Public Anthropology as Public Pedagogy: An Autobiographical Account

ERIC Educational Resources Information Center

Beck, Sam

2011-01-01

This autobiographical account provides a historical map of landmarks in the author's personal and professional life that led him to his present understanding of public anthropology as public pedagogy and vice versa. He indicates that his experiences led him to study sociocultural anthropology to investigate learning from experience, a foundational…

Interaction of light quality and fertility on biomass, shoot pigmentation and xanthophyll cycle flux in Chinese kale.

PubMed

Kopsell, Dean A; Sams, Carl E; Morrow, Robert C

2017-02-01

Nutritionally important carotenoids in 21-day-old brassica microgreens increase following short and long-term exposure to narrow-band wavelengths from light-emitting diodes (LED). The present study aimed to measure the impact of: (1) fluorescent/incandescent light and different percentages of blue/red LED light and (2) different levels of nutrient fertility on biomass and pigment concentrations in 30-day-old 'Green Lance' Chinese kale (Brassica oleracea var. alboglabra). Kale plants were exposed to four light treatments and two fertility levels and were harvested 30 days after seeding and analyzed for nutritionally important shoot pigments. Kale under the fluorescent/incandescent light treatment had a significantly higher shoot fresh and dry mass. The shoot tissue concentrations of most pigment were significantly higher under blue/red LED light treatments. The higher fertility level resulted in higher concentrations for most pigments. Interestingly, the pool of xanthophyll cycle pigments and de-epoxidized xanthophylls was higher under all LED treatments. The results obtained in the present study support previous data demonstrating the stimulation of nutritionally important shoot tissue pigment concentrations following exposure to sole source blue/red LEDs compared to traditional lighting. Xanthophyll cycle flux was impacted by LEDs and this may support the role of zeaxanthin in blue light perception in leafy specialty crops. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

A comparative study of fluorescent and LED lighting in industrial facilities

NASA Astrophysics Data System (ADS)

Perdahci PhD, C.; Akin BSc, H. C.; Cekic Msc, O.

2018-05-01

Industrial facilities have always been in search for reducing outgoings and minimizing energy consumption. Rapid developments in lighting technology require more energy efficient solutions not only for industries but also for many sectors and for households. Addition of solid-state technology has brought LED lamps into play and with LED lamp usage, efficacy level has reached its current values. Lighting systems which uses fluorescent and LED lamps have become the prior choice for many industrial facilities. This paper presents a comparative study about fluorescent and LED based indoor lighting systems for a warehouse building in an industrial facility in terms of lighting distribution values, colour rendering, power consumption, energy efficiency and visual comfort. Both scenarios have been modelled and simulated by using Relux and photometric data for the luminaires have been gathered by conducting tests and measurements in an accredited laboratory.

Renaissance Neurosurgery: Italy's Iconic Contributions.

PubMed

Nanda, Anil; Khan, Imad Saeed; Apuzzo, Michael L

2016-03-01

Various changes in the sociopolitical milieu of Italy led to the increasing tolerance of the study of cadavers in the late Middle Ages. The efforts of Mondino de Liuzzi (1276-1326) and Guido da Vigevano (1280-1349) led to an explosion of cadaver-centric studies in centers such as Bologna, Florence, and Padua during the Renaissance period. Legendary scientists from this era, including Leonardo Da Vinci, Andreas Vesalius, Bartolomeo Eustachio, and Costanzo Varolio, furthered the study of neuroanatomy. The various texts produced during this period not only helped increase the understanding of neuroanatomy and neurophysiology but also led to the formalization of medical education. With increased understanding came new techniques to address various neurosurgical problems from skull fractures to severed peripheral nerves. The present study aims to review the major developments in Italy during the vibrant Renaissance period that led to major progress in the field of neurosurgery. Published by Elsevier Inc.

Community Peer-Led Falls Prevention Presentations: What Do the Experts Suggest?

PubMed

Khong, Linda A M; Berlach, Richard G; Hill, Keith D; Hill, Anne-Marie

2018-04-01

Falls among older adults are a major problem. Despite considerable progress in falls prevention research, older adults often show low motivation to engage in recommended preventive strategies. Peer-led falls prevention education for older adults may have potential for bridging the research evidence-practice gap, thereby promoting the uptake of falls prevention strategies. We evaluated peer educators' presentations of falls prevention education to community-dwelling older adults in regard to established criteria that were consistent with adult learning principles, the framework of health behaviour change, falls prevention guidelines, and recommendations for providing falls prevention information. We conducted a within-stage mixed model study using purposive and snowball sampling techniques to recruit 10 experts to evaluate video recordings of the delivery of three peer-led falls prevention presentations. Each expert viewed three videos and rated them using a questionnaire containing both open-ended and closed items. There was a good level of expert agreement across the questionnaire domains. Though the experts rated some aspects of the presentations highly, they thought that the presentations were mainly didactic in delivery, not consistently personally relevant to the older adult audience, and did not encourage older adults to engage in the preventive strategies that were presented. Based on the experts' findings, we developed five key themes and recommendations for the effective delivery of peer-led falls prevention presentations. These included recommending that peer educators share falls prevention messages in a more interactive and experiential manner and that uptake of strategies should be facilitated by encouraging the older adults to develop a personalised action plan. Findings suggest that if peer-led falls prevention presentations capitalise on older adults' capability, opportunity, and motivation, the older adults may be more receptive to take up falls prevention messages.

Effect of the laser and light-emitting diode (LED) phototherapy on midpalatal suture bone formation after rapid maxilla expansion: a Raman spectroscopy analysis.

PubMed

Rosa, Cristiane Becher; Habib, Fernando Antonio Lima; de Araújo, Telma Martins; Aragão, Juliana Silveira; Gomes, Rafael Soares; Barbosa, Artur Felipe Santos; Silveira, Landulfo; Pinheiro, Antonio L B

2014-05-01

The aim of this study was to analyze the effect of laser or light-emitting diode (LED) phototherapy on the bone formation at the midpalatal suture after rapid maxilla expansion. Twenty young adult male rats were divided into four groups with 8 days of experimental time: group 1, no treatment; group 2, expansion; group 3, expansion and laser irradiation; and group 4, expansion and LED irradiation. In groups 3 and 4, light irradiation was in the first, third, and fifth experimental days. In all groups, the expansion was accomplished with a helicoid 0.020" stainless steel orthodontic spring. A diode laser (λ780 nm, 70 mW, spot of 0.04 cm(2), t = 257 s, spatial average energy fluence (SAEF) of 18 J/cm(2)) or a LED (λ850 nm, 150 mW ± 10 mW, spot of 0.5 cm(2), t = 120 s, SAEF of 18 J/cm(2)) were used. The samples were analyzed by Raman spectroscopy carried out at midpalatal suture and at the cortical area close to the suture. Two Raman shifts were analyzed: ∼ 960 (phosphate hydroxyapatite) and ∼ 1,450 cm(-1) (lipids and protein). Data was submitted to statistical analysis. Significant statistical difference (p ≤ 0.05) was found in the hydroxyapatite (CHA) peaks among the expansion group and the expansion and laser or LED groups. The LED group presented higher mean peak values of CHA. No statistical differences were found between the treated groups as for collagen deposition, although LED also presented higher mean peak values. The results of this study using Raman spectral analysis indicate that laser and LED light irradiation improves deposition of CHA in the midpalatal suture after orthopedic expansion.

Semiconductor lasers vs LEDs in diagnostic and therapeutic medicine

NASA Astrophysics Data System (ADS)

Gryko, Lukasz; Zajac, Andrzej; Szymanska, Justyna; Blaszczak, Urszula; Palkowska, Anna; Kulesza, Ewa

2016-12-01

Semiconductor emitters are used in many areas of medicine, allowing for new methods of diagnosis, treatment and effective prevention of many diseases. The article presents selected areas of application of semiconductor sources in UVVIS- NIR range, where in recent years competition in semiconductor lasers and LEDs applications has been observed. Examples of applications of analyzed sources are indicated for LLLT, PDT and optical diagnostics using the procedure of color contrast. Selected results of LLLT research of the authors are presented that were obtained by means of the developed optoelectronic system for objectified irradiation and studies on the impact of low-energy laser and LED on lines of endothelial cells of umbilical vein. Usefulness of the spectrally tunable LED lighting system for diagnostic purposes is also demonstrated, also as an illuminator for surface applications - in procedure of variable color contrast of the illuminated object.

High-power UV-LED degradation: Continuous and cycled working condition influence

NASA Astrophysics Data System (ADS)

Arques-Orobon, F. J.; Nuñez, N.; Vazquez, M.; Segura-Antunez, C.; González-Posadas, V.

2015-09-01

High-power (HP) UV-LEDs can replace UV lamps for real-time fluoro-sensing applications by allowing portable and autonomous systems. However, HP UV-LEDs are not a mature technology, and there are still open issues regarding their performance evolution over time. This paper presents a reliability study of 3 W UV-LEDs, with special focus on LED degradation for two working conditions: continuous and cycled (30 s ON and 30 s OFF). Accelerated life tests are developed to evaluate the influence of temperature and electrical working conditions in high-power LEDs degradation, being the predominant failure mechanism the degradation of the package. An analysis that includes dynamic thermal and optical HP UV-LED measurements has been performed. Static thermal and stress simulation analysis with the finite element method (FEM) identifies the causes of package degradation. Accelerated life test results prove that HP UV-LEDs working in cycled condition have a better performance than those working in continuous condition.

Enhanced Phycocyanin Production from Spirulina platensis using Light Emitting Diode

NASA Astrophysics Data System (ADS)

Bachchhav, Manisha Bhanudas; Kulkarni, Mohan Vinayak; Ingale, Arun G.

2017-06-01

This work investigates the performance of different cultivation conditions using Light Emitting Diode (LED) as a light source for the production of phycocyanin from Spirulina platensis. With LEDs under autotrophic conditions, red LED produced maximum amount of biomass (8.95 g/l). As compared to autotrophic cultivation with fluorescent lamp (control), cultivations using LEDs under autotrophic and mixotrophic mode significantly enhanced the phycocyanin content. For autotrophic conditions (with LED) phycocyanin content was in the range of 103-242 mg/g of dry biomass, whereas for mixotrophic conditions (0.1% glucose and LED) it was in the range of 254-380 mg/g of dry biomass. Spirulina cultivated with yellow LED under mixotrophic conditions had 5.4-fold more phycocyanin (380 mg/g of dry biomass) than control (70 mg/g of dry biomass). The present study demonstrates that the LEDs under mixotrophic conditions gave sixfold (2497 mg/l) higher yields of phycocyanin as compared to autotrophic condition under white light (415 mg/l).

When Worlds Collide: Identity, Culture and the Lived Experiences of Research When "Teaching-Led"

ERIC Educational Resources Information Center

Sharp, John G.; Hemmings, Brian; Kay, Russell; Callinan, Carol

2015-01-01

This article presents detailed findings from the qualitative or interpretive phase of a mixed-methods case study focusing on the professional identities and lived experiences of research among six lecturers working in different capacities across the field of education in a "teaching-led" higher education institution. Building upon the…

Feasibility of light-emitting diode uses for annular reactor inner-coated with TiO2 or nitrogen-doped TiO2 for control of dimethyl sulfide.

PubMed

Jo, Wan-Kuen; Eun, Sung-Soo; Shin, Seung-Ho

2011-01-01

Limited environmental pollutants have only been investigated for the feasibility of light-emitting diodes (LED) uses in photocatalytic decomposition (PD). The present study investigated the applicability of LEDs for annular photocatalytic reactors by comparing PD efficiencies of dimethyl sulfide (DMS), which has not been investigated with any LED-PD system, between photocatalytic systems utilizing conventional and various LED lamps with different wavelengths. A conventional 8 W UV/TiO(2) system exhibited a higher DMS PD efficiency as compared with UV-LED/TiO(2) system. Similarly, a conventional 8 W visible-lamp/N-enhanced TiO(2) (NET) system exhibited a higher PD efficiency as compared with six visible-LED/NET systems. However, the ratios of PD efficiency to the electric power consumption were rather high for the photocatalytic systems using UV- or visible-LED lamps, except for two LED lamps (yellow- and red-LED lamps), compared to the photocatalytic systems using conventional lamps. For the photocatalytic systems using LEDs, lower flow rates and input concentrations and shorter hydraulic diameters exhibited higher DMS PD efficiencies. An Fourier-transformation infrared analysis suggested no significant absorption of byproducts on the catalyst surface. Consequently, it was suggested that LEDs can still be energy-efficiently utilized as alternative light sources for the PD of DMS, under the operational conditions used in this study. © 2011 The Authors. Photochemistry and Photobiology © 2011 The American Society of Photobiology.

Power management of direct-view LED backlight for liquid crystal display

NASA Astrophysics Data System (ADS)

Lee, Xuan-Hao; Lin, Che-Chu; Chang, Yu-Yu; Chen, He-Xiang; Sun, Ching-Cherng

2013-03-01

In this paper, we present a study of management of power in function of luminous efficacy of white LED as well as the efficiency enhancement of the direct-view backlight with photon recycling. A cavity efficiency as high as 90.7% is demonstrated for a direct-view backlight with photon recycling. In the future, with a 90% backlight cavity, luminous efficacy of 200 lm/W for white LEDs, and a transmission efficiency of 10% for the liquid crystal panel, the required power of LEDs could be only 16 W. Up to 85% energy saving could be achieved in comparison to the power of the current liquid crystal display.

830 nm light-emitting diode (led) phototherapy significantly reduced return-to-play in injured university athletes: a pilot study.

PubMed

Foley, John; Vasily, David B; Bradle, Jeanna; Rudio, Catharine; Calderhead, R Glen

2016-03-31

For any committed athlete, getting back to conditioning and participation post-injury (return to play [RTP]) needs to be as swift as possible. The effects of near-infrared light-emitting diode (LED) therapy on pain control, blood flow enhancement and relaxation of muscle spasm (all aspects in the treatment of musculoskeletal injury) have attracted attention. The present pilot study was undertaken to assess the role of 830 nm LED phototherapy in safely accelerating RTP in injured university athletes. Over a 15-month period, a total of 395 injuries including sprains, strains, ligament damage, tendonitis and contusions were treated with 1,669 sessions of 830 nm LED phototherapy (mean of 4.3 treatments per injury, range 2 - 6). Efficacy was measured with pain attenuation on a visual analog scale (VAS) and the RTP period compared with historically-based anticipated RTP with conventional therapeutic intervention. A full set of treatment sessions and follow-up data was able to be recorded in 65 informed and consenting subjects who achieved pain relief on the VAS of up to 6 points in from 2-6 sessions. The average LED-mediated RTP in the 65 subjects was significantly shorter at 9.6 days, compared with the mean anticipated RTP of 19.23 days (p = 0.0066, paired two-tailed Student's t-test). A subjective satisfaction survey was carried out among the 112 students with injuries incurred from January to May, 2015. Eighty-eight (78.5%) were either very satisfied or satisfied, and only 8 (7.2%) were dissatisfied. For any motivated athlete, RTP may be the most important factor postinjury based on the resolution of pain and inflammation and repair to tissue trauma. 830 nm LED phototherapy significantly and safely reduced the RTP in dedicated university athletes over a wide range of injuries with no adverse events. One limitation of the present study was the subjective nature of the assessments, and the lack of any control groups. However, further controlled studies are warranted to enable confirmation and generalization of the very good results in the present study.

830 nm light-emitting diode (led) phototherapy significantly reduced return-to-play in injured university athletes: a pilot study

PubMed Central

Vasily, David B; Bradle, Jeanna; Rudio, Catharine; Calderhead, R Glen

2016-01-01

Background and Aims: For any committed athlete, getting back to conditioning and participation post-injury (return to play [RTP]) needs to be as swift as possible. The effects of near-infrared light-emitting diode (LED) therapy on pain control, blood flow enhancement and relaxation of muscle spasm (all aspects in the treatment of musculoskeletal injury) have attracted attention. The present pilot study was undertaken to assess the role of 830 nm LED phototherapy in safely accelerating RTP in injured university athletes. Subjects and Methods: Over a 15-month period, a total of 395 injuries including sprains, strains, ligament damage, tendonitis and contusions were treated with 1,669 sessions of 830 nm LED phototherapy (mean of 4.3 treatments per injury, range 2 – 6). Efficacy was measured with pain attenuation on a visual analog scale (VAS) and the RTP period compared with historically-based anticipated RTP with conventional therapeutic intervention. Results: A full set of treatment sessions and follow-up data was able to be recorded in 65 informed and consenting subjects who achieved pain relief on the VAS of up to 6 points in from 2–6 sessions. The average LED-mediated RTP in the 65 subjects was significantly shorter at 9.6 days, compared with the mean anticipated RTP of 19.23 days (p = 0.0066, paired two-tailed Student's t-test). A subjective satisfaction survey was carried out among the 112 students with injuries incurred from January to May, 2015. Eighty-eight (78.5%) were either very satisfied or satisfied, and only 8 (7.2%) were dissatisfied. Conclusions: For any motivated athlete, RTP may be the most important factor postinjury based on the resolution of pain and inflammation and repair to tissue trauma. 830 nm LED phototherapy significantly and safely reduced the RTP in dedicated university athletes over a wide range of injuries with no adverse events. One limitation of the present study was the subjective nature of the assessments, and the lack of any control groups. However, further controlled studies are warranted to enable confirmation and generalization of the very good results in the present study. PMID:27141153

Do patients discharged from advanced practice physiotherapy-led clinics re-present to specialist medical services?

