal computer(PC) based double beam spectro photo meter. Kruskal Wallis test and Mann WhitneyU test were used for statistical analysis.

Results: Statistically significant difference (p<0.005) was seen in the quantity of DNA obtained from pulp subjected to higher temperatures as compared to oral temperature. However, there was no significant difference (p>0.05) in the quantity of DNA obtained from teeth subjected to-80°C

Conclusions: Increase in temperature decreases the amount of DNA from the tooth pulp where as a decrease in temperature does not cause any change in the quantity of DNA.
Factors Responsible For Low Access and Utilization of Janani Sureksh Yaojan (Scheme for Institutional Delivery) Among Rural Women: A Case of South Karnataka - India
Authors: Nanjunda D.C.
Published: April 2020

This paper examines the access and low utilization ofJanani Sureksh Yaojan(JSY) in the selected rural parts of south Karnataka at the overall level and also separately for the SCs women and identifies crucial factors that hinder and facilitate access to the scheme and the factors that are play crucial role in theunderutilization of the health servicesand caste issues SC women beneficiaries. This paper predominantlyemphasis on the caste discrimination in terms of accessing the public health services and in the end, enlists all the likely measures to combat this discrimination. This study has been conducted in oneof the backward district of the sate Chamaraj nagar –south India. Thisarticle concludes that there are an assortment of factors causing low access and utilization of JSY service including the caste and other factors. It is further ascertain in that JSY is not just about promoting institutional deliveries rather programme objectives for diminution of maternal mortality and morbidity can be achieved when particularly rural women arefacilitating to receivethe quality delivery and post-partum care services.
Cephalometric Norms for Orthognathic Surgery in Kerala Population
Authors: Patla Murali , Achalli Sonika , Saidath K. , Soans Crystal Runa , Nayak U.S. Krishna
Published: April 2020

Background and objectives: The successful treatment of orthognathic surgical patient is dependent on careful diagnosis. The first step in the diagnosis of the patient for orthognathic surgery is to determine the nature of the skeletal, dental and soft tissue defects. Cephalometrics for orthognathic surgery (COGS) analysis by Burstone and colleagues is especially adapted for the diagnosis and treatment planning of orthognathic surgery cases. Burstone and colleagues' COGS analysis are based on Caucasian whites; they may not be applicable as a reference for the diagnosis and treatment of Kerala population patients. Therefore it has become important to determine the cephalometric parameters for this ethnic group.

Methodology: Cephalometric radiographs of 50 Keralite adults (25 Males and 25 Females) were analysed who met criteria of the study. The Mean values of various skeletal, dental, angular and linear measurements of Keralites were compared with the White Americans values, originally obtained by Burstone.

Results: Statistically significant differences were found in the Keralite samples, who had a greater Anterior and Posterior Cranial base length, Mandibular protrusion, Lower anterior facial heights, Anterior and Posterior Dental heights, Proclined Upper and Lower incisor with less Prominent Chin in comparison to Caucasian.

Interpretation and conclusion: This is indicative of disparity between cephalometric norms of Caucasians and Keralites. However conclusions can't be drawn from a single study, hence further studies to establish the cephalometric norms for different ethnic groups across the country may be advisable.
Management of Oral Lesions in Paraquat Poisoning - A Case Report
Authors: C. Muralee Mohan , Shetty Pratiksha , Gohil Saurabh M. , Sharma Jitesh , Roy Satadru
Published: April 2020

Paraquat is a herbicide with a good occupational safety record, but a high mortality after intentional ingestion that has proved refractory to treatment. For nearly three decades p concentration–time data have been used to predict the outcome following ingestion, however, none of the published methods has been independently or prospectively validated. However, poisoning is an uncommon entity in India. We report a case of oral lesions associated with poisoning and management of the mucosal burns associated with it along with medical management of poisoning in general.
Assessment and Comparison of Oropharyngeal Airway Dimensions in Skeletal Class II Cases Treated With Forsus FRD and Twin Block Appliances
Authors: Shetty Kaushik , K. Saidath , Shetty Akhil , Ravi M. S. , Shashidhar Keerthan , A. Anushree
Published: April 2020

Aims: To assess the changes in the oropharyngeal airway (OAW) dimensions in individuals with retrognathic mandible treated with Forsus FRD and Twin Block appliance to correct the skeletal Class II mal relationship.

Methodology: 40 individuals, with Class II skeletal pattern were selected as per inclusion criteria. Pre-treatment lateral cephalograms and hand wrist radiographs were obtained and analyzed. Group 1 with 20 individuals were treated with Forsus FRD and Group 2 with 20 individuals were treated with conventional Twin Block Appliance. Post treatment records were taken after the Class I molar relationship had been obtained. Pre and post treatment cephalograms were compared and analyzed. The data obtained was statistically evaluated using paired t test and unpaired t test.

Results: On comparison of pre-treatment and post-treatment cephalograms, increase in Oropharyngeal Airway (OAW) measurements, such as Superior posterior airway space (SPAS), Middle airway space (MAS) and Inferior airway space (IAS) was very highly significant.

Conclusion: Our results suggest the existence of a relationship between functional-orthopaedic treatment and increases in OAW dimensions in skeletal Class II growing subjects.
The Charming Tale of Charm Needles!
Authors: Kanneppady Sham Kishor , Kanneppady Sowmya Sham , Lakshman Anusha Rangare , Phaik Khoo Suan , Shetty Shishir Ram
Published: April 2020

Charm needles or susuk are needle-shaped metallic objects inserted subcutaneously in different parts of the body. The practice of inserting susuk is, an indisputably cultural and superstitious traditional belief common in the south-east Asian region, especially to the people of Malaysia, Thailand, Singapore, Indonesia and Brunei. With increased use of diagnostic radiographs in dental or medical practice, the discovery of charm needles has become more frequent. We report one such case of charm needles inserted in oro-facial region which was discovered in routine dental radiograph, with emphasis on cultural and traditional belief.
A simulation model shows how individual differences affect major life decisions
Authors: van der Gaag Mandy A. E. , van den Berg Pieter , Kunnen E. Saskia , van Geert Paul L. C.
Published: April 2020

Individuals are faced with a number of major decisions throughout their lives, including the choice of a suitable education, career, and life partner. Making such major life decisions is challenging, as is evidenced by substantial rates of divorce and drop-out from higher education. Although poor major life decisions can lead to considerable costs for both individuals and society, little is known about how people make these decisions. This is because major life decisions are not simple short-term weighings of options—they are strongly intertwined with identity development. Here, we present a simulation model of major life decisions that integrates the short-term perspective of decision science with the long-term perspective of identity theory. We model major life decisions as a process comprising many explorations of available options, resulting in changing commitments, and eventually leading to a decision. Using our model, we run a large-scale in silico experiment, systematically simulating how three key individual characteristics affect the choice process and the quality of the decision: (1) exploration tendency (broad vs. in-depth), (2) accuracy in assessing how well options fit, and (3) selectiveness. We identify the types of individuals who are at risk of exhibiting ‘maladaptive’ decision dynamics, including ruminative exploration and rash decision making, and conclude that these features often, but not always, lead to bad decisions. Our simulation results generate concrete predictions that can be empirically tested and may eventually result in individually tailored tools to aid individuals in making major life decisions.
Infrared photothermal heterodyne imaging: Contrast mechanism and detection limits
Authors: Pavlovetc Ilia M. , Podshivaylov Eduard A. , Chatterjee Rusha , Hartland Gregory V. , Frantsuzov Pavel A. , Kuno Masaru
Published: April 2020