PubMed

Chang, Angela T; Gavaghan, Belinda; O'Leary, Shaun; McBride, Liza-Jane; Raymer, Maree

2017-05-15

Objective The aim of the present study was to determine the rates of re-referral to specialist out-patient clinics for patients previously managed and discharged from an advanced practice physiotherapy-led service in three metropolitan hospitals. Methods A retrospective audit was undertaken of 462 patient cases with non-urgent musculoskeletal conditions discharged between 1 April 2014 and 30 March 2015 from three metropolitan hospitals. These patients had been discharged from the physiotherapy-led service without requiring specialist medical review. Rates and patterns of re-referral to specialist orthopaedic, neurosurgical, chronic pain, or rheumatology services within 12 months of discharge were investigated. Results Forty-six of the 462 patients (10.0%) who were managed by the physiotherapy-led service were re-referred to specialist medical orthopaedic, neurosurgical, chronic pain or rheumatology departments within 12 months of discharge. Only 22 of these patients (4.8%) were re-referred for the same condition as managed previously and discharged. Conclusions Ninety-five per cent of patients with non-urgent musculoskeletal conditions managed by an advanced practice physiotherapy-led service at three metropolitan hospitals did not re-present to access public specialist medical services for the same condition within 12 months of discharge. This is the first time that re-presentation rates have been reported for patients managed in advanced practice physiotherapy services and the findings support the effectiveness of these models of care in managing demand for speciality out-patient services. What is known about the topic? Advanced practice physiotherapy-led services have been implemented to address the needs of patients referred with non-urgent musculoskeletal conditions to hospital specialist out-patient services. Although this model is widely used in Australia, there has been very little information about whether patients managed in these services subsequently re-present for further specialist medical care. What does this paper add? This paper identifies that the majority (95%) of patients managed by an advanced practice physiotherapy-led service did not re-present for further medical care for the same condition within 12 months of discharge. What are the implications for practitioners? This paper supports the use of advanced practice physiotherapy-led services in the management of overburdened neurosurgical and orthopaedic specialist out-patient waiting lists.

Photodynamic Therapy for Actinic Keratoses: A Randomized Prospective Non-sponsored Cost-effectiveness Study of Daylight-mediated Treatment Compared with Light-emitting Diode Treatment.

PubMed

Neittaanmäki-Perttu, Noora; Grönroos, Mari; Karppinen, Toni; Snellman, Erna; Rissanen, Pekka

2016-02-01

Daylight-mediated photodynamic therapy (DL-PDT) is considered as effective as conventional PDT using artificial light (light-emitting diode (LED)-PDT) for treatment of actinic keratoses (AK). This randomized prospective non-sponsored study assessed the cost-effectiveness of DL-PDT compared with LED-PDT. Seventy patients with 210 AKs were randomized to DL-PDT or LED-PDT groups. Effectiveness was assessed at 6 months. The costs included societal costs and private costs, including the time patients spent in treatment. Results are presented as incremental cost-effectiveness ratio (ICER). The total costs per patient were significantly lower for DL-PDT (€132) compared with LED-PDT (€170), giving a cost saving of €38 (p = 0.022). The estimated probabilities for patients' complete response were 0.429 for DL-PDT and 0.686 for LED-PDT; a difference in probability of being healed of 0.257. ICER showed a monetary gain of €147 per unit of effectiveness lost. DL-PDT is less costly and less effective than LED-PDT. In terms of cost-effectiveness analysis, DL-PDT provides lower value for money compared with LED-PDT.

Evaluation of the effect of LED radiation in the repair of skin wounds on the dorsum of rats with iron deficiency anemia

NASA Astrophysics Data System (ADS)

de Oliveira, Susana Carla Pires Sampaio; de Carvalho Monteiro, Juliana Santos; dos Santos Aciole, Gilberth Tadeu; DeCastro, Isabele Cardoso V.; Menezes, Diego Silva; de Fátima Lima Ferreira, Maria; dos Santos, Jean Nunes; Zanin, Fátima; Barbosa Pinheiro, Antônio Luiz

2010-05-01

Iron deficiency anemia causes reduction on the level of hemoglobin and of the number of RBC and affects around 35% of the human population. Laser and LED therapies have been successfully used on wound healing studies. The aim of the present study was to assess histologically the effect of LED Phototherapy on the healing of cutaneous wounds on anemic rats. Fifty one 21 days old male wistar rats weighting around 50 g were kept under iron free die (Sem ferro-AIN93-G) during 15 days in order to induce anemia. Non treated animals acted as controls. A standartized cutaneous wound was created on the dorsum of each animal whom were distributed into four groups: Group I—Anemia+LED, Group II—Non anemic+LED, Group III—Anemia+no treatment, Group IV—No anemic+no-treatment. Irradiation started immediately after surgery and repeated at 48 h intervals during 21 days. Animal death occurred after 7, 14 and 21 days after wounding. The results of the histologic analysis showed that LED Phototherapy stimulated fibroblastic proliferation. It is concluded that LED irradiation improves wound healing on iron deficient anemic animals.

Design of a detection system of highlight LED arrays' effect on the human organization

NASA Astrophysics Data System (ADS)

Chen, Shuwang; Shi, Guiju; Xue, Tongze; Liu, Yanming

2009-05-01

LED (Light Emitting Diode) has many advantages in the intensity, wavelength, practicality and price, so it is feasible to apply in biomedicine engineering. A system for the research on the effect of highlight LED arrays to human organization is designed. The temperature of skin surface can rise if skin and organization are in irradiation by highlight LED arrays. The metabolism and blood circulation of corresponding position will be quicker than those not in the shine, so the surface temperature will vary in different position of skin. The structure of LED source arrays system is presented and a measure system for studying LED's influence on human organization is designed. The temperature values of shining point are detected by infrared temperature detector. Temperature change is different according to LED parameters, such as the number, irradiation time and luminous intensity of LED. Experimental device is designed as an LED arrays pen. The LED arrays device is used to shine the points of human body, then it may effect on personal organization as well as the acupuncture. The system is applied in curing a certain skin disease, such as age pigment, skin cancer and fleck.

Influence of gel/LED-laser application on cervical microleakage of two barrier materials used for endodontically treated teeth whitening

NASA Astrophysics Data System (ADS)

Marchesan, Melissa Andréia; Barros, Felipe; Porto, Saulo; Zaitter, Suellen; Brugnera, Aldo, Jr.; Sousa-Neto, Manoel D.

2007-02-01

This study evaluated ex vivo the influence of the number of gel/LED-laser applications/activations on cervical microleakage of two different barrier materials used for protection during whitening of endodontically treated teeth. Eighty-four canines were instrumented and obturated with epoxy resin sealer. The seal was removed 2 mm beyond the cemento-enamel junction for barrier placement and the teeth were divided into two groups of 40 teeth each: G1, zinc phosphate cement; G2, glass ionomer cement. The two groups were subdivided into 4 subgroups (n=10 each): I) no gel or LED-laser application; II) one gel application and two LED-laser activations; III) two gel applications and four LED-laser activations; IV) three gel applications and six LED-laser activations. The teeth were immersed in India ink for 7 days, decalcified and cleared. Cervical microleakage was quantified with a measurement microscope. Statistical analysis showed that zinc phosphate caused significantly lower microleakage than glass ionomer cement (presented microleakage in all subgroups). However, after two (p<0.01) and three (p<0.001) applications of gel, there was statistially significant microleakage in zinc phosphate barriers. Based on the present results, it can be concluded that cervical barriers with zinc phosphate cement show less cervical microleakage and that two or more applications/activations of gel/LED-laser significantly increase microleakage.

Effectiveness of nurse-led clinics on service delivery and clinical outcomes in adults with chronic ear, nose and throat complaints: a systematic review.

PubMed

Whiteford, Caroline; White, Sarahlouise; Stephenson, Matthew

2016-04-01

Ear, nose and throat complaints are very common and can cause significant disruption to patients' lives. Many conditions are of a chronic nature and are not currently managed in a timely manner by general practitioners in the community. This may be due to a lack of specialized knowledge, necessary diagnostic equipment or time for lengthy patient education on management of their condition. A nurse-led model of care may be an effective alternative. To examine the effectiveness of nurse-led clinics on adults with chronic ear, nose and throat complaints. Adult patients, aged 18 years and older, attending ear, nose and throat clinics, regardless of the complaint. Nurse-led care in general practice and acute care in which the nurse was identified as taking a lead role in the care of the patients with chronic ear, nose and throat complaints. General practitioner-led care, or ear, nose and throat consultant-led care, sometimes described as "standard care". Service delivery outcomes, clinical and health outcomes and financial outcomes. Any relevant quantitative studies published in English between 1980 and 2013 were considered. A standardized three-step search strategy aimed to find both published and unpublished studies. Databases searched include PubMed, CINAHL, Cochrane Library (CENTRAL), Scopus, Embase, MedNar and ProQuest Theses and Dissertations. Methodological validity was assessed independently by two reviewers using standardized critical appraisal instruments from the Joanna Briggs Institute. Due to methodological heterogeneity of the included studies, no statistical pooling was possible and all results are presented narratively. The search identified 13,536 titles, of which 20 potentially relevant articles were retrieved. Of these 20, 17 were excluded following full-text review leaving three studies that were assessed for methodological quality and included in the review. Service delivery outcome findings were that patient satisfaction was equal or higher and waiting times were shorter in nurse led clinics. The other service delivery outcomes were not addressed. Clinical and health outcomes findings were that lower pain/discomfort levels were demonstrated in nurse led clinics but other clinical/health outcomes were not addressed. Financial outcomes findings were that nurse-led clinics were cost effective when compared with medical-led clinics. While all studies reported evidence of the effectiveness of nurse-led clinics in service delivery and clinical outcomes in adults with chronic ear, nose and throat complaints, most of the data was self-reported and many of the outcomes of interest were not considered. The lack of experimental trials means that the level of evidence is low and further research is needed. There was also not enough detail in the financial outcomes from which clear conclusions of the cost benefit of nurse-led clinics could be drawn. Evidence from included studies indicated higher levels of patient satisfaction, cost benefits and lower levels of pain/discomfort in nurse-led clinics, which suggests that nurse-led ear, nose and throat clinics may be considered in the management of adult patients with ear, nose and throat complaints. Currently there is little evidence examining the effectiveness of nurse-led ear, nose and throat clinics. Areas to be addressed by future research should include: levels of patient education, booking queues, levels of self-treatment change in presentation to clinic episodes, reinfection rates, prevention and cure and representation of patients at clinics for same complaint.

LED photochemotherapy against Staphylococcus aureus: an in vitro study

NASA Astrophysics Data System (ADS)

de Oliveira, Susana C. P. S.; Monteiro, Juliana S. C.; Pires-Santos, Gustavo M.; Sampaio, Fernando José Pires; Soares, Luiz Guilherme P.; Soares, Amanda P.; Pinheiro, Antônio L. B.

2018-02-01

Bacterial resistance to antibiotics is reality and need for alternative treatments is urgent. The aim of this work was to evaluate, in vitro, the effect of LED photochemotherapy on Staphylococcus aureus (ATCC 23529) using 25 μg / mL of phenothiazine compound combined with LED light (λ632 +/- 2ηm) using 12 J/cm2 energy density. The experiments were carried out in triplicate and the samples were divided into groups: Control, Irradiated (treated only with light), Photosensitizer (treated only in the presence of the dye), LED-Photochemotherapy (treatment with light associated with dye). Counts of the colony forming units and the data obtained were statistically analyzed (ANOVA, Tukey's test, p<0.05). The present study demonstrated that the efficacy of LED-Photochemotherapy as the use of 25 μg/mL x 12 J/cm2 caused 91.57 % of inhibition of bacterial growth. It is concluded that using energy density of 12 J/cm2 associated to 25 μg/mL caused high in vitro inhibition of S. aureus.

Preliminary studies on LED-activated pyropheophorbide-α methyl ester killing cisplatin-resistant ovarian carcinoma cells

NASA Astrophysics Data System (ADS)

Tan, Yong; Xu, Chuan Shan; Xia, Xin Shu; Yu, He Ping; Bai, Ding Qun; He, Yong; Xu, Jing; Wang, Ping; Wang, Xin Na; Leung, Albert Wing Nang

2009-05-01

In the present study, a novel LED source was applied for activating pyropheophorbids-a methyl ester (MPPa) in cisplatin-resistant ovarian cell line COC1/DDP cells. MPPa concentration was 2 μM and light energy from 0.125-8 J/cm2. Cytotoxicity was investigated 24 h using MTT reduction assay and light microscopy after treatment. Cellular ultrastructure was observed using transmission electron microscopy (TEM) and nuclear chromatin by fluorescent microscope with Hoechst33258 staining. MTT reduction assay showed that the cytotoxicity of LED-activated MPPa in the COC1/DDP cells increased along with the light dose of LED source and LED-activated MPPa resulted in light-dependent cytotoxicity. The observations from light microscopy reinforced the above results. TEM showed that necrotic cells with the disruption of karyotheca, karyorrhexis, and karyolysis of nucleus and apoptotic cells, especially the apoptotic body, can be seen post LED-activated MPPa. Hoechst33258 staining showed that condensation of chromatin and nuclear fragmentations could be found in many treated cells and some of them formed the structure of apoptotic bodies when COC1/DDP cells were exposed to 2 μM MPPa for 20 h and then 1 J/cm2 irradiation of LED source. The findings demonstrated that the novel LED source could efficiently activated MPPa and LED-activated MPPa could significantly kill cisplatin-resistant ovarian cell line COC1/DDP cells through two major pathways including necrosis and apoptosis, suggesting that LED is a novel and efficient light source and LED-activated MPPa might be potential therapeutic modality for treating cisplatin-resistant ovarian carcinoma.

Stakeholder Participation in System Change: A New Conceptual Model.

PubMed

O'Rourke, Tammy; Higuchi, Kathryn S; Hogg, William

2016-08-01

A recent change in Canada's primary care system led to the introduction of Nurse Practitioner-Led clinics. The literature suggests that stakeholders can influence system change initiatives. However, very little is known about healthcare stakeholder motivations, particularly stakeholders who are seen as resistors to change. To examine stakeholder participation in the system change process that led to the introduction of the first Nurse Practitioner-Led clinic in Ontario. This single case study included two site visits, semistructured individual tape-recorded interviews, and the examination of relevant public documents. Qualitative content analysis was used to analyze the data. Sixteen individuals from different healthcare sectors and professions participated in the interviews and 20 documents were reviewed. Six key themes emerged from the data. Linking Evidence to Action The findings from the study present a new perspective on stakeholder participation that includes both those who supported the proposed change and those who advocated for a different change. The findings identify stakeholder activities used to shape, share, and protect their visions for system change. The conceptual model presented in this study adds to the understanding of challenges and complexities involved in healthcare system change. Understanding why and how stakeholders participate in change can help healthcare leaders in planning activities to enhance stakeholder involvement in healthcare system change. © 2016 Sigma Theta Tau International.

Luminescence study and CIE diagram of certain alkaline sodium lead borate glass for LED applications

NASA Astrophysics Data System (ADS)

Lenkennavar, S. K.; Madhu, A.; Eraiah, B.; Kokila, M. K.

2018-04-01

In the present work, the glass composition 20Na2O -10PbO-10MO -60B2O3 doped with Praseodymium ions have been synthesised using muffle furnace by the conventional melt quenching technique and the effect of Pr3+ ions on optical properties of present glasses have been examined. The emission spectra were recorded in the wavelength range of 450-750nm upon excitation at 450 and 550nm. The Commission International deI'Eclairage (CIE) chromaticity coordinates are determined to estimate the emission colour of the Pr3+ incorporated barium/calcium/strontium sodium lead borate glasses. It is observed that blue LED and red LED applications can be expected by tuning the excitation wavelength applied to the same glass matrices.

Effect of blue LED light intensity on carotenoid accumulation in citrus juice sacs.

PubMed

Zhang, Lancui; Ma, Gang; Yamawaki, Kazuki; Ikoma, Yoshinori; Matsumoto, Hikaru; Yoshioka, Terutaka; Ohta, Satoshi; Kato, Masaya

2015-09-01

In the present study, the effects of blue LED light intensity on carotenoid accumulation and expression of genes related to carotenoid biosynthesis were investigated in the juice sacs of Satsuma mandarin (Citrus unshiu Marc.) and Valencia orange (Citrus sinensis Osbeck) in vitro. The results showed that 100 μmol m(-2)s(-1) blue LED light (100B) was effective for increasing carotenoid content, especially β-cryptoxanthin, in Satsuma mandarin after cultured in vitro for four weeks. In Valencia orange, in contrast, 50 μmol m(-2)s(-1) blue LED light (50B) treatment was effective for inducing carotenoid accumulation through increasing the contents of two major carotenoids, all-trans-violaxanthin and 9-cis-violaxanthin. In addition, gene expression results showed that the simultaneous increases in the expression of genes (CitPSY, CitPDS, CitZDS, CitLCYb2, and CitHYb) involved in producing β,β-xanthophylls were well consistent with the accumulation of β-cryptoxanthin in Satsuma mandarin under 100B, and violaxanthin in Valencia orange under 50B. The results presented herein contribute to further elucidating the regulatory mechanism of carotenoid accumulation by blue LED light. Copyright © 2015 Elsevier GmbH. All rights reserved.