Infrared photothermal heterodyne imaging (IR-PHI) is an ultrasensitive technique for achieving super-resolution, infrared imaging throughout the mid-infrared “fingerprint” spectral region (2.5–10μm). An achieved spatial resolution of ∼300nm is up to 30-fold smaller than the infrared diffraction limit. In this study, we establish IR-PHI’s signal contrast mechanism and benchmark the technique’s capabilities using the characteristic infrared vibrational transitions of individual polystyrene (PS) and poly(methyl methacrylate) (PMMA) beads. The analysis of acquired results reveals that IR-PHI contrast originates from a competing, photothermally induced specimen size and refractive index changes to backscattering cross sections. For PS and PMMA, thermo-optic refractive index contributions dominate and are responsible for medium-free IR-PHI signal contrast. Our analysis simultaneously establishes IR-PHI’s current, medium-free peak absorption cross-sectional limit-of-detection to be σabs=3×10−18m2. This improved understanding of IR-PHI signal contrast provides a framework for future developments in super-resolution infrared absorption microscopy and spectroscopy.
Investigation of effects of charge injection and intrinsic ionic carriers in low-density polyethylene and cross-linked polyethylene
Authors: Su Rui , Wu Kai , Dissado L. A. , Cheng Chuanhui , Dodd S. J. , Lv Zepeng , Zhong Lisheng , Wang Xia
Published: April 2020

The effects of charge carrier injection and intrinsic ionic carriers on the conduction process in superclean low-density polyethylene and cross-linked polyethylene (LDPE and XLPE) and the associated development of space charge are investigated. The carrier mobility is measured directly by space charge measurements in a double- and triple-layer structure. It is shown that the difference between superclean LDPE and XLPE in the field-dependence of the current density results from the dominance of ions in XLPE introduced by cross-linking as compared to injected carriers in the case of superclean LDPE.
Flat-evaporator-type loop heat pipe with hydrophilic polytetrafluoroethylene porous membranes
Authors: Phan Nguyen , Watanabe Noriyuki , Saito Yuki , Hayashi Shota , Katayama Naoki , Nagano Hosei
Published: April 2020

This paper describes an experimental study of a flat-evaporator-type loop heat pipe (LHP) with wicks made from hydrophilic polytetrafluoroethylene (PTFE) porous membranes, which have small pore sizes but high porosity and permeability. To demonstrate the applicability of these membranes, the LHP was designed completely and fabricated, after which the performance was experimentally investigated under a 0.52 m anti-gravity condition at a constant heat sink temperature of 80 °C. Two types of membranes were used, possessing different pore diameters and permeabilities. The pore diameter and permeability of wick 1 were 0.44 µm and 2 × 10−14 m2, respectively, while wick 2 had a pore diameter and permeability of 1.40 µm and 5 × 10−14 m2, respectively. A special wick support was designed and fabricated to ensure contact between the wick and the groove fins and to prevent the shrinkage of the PTFE membranes. Pure water was used as the working fluid. The effect of the PTFE wick characteristics on the LHP thermal performance was investigated by measuring the temperature at each point and the compensation chamber pressure. The LHP achieved steady-state operation at heat loads up to 1000 W, with a minimum thermal resistance of 0.052 K/W. Wick 2, which had a larger pore size and higher permeability, exhibited better performance than wick 1. The LHP operating temperature decreased by 10 °C, and the thermal resistance decreased by approximately 20% between wick 1 and wick 2.
The influence of rotation on natural frequencies of wind turbine blades with pre-bend
Authors: Xu Jin , Zhang Lei , Li Shuang , Xu Jianzhong
Published: April 2020

The natural frequencies of wind turbine blades in the rotating state differ significantly from those in free vibration conditions. In this paper, an established model blade analysis with the multi-body method and modal parameter identification were used to investigate the influence of rotation on natural frequencies of wind turbine blades. For the blades with rated powers of 100 kW, 1.5 MW, and 2.3 MW, the frequency growth with the increase in rotating speed, as well as the influence of gravity and pre-bend on frequencies and intensity of vibrations, was investigated. Additionally, the Campbell diagrams were analyzed. The results reveal that the combined effect of centrifugal force and pre-bend can induce the vibration of flap-edge coupling, and the intensity of the coupled vibration enhances with the increase in rotating speed. Gravity has little effect on the natural frequencies of rotating blades, but it enhances the edgewise vibration. Blades with stronger flexibility have a greater dynamic stiffening effect mainly in the flapwise direction. As rotating speed increases, the first-order flapwise (1st flap) natural frequency increases significantly, while the growth rate of higher-order frequencies decreases successively. When the 100 kW, 1.5 MW, and 2.3 MW wind turbines reached their rated speeds, the 1st flap natural frequencies increased by 19.41%, 20%, and 15.91%, respectively. Additionally, in the Campbell diagram, the corresponding rotating speed at the intersection of the 1st flap frequency and 3P (3P is three times the rotation frequency of the wind rotor) increases when rotation is considered.
1D fluid model of RF-excited cold atmospheric plasmas in helium with air gas impurities
Authors: Liu Yifan , Liu Dingxin , Zhang Jishen , Sun Bowen , Yang Aijun , Kong Michael G.
Published: April 2020

Cold atmospheric plasmas (CAPs) in helium with air gas impurities (He+Air for abbreviation) compromise the discharge stability of helium and the chemical reactivity of air, having great prospects for various applications such as plasma biomedicine. However, different kinds of reactive species are produced in He+Air CAPs but only a few of them could be measured, and the plasma chemistry is so complex that the reported simulation models are simplified to a large extent, such as neglecting the space variation of CAPs by using a 0D model. As a result, much remains unknown for He+Air CAPs, which hinders the development of their applications. For that reason, a 1D fluid model of He+Air CAPs is developed in this paper, incorporating 48 chemical species and 118 volume reactions, which are extracted from a complex chemistry set by a reported 0D model, and then the density distribution of reactive species, the power dissipation pathways, and the chemistry pathways among the reactive species are obtained as a function of air concentration from 500 to 10 000 ppm. It is found that O and NO are the dominant reactive oxygen species (ROS) and reactive nitrogen species (RNS), respectively. Taking the ROS as a whole, it is mainly produced by the electron impact dissociation and excitation of O2; taking the RNS as a whole, it is mainly produced by the oxidation of atomic nitrogen [N and N(2D)], and NO is the precursor for all the other RNS.
Simulations demonstrate how reactive species are produced by cold atmospheric plasmas
Authors: Bandari Anashe
Published: April 2020

Cold atmospheric plasmas have many biomedical applications ranging from antibacterial agents to wound healing, but careful modeling is required to predict the production useful reactive particles.
A compact electron source for the dielectric laser accelerator
Authors: Hirano Tomohiko , Urbanek Karel E. , Ceballos Andrew C. , Black Dylan S. , Miao Yu , Joel England R. , Byer Robert L. , Leedle Kenneth J.
Published: April 2020

In this work, we design and demonstrate a compact electron source that combines an integrated silicon nanotip photoemitter with a compact silicon-based electrostatic lens. The lens simultaneously accelerates electrons to 30 keV and focuses the resulting beam to a 0.4 μm (RMS) beam diameter with 62 pm-rad normalized emittance at a distance of 20 mm from the cathode. The compact nature of this lens provides a compelling source for dielectric laser accelerator (DLA) beamlines, ultrafast electron diffraction, or ultrafast electron microscopy. Driven by a 220 fs, 1960 nm pulsed laser beam, electron currents up to 28 electrons/pulse at 100 kHz are demonstrated. The electron bunch length is 540 ± 50 fs for photocurrents of <1 electron/pulse, increasing to 700 ± 80 fs for 28 electrons/pulse, as measured by cross correlation with a 220 fs pulsed laser beam. The maximum 5D peak brightness is measured to be 6.8 × 1013 A/(m2 rad2) at 28 electrons/pulse. These results represent a significant step toward developing practical benchtop-sized linear accelerators based on DLA technology or compact ultrafast electron microscopy and diffraction applications.
Elastic wave localization and harvesting using double defect modes of a phononic crystal
Authors: Jo Soo-Ho , Yoon Heonjun , Shin Yong Chang , Kim Miso , Youn Byeng D.
Published: April 2020