[Nurse-led in Primary Health Care setting: a well-timed and promising organizational innovation].

PubMed

Torres-Ricarte, Marc; Crusat-Abelló, Ernest; Peñuelas-Rodríguez, Silvia; Zabaleta-del-Olmo, Edurne

2015-01-01

At present, the severe economic crisis along with the increasing prevalence of chronic diseases is leading to different countries to consider updating their Primary Health Care (PHC) services in order to make them more efficient and reduce health inequalities. To that end, various initiatives are being carried out, such as the provision of Nurse-led services and interventions. The purpose of this article is to present the available knowledge, controversies and opportunities for Nurse-led initiatives in the setting of PHC. Nurse- led interventions or health services in PHC have proven to be equal or more effective than usual care in disease prevention, the routine follow-up of patients with chronic conditions, and first contact care for people with minor illness. However, as there are only a few health economic evaluation studies published their efficiency is still potential. In conclusion, the Nurse-led care could be an innovative organizational initiative with the potential to provide an adequate response to the contemporary health needs of the population, as well as an opportunity for the nursing profession and for PHC and health systems in general. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

Thermoresponsive scattering coating for smart white LEDs.

PubMed

Bauer, Jurica; Verbunt, Paul P C; Lin, Wan-Yu; Han, Yang; Van, My-Phung; Cornelissen, Hugo J; Yu, Joan J H; Bastiaansen, Cees W M; Broer, Dirk J

2014-12-15

White light emitting diode (LED) systems, capable of lowering the color temperature of emitted light on dimming, have been reported in the literature. These systems all use multiple color LEDs and complex control circuitry. Here we present a novel responsive lighting system based on a single white light emitting LED and a thermoresponsive scattering coating. The coated LED automatically emits light of lower correlated color temperature (CCT) when the power is reduced. We also present results on the use of multiple phosphors in the white light LED allowing for the emission of warm white light in the range between 2900 K and 4150 K, and with a chromaticity complying with the ANSI standards (C78.377). This responsive warm white light LED-system with close-to-ideal emission characteristics is highly interesting for the lighting industry.

Study and Implementation of White Power-LED Based Indoor Lighting Application for the Healthcare Sector

NASA Astrophysics Data System (ADS)

Chakraborty, A.; Ganguly, R.

With the current technological growth in the field of device fabrication, white power-LED's are available for solid state lighting applications. This is a paradigm shift from electrical lighting to electronic lighting. The implemented systems are showing some promise by saving a considerable amount of energy as well as providing a good and acceptable illumination level. However, the `useful life' of such devices is an important parameter. If the proper device is not chosen, the desired reliability and performance will not be obtained. In the present work, different parameters associated with reliability of such LED's are studied. Four different varieties of LED's are put to test the `useful life' as per IESNA LM 79 standard. From the results obtained, the proper LED is chosen for further application. Subsequently, lighting design is done for a hospital waiting room (indoor application) with 24 × 7 lighting requirements for replacement of existing CFLs there. The calculations show that although the initial cost is higher for LED based lighting, yet the savings on energy and replacement of the lamp results in a payback time of less than a year.

High speed, high current pulsed driver circuit

DOEpatents

Carlen, Christopher R.

2017-03-21

Various technologies presented herein relate to driving a LED such that the LED emits short duration pulses of light. This is accomplished by driving the LED with short duration, high amplitude current pulses. When the LED is driven by short duration, high amplitude current pulses, the LED emits light at a greater amplitude compared to when the LED is driven by continuous wave current.

830 nm light-emitting diode low level light therapy (LED-LLLT) enhances wound healing: a preliminary study.

PubMed

Min, Pok Kee; Goo, Boncheol Leo

2013-01-01

The application of light-emitting diodes in a number of clinical fields is expanding rapidly since the development in the late 1990s of the NASA LED. Wound healing is one field where low level light therapy with LEDs (LED-LLLT) has attracted attention for both accelerating wound healing and controlling sequelae. The present study evaluated LED-LLLT in 5 wounds of various etiologies. There were 5 patients with ages ranging from 7 to 54 years, comprising 2 males and 3 females. The study followed 5 wounds, namely 2 acute excoriation wounds; 1 acute/subacute dog bite with infection; 1 subacute post-filler ulcerated wound with necrotic ischemic tissue and secondary infection; and 1 subacute case of edema and infection of the lips with herpes simplex involvement after an illegal cosmetic tattoo operation. All patients were in varying degrees of pain. All wounds were treated with multiple sessions (daily, every other day or twice weekly) using an LED-LLLT system (830 nm, CW, irradiance of 100 mW/cm(2) and fluence of 60 J/cm(2)) till improvement was achieved. Full wound healing and control of infection and discomfort were achieved in all patients, with wound condition-mediated treatment periods ranging from 1 to 8 weeks. No recurrence of the herpes simplex case was seen in a 4-month follow-up. 830 nm LED-LLLT successfully brought about accelerated healing in wounds of different etiologies and at different stages, and successfully controlled secondary infection. LED-LLLT was easy and pain-free to apply, and was well-tolerated by all patients. The good results warrant the design of controlled studies with a larger patient population.

830 nm light-emitting diode low level light therapy (LED-LLLT) enhances wound healing: a preliminary study

PubMed Central

Min, Pok Kee; Goo, Boncheol Leo

2013-01-01

Background and aims: The application of light-emitting diodes in a number of clinical fields is expanding rapidly since the development in the late 1990s of the NASA LED. Wound healing is one field where low level light therapy with LEDs (LED-LLLT) has attracted attention for both accelerating wound healing and controlling sequelae. The present study evaluated LED-LLLT in 5 wounds of various etiologies. Subjects and methods: There were 5 patients with ages ranging from 7 to 54 years, comprising 2 males and 3 females. The study followed 5 wounds, namely 2 acute excoriation wounds; 1 acute/subacute dog bite with infection; 1 subacute post-filler ulcerated wound with necrotic ischemic tissue and secondary infection; and 1 subacute case of edema and infection of the lips with herpes simplex involvement after an illegal cosmetic tattoo operation. All patients were in varying degrees of pain. All wounds were treated with multiple sessions (daily, every other day or twice weekly) using an LED-LLLT system (830 nm, CW, irradiance of 100 mW/cm2 and fluence of 60 J/cm2) till improvement was achieved. Results: Full wound healing and control of infection and discomfort were achieved in all patients, with wound condition-mediated treatment periods ranging from 1 to 8 weeks. No recurrence of the herpes simplex case was seen in a 4-month follow-up. Conclusions: 830 nm LED-LLLT successfully brought about accelerated healing in wounds of different etiologies and at different stages, and successfully controlled secondary infection. LED-LLLT was easy and pain-free to apply, and was well-tolerated by all patients. The good results warrant the design of controlled studies with a larger patient population. PMID:24155549

Working Memory and the Mind.

ERIC Educational Resources Information Center

Goldman-Rakic, Patricia S.

1992-01-01

Discusses studies of the neurobiology of memory and cognition. Presents the findings of anatomic and physiological studies of monkeys that have led to discoveries about the structure of working memory. (MCO)

Study on the structural, optical, and electrical properties of the yellow light-emitting diode grown on free-standing (0001) GaN substrate

NASA Astrophysics Data System (ADS)

Deng, Gaoqiang; Zhang, Yuantao; Yu, Ye; Yan, Long; Li, Pengchong; Han, Xu; Chen, Liang; Zhao, Degang; Du, Guotong

2018-04-01

In this paper, GaN-based yellow light-emitting diodes (LEDs) were homoepitaxially grown on free-standing (0001) GaN substrates by metal-organic chemical vapor deposition. X-ray diffraction (XRD), photoluminescence (PL), and electroluminescence (EL) measurements were conducted to investigate the structural, optical, and electrical properties of the yellow LED. The XRD measurement results showed that the InGaN/GaN multiple quantum wells (MQWs) in the LED structure have good periodicity because the distinct MQWs related higher order satellite peaks can be clearly observed from the profile of 2θ-ω XRD scan. The low temperature (10 K) and room temperature PL measurement results yield an internal quantum efficiency of 16% for the yellow LED. The EL spectra of the yellow LED present well Gaussian distribution with relatively low linewidth (47-55 nm), indicating the homogeneous In-content in the InGaN quantum well layers in the yellow LED structure. It is believed that this work will aid in the future development of GaN on GaN LEDs with long emission wavelength.

Hybrid sunlight/LED illumination and renewable solar energy saving concepts for indoor lighting.

PubMed

Tsuei, Chih-Hsuan; Sun, Wen-Shing; Kuo, Chien-Cheng

2010-11-08

A hybrid method for using sunlight and light-emitting diode (LED) illumination powered by renewable solar energy for indoor lighting is simulated and presented in this study. We can illuminate an indoor space and collect the solar energy using an optical switching system. When the system is turned off, the full spectrum of the sunlight is concentrated by a concentrator, to be absorbed by solar photovoltaic devices that provide the electricity to power the LEDs. When the system is turned on, the sunlight collected by the concentrator is split into visible and non-visible rays by a beam splitter. The visible rays pass through the light guide into a light box where it is mixed with LED light to ultimately provide uniform illumination by a diffuser. The non-visible rays are absorbed by the solar photovoltaic devices to provide electrical power for the LEDs. Simulation results show that the efficiency of the hybrid sunlight/LED illumination with the renewable solar energy saving design is better than that of LED and traditional lighting systems.

Discharge of Non-Acute Coronary Syndrome Chest Pain Patients From Emergency Care to an Advanced Nurse Practitioner-Led Chest Pain Clinic: A Cross-Sectional Study of Referral Source and Final Diagnosis.

PubMed

Ingram, Shirley J; McKee, Gabrielle; Quirke, Mary B; Kelly, Niamh; Moloney, Ashling

Chest pain is a common presentation to emergency departments (EDs). Pathways for patients with non-acute coronary syndrome (ACS) chest pain are not optimal. An advanced cardiology nurse-led chest pain service was commenced to address this. The aim of the study was to assess the outcomes of non-ACS patients discharged from ED to an advanced cardiology nurse-led chest pain clinic and compare by referral type (nurse or ED physician). The service consisted of advanced cardiology nurse or ED physician consultation in the ED and discharge to advanced nurse-led chest pain clinic review less than 72 hours after discharge. Referrals were by the advanced nurses during consult hours and out-of-hours were by the ED physicians. Data were extracted from case notes. This was a 1-site cross-sectional study of patients attending the chest pain clinic over 2 years. Confirmed coronary disease was diagnosed in 24% of patients. Of the 1041 patients, 45% were referred by the advanced nurses, who referred significantly more patients who were older (56.5 years/52.3 years), had positive exercise stress test results (21%/12%), and were diagnosed with stable coronary artery disease (19%/11%) and less patients with musculoskeletal diagnosis (5%/13%) and other noncardiac pain (36%/45%). The study fills a gap in the literature on the follow up of non-ACS patients who present to ED and used advanced cardiology nursing expertise in the ED and chest pain clinic. The advanced nurse referred more patients who were diagnosed with coronary disease, reflecting the expertise, experience, and efficiency of the advanced cardiology nurse-led service.

Toward blue emission in ZnO based LED

NASA Astrophysics Data System (ADS)

Viana, Bruno; Pauporté, Thierry; Lupan, Oleg; Le Bahers, Tangui; Ciofini, Ilaria

2012-03-01

The bandgap engineering of ZnO nanowires by doping is of great importance for tunable light emitting diode (LED) applications. We present a combined experimental and computational study of ZnO doping with Cd or Cu atoms in the nanomaterial. Zn1-xTMxO (TM=Cu, Cd) nanowires have been epitaxially grown on magnesium-doped p-GaN by electrochemical deposition. The Zn1-xTMxO/p-GaN heterojunction was integrated in a LED structure. Nanowires act as the light emitters and waveguides. At room temperature, TM-doped ZnO based LEDs exhibit low-threshold emission voltage and electroluminescence emission shifted from ultraviolet to violet-blue spectral region compared to pure ZnO LEDs. The emission wavelength can be tuned by changing the transition metal (TM) content in the ZnO nanomaterial and the shift is discussed, including insights from DFT computational investigations.

Lens design of LED searchlight of high brightness and distant spot.

PubMed

Zhao, Shuang; Wang, Kai; Chen, Fei; Wu, Dan; Liu, Sheng

2011-05-01

The study related in this paper is the design of a ship-mounted LED of high brightness and distant spot. The freeform lens design obeying the edge ray principle and Snell's law is presented first. Then, to fit the illumination requirement of the searchlight, we designed a freeform lens to collimate all the light rays coming from the LED. However, theoretical analysis proves that there is a critical angle for incident rays beyond which the rays cannot be collimated, and 55% is the light-efficiency limit for polymethyl methacrylate freeform lens. We then designed a combination of a freeform lens-coupled parabolic reflector that improved light efficiency to 70%. In this paper, the design of the freeform lens-coupled parabolic reflector is given in detail. In addition, tolerance analysis and the effect of manufacturing defect are presented.

Competitive interactions of attentional resources in early visual cortex during sustained visuospatial attention within or between visual hemifields: evidence for the different-hemifield advantage.

PubMed

Walter, Sabrina; Quigley, Cliodhna; Mueller, Matthias M

2014-05-01

Performing a task across the left and right visual hemifields results in better performance than in a within-hemifield version of the task, termed the different-hemifield advantage. Although recent studies used transient stimuli that were presented with long ISIs, here we used a continuous objective electrophysiological (EEG) measure of competitive interactions for attentional processing resources in early visual cortex, the steady-state visual evoked potential (SSVEP). We frequency-tagged locations in each visual quadrant and at central fixation by flickering light-emitting diodes (LEDs) at different frequencies to elicit distinguishable SSVEPs. Stimuli were presented for several seconds, and participants were cued to attend to two LEDs either in one (Within) or distributed across left and right visual hemifields (Across). In addition, we introduced two reference measures: one for suppressive interactions between the peripheral LEDs by using a task at fixation where attention was withdrawn from the periphery and another estimating the upper bound of SSVEP amplitude by cueing participants to attend to only one of the peripheral LEDs. We found significantly greater SSVEP amplitude modulations in Across compared with Within hemifield conditions. No differences were found between SSVEP amplitudes elicited by the peripheral LEDs when participants attended to the centrally located LEDs compared with when peripheral LEDs had to be ignored in Across and Within trials. Attending to only one LED elicited the same SSVEP amplitude as Across conditions. Although behavioral data displayed a more complex pattern, SSVEP amplitudes were well in line with the predictions of the different-hemifield advantage account during sustained visuospatial attention.

Essentials for Successful and Widespread LED Lighting Adoption

NASA Astrophysics Data System (ADS)

Khan, Nisa

2011-03-01

Solid-state lighting (SSL), with light-emitting diodes (LEDs) as the light source, is a growing and essential field, particularly in regard to the heightened need for global energy efficiency. In recent years, SSL has experienced remarkable advances in efficiency, light output magnitude and quality. Thus such diverse applications as signage, message centers, displays, and special lighting are now adopting LEDs, taking 2010's market to 9.1 billion - 68% growth from the previous year! While this is promising, future growth in both display and lighting applications will rely upon unveiling deeper understanding and key innovations in LED lighting science and technologies. In this presentation, some LED lighting fundamentals, engineering challenges and novel solutions will be discussed to address reduction in efficiency (a.k.a. droop) at high currents, and to obtain uniform light distribution for overcoming LEDs' directional nature. The droop phenomenon has been a subject of much controversy in the industry and despite several studies and claims, a widely-accepted explanation still lacks because of counter arguments and experiments. Recently several research studies have identified that the droop behavior in nitride-based LEDs beyond certain current density ranges can only be comprehensively explained if the current leaking beyond the LED active region is included. Although such studies have identified a few useful current leakage mechanisms outside the active region, no one has included current leakage, due to non-ideal, 3-D device structures that create undesirable current distribution inside and outside the active region. This talk will address achieving desirable current distributions from optimized 3-D device structures that should reduce current leakage and hence the droop behavior. In addition to novel LED design solutions for droop reduction and uniform light distribution, the talk will address cost and yield concerns as they pertain to core material scarcity. Such solutions are expected to make LED lights more energy efficient, pleasant in appearance, longer-lasting, affordable, and thus suitable for green living.