Phononic crystals (PnCs) have been utilized to amplify the amount of input energy transferred to a piezoelectric energy harvesting (PEH) device by manipulating elastic wave propagation. When introducing a defect that has material properties and/or geometry different from a unit cell, mechanical resonance of the defect leads to localizing elastic waves inside the defect. This is called a defect mode. Several prior studies have explored a defect mode for PEH purpose; however, they have focused only on a single defect. When introducing an additional defect into a PnC, the coupling between two defects leads to splitting the defect band. Incorporating such split defect band phenomena into PEH can potentially widen frequency bandwidth and realize broadband energy harvesting. Thus, this study newly proposes a PnC-based PEH system that uses double defect modes under elastic waves. In particular, this study examines how an electrical circuit connection (i.e., Independent, Series, or Parallel) between two PEH devices attached on each defect affects PEH performances. Key findings from this study include (1) the shift in split defect bands as well as harvesting performance varies with the type of electrical circuit connection; (2) split defect band phenomena amplify the output electric power at double resonance peaks in an Independent connection; and (3) despite displacement amplification at certain resonance frequencies, no peak output voltage occurs due to the current source direction (for Series connections) and voltage cancellation (for Parallel connections). These key findings can provide design and selection guidelines for electrical circuit configurations between double defects for enhanced PEH.
Dynamically tunable excellent absorber based on plasmon-induced absorption in black phosphorus nanoribbon
Authors: Liu Chao , Li Hongjian , Xu Hui , Zhao Mingzhuo , Xiong Cuixiu , Li Min , Ruan Banxian , Zhang Baihui , Wu Kuan
Published: April 2020

The realization of plasmon-induced absorption (PIA) via local plasmon resonance coupling on the surface of two-dimensional metamaterials based on nanostructures heavily depends on the well-designed patterned antenna. However, due to the limitation of nanostructures’ size and the difficulty of material formation, it is challenging to achieve the expected performance of such a device. We propose and numerically simulate PIA in response to mid-infrared using two black phosphorus (BP) layers that are composed of upper double BP ribbons and lower single BP ribbons to avoid BP chips patterning. The theoretical transmission spectrum of the structure calculated by the coupled mode theory is in good agreement with the simulated curve. The resonant intensity of the reflection window is affected by interlayer spacing, and the resonant wavelength of the reflection window can be realized by dynamically varying carrier density. The absorption performance of the system can be enhanced not only by the gold mirror that is totally reflected at the bottom of the structure but also by the polarization angle of the incident wave. The designed system could be expected on various optical devices, including plasmonic sensors, dual-frequency absorbers, and switch controllers.
Forward–backward asymmetry in electron impact ionization of CO
Authors: Watanabe Noboru , Takahashi Masahiko
Published: April 2020

We experimentally investigate the molecular-orientation dependence of high-energy electron-impact ionization of CO. The direction of the molecular-axis with respect to the momentum transfer vector K is deduced from the angular correlation between the fragment ion and the scattered electron. The experimental results on the 3 2Π ionization reveal that at small momentum transfer, the ionization probability near the threshold is higher when K points toward the C atom along the molecular axis than when it is in the opposite direction. Such a forward–backward asymmetry does not appear in single-photon ionization and requires non-dipole contributions. It is also shown that the {4 2Σ+ + 5 2Σ+ + 6 2Σ+} ionization preferentially takes place in the vicinity of the molecular orientation parallel to K at small momentum transfer, while non-dipole contributions cause the decrease in the relative intensity of the parallel direction.
Soft material perforation via double-bubble laser-induced cavitation microjets
Authors: Robles V. , Gutierrez-Herrera E. , Devia-Cruz L. F. , Banks D. , Camacho-Lopez S. , Aguilar G.
Published: April 2020