Low Emission Development Strategies: The Role of Networks and Knowledge Platforms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benioff, Ron; Bazilian, Morgan; Cox, Sadie

2013-09-01

Considerable effort has been made to address the transition to low-carbon economy. A key focus of these efforts has been on the development of national low-emissions developments strategies (LEDS). One enabler of these plans is the existence of well-functioning national, regional and international low-emission development networks and knowledge platforms. To better understand the role of LEDS, weexamine this area in relation to network theory. We present a review of strengths and weaknesses of existing LEDS networks that builds on the findings of a study conducted by the Coordinated Low Emission Assistance Network (CLEAN). Based on the insights from theory andmore » a mapping of the climate-related network space, we identify opportunities for further refinement of LEDS networks.« less

Luminescence and efficiency optimization of InGaN/GaN core-shell nanowire LEDs by numerical modelling

NASA Astrophysics Data System (ADS)

Römer, Friedhard; Deppner, Marcus; Andreev, Zhelio; Kölper, Christopher; Sabathil, Matthias; Strassburg, Martin; Ledig, Johannes; Li, Shunfeng; Waag, Andreas; Witzigmann, Bernd

2012-02-01

We present a computational study on the anisotropic luminescence and the efficiency of a core-shell type nanowire LED based on GaN with InGaN active quantum wells. The physical simulator used for analyzing this device integrates a multidimensional drift-diffusion transport solver and a k . p Schrödinger problem solver for quantization effects and luminescence. The solution of both problems is coupled to achieve self-consistency. Using this solver we investigate the effect of dimensions, design of quantum wells, and current injection on the efficiency and luminescence of the core-shell nanowire LED. The anisotropy of the luminescence and re-absorption is analyzed with respect to the external efficiency of the LED. From the results we derive strategies for design optimization.

Evaluation of the Centres of Excellence in Higher Education

ERIC Educational Resources Information Center

Kettunen, Juha Matti

2011-01-01

This study presents an evaluation of the centres of excellence in higher education in Finland. This approach is an example of enhancement-led evaluation aiming to improve the long-term development of education. The study presents the Degree Programme in Civil Engineering of the Turku University of Applied Sciences, which was awarded the…

Effects of color temperatures (Kelvin) of LED bulbs on blood physiological variables of broilers grown to heavy weights.

PubMed

Olanrewaju, H A; Purswell, J L; Collier, S D; Branton, S L

2015-08-01

Light-emitting diode (LED) lighting is being used in the poultry industry to reduce energy usage in broiler production facilities. However, limited data are available comparing efficacy of different spectral distribution of LED bulbs on blood physiological variables of broilers grown to heavy weights (>3 kg). The present study evaluated the effects of color temperature (Kelvin) of LED bulbs on blood physiological variables of heavy broilers in 2 trials with 4 replicates/trial. The study was a randomized complete block design. Four light treatments consisted of 3 LED light bulbs [2,700 K, (Warm-LED); 5,000 K, (Cool-LED-#1); 5,000 K, (Cool-LED-#2)] and incandescent light (ICD, standard) from 1 to 56 d age. A total of 960 1-day-old Ross × Ross 708 chicks (30 males/room 30 females/room) were equally and randomly distributed among 16 environmentally controlled rooms at 50% RH. Each of the 4 treatments was represented by 4 rooms. Feed and water were provided ad libitum. All treatment groups were provided the same diet. Venous blood samples were collected on d 21, 28, 42, and 56 for immediate analysis of selected physiological variables and plasma collection. In comparison with ICD, Cool-LED-#1 had greater (P < 0.05) effects on pH, partial pressure of CO₂(pCO₂), partial pressure of O₂(pO₂), saturated O₂(sO₂), and K⁺. However, all these acid-base changes remained within the normal venous acid-base homeostasis and physiological ranges. In addition, no effect of treatments was observed on HCO(3)(-), hematocrit (Hct), hemoglobin (Hb), Na⁺, Ca²⁺, Cl⁻, mean corpuscular hemoglobin concentration (McHc), osmolality, and anion gap. Moreover, blood glucose concentrations were not affected by treatments. This study shows that the 3 LED light bulbs evaluated in this study may be suitable for replacement of ICD light sources in commercial poultry facilities to reduce energy cost and optimize production efficiency without inducing physiological stress on broilers grown to heavy weights. © 2015 Poultry Science Association Inc.

An elegant route to overcome fundamentally-limited light extraction in AlGaN deep-ultraviolet light-emitting diodes: preferential outcoupling of strong in-plane emission (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kim, Jong Kyu; Lee, Jong Won; Kim, Dong-Yeong; Park, Jun Hyuk; Schubert, E. Fred; Kim, Jungsub; Kim, Yong-Il

2016-09-01

AlGaN-based deep ultraviolet (DUV) light-emitting diodes (LEDs) are being developed for their numerous applications such as purification of air and water, sterilization in food processing, UV curing, medical-, and defense-related light sources. However, external quantum efficiency (EQE) of AlGaN-based DUV LEDs is very poor (<5% for 250nm) particularly due to low hole concentration and light extraction efficiency (LEE). Conventional LEE-enhancing techniques used for GaInN-based visible LEDs turned out to be ineffective for DUV LEDs due to difference in intrinsic material property between GaInN and AlGaN (Al< 30%). Unlike GaInN visible LEDs, DUV light from a high Al-content AlGaN active region is strongly transverse-magnetic (TM) polarized, that is, the electric field vector is parallel to the (0001) c-axis and shows strong sidewall emission through m- or a-plane due to crystal-field split-off hole band being top most valence band. Therefore, a new LEE-enhancing approach addressing the unique intrinsic property of AlGaN DUV LEDs is strongly desired. In this study, an elegant approach based on a DUV LED having multiple mesa stripes whose inclined sidewalls are covered by a MgF2/Al omni-directional mirror to take advantage of the strongly anisotropic transverse-magnetic polarized emission pattern of AlGaN quantum wells is presented. The sidewall-emission-enhanced DUV LED breaks through the fundamental limitations caused by the intrinsic properties of AlGaN, thus shows a remarkable improvement in light extraction as well as operating voltage simultaneously. Furthermore, an analytic model is developed to understand and precisely estimate the extraction of DUV photons from AlGaN DUV LEDs, and hence to provide promising routes to maximize the power conversion efficiency.

Investigation of Passive Filter for LED Lamp

NASA Astrophysics Data System (ADS)

Sarwono, Edi; Facta, Mochammad; Handoko, Susatyo

2017-04-01

Light Emitting Diode lamp or LED lamp is one of the energy saving lamps nowadays widely used by consumers. However, LED lamp has contained harmonics caused by the rectifier circuit inside the lamp. Harmonics cause a quality problem in power system. As the harmonics present in current or voltage, the waveforms are distorted. Harmonics can lead to overheating in magnetic core of electrical equipments. In this paper, several tests are carried out to investigate the harmonic content of voltage and currents, and also the level of light intensity of the two brands of LED lamps. Measurements in this study are conducted by using HIOKI Power Quality Analyzer 3197. The test results show that the total harmonic distortion or THD of voltage on various brands of LED lamps did not exceed 5% as in compliance to the limit of IEEE standard 519-1992. The largest harmonic voltage is 2.9%, while maximum harmonic current for tested brands of LED lamp is 170.6%. The use of low pass filter in the form of LC filter was proposed. Based on experimental results, the application of LC filter at input side of LED lamp has successfully reduced THD current in the range of 85%-88%.

New reversing freeform lens design method for LED uniform illumination with extended source and near field

NASA Astrophysics Data System (ADS)

Zhao, Zhili; Zhang, Honghai; Zheng, Huai; Liu, Sheng

2018-03-01

In light-emitting diode (LED) array illumination (e.g. LED backlighting), obtainment of high uniformity in the harsh condition of the large distance height ratio (DHR), extended source and near field is a key as well as challenging issue. In this study, we present a new reversing freeform lens design algorithm based on the illuminance distribution function (IDF) instead of the traditional light intensity distribution, which allows uniform LED illumination in the above mentioned harsh conditions. IDF of freeform lens can be obtained by the proposed mathematical method, considering the effects of large DHR, extended source and near field target at the same time. In order to prove the claims, a slim direct-lit LED backlighting with DHR equal to 4 is designed. In comparison with the traditional lenses, illuminance uniformity of LED backlighting with the new lens increases significantly from 0.45 to 0.84, and CV(RMSE) decreases dramatically from 0.24 to 0.03 in the harsh condition. Meanwhile, luminance uniformity of LED backlighting with the new lens is obtained as high as 0.92 at the condition of extended source and near field. This new method provides a practical and effective way to solve the problem of large DHR, extended source and near field for LED array illumination.

Fluorescence errors in integrating sphere measurements of remote phosphor type LED light sources

NASA Astrophysics Data System (ADS)

Keppens, A.; Zong, Y.; Podobedov, V. B.; Nadal, M. E.; Hanselaer, P.; Ohno, Y.

2011-05-01

The relative spectral radiant flux error caused by phosphor fluorescence during integrating sphere measurements is investigated both theoretically and experimentally. Integrating sphere and goniophotometer measurements are compared and used for model validation, while a case study provides additional clarification. Criteria for reducing fluorescence errors to a degree of negligibility as well as a fluorescence error correction method based on simple matrix algebra are presented. Only remote phosphor type LED light sources are studied because of their large phosphor surfaces and high application potential in general lighting.

The effect of 580 nm-based-LED mixed light on growth, adipose deposition, skeletal development, and body temperature of chickens.

PubMed

Yang, Yefeng; Zhen, Chenghuang; Yang, Bo; Yu, Yonghua; Pan, Jinming

2018-06-01

Though previous study indicated that the 580 nm-yellow-LED-light showed an stimulating effect on growth of chickens, the low luminous efficiency of the yellow LED light cannot reflect the advantage of energy saving. In present study, the cool white LED chips and yellow LED chips have been combined to fabricate the white × yellow mixed LED light, with an enhanced luminous efficiency. A total 300 newly hatched chickens were reared under various mixed LED light. The results indicated that the white × yellow mixed LED light had "double-edged sword" effects on bird's body weight, bone development, adipose deposition, and body temperature, depending on variations in ratios of yellow component. Low yellow ratio of mixed LED light (Low group) inhibited body weight, whereas medium and high yellow ratio of mixed LED light (Medium and High groups) promoted body weight, compared with white LED light (White group). A progressive change in yellow component gave rise to consistent changes in body weight over the entire experiment. Moreover, a positive relationship was observed between yellow component and feed conversion ratio. High group-treated birds had greater relative abdominal adipose weight than Medium group-treated birds (P = 0.048), whereas Medium group-treated birds had greater relative abdominal adipose weight than Low group-treated birds (P = 0.044). We found that mixed light improved body weight by enhancing skeletal development (R 2  = 0.5023, P = 0.0001) and adipose deposition (R 2  = 0.6012, P = 0.0001). Birds in the Medium, High and Yellow groups attained significantly higher surface temperatures compared with the White group (P = 0.010). The results suggest that the application of the mixed light with high level of yellow component can be used successfully to improve growth and productive performance in broilers. Copyright © 2018. Published by Elsevier B.V.

Design and fabrication of adjustable red-green-blue LED light arrays for plant research

PubMed Central

Folta, Kevin M; Koss, Lawrence L; McMorrow, Ryan; Kim, Hyeon-Hye; Kenitz, J Dustin; Wheeler, Raymond; Sager, John C

2005-01-01

Background Although specific light attributes, such as color and fluence rate, influence plant growth and development, researchers generally cannot control the fine spectral conditions of artificial plant-growth environments. Plant growth chambers are typically outfitted with fluorescent and/or incandescent fixtures that provide a general spectrum that is accommodating to the human eye and not necessarily supportive to plant development. Many studies over the last several decades, primarily in Arabidopsis thaliana, have clearly shown that variation in light quantity, quality and photoperiod can be manipulated to affect growth and control developmental transitions. Light emitting diodes (LEDs) has been used for decades to test plant responses to narrow-bandwidth light. LEDs are particularly well suited for plant growth chambers, as they have an extraordinary life (about 100,000 hours), require little maintenance, and use negligible energy. These factors render LED-based light strategies particularly appropriate for space-biology as well as terrestrial applications. However, there is a need for a versatile and inexpensive LED array platform where individual wavebands can be specifically tuned to produce a series of light combinations consisting of various quantities and qualities of individual wavelengths. Two plans are presented in this report. Results In this technical report we describe the practical construction of tunable red-green-blue LED arrays to support research in plant growth and development. Two light fixture designs and corresponding circuitry are presented. The first is well suited for a laboratory environment for use in a finite area with small plants, such as Arabidopsis. The second is expandable and appropriate for growth chambers. The application of these arrays to early plant developmental studies has been validated with assays of hypocotyl growth inhibition/promotion and phototropic curvature in Arabidopsis seedlings. Conclusion The presentation of these proven plans for LED array construction allows the teacher, researcher or electronics aficionado a means to inexpensively build efficient, adjustable lighting modules for plant research. These simple and effective designs permit the construction of useful tools by programs short on electronics expertise. These arrays represent a means to modulate precise quality and quantity in experimental settings to test the effect of specific light combinations in regulating plant growth, development and plant-product yield. PMID:16117835

Interactive effect of light colours and temporal synergism of circadian neural oscillations in reproductive regulation of Japanese quail.

PubMed

Yadav, Suneeta; Chaturvedi, Chandra Mohini

2016-09-01

Avian literature reports the modulation of 'photoperiodic gonadal responses' by the temporal phase relation of serotonergic and dopaminergic oscillations in Japanese quail. But, the modulation of 'light colour responses' by the temporal synergism of neural oscillations is not yet known. Hence the present study was designed to investigate the interaction of the light colour (blue, red) and the phase relation of neural oscillations in the reproductive regulation of Japanese quail. Three week old male Japanese quail were divided into two groups and maintained under a long day length condition (16L:8D) and were exposed to a 30 lux intensity of blue LED (light emitting diode) (B LED) and a red LED light (R LED). At the age of 15.5weeks, quail of one subgroup of B LED were injected with serotonin precursor (5-HTP) and dopamine precursor (l-DOPA) 12hrs apart (B LED+12-hr) and those of the R LED group were injected with the same drugs (5mg/100g body weight over a period of thirteen days) but 8hrs apart (R LED+8-hr). The remaining subgroups of both the light colour groups (B LED & R LED) received normal saline twice daily and served as controls. Cloacal gland volume was recorded weekly until 35.5weeks of age when the study was terminated and reproductive parameters (testicular volume, GSI, seminiferous tubule diameter and plasma testosterone) were assessed. Results indicate that the 8-hr temporal phase relation of neural oscillations suppresses reproductive activity even during the photosensitive phase of the red light exposed quail (R LED+8-hr) compare to the R LED controls. On the other hand, the 12-hr temporal phase relation stimulates the gonadal development of the B LED+12-hr quail compared to the B LED controls which after completing one cycle entered into a regressive phase and remained sexually quiescent. These experiments suggest that the temporal phase relations of circadian neural oscillations, in addition to modulating the classical photoperiodic responses, may also modulate the gonadal responses to blue (suppressive) and red (stimulatory) light. These studies led us to conclude that the temporal phase relation of serotonergic and dopaminergic oscillations is not only an important regulator of avian reproduction but may also override the classical effects of light colours in Japanese quail. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluating the impact of LED bulb development on the economic viability of ultraviolet technology for disinfection.

PubMed

Ibrahim, Mohamed A S; MacAdam, Jitka; Autin, Olivier; Jefferson, Bruce

2014-01-01

Ultraviolet (UV) technologies have been very successful in disinfection applications due to their ability to inactivate microorganisms without producing harmful disinfection by-products. However, there have been a number of concerns associated with the use of conventional UV systems such as hazardous mercury content, high capital investment and reduced electrical efficiency. These concerns have set limitations for the use of UV processes. The study evaluates the development of light emitting diode (LED) technology as an alternative UV source over the last 5 years, analyses the projections provided by the researchers and UV LED manufacturers and presents the information in a cost model with the aim to predict the timeline at which UV LED will compete with traditional UV low pressure high output technology in the commercial market at full-scale residential and industrial disinfection applications.

An enhanced surface passivation effect in InGaN/GaN disk-in-nanowire light emitting diodes for mitigating Shockley-Read-Hall recombination.

PubMed

Zhao, Chao; Ng, Tien Khee; Prabaswara, Aditya; Conroy, Michele; Jahangir, Shafat; Frost, Thomas; O'Connell, John; Holmes, Justin D; Parbrook, Peter J; Bhattacharya, Pallab; Ooi, Boon S

2015-10-28

We present a detailed study of the effects of dangling bond passivation and the comparison of different sulfide passivation processes on the properties of InGaN/GaN quantum-disk (Qdisk)-in-nanowire based light emitting diodes (NW-LEDs). Our results demonstrated the first organic sulfide passivation process for nitride nanowires (NWs). The results from Raman spectroscopy, photoluminescence (PL) measurements, and X-ray photoelectron spectroscopy (XPS) showed that octadecylthiol (ODT) effectively passivated the surface states, and altered the surface dynamic charge, and thereby recovered the band-edge emission. The effectiveness of the process with passivation duration was also studied. Moreover, we also compared the electro-optical performance of NW-LEDs emitting at green wavelength before and after ODT passivation. We have shown that the Shockley-Read-Hall (SRH) non-radiative recombination of NW-LEDs can be greatly reduced after passivation by ODT, which led to a much faster increasing trend of quantum efficiency and higher peak efficiency. Our results highlighted the possibility of employing this technique to further design and produce high performance NW-LEDs and NW-lasers.

Design, fabrication, and packaging of an integrated, wirelessly-powered optrode array for optogenetics application

PubMed Central

Kwon, Ki Yong; Lee, Hyung-Min; Ghovanloo, Maysam; Weber, Arthur; Li, Wen

2015-01-01

The recent development of optogenetics has created an increased demand for advancing engineering tools for optical modulation of neural circuitry. This paper details the design, fabrication, integration, and packaging procedures of a wirelessly-powered, light emitting diode (LED) coupled optrode neural interface for optogenetic studies. The LED-coupled optrode array employs microscale LED (μLED) chips and polymer-based microwaveguides to deliver light into multi-level cortical networks, coupled with microelectrodes to record spontaneous changes in neural activity. An integrated, implantable, switched-capacitor based stimulator (SCS) system provides high instantaneous power to the μLEDs through an inductive link to emit sufficient light and evoke neural activities. The presented system is mechanically flexible, biocompatible, miniaturized, and lightweight, suitable for chronic implantation in small freely behaving animals. The design of this system is scalable and its manufacturing is cost effective through batch fabrication using microelectromechanical systems (MEMS) technology. It can be adopted by other groups and customized for specific needs of individual experiments. PMID:25999823

Energy saving through LED in signaling functions for automotive exterior lighting

NASA Astrophysics Data System (ADS)

Bony, Alexis; Hamami, Khaled; Tebbe, Frank; Mertens, Jens

2011-05-01

Safety considerations have always driven the way for improving exterior automotive lighting legal requirements. With the recent adoption of day-time running lamps for passenger cars, the steadily increasing need for reduction of vehicle power consumption has led to the introduction of LED-based day-time running lamps. Solutions with incandescent bulbs have also been implemented, as they present price advantages while offering limited design perspectives. In the meantime, technology developments has turned LED sources into ideal candidates for daytime running lamps by increasing their lumen per watt efficiency ratio towards values around 100 lm/W or higher. In this work, taking as an example the new Mercedes-Benz roadster SLK (R172), we present the first single LED daytime- running lamp, with a total power consumption below 5W per vehicle. After reviewing legal requirements, the optical and electronic concepts are discussed. Details on the tail lamp LED functions are also discussed, and particularly the advantages from the realization of fog lamp with LEDs.

Solid state lighting component

DOEpatents

Yuan, Thomas; Keller, Bernd; Tarsa, Eric; Ibbetson, James; Morgan, Frederick; Dowling, Kevin; Lys, Ihor

2017-10-17

An LED component according to the present invention comprising an array of LED chips mounted on a submount with the LED chips capable of emitting light in response to an electrical signal. The array can comprise LED chips emitting at two colors of light wherein the LED component emits light comprising the combination of the two colors of light. A single lens is included over the array of LED chips. The LED chip array can emit light of greater than 800 lumens with a drive current of less than 150 milli-Amps. The LED chip component can also operate at temperatures less than 3000 degrees K. In one embodiment, the LED array is in a substantially circular pattern on the submount.

Smart LED allocation scheme for efficient multiuser visible light communication networks.

PubMed

Sewaiwar, Atul; Tiwari, Samrat Vikramaditya; Chung, Yeon Ho

2015-05-18

In a multiuser bidirectional visible light communication (VLC), a large number of LEDs or an LED array needs to be allocated in an efficient manner to ensure sustainable data rate and link quality. Moreover, in order to support an increasing or decreasing number of users in the network, the LED allocation is required to be performed dynamically. In this paper, a novel smart LED allocation scheme for efficient multiuser VLC networks is presented. The proposed scheme allocates RGB LEDs to multiple users in a dynamic and efficient fashion, while satisfying illumination requirements in an indoor environment. The smart LED array comprised of RGB LEDs is divided into sectors according to the location of the users. The allocated sectors then provide optical power concentration toward the users for efficient and reliable data transmission. An algorithm for the dynamic allocation of the LEDs is also presented. To verify its effective resource allocation feature of the proposed scheme, simulations were performed. It is found that the proposed smart LED allocation scheme provides the effect of optical beamforming toward individual users, thereby increasing the collective power concentration of the optical signals on the desirable users and resulting in significantly increased data rate, while ensuring sufficient illumination in a multiuser VLC environment.

Conduction-driven cooling of LED-based automotive LED lighting systems for abating local hot spots

NASA Astrophysics Data System (ADS)

Saati, Ferina; Arik, Mehmet

2018-02-01

Light-emitting diode (LED)-based automotive lighting systems pose unique challenges, such as dual-side packaging (front side for LEDs and back side for driver electronics circuit), size, harsh ambient, and cooling. Packaging for automotive lighting applications combining the advanced printed circuit board (PCB) technology with a multifunctional LED-based board is investigated with a focus on the effect of thermal conduction-based cooling for hot spot abatement. A baseline study with a flame retardant 4 technology, commonly known as FR4 PCB, is first compared with a metal-core PCB technology, both experimentally and computationally. The double-sided advanced PCB that houses both electronics and LEDs is then investigated computationally and experimentally compared with the baseline FR4 PCB. Computational models are first developed with a commercial computational fluid dynamics software and are followed by an advanced PCB technology based on embedded heat pipes, which is computationally and experimentally studied. Then, attention is turned to studying different heat pipe orientations and heat pipe placements on the board. Results show that conventional FR4-based light engines experience local hot spots (ΔT>50°C) while advanced PCB technology based on heat pipes and thermal spreaders eliminates these local hot spots (ΔT<10°C), leading to a higher lumen extraction with improved reliability. Finally, possible design options are presented with embedded heat pipe structures that further improve the PCB performance.

Observation of Pollution from Space

NASA Astrophysics Data System (ADS)

Burrows, J. P.; Richter, A.; Bovensmann, H.; Buchwitz, M.; Andrés Hernández, M. D.; Hilboll, A.; Schoenhardt, A.; Blechschmidt, A.; Alvarado, L.; Wittrock, F.

2016-12-01

The rapid growth of population since the industrial revolution has led to large changes in surface emissions and land use change. It is now over 30 years since the SCIAMACHY project was initiated. This project has led to the GOME (ESA ERS-2 1995-2011), SCIAMACHY (ESA Envisat 2002 to 2011) GOME-2 (EUMETSAT/ESA Metop A, 2006 to present, Metop B 2012 to present, Metop C planned launch 2018) and the spin offs OMI (NASA AURA 2004-present) . This presentation addresses observations of tropospheric trace gas pollutants retrieved these instruments with a focus on recent studies of the ozone precursors NO2, HCHO and CHO.CHO, the halogen oxides BrO, IO and CH4 and CO2. It will discuss the objectives of the DLR HALO EMeRGe mission. The latter is research mission combining satelltie and aircraft observations, whihc aims to study pollution from major pollution centers in Europe and Asia, and is planned to take palce in 2017 and 2018.

Token reinforcement, choice, and self-control in pigeons.

PubMed Central

Jackson, K; Hackenberg, T D

1996-01-01

Pigeons were exposed to self-control procedures that involved illumination of light-emitting diodes (LEDs) as a form of token reinforcement. In a discrete-trials arrangement, subjects chose between one and three LEDs; each LED was exchangeable for 2-s access to food during distinct posttrial exchange periods. In Experiment 1, subjects generally preferred the immediate presentation of a single LED over the delayed presentation of three LEDs, but differences in the delay to the exchange period between the two options prevented a clear assessment of the relative influence of LED delay and exchange-period delay as determinants of choice. In Experiment 2, in which delays to the exchange period from either alternative were equal in most conditions, all subjects preferred the delayed three LEDs more often than in Experiment-1. In Experiment 3, subjects preferred the option that resulted in a greater amount of food more often if the choices also produced LEDs than if they did not. In Experiment 4, preference for the delayed three LEDs was obtained when delays to the exchange period were equal, but reversed in favor of an immediate single LED when the latter choice also resulted in quicker access to exchange periods. The overall pattern of results suggests that (a) delay to the exchange period is a more critical determinant of choice than is delay to token presentation; (b) tokens may function as conditioned reinforcers, although their discriminative properties may be responsible for the self-control that occurs under token reinforcer arrangements; and (c) previously reported differences in the self-control choices of humans and pigeons may have resulted at least in part from the procedural conventions of using token reinforcers with human subjects and food reinforcers with pigeon subjects. PMID:8755699

Characterization of electrically-active defects in ultraviolet light-emitting diodes with laser-based failure analysis techniques

DOE PAGES

Miller, Mary A.; Tangyunyong, Paiboon; Edward I. Cole, Jr.

2016-01-12

In this study, laser-based failure analysis techniques demonstrate the ability to quickly and non-intrusively screen deep ultraviolet light-emitting diodes(LEDs) for electrically-active defects. In particular, two laser-based techniques, light-induced voltage alteration and thermally-induced voltage alteration, generate applied voltage maps (AVMs) that provide information on electrically-active defect behavior including turn-on bias, density, and spatial location. Here, multiple commercial LEDs were examined and found to have dark defect signals in the AVM indicating a site of reduced resistance or leakage through the diode. The existence of the dark defect signals in the AVM correlates strongly with an increased forward-bias leakage current. This increasedmore » leakage is not present in devices without AVM signals. Transmission electron microscopyanalysis of a dark defect signal site revealed a dislocation cluster through the pn junction. The cluster included an open core dislocation. Even though LEDs with few dark AVM defect signals did not correlate strongly with power loss, direct association between increased open core dislocation densities and reduced LED device performance has been presented elsewhere [M. W. Moseley et al., J. Appl. Phys. 117, 095301 (2015)].« less

Inhibition of enamel remineralization with blue LED: an in vitro study

NASA Astrophysics Data System (ADS)

Kato, Ilka Tiemy; Mendes, Fausto Medeiros; Zezell, Denise Maria; Zanardi de Freitas, Anderson; Raele, Marcus Paulo; Wetter, Niklaus Ursus

2009-02-01

Blue light, especially from LED devices, is a tool very frequently used in dental procedures. However, the investigations of its effects on dental enamel are focused primarily on enamel demineralization and fluoride retention. Despite the fact that this spectral region can inhibit enamel demineralization, the consequences of the irradiation on demineralized enamel are not known. For this reason, we evaluated the effects of blue LED on enamel remineralization. Artificial lesions formed in bovine dental enamel samples by immersion in undersaturated acetate buffer were divided into three groups. In the first group (DE), the lesions were not submitted to any treatment. In the second (RE), the lesions were submitted to remineralization. The lesions from the third group (LED+RE) were irradiated with blue LED (455nm, 1.38W/cm2, 13.75J/cm2 and 10s) before the remineralization. Cross-sectional microhardness was used to assess mineral changes induced by remineralization under pH-cycling. The mineral deposition occurred preferably in the middle portion of the lesions. Specimens from group RE showed higher hardness value than the DE ones. On the other hand, the mean hardness value of the LED+RE samples was not statistically different from the DE samples. Results obtained in the present study show that the blue light is not innocuous for the dental enamel and inhibition of its remineralization can occur.

Penetration of 35% hydrogen peroxide into the pulp chamber in bovine teeth after LED or Nd:YAG laser activation.

PubMed

Camargo, Samira Esteves Afonso; Cardoso, Paula Elaine; Valera, Marcia Carneiro; de Araújo, Maria Amélia Máximo; Kojima, Alberto Noriyuki

2009-01-01

This aim of the present study was to evaluate the pulp chamber penetration of 35% hydrogen peroxide activated by LED (light-emitting diode) or Nd:YAG laser in bovine teeth, after an in-office bleaching technique. Forty-eight bovine lateral incisors were divided into four groups, acetate buffer was placed into the pulp chamber and bleaching agent was applied as follows: for group A (n = 12), activation was performed by LED; for group B (n = 12), activation was performed by Nd:YAG laser (60 mJ, 20 Hz); group C (n = 12) received no light or laser activation; and the control group (n = 12) received no bleaching gel application or light or laser activation. The acetate buffer solution was transferred to a glass tube and Leuco Crystal Violet and horseradish peroxidase were added, producing a blue solution. The optical density of this solution was determined spectrophotometrically and converted into microgram equivalents of hydrogen peroxide. The results were analysed using ANOVA and Tukey's test (5%). It was verified that the effect of activation was significant, as groups activated by LED or laser presented greater hydrogen peroxide penetration into the pulp chamber (0.499 +/- 0.622 microg) compared with groups that were not (0.198 +/- 0.218 microg). There was no statistically significant difference in the penetration of hydrogen peroxide into the pulp chamber between the two types of activation (LED or laser). The results suggest that activation by laser or LED caused an increase in hydrogen peroxide penetration into the pulp chamber.

Effects of transcranial LED therapy on the cognitive rehabilitation for diffuse axonal injury due to severe acute traumatic brain injury: study protocol for a randomized controlled trial.

PubMed

Santos, João Gustavo Rocha Peixoto Dos; Zaninotto, Ana Luiza Costa; Zângaro, Renato Amaro; Carneiro, Ana Maria Costa; Neville, Iuri Santana; de Andrade, Almir Ferreira; Teixeira, Manoel Jacobsen; Paiva, Wellingson Silva

2018-04-24

Photobiomodulation describes the use of red or near-infrared light to stimulate or regenerate tissue. It was discovered that near-infrared wavelengths (800-900 nm) and red (600 nm) light-emitting diodes (LED) are able to penetrate through the scalp and skull and have the potential to improve the subnormal cellular activity of compromised brain tissue. Different experimental and clinical studies were performed to test LED therapy for traumatic brain injury (TBI) with promising results. One of the proposals of this present study is to develop different approaches to maximize the positive effects of this therapy and improve the quality of life of TBI patients. This is a double-blinded, randomized, controlled trial of patients with diffuse axonal injury (DAI) due to a severe TBI in an acute stage (less than 8 h). Thirty two patients will be randomized to active coil helmet and inactive coil (sham) groups in a 1:1 ratio. The protocol includes 18 sessions of transcranial LED stimulation (627 nm, 70 mW/cm 2 , 10 J/cm 2 ) at four points of the frontal and parietal regions for 30 s each, totaling 120 s, three times per week for 6 weeks, lasting 30 min. Patients will be evaluated with the Glasgow Outcome Scale Extended (GOSE) before stimulation and 1, 3, and 6 months after the first stimulation. The study hypotheses are as follows: (1) transcranial LED therapy (TCLT) will improve the cognitive function of DAI patients and (2) TCLT will promote beneficial hemodynamic changes in cerebral circulation. This study evaluates early and delayed effects of TCLT on the cognitive rehabilitation for DAI following severe acute TBI. There is a paucity of studies regarding the use of this therapy for cognitive improvement in TBI. There are some experimental studies and case series presenting interesting results for TBI cognitive improvement but no clinical trials. ClinicalTrials.gov, NCT03281759 . Registered on 13 September 2017.

White LED sources for vehicle forward lighting

NASA Astrophysics Data System (ADS)

Van Derlofske, John F.; McColgan, Michele W.

2002-11-01

Considerations for the use of white light emitting diode (LED) sources to produce illumination for automotive forward lighting is presented. Due to their reliability, small size, lower consumption, and lower heat generation LEDs are a natural choice for automotive lighting systems. Currently, LEDs are being sucessfully employed in most vehicle lighting applications. In these applications the light levels, distributions, and colors needed are achievable by present LED technologies. However, for vehicle white light illumination applications LEDs are now only being considered for low light level applications, such as back-up lamps. This is due to the relatively low lumen output that has been available up to now in white LEDs. With the advent of new higher lumen packages, and with the promise of even higher light output in the near future, the use of white LEDs sources for all vehicle forward lighting applications is beginning to be considered. Through computer modeling and photometric evaluation this paper examines the possibilities of using currently available white LED technology for vehicle headlamps. It is apparent that optimal LED sources for vehicle forward lighting applications will be constructed with hereto undeveloped technology and packaging configurations. However, the intent here in exploring currently available products is to begin the discussion on the design possibilities and significant issues surrounding LEDs in order to aid in the design and development of future LED sources and systems. Considerations such as total light output, physical size, optical control, power consumption, color appearance, and the effects of white LED spectra on glare and peripheral vision are explored. Finally, conclusions of the feasibility of current LED technology being used in these applications and recommendations of technology advancements that may need to occur are made.

Photodynamic action of LED-activated pyropheophorbide-α methyl ester in cisplatin-resistant human ovarian carcinoma cells

NASA Astrophysics Data System (ADS)

Tan, Y.; Xu, C. S.; Xia, X. S.; Yu, H. P.; Bai, D. Q.; He, Y.; Leung, A. W. N.

2009-04-01

Cisplatin-resistance is a major obstacle for the successful therapy to ovarian cancer, and exploring novel approach to deactivate cisplatin-resistant ovarian cells will improve the clinical outcomes. Our present study showed that there was no dark cytotoxicity of MPPa in the COC1/DDP cells at the dose of 0.25 - 4 μM, and LED-activated MPPa resulted in drug dose- and light-dependent cytotoxicity. Apoptotic rate 6 h after LED-activated MPPa (2 μM) increased to 16.71% under the light energy of 1 J/cm2. Confocal laser scanning microscopy showed that MPPa mainly localized in the intracellular membrane system, namely the endoplasmic reticulum, Golgi apparatus, lysosomes and mitochondria in the COC1/DDP cells. Mitochondrial membrane potential (ΔΨm) was collapsed when COC1/DDP cells were exposed to 2 μM MPPa for 20 h and then 1 J/cm2 irradiation of LED source. These data demonstrated that LED-activated MPPa significantly deactivated cisplatin-resistant ovarian cell line COC1/DDP cells and enhanced apoptosis and decreased ΔΨm, which suggests LED is an efficient light source for PDT and LED-activated MPPa can be developed as new modality for treating cisplatin-resistant ovarian.