The resulting jet of two interacting laser-induced cavitation bubbles is optimized and studied as a technique for micro-scale targeting of soft materials. High controllability of double-bubble microjets can make such configurations favorable over single bubbles for applications where risk of ablation or thermal damage should be minimized such as in soft biological structures. In this study, double-bubble jets are directed toward an agar gel-based skin phantom to explore the application of micro-scale injection and toward a soft paraffin to quantify the targeting effectiveness of double-bubble over single-bubble jetting. The sharp elongation during the double-bubble process leads to fast, focused jets reaching average magnitudes of Ujet = 87.6 ± 9.9 m/s. When directed to agar, the penetration length and injected volume increase at ∼250 μm and 5 nl per subsequent jets. Such values are achieved without the use of fabricated micro-nozzles seen in existing needle-free laser injection systems. In soft paraffin, double-bubble jetting produces the same penetration length as single-bubble jetting, but with ∼45% reduction in damage area at a 3× greater target distance. Thus, double-bubble jetting can achieve smaller impact areas and greater target distances, potentially reducing collateral thermal damage and effects of strong shockwave pressures.
Polaritonic normal modes in transition state theory
Authors: Campos-Gonzalez-Angulo Jorge A. , Yuen-Zhou Joel
Published: April 2020

A series of experiments demonstrates that strong light–matter coupling between vibrational excitations in isotropic solutions of molecules and resonant infrared optical microcavity modes leads to modified thermally activated kinetics. However, Galego et al. [Phys. Rev. X 9, 021057 (2019)] recently demonstrated that, within transition state theory, effects of strong light–matter coupling with reactive modes are mostly electrostatic and essentially independent of light–matter resonance or even of the formation of vibrational polaritons. To analyze this puzzling theoretical result in further detail, we revisit it under a new light, invoking a normal mode analysis of the transition state and reactant configurations for an ensemble of an arbitrary number of molecules in a cavity, obtaining simple analytical expressions that produce similar conclusions as Feist. While these effects become relevant in optical microcavities if the molecular dipoles are anisotropically aligned, or in cavities with extreme confinement of the photon modes, they become negligible for isotropic solutions in microcavities. It is concluded that further studies are necessary to track the origin of the experimentally observed kinetics.
Cycling‐based repeat sprint training in the heat enhances running performance in team sport players
Authors: Gale Rachel M. , Etxebarria Naroa , Pumpa Kate L. , Pyne David B.
Published: April 2020

Applying heat training interventions in a team sports setting remains challenging. This study investigated the effects of integrating short‐term, repeat sprint heat training with passive heat exposure on running performance and general conditioning in team sport players. Thirty male club‐level Australian Football players were assigned randomly to: Passive + Active Heat (PAH; n = 10), Active Heat (AH; n = 10) or Control (CON; n = 10) to complete 6 × 40 min high‐intensity cycling training sessions over 12 days in 35°C (PAH and AH) or 18°C (CON), 50% RH in parallel with mid‐season sports‐specific training and games. Players in PAH were exposed to 20 min pre‐exercise passive heat. Physiological adaptation and running capacity were assessed via a treadmill submaximal heat stress test followed by a time‐to‐exhaustion run in 35°C, 50% RH. Running capacity increased by 26% ± 8% PAH (0.88, ±0.23; standardised mean, ± 90% confidence limits), 29% ± 12% AH (1.23, ±0.45) and 10% ± 11% CON (0.45, ±0.48) compared with baseline. Both PAH (0.52, ±0.42; standardised mean, ± 90% confidence limits) and AH (0.35, ±0.57) conditions yielded a greater improvement in running capacity than CON. Physiological and perceptual measures remained relatively unchanged between baseline and post‐intervention heat stress tests, within and between conditions. When thermal adaptation is not a direct priority, short‐term, repeat effort high‐intensity cycling in hot conditions combined with sports‐specific training can further enhance running performance in team sport players. Six heat exposures across 12‐days should improve running performance while minimising lower limb load and cumulative fatigue for team sports players.