Regulation of ascorbic acid metabolism by blue LED light irradiation in citrus juice sacs.

PubMed

Zhang, Lancui; Ma, Gang; Yamawaki, Kazuki; Ikoma, Yoshinori; Matsumoto, Hikaru; Yoshioka, Terutaka; Ohta, Satoshi; Kato, Masaya

2015-04-01

In the present study, the effects of red and blue LED lights on the accumulation of ascorbic acid (AsA) were investigated in the juice sacs of three citrus varieties, Satsuma mandarin, Valencia orange, and Lisbon lemon. The results showed that the blue LED light treatment effectively increased the AsA content in the juice sacs of the three citrus varieties, whereas the red LED light treatment did not. By increasing the blue LED light intensity, the juice sacs of the three citrus varieties accumulated more AsA. Moreover, continuous irradiation with blue LED light was more effective than pulsed irradiation for increasing the AsA content in the juice sacs of the three citrus varieties. Gene expression results showed that the modulation of AsA accumulation by blue LED light was highly regulated at the transcription level. The up-regulation of AsA biosynthetic genes (CitVTC1, CitVTC2, CitVTC4, and CitGLDH), AsA regeneration genes (CitMDAR1, CitMDAR2, and CitDHAR) and two GSH-producing genes (CitGR and CitchGR) contributed to these increases in the AsA content in the three citrus varieties. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Prognostics-based qualification of high-power white LEDs using Lévy process approach

NASA Astrophysics Data System (ADS)

Yung, Kam-Chuen; Sun, Bo; Jiang, Xiaopeng

2017-01-01

Due to their versatility in a variety of applications and the growing market demand, high-power white light-emitting diodes (LEDs) have attracted considerable attention. Reliability qualification testing is an essential part of the product development process to ensure the reliability of a new LED product before its release. However, the widely used IES-TM-21 method does not provide comprehensive reliability information. For more accurate and effective qualification, this paper presents a novel method based on prognostics techniques. Prognostics is an engineering technology predicting the future reliability or determining the remaining useful lifetime (RUL) of a product by assessing the extent of deviation or degradation from its expected normal operating conditions. A Lévy subordinator of a mixed Gamma and compound Poisson process is used to describe the actual degradation process of LEDs characterized by random sporadic small jumps of degradation degree, and the reliability function is derived for qualification with different distribution forms of jump sizes. The IES LM-80 test results reported by different LED vendors are used to develop and validate the qualification methodology. This study will be helpful for LED manufacturers to reduce the total test time and cost required to qualify the reliability of an LED product.

Increased effective reflection and transmission at the GaN-sapphire interface of LEDs grown on patterned sapphire substrates

NASA Astrophysics Data System (ADS)

Dongxue, Wu; Ping, Ma; Boting, Liu; Shuo, Zhang; Junxi, Wang; Jinmin, Li

2016-10-01

The effect of patterned sapphire substrate (PSS) on the top-surface (P-GaN-surface) and the bottom-surface (sapphire-surface) of the light output power (LOP) of GaN-based LEDs was investigated, in order to study the changes in reflection and transmission of the GaN-sapphire interface. Experimental research and computer simulations were combined to reveal a great enhancement in LOP from either the top or bottom surface of GaN-based LEDs, which are prepared on patterned sapphire substrates (PSS-LEDs). Furthermore, the results were compared to those of the conventional LEDs prepared on the planar sapphire substrates (CSS-LEDs). A detailed theoretical analysis was also presented to further support the explanation for the increase in both the effective reflection and transmission of PSS-GaN interface layers and to explain the causes of increased LOP values. Moreover, the bottom-surface of the PSS-LED chip shows slightly increased light output performance when compared to that of the top-surface. Therefore, the light extraction efficiency (LEE) can be further enhanced by integrating the method of PSS and flip-chip structure design. Project supported by the National High Technology Program of China (No. Y48A040000) and the National High Technology Program of China (No. Y48A040000).

eHealth in Denmark: a case study.

PubMed

Kierkegaard, Patrick

2013-12-01

Denmark is widely regarded as a leading country in terms of eHealth integration and healthcare delivery services. The push for eHealth adoption over that past 20 years in the Danish health sector has led to the deployment of multiple eHealth technologies. However, in reality the Danish healthcare suffers from eHealth system fragmentation which has led to eHealth's inability to reach full potential in delivering quality healthcare service. This paper will presents a case study of the current state of eHealth in the Danish healthcare system and discuss the current challenges the country is facing today.

Diagnosis and Management of Transplanted Kidney Extrarenal Pseudoaneurysms: A Series of Four Cases and a Review of the Literature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fananapazir, Ghaneh, E-mail: fananapazir@ucdavis.edu; Hannsun, Gemmy; Wright, Luke A.

Extrarenal pseudoaneurysms of transplanted kidneys are very rare but can have devastating consequences. In the past, these extrarenal pseudoaneurysms have often led to graft loss as well as significant morbidity and mortality. The role of advanced diagnostic imaging studies and of modern radiologic interventional management has not been studied. In this case series, we present four cases of extrarenal pseudoaneurysms of transplanted kidneys, describe the clinical scenarios and imaging that led to the angiographic diagnosis, and discuss the various endovascular and surgical approaches to management.

Follow-up after colon cancer treatment in the Netherlands; a survey of patients, GPs, and colorectal surgeons.

PubMed

Wind, J; Duineveld, L A; van der Heijden, R P; van Asselt, K M; Bemelman, W A; van Weert, H C

2013-08-01

Follow-up to detect recurrence is an important feature of care after colon cancer treatment. Currently, follow-up visits are surgeon-led with focus on recurrence. To date, there is increasing interest for general practitioners (GPs) providing this care, as GPs might provide more holistic care. The present study assessed how surgeons, GPs, and patients evaluate current surgeon-led colon cancer follow-up and to list their views on possible future GP-led follow-up. The study consists of a cross-sectional survey including colorectal surgeons, patients who participate or recently finished a follow-up programme, and GPs in the Netherlands. Eighty-seven out of 191 GPs, 113 out of 238 surgeons, and 186 out of 243 patients responded. Patients are satisfied about current surgeon-led follow-up, especially about recurrence detection and identification of physical problems (94% and 85% respectively). However, only 56% and 49% of the patients were satisfied about the identification of psychological and social problems respectively. Only 16% of the patients evaluated future GP-led follow-up positively. Regarding healthcare providers, surgeons were more positive compared to GPs; 49% of the surgeons, and only 30% of the GPs evaluated future GP-led follow-up positively (P = 0.002). Furthermore, several reservations and principle requirements for GP-led follow-up were identified. The results suggest an unfavourable view among patients and healthcare providers, especially GPs, regarding a central role for GPs in colon cancer follow-up. However, low satisfaction on psychosocial aspects in current follow-up points out a lack in care. Therefore, the results provide a justification to explore future GP-led care further. Copyright © 2013 Elsevier Ltd. All rights reserved.

LEDs/ALAN-Working To Be Good Neighbors

NASA Astrophysics Data System (ADS)

Adams, Robert

2015-08-01

ALAN (Artificial Light At Night) and LEDs have recently become major discussion topics in the areas of astronomy, light pollution, endangered species and human health to mention but a few. In years past, MH, LPS and HPS dominated night lighting with LPS and its associated narrow spectrum as the preferred source around observatories and shorelines. LEDs offer the ability to modify the spectrum, realize substantial energy savings and other associated benefits while meeting the requirements of the astronomy community.The primary concern of the different groups relates to blue light content of the LED. For astronomers, the molecular (Raleigh) scattering related to the blue light interferes with certain portions of the spectrum used for deep space studies. The ecologists studying various endangered species find blue and green light can be related to declining leatherback turtle population in certain areas of the world. Other animals ranging from bats to moths and other insects are now being studied to determine the effect of the blue light spectrum on their behavior. The impact of blue light on the human circadian rhythm and vision, especially in the older population, is being extensively studied today.This presentation will discuss the spectral power distribution (SPD) of various light sources, the performance of new LED solutions and how the SPD of these new LED’s can be adapted to address some of the issues raised by various constituencies. A discussion describing why some of the metrics used to describe standard lighting are not adequate for specifying the new LED solutions with the modified spectra will be included.Today, lighting plans and implementation are all too often based on opinions and limited data. The ensuing problems and repercussions make it imperative to collect accurate and thorough information. Data collection is now ongoing using a variety of techniques analyzing the “before” and “after” lighting results from the C of HI LED streetlight conversion. The studies will focus on any quantifiable impact LEDs may have on such topics as light pollution, endangered animals, astronomy and, most importantly, the citizens of our local communities.

Leadership in Boys' Education: 16 Case Studies from Public and Private, Rural and Urban, Primary and Secondary Schools.

ERIC Educational Resources Information Center

Fletcher, Richard, Ed.; Hartman, Deborah, Ed.; Browne, Rollo, Ed.

Concern about boys' education in Australia and New Zealand led to the Leadership in Boys' Education Conference in May 1999. This book contains edited conference presentations focusing on boys' educational needs. The book also presents case studies related to academic achievement, school structure, discipline and bullying, broadening boys' options,…

Dome diagnostics system of optical parameters and characteristics of LEDs

NASA Astrophysics Data System (ADS)

Peretyagin, Vladimir S.; Pavlenko, Nikita A.

2017-09-01

Scientific and technological progress of recent years in the production of the light emitting diodes (LEDs) has led to the expansion of areas of their application from the simplest systems to high precision lighting devices used in various fields of human activity. However, development and production (especially mass production) of LED lighting devices are impossible without a thorough analysis of its parameters and characteristics. There are many ways and devices for analysis the spatial, energy and colorimetric parameters of LEDs. The most methods are intended for definition only one parameter (for example, luminous flux) or one characteristic (for example, the angular distribution of energy or the spectral characteristics). Besides, devices used these methods are intended for measuring parameters in only one point or plane. This problem can be solved by using a dome diagnostics system of optical parameters and characteristics of LEDs, developed by specialists of the department OEDS chair of ITMO University in Russia. The paper presents the theoretical aspects of the analysis of LED's spatial (angular), energy and color parameters by using mentioned of diagnostics system. The article also presents the results of spatial), energy and color parameters measurements of some LEDs brands.

Correlating electroluminescence characterization and physics-based models of InGaN/GaN LEDs: Pitfalls and open issues

NASA Astrophysics Data System (ADS)

Calciati, Marco; Goano, Michele; Bertazzi, Francesco; Vallone, Marco; Zhou, Xiangyu; Ghione, Giovanni; Meneghini, Matteo; Meneghesso, Gaudenzio; Zanoni, Enrico; Bellotti, Enrico; Verzellesi, Giovanni; Zhu, Dandan; Humphreys, Colin

2014-06-01

Electroluminescence (EL) characterization of InGaN/GaN light-emitting diodes (LEDs), coupled with numerical device models of different sophistication, is routinely adopted not only to establish correlations between device efficiency and structural features, but also to make inferences about the loss mechanisms responsible for LED efficiency droop at high driving currents. The limits of this investigative approach are discussed here in a case study based on a comprehensive set of current- and temperature-dependent EL data from blue LEDs with low and high densities of threading dislocations (TDs). First, the effects limiting the applicability of simpler (closed-form and/or one-dimensional) classes of models are addressed, like lateral current crowding, vertical carrier distribution nonuniformity, and interband transition broadening. Then, the major sources of uncertainty affecting state-of-the-art numerical device simulation are reviewed and discussed, including (i) the approximations in the transport description through the multi-quantum-well active region, (ii) the alternative valence band parametrizations proposed to calculate the spontaneous emission rate, (iii) the difficulties in defining the Auger coefficients due to inadequacies in the microscopic quantum well description and the possible presence of extra, non-Auger high-current-density recombination mechanisms and/or Auger-induced leakage. In the case of the present LED structures, the application of three-dimensional numerical-simulation-based analysis to the EL data leads to an explanation of efficiency droop in terms of TD-related and Auger-like nonradiative losses, with a C coefficient in the 10-30 cm6/s range at room temperature, close to the larger theoretical calculations reported so far. However, a study of the combined effects of structural and model uncertainties suggests that the C values thus determined could be overestimated by about an order of magnitude. This preliminary attempt at uncertainty quantification confirms, beyond the present case, the need for an improved description of carrier transport and microscopic radiative and nonradiative recombination mechanisms in device-level LED numerical models.

Assessment of different energy delivery settings in laser and LED phototherapies in the inflammatory process of rat's TMJ induced by carrageenan.

PubMed

de Castro, Isabele C V; Rosa, Cristiane B; Carvalho, Carolina M; Aragão, Juliana S; Cangussu, Maria Cristina T; Dos Santos, Jean N; Pinheiro, Antonio L B

2015-11-01

Temporomandibular disorders (TMDs) are mostly inflammatory conditions widespread in the population. Previous studies have shown positive effects of either laser or light-emitting diode (LED) phototherapies on treating TMDs, but their action and mechanism in the inflammatory infiltrate of the temporomandibular joint are still poorly understood. The aim of this study was to assess, through histological analysis, the effectiveness of using laser light (λ 780 nm, 70 mW, continous wave (CW), 10 J) and LED (λ 850 ± 10 nm, 100 mW, CW, 10 J) on the inflammation of the temporomandibular joint of rats induced by carrageenan. Forty-five animals were divided into three groups with five animals each according to the experimental times of 2, 3, and 7 days: inflammation, inflammation+laser phototherapy, and inflammation+LED phototherapy. The first irradiation was performed 24 h after induction with an interval of 48 h between sessions. After animal death, specimens were processed and stained with hematoxylin-eosin (HE) and picrosirius. Then, the samples were examined histologically. Data were statistically analyzed. The inflammation group showed mild to moderate chronic inflammatory infiltrate between bone trabecules of the condyle. Over the time course of the study in the laser group, the region of the condyle presented mild chronic inflammation and intense vascularization. In the LED group, the condyle showed aspects of normality and absence of inflammation in some specimens. In all the time points, the laser-irradiated groups showed greater amount of collagen deposition in the condyle (p = 0.04) and in the disc (p = 0.03) when compared to the inflammation and LED groups, respectively. Laser- and LED-treated groups demonstrate a smaller number of layers of the synovial membrane when compared to the non-irradiated groups. It was concluded that, in general, laser and LED phototherapies resulted in a reduction of inflammatory infiltrate in the temporomandibular joint of rat.

How challenges in auditory fMRI led to general advancements for the field.

PubMed

Talavage, Thomas M; Hall, Deborah A

2012-08-15

In the early years of fMRI research, the auditory neuroscience community sought to expand its knowledge of the underlying physiology of hearing, while also seeking to come to grips with the inherent acoustic disadvantages of working in the fMRI environment. Early collaborative efforts between prominent auditory research laboratories and prominent fMRI centers led to development of a number of key technical advances that have subsequently been widely used to elucidate principles of auditory neurophysiology. Perhaps the key imaging advance was the simultaneous and parallel development of strategies to use pulse sequences in which the volume acquisitions were "clustered," providing gaps in which stimuli could be presented without direct masking. Such sequences have become widespread in fMRI studies using auditory stimuli and also in a range of translational research domains. This review presents the parallel stories of the people and the auditory neurophysiology research that led to these sequences. Copyright © 2011 Elsevier Inc. All rights reserved.

UV LED lighting for automated crystal centring

PubMed Central

Chavas, Leonard M. G.; Yamada, Yusuke; Hiraki, Masahiko; Igarashi, Noriyuki; Matsugaki, Naohiro; Wakatsuki, Soichi

2011-01-01

A direct outcome of the exponential growth of macromolecular crystallography is the continuously increasing demand for synchrotron beam time, both from academic and industrial users. As more and more projects entail screening a profusion of sample crystals, fully automated procedures at every level of the experiments are being implemented at all synchrotron facilities. One of the major obstacles to achieving such automation lies in the sample recognition and centring in the X-ray beam. The capacity of UV light to specifically react with aromatic residues present in proteins or with DNA base pairs is at the basis of UV-assisted crystal centring. Although very efficient, a well known side effect of illuminating biological samples with strong UV sources is the damage induced on the irradiated samples. In the present study the effectiveness of a softer UV light for crystal centring by taking advantage of low-power light-emitting diode (LED) sources has been investigated. The use of UV LEDs represents a low-cost solution for crystal centring with high specificity. PMID:21169682

Influence of phototherapies on the outcome of complete tibial fractures grafted or not with MTA: Raman spectroscopic study on rabbits

NASA Astrophysics Data System (ADS)

Pinheiro, Antônio L. B.; Soares, Luiz G. P.; da Silva, Aline C. P.; Santos, Nicole R. S.; da Silva, Anna Paula L. T.; Neves, Bruno Luiz R. C.; Soares, Amanda P.; Silveira, Landulfo

2018-02-01

The aim of the present study was to assess, by means of Raman spectroscopy, the repair of complete surgical tibial fractures fixed with wire osteosynthesis or miniplates treated or not with infrared laser (λ780 nm) or infrared LED (λ850 +/- 10 nm) lights, 142.8 J/cm2 per treatment, associated or not to the use of mineral trioxide aggregate (MTA) cement. Surgical fractures were created on 36 rabbits and fixed with WO or miniplates and some groups were grafted with MTA. Irradiated groups received lights at every other day for 15 days and sacrifice occurred after 30 days. The results showed that only irradiation with either laser or LED influenced the peaks of phosphate ( 960 cm-1) and carbonated ( 1,070 cm-1) hydroxyapatite. Collagen peak (1,450 cm-1) was influenced by both the use of MTA and irradiation with either laser or LED. It is concluded that the use of either laser or LED phototherapy associated to MTA cement was efficacious on improving the repair of complete tibial fractures treated with wire osteosynthesis or miniplates.

The effect of two phototherapy protocols on pain control in orthodontic procedure--a preliminary clinical study.

PubMed

Esper, Maria Angela Lacerda Rangel; Nicolau, Renata Amadei; Arisawa, Emília Angela Lo Schiavo

2011-09-01

Phototherapy with low-level coherent light (laser) has been reported as an analgesic and anti-inflammatory as well as having a positive effect in tissue repair in orthodontics. However, there are few clinical studies using low-level LED therapy (non-coherent light). The aim of the present study was to analyze the pain symptoms after orthodontic tooth movement associated with and not associated with coherent and non-coherent phototherapy. Fifty-five volunteers (mean age = 24.1 ± 8.1 years) were randomly divided into four groups: G1 (control), G2 (placebo), G3 (protocol 1: laser, InGaAlP, 660 nm, 4 J/cm(2), 0.03 W, 25 s), G4 (protocol 2: LED, GaAlAs, 640 nm with 40 nm full-bandwidth at half-maximum, 4 J/cm(2), 0.10 W, 70 s). Separators were used to induce orthodontic pain and the volunteers pain levels were scored with the visual analog scale (VAS) after the separator placement, after the therapy (placebo, laser, or LED), and after 2, 24, 48, 72, 96, and 120 h. The laser group did not have statistically significant results in the reduction of pain level compared to the LED group. The LED group had a significant reduction in pain levels between 2 and 120 h compared to the control and the laser groups. The LED therapy showed a significant reduction in pain sensitivity (an average of 56%), after the orthodontic tooth movement when compared to the control group.

Comparative transcriptome analysis of Haematococcus pluvialis on astaxanthin biosynthesis in response to irradiation with red or blue LED wavelength.

PubMed

Lee, Changsu; Ahn, Joon-Woo; Kim, Jin-Baek; Kim, Jee Young; Choi, Yoon-E

2018-06-18

The unicellular green microalga Haematococcus pluvialis has the highest content of the natural antioxidant, astaxanthin. Previously, it was determined that astaxanthin accumulation in H. pluvialis could be induced by blue-wavelength irradiation; however, the molecular mechanism remains unknown. The present study aimed to compare the transcriptome of H. pluvialis, with respect to astaxanthin biosynthesis, under the monochromatic red (660 nm) or blue (450 nm) light-emitting diode (LED) irradiation. Among a total of 165,372 transcripts, we identified 67,703 unigenes, of which 2245 and 171 were identified as differentially expressed genes (DEGs) in response to blue and red irradiation, respectively. Interestingly, expressional changes of blue light receptor cryptochromes were detected in response to blue and/or red LED irradiation in H. pluvialis, which may directly and indirectly regulate astaxanthin biosynthesis. In accordance with this observation, expression of the BKT and CHY genes, which are part of the downstream section of the astaxanthin biosynthetic pathway, was significantly upregulated by blue LED irradiation compared with their expression under control white irradiation. Contrastingly, they were downregulated by red LED irradiation. Our transcriptome study provided molecular insights that highlighted the different of responses of H. pluvialis to red and blue irradiation, especially for astaxanthin biosynthesis.

Thermal and optical design analyses, optimizations, and experimental verification for a novel glare-free LED lamp for household applications.

PubMed

Khan, M Nisa

2015-07-20

Light-emitting diode (LED) technologies are undergoing very fast developments to enable household lamp products with improved energy efficiency and lighting properties at lower cost. Although many LED replacement lamps are claimed to provide similar or better lighting quality at lower electrical wattage compared with general-purpose incumbent lamps, certain lighting characteristics important to human vision are neglected in this comparison, which include glare-free illumination and omnidirectional or sufficiently broad light distribution with adequate homogeneity. In this paper, we comprehensively investigate the thermal and lighting performance and trade-offs for several commercial LED replacement lamps for the most popular Edison incandescent bulb. We present simulations and analyses for thermal and optical performance trade-offs for various LED lamps at the chip and module granularity levels. In addition, we present a novel, glare-free, and production-friendly LED lamp design optimized to produce very desirable light distribution properties as demonstrated by our simulation results, some of which are verified by experiments.

Investigation of the effect of UV-LED exposure conditions on the production of vitamin D in pig skin.

PubMed

Barnkob, Line Lundbæk; Argyraki, Aikaterini; Petersen, Paul Michael; Jakobsen, Jette

2016-12-01

The dietary intake of vitamin D is currently below the recommended intake of 10-20μg vitamin D/day. Foods with increased content of vitamin D or new products with enhanced vitamin D are warranted. Light-emitting diodes (LEDs) are a potential new resource in food production lines. In the present study the exposure conditions with ultraviolet (UV) LEDs were systematically investigated in the wavelength range 280-340nm for achieving optimal vitamin D bio-fortification in pig skin. A wavelength of 296nm was found to be optimal for vitamin D3 production. The maximum dose of 20kJ/m(2) produced 3.5-4μg vitamin D3/cm(2) pig skin. Vitamin D3 produced was independent on the combination of time and intensity of the LED source. The increased UV exposure by UV-LEDs may be readily implemented in existing food production facilities, without major modifications to the process or processing equipment, for bio-fortifying food products containing pork skin. Copyright © 2016 Elsevier Ltd. All rights reserved.

Thermal Analysis of LED Phosphor Layer

NASA Astrophysics Data System (ADS)

Perera, Ukwatte Lokuliyanage Indika Upendra

Solid-state lighting technology has progressed to a level where light-emitting diode (LED) products are either on par or better than their traditional lighting technology counterparts with respect to efficacy and lifetime. At present, the most common method to create "white" light from LEDs for illumination applications is by using the LED primary radiation and wavelength-converting materials. In this method, the re-emission from the wavelength-converting materials excited by the LED primary radiation is combined with the LED primary radiation to create the "white" light. During this conversion process, heat is generated as a result of conversion inefficiencies and other loss mechanisms in the LED and the wavelength-converting materials. This generated heat, if not properly dissipated, increases the operating temperature, thereby increasing the light output degradation of the system over both the short and long term. The heat generation of the LED and thermal management of the LED have been studied extensively. Methods to effectively dissipate heat from the LEDs and maintain lower LED operating temperature are well understood. However, investigation of factors driving heat generation, the resulting temperature distribution in the phosphor layer, and the influence of the phosphor layer temperature on LED performance and reliability have not received the same focus. The goal of this dissertation was to understand the main factors driving heat and light generation and the transport of light and heat in the wavelength-converting layer of an LED system. Another goal was to understand the interaction between heat and light in the system and to develop and analyze a solution to reduce the wavelength-converting layer operating temperature, thereby improving light output and reliability. Even though past studies have explored generation and transfer separately for light and heat, to the best of the author's knowledge, this is the first study that has analyzed both factors simultaneously to optimize the performance of a phosphor-converted LED system, thus contributing new knowledge to the field. In this dissertation, a theoretical model was developed that modeled both light propagation and heat transfer in the wavelength-converting layer for identifying the factors influencing heat generation. This theoretical model included temperature-dependent phosphor efficiency and light absorption in the phosphor layer geometry. Experimental studies were used to validate the developed model. The model indicated good agreement with the experimental results. The developed theoretical model was then used to model experimental studies. These experiment results were compared with the model predicted results for total radiant power output of LED systems and phosphor layer surface temperature. These comparisons illustrated the effectiveness of a dedicated heat dissipation method in reducing the operating temperature of the wavelength-converting layer, and the contribution of different heat dissipation mechanisms were quantified using the developed numerical model. In addition to these short-term studies, an experiment was conducted to validate the effectiveness of the dedicated wavelength-converting heat sink design to improve system lifetime by reducing phosphor layer operating temperature. The proposed heat sink design decreased the operating temperature of the phosphor layer by ~10°C, improving lifetime by twofold. Finally, this dissertation investigated the potential of the developed theoretical model being used as a tool for prioritizing research tasks and as a design tool during the material selection and system configuration phases.

A devolved model for public involvement in the field of mental health research: case study learning.

PubMed

Moule, Pam; Davies, Rosie

2016-12-01

Patient and public involvement in all aspects of research is espoused and there is a continued interest in understanding its wider impact. Existing investigations have identified both beneficial outcomes and remaining issues. This paper presents the impact of public involvement in one case study led by a mental health charity conducted as part of a larger research project. The case study used a devolved model of working, contracting with service user-led organizations to maximize the benefits of local knowledge on the implementation of personalized budgets, support recruitment and local user-led organizations. To understand the processes and impact of public involvement in a devolved model of working with user-led organizations. Multiple data collection methods were employed throughout 2012. These included interviews with the researchers (n = 10) and research partners (n = 5), observation of two case study meetings and the review of key case study documentation. Analysis was conducted in NVivo10 using a coding framework developed following a literature review. Five key themes emerged from the data; Devolved model, Nature of involvement, Enabling factors, Implementation challenges and Impact. While there were some challenges of implementing the devolved model it is clear that our findings add to the growing understanding of the positive benefits research partners can bring to complex research. A devolved model can support the involvement of user-led organizations in research if there is a clear understanding of the underpinning philosophy and support mechanisms are in place. © 2015 The Authors. Health Expectations Published by John Wiley & Sons Ltd.

How the Contents of a Bachelor's Degree Final Project of Engineering Evolve towards Innovative Scientific Knowledge: Keys to Success

ERIC Educational Resources Information Center

Núñez, Cristina; Guinea, Ana; Callau, Sara; Bengoa, Christophe; Basco, Josep; Gavaldà, Jordi

2017-01-01

The Bachelor's Degree Final Project (BDFP) of our school aims to develop a real constructive project, enhance cooperative teamwork and increase productivity of students. We present a real case study, related with engineering and scientific innovation results obtained by BDFP, which has led to an innovative scientific study presented at the 7th…

Testing high brightness LEDs relative to application environment

NASA Astrophysics Data System (ADS)

Singer, Jeffrey; Mangum, Scott; Lundberg, John

2006-08-01

Application of light emitting diodes is expanding as the luminous output and efficiencies of these devices improve. At the same time, the number of LED package types is increasing, making it challenging to determine the appropriate device for use in lighting product designs. A range of factors should be considered when selecting a LED for an application including color coordinates, luminous efficacy, cost, lumen maintenance, application life, packaging and manufacturability. Additional complexities can be introduced as LED packages become obsolete and replacement parts must be selected. The replacement LED characteristics must be understood and assessed against the parameters of the original device, in order to determine if the change will be relatively simple or will force other end-product changes. While some characteristics are readily measured and compared, other factors, such as lumen maintenance, are difficult to verify. This paper will discuss the characteristics of a LED that should be considered during the design process as well as methods to validate these characteristics, particularly those which are not typically on data sheets or, are critical to the design and warrant additional validation. Particular attention will be given to LED lumen maintenance. While published manufacturer data typically provides temperature versus performance curves, the data may not be useful depending upon the application's operating environment. Models must be created to estimate the LED's junction temperature and degradation curve at the applied temperature in order to develop a more precise life estimate. This paper presents one approach to a LED device life and performance study designed with application environments in mind.

Photodynamic antimicrobial chemotherapy on Streptococcus mutans using curcumin and toluidine blue activated by a novel LED device.

PubMed

Paschoal, Marco Aurelio; Lin, Meng; Santos-Pinto, Lourdes; Duarte, Simone

2015-02-01

Photodynamic antimicrobial chemotherapy (PACT) is an antimicrobial approach that uses photosensitizers (PS) in combination with light sources at specific wavelengths aiming the production of reactive oxygen species. The long illumination time necessary to active PS is a challenge in PACT. Thus, this study investigated the antimicrobial effect of a novel single source of light-emitting diode (LED) light that covers the entire spectrum of visible light beyond interchangeable probes at high power intensity. Blue and red LED probes were used into different exposure times to active different concentrations of curcumin (C) and toluidine blue (T) on planktonic suspensions of Streptococcus mutans UA 159 (S. mutans). S. mutans were standardized and submitted to (1) PACT treatment at three concentrations of C and T exposure at three radiant exposures of a blue LED (BL) (C+BL+) and a red LED (RL) (T+RL+), (2) C (C+BL-) or T alone (T+RL-), (3) both LED lights (C-BL+ and T-RL+), and (4) neither PS nor LED illumination (control group: C-BL- and T-RL-). Aliquots of the suspensions were diluted and cultured on blood agar plates. The number of colony-forming units was calculated after 48 h. The groups submitted to PACT presented a lethal photokilling rate to all PS concentrations at tested dosimetries. The comparison to control group when PS and LED lights used alone demonstrated no decrease in the number of viable bacterial counts. The novel LED device in combination with curcumin and toluidine blue promoted an effective photoinactivation of S. mutans suspensions at ultrashort light illumination times.

Effect of LED phototherapy (λ630 +/- 20nm) on mast cells during wound healing in hypothyroid

NASA Astrophysics Data System (ADS)

Paraguassú, Gardênia M.; De Castro, Isabele Cardoso V.; Vasconcelos, Rebeca M.; da Guarda, Milena G.; Rodriguez, Tânia T.; Ramalho, Maria José P.; Pinheiro, Antônio Luiz B.; Ramalho, Luciana Maria P.

2014-02-01

Hypothyroidism has been associated with the disruption of the body's metabolism, including the healing process. LED phototherapy has been studied using several healing models, but their effects on mast cells proliferation associated to hypothyroidism remains unknown. The aim of this study was to assess the effect LED (λ630+/-20nm) phototherapy on mast cells proliferation during tissue repair in hypothyroid rats. Under general anesthesia, a standard surgical wound (1cm2) was created on the dorsum of 24 male Wistar rats divided into 4 groups of 6 animals each: EC-Control Euthyroid; ED-Euthyroid+LED; HC-Control Hypothyroid and HD-Hypothyroid+LED. The irradiation started immediately after surgery and was repeated every other day for 7 days, when animals death occurred. Hypothyroidism was induced in rats with propylthiouracil (0.05g/100mL) administered orally for 4 weeks and maintained until the end of the experiment. The specimens removed were processed to wax and stained with toluidine blue for mast cell identification. The mast cell proliferation was significantly higher in HC group than in EC group (Mann Whitney, p<0.05), but when ED group was compared to HD group, no significant difference was found. Our results showed that there was increase of mast cells in the presence of hypothyroidism, prolonging the inflammatory phase of repair, and the LED light has a biomodulative effect on mast cell population, even when hipothyroidism was present.

Positive affect and physical activity: Testing effects on goal setting, activation, prioritisation, and attainment.

PubMed

Cameron, David S; Bertenshaw, Emma J; Sheeran, Paschal

2018-02-01

The present research tested whether incidental positive affect promotes pursuit of physical activity goals. Four key features of goal pursuit were examined - setting physical activity goals (Study 1), goal activation (Study 2), and goal prioritization and goal attainment (Study 3). Participants (N s = 80, 81, and 59, in Studies 1-3, respectively) were randomized to positive affect (joy, hope) or neutral affect (control) conditions in each study. Questionnaire measures of goal level, goal commitment, and means selection (Study 1); a lexical decision task indexed goal activation (Study 2), a choice task captured goal prioritization and MET minutes quantified goal attainment (Study 3). Study 1 showed that positive affect led to a greater number of intended physical activities, and that joy engendered greater willingness to try activities. In Study 2, a positive affect induction led to heightened activation of the physical activity goal compared to the control condition. The joy induction in Study 3 led to greater physical activity, and a trend towards greater goal prioritization. These findings suggest that positive affect enhances the pursuit of physical activity goals. Implications for health behavior theories and interventions are outlined.

LED therapy or cryotherapy between exercise intervals in Wistar rats: anti-inflammatory and ergogenic effects.

PubMed

da Costa Santos, Vanessa Batista; de Paula Ramos, Solange; Milanez, Vinícius Flávio; Corrêa, Julio Cesar Molina; de Andrade Alves, Rubens Igor; Dias, Ivan Frederico Lupiano; Nakamura, Fábio Yuzo

2014-03-01

The aim of this study was to test, between two bouts of exercise, the effects of light-emitting diode (LED) therapy and cryotherapy regarding muscle damage, inflammation, and performance. Male Wistar rats were allocated in four groups: control, passive recovery (PR), cryotherapy (Cryo), and LED therapy. The animals were submitted to 45 min of swimming exercise followed by 25 min of recovery and then a second bout of either 45 min of exercise (muscle damage analysis) or time to exhaustion (performance). During the rest intervals, the rats were kept in passive rest (PR), submitted to cold water immersion (10 min, 10 °C) or LED therapy (940 nm, 4 J/cm(2)) of the gastrocnemius muscle. Blood samples were collected to analyze creatine kinase activity (CK), C-reactive protein (CRP), and leukocyte counts. The soleus muscles were evaluated histologically. Time to exhaustion was recorded during the second bout of exercise. After a second bout of 45 min, the results demonstrated leukocytosis in the PR and Cryo groups. Neutrophil counts were increased in all test groups. CK levels were increased in the Cryo group. CRP was increased in PR animals. The PR group presented a high frequency of necrosis, but the LED group had fewer necrotic areas. Edema formation was prevented, and fewer areas of inflammatory cells were observed in the LED group. The time to exhaustion was greater in both the LED and Cryo groups, without differences in CK levels. CRP was decreased in LED animals. We conclude that LED therapy and cryotherapy can improve performance, although LED therapy is more efficient in preventing muscle damage and local and systemic inflammation.

Rationale and Design of the Randomized Evaluation of an Ambulatory Care Pharmacist-Led Intervention to Optimize Urate Lowering Pathways (RAmP-UP) Study

PubMed Central

Coburn, Brian W; Cheetham, T Craig; Rashid, Nazia; Chang, John M; Levy, Gerald D; Kerimian, Artak; Low, Kimberly J; Redden, David T; Bridges, S Louis; Saag, Kenneth G; Curtis, Jeffrey R; Mikuls, Ted R

2016-01-01

Background Despite the availability of effective therapies, most gout patients achieve suboptimal treatment outcomes. Current best practices suggest gradual dose-escalation of urate lowering therapy and serial serum urate (sUA) measurement to achieve sUA < 6.0 mg/dl. However, this strategy is not routinely used. Here we present the study design rationale and development for a pharmacist-led intervention to promote sUA goal attainment. Methods To overcome barriers in achieving optimal outcomes, we planned and implemented the Randomized Evaluation of an Ambulatory Care Pharmacist-Led Intervention to Optimize Urate Lowering Pathways (RAmP-UP) study. This is a large pragmatic cluster-randomized trial designed to assess a highly automated, pharmacist-led intervention to optimize allopurinol treatment in gout. Ambulatory clinics (n=101) from a large health system were randomized to deliver either the pharmacist-led intervention or usual care to gout patients over the age of 18 years newly initiating allopurinol. All participants received educational materials and could opt-out of the study. For intervention sites, pharmacists conducted outreach primarily via an automated telephone interactive voice recognition system. The outreach, guided by a gout care algorithm developed for this study, systematically promoted adherence assessment, facilitated sUA testing, provided education, and adjusted allopurinol dosing. The primary study outcomes are achievement of sUA < 6.0 mg/dl and treatment adherence determined after one year. With follow-up ongoing, study results will be reported subsequently. Conclusion Ambulatory care pharmacists and automated calling technology represent potentially important, underutilized resources for improving health outcomes for gout patients. PMID:27449546

Rationale and design of the randomized evaluation of an Ambulatory Care Pharmacist-Led Intervention to Optimize Urate Lowering Pathways (RAmP-UP) Study.

PubMed

Coburn, Brian W; Cheetham, T Craig; Rashid, Nazia; Chang, John M; Levy, Gerald D; Kerimian, Artak; Low, Kimberly J; Redden, David T; Bridges, S Louis; Saag, Kenneth G; Curtis, Jeffrey R; Mikuls, Ted R

2016-09-01

Despite the availability of effective therapies, most gout patients achieve suboptimal treatment outcomes. Current best practices suggest gradual dose-escalation of urate lowering therapy and serial serum urate (sUA) measurement to achieve sUA<6.0mg/dl. However, this strategy is not routinely used. Here we present the study design rationale and development for a pharmacist-led intervention to promote sUA goal attainment. To overcome barriers in achieving optimal outcomes, we planned and implemented the Randomized Evaluation of an Ambulatory Care Pharmacist-Led Intervention to Optimize Urate Lowering Pathways (RAmP-UP) study. This is a large pragmatic cluster-randomized trial designed to assess a highly automated, pharmacist-led intervention to optimize allopurinol treatment in gout. Ambulatory clinics (n=101) from a large health system were randomized to deliver either the pharmacist-led intervention or usual care to gout patients over the age of 18years newly initiating allopurinol. All participants received educational materials and could opt-out of the study. For intervention sites, pharmacists conducted outreach primarily via an automated telephone interactive voice recognition system. The outreach, guided by a gout care algorithm developed for this study, systematically promoted adherence assessment, facilitated sUA testing, provided education, and adjusted allopurinol dosing. The primary study outcomes are achievement of sUA<6.0mg/dl and treatment adherence determined after one year. With follow-up ongoing, study results will be reported subsequently. Ambulatory care pharmacists and automated calling technology represent potentially important, underutilized resources for improving health outcomes for gout patients. Copyright © 2016 Elsevier Inc. All rights reserved.

The involvement of ATF4 and S-opsin in retinal photoreceptor cell damage induced by blue LED light.

PubMed

Ooe, Emi; Tsuruma, Kazuhiro; Kuse, Yoshiki; Kobayashi, Saori; Shimazawa, Masamitsu; Hara, Hideaki

2017-01-01

Blue light is a high-energy emitting light with a short wavelength in the visible light spectrum. Blue light induces photoreceptor apoptosis and causes age-related macular degeneration or retinitis pigmentosa. In the present study, we investigated the roles of endoplasmic reticulum (ER) stress induced by blue light-emitting diode (LED) light exposure in murine photoreceptor cells. The murine photoreceptor cell line was incubated and exposed to blue LED light (464 nm blue LED light, 450 lx, 3 to 24 h). The expression of the factors involved in the unfolded protein response pathway was examined using quantitative real-time reverse transcription (RT)-PCR and immunoblot analysis. The aggregation of short-wavelength opsin (S-opsin) in the murine photoreceptor cells was observed with immunostaining. The effect of S-opsin knockdown on ATF4 expression in the murine photoreceptor cell line was also investigated. Exposure to blue LED light increased the bip , atf4 , and grp94 mRNA levels, induced the expression of ATF4 protein, and increased the levels of ubiquitinated proteins. Exposure to blue LED light in combination with ER stress inducers (tunicamycin and dithiothreitol) induced the aggregation of S-opsin. S-opsin mRNA knockdown prevented the induction of ATF4 expression in response to exposure to blue LED light. These findings indicate that the aggregation of S-opsin induced by exposure to blue LED light causes ER stress, and ATF4 activation in particular.

Evaluation of LED photobiomodulation on wound healing in hypothyroid and euthyroid rats

NASA Astrophysics Data System (ADS)

Paraguassú, Gardênia Matos; Xavier, Flávia Calo Aquino; Rodriguez, Tânia Tavares; Ramalho, Maria José Pedreira; Pinheiro, Antônio Luiz Barbosa; Ramalho, Luciana Maria Pedreira

2012-09-01

Thyroid hormone deficiency has been associated to disruption of the body's metabolism, including healing process. LED phototherapy has been shown to be effective in improving healing in many situations, but their usefulness in the improvement of hypothyroidism wound healing remains unknown. The aim of this study was to assess histologically the effect of LED (λ630 ± 20nm, 150mW, CW, φ=0.5 cm2, 24J/cm2 per session) on wounds healing in hypothyroid and euthyroid Wistar rats. Standard cutaneous wound (1cm2) was created on the dorsum of 24 animals divided into four groups of 6 animals each: G1: Euthyroid; G2: Euthyroid + LED; G3: Hypothyroid; G4: Hypothyroid + LED. Hypothyroidism was induced in rats with propylthiouracil (0.05g/100mL) administered orally for 4 weeks and maintained until the end of the experiment. The irradiation started immediately after surgery and was repeated every other day for 7 days. Animals were killed 8 days after surgery. The specimens were removed, routinely processed and stained with H&E and Sirius red. Statistical analysis was performed using the Fisher's Test and significance level was 5%. The results of the present investigation showed delayed wounds healing process in hypothyroid rats characterized by incomplete reepithelialization and formation of disorganized collagen fibers (p<0.05) when compared to the euthyroid group, and that in the irradiated groups the reepithelialization was statistically higher when compared with non-irradiated ones (p<0.05). There was improved collagen fibers deposition on irradiated animals (euthyroid and hypothyroid) when compared to non-irradiated ones, but no statistically significant difference (p>0.05). It is concluded that LED light has a positive biomodulative effect on the wound healing process, even when hipothyroidism was present.

The importance of illumination in a non-contact photoplethysmography imaging system for burn wound assessment

NASA Astrophysics Data System (ADS)

Mo, Weirong; Mohan, Rachit; Li, Weizhi; Zhang, Xu; Sellke, Eric W.; Fan, Wensheng; DiMaio, J. Michael; Thatcher, Jeffery E.

2015-02-01

We present a non-contact, reflective photoplethysmogram (PPG) imaging method and a prototype system for identifying the presence of dermal burn wounds during a burn debridement surgery. This system aims to provide assistance to clinicians and surgeons in the process of dermal wound management and wound triage decisions. We examined the system variables of illumination uniformity and intensity and present our findings. An LED array, a tungsten light source, and eventually high-power LED emitters were studied as illumination methods for our PPG imaging device. These three different illumination sources were tested in a controlled tissue phantom model and an animal burn model. We found that the low heat and even illumination pattern using high power LED emitters provided a substantial improvement to the collected PPG signal in our animal burn model. These improvements allow the PPG signal from different pixels to be comparable in both time-domain and frequency-domain, simplify the illumination subsystem complexity, and remove the necessity of using high dynamic range cameras. Through the burn model output comparison, such as the blood volume in animal burn data and controlled tissue phantom model, our optical improvements have led to more clinically applicable images to aid in burn assessment.

Cost-effective analysis of conventional and nurse-led clinics for common otological procedures.

PubMed

Uppal, S; Jose, J; Banks, P; Mackay, E; Coatesworth, A P

2004-03-01

The need to reduce costs while providing a first-class service has led to the expansion in the role of nurses in recent years. We present results of a comparison of the cost-effectiveness of conventional and nurse-led out-patient ear clinics. Our results indicate that cost-effective health care is a distinct competitive advantage for nurses taking up some roles conventionally performed by doctors. The difference in mean cost of out-patient visit per patient between the two groups is 75.28 pounds. This is equivalent to a reduction in cost to the hospital of more than 47,000 pounds for the 626 patients seen in a nurse-led ear clinic in a year. The nurse-led service is thus more cost-effective and presents an opportunity by freeing up otolaryngologists' time to see more complex patients and has the potential for reducing out-patient access time in the NHS.

Systems-based accident analysis in the led outdoor activity domain: application and evaluation of a risk management framework.

PubMed

Salmon, P; Williamson, A; Lenné, M; Mitsopoulos-Rubens, E; Rudin-Brown, C M

2010-08-01

Safety-compromising accidents occur regularly in the led outdoor activity domain. Formal accident analysis is an accepted means of understanding such events and improving safety. Despite this, there remains no universally accepted framework for collecting and analysing accident data in the led outdoor activity domain. This article presents an application of Rasmussen's risk management framework to the analysis of the Lyme Bay sea canoeing incident. This involved the development of an Accimap, the outputs of which were used to evaluate seven predictions made by the framework. The Accimap output was also compared to an analysis using an existing model from the led outdoor activity domain. In conclusion, the Accimap output was found to be more comprehensive and supported all seven of the risk management framework's predictions, suggesting that it shows promise as a theoretically underpinned approach for analysing, and learning from, accidents in the led outdoor activity domain. STATEMENT OF RELEVANCE: Accidents represent a significant problem within the led outdoor activity domain. This article presents an evaluation of a risk management framework that can be used to understand such accidents and to inform the development of accident countermeasures and mitigation strategies for the led outdoor activity domain.

In-vivo wound healing modulation after irradiation with a blue LED photocoagulator

NASA Astrophysics Data System (ADS)

Rossi, Francesca; Cicchi, Riccardo; Magni, Giada; Tatini, Francesca; Bacci, Stefano; Paroli, Gaia; Alfieri, Domenico; Tripodi, Cristina; De Siena, Gaetano; Pavone, Francesco S.; Pini, Roberto

2017-07-01

A faster healing process was observed in superficial skin wounds after irradiation with a blue LED (EmoLED) photocoagulator. EmoLED is a compact handheld device, used to induce a thermal effect and thus coagulation in superficial abrasions. We present the results of an in vivo study, conducted in different mouse model, to analyze the induced wound healing. Two superficial abrasions were produced on the back of the mice: one area was treated with EmoLED (1.4 W/cm2, 30 s treatment time), while the other one was left naturally recovering. During the treatment, a temperature around 40-45°C was induced on the abrasion surface. Mice back healthy skin was used as a control. We compared the treatment in black mice, healthy albino mice, diabetic albino mice and albino mice with coagulation problem. The animals underwent a follow up study and were sacrificed at 0, 3, 6, 9, 18, 24 hours p.o.. Samples from the two abraded areas were harvested and examined by histopathological and immunofluorescence analysis, SHG imaging and confocal microscopy. The aim of the study was to compare the effects in the different target groups and to investigate the early phase of the wound healing process. Our results show that the effects are comparable in all the treated groups and that the healing process appears to be faster in respect to the naturally recovered wounds. This study confirms the previous results obtained in a study on a rat model an in a study on healthy albino mice: the selective photothermal effect we used for inducing immediate coagulation in superficial wounds seems to be associated to a faster and improved healing process.

Effect of NASA light-emitting diode irradiation on wound healing.

PubMed

Whelan, H T; Smits, R L; Buchman, E V; Whelan, N T; Turner, S G; Margolis, D A; Cevenini, V; Stinson, H; Ignatius, R; Martin, T; Cwiklinski, J; Philippi, A F; Graf, W R; Hodgson, B; Gould, L; Kane, M; Chen, G; Caviness, J

2001-12-01

The purpose of this study was to assess the effects of hyperbaric oxygen (HBO) and near-infrared light therapy on wound healing. Light-emitting diodes (LED), originally developed for NASA plant growth experiments in space show promise for delivering light deep into tissues of the body to promote wound healing and human tissue growth. In this paper, we review and present our new data of LED treatment on cells grown in culture, on ischemic and diabetic wounds in rat models, and on acute and chronic wounds in humans. In vitro and in vivo (animal and human) studies utilized a variety of LED wavelength, power intensity, and energy density parameters to begin to identify conditions for each biological tissue that are optimal for biostimulation. LED produced in vitro increases of cell growth of 140-200% in mouse-derived fibroblasts, rat-derived osteoblasts, and rat-derived skeletal muscle cells, and increases in growth of 155-171% of normal human epithelial cells. Wound size decreased up to 36% in conjunction with HBO in ischemic rat models. LED produced improvement of greater than 40% in musculoskeletal training injuries in Navy SEAL team members, and decreased wound healing time in crew members aboard a U.S. Naval submarine. LED produced a 47% reduction in pain of children suffering from oral mucositis. We believe that the use of NASA LED for light therapy alone, and in conjunction with hyperbaric oxygen, will greatly enhance the natural wound healing process, and more quickly return the patient to a preinjury/illness level of activity. This work is supported and managed through the NASA Marshall Space Flight Center-SBIR Program.

Failure Analysis of Fractured Poppet from Space Shuttle Orbiter Flow Control Valve

NASA Technical Reports Server (NTRS)

Russell, Richard

2010-01-01

This slide presentation reviews the failure analysis of a fractured poppet from a flow control valve (FCV) used on the space shuttle. This presentation has focused on the laboratory analysis of the failed hardware. The use of Scanning electron fractography during the investigation led to the conclusion that the poppet failed due to fatigue cracking that, most likely, occurred under changing loading conditions. The initial investigation led to a more thorough test of poppets that had been retired, this testing led to the conclusion that the thumbnail cracks in the flight hardware had existed for the life of the shuttle program. This led to a program to develop an eddy current technique that was capable of detecting small very tight cracks.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tuenge, Jason R.; Hollomon, Brad; Dillon, Heather E.

This report covers the third part of a larger U.S. Department of Energy (DOE) project to assess the life-cycle environmental and resource impacts in the manufacturing, transport, use, and disposal of light-emitting diode (LED) lighting products in relation to incumbent lighting technologies. All three reports are available on the DOE website (www.ssl.energy.gov/tech_reports.html). • Part 1: Review of the Life-Cycle Energy Consumption of Incandescent, Compact Fluorescent and LED Lamps; • Part 2: LED Manufacturing and Performance; • Part 3: LED Environmental Testing. Parts 1 and 2 were published in February and June 2012, respectively. The Part 1 report included a summarymore » of the life-cycle assessment (LCA) process and methodology, provided a literature review of more than 25 existing LCA studies of various lamp types, and performed a meta-analysis comparing LED lamps with incandescent and compact fluorescent lamps (CFLs). Drawing from the Part 1 findings, Part 2 performed a more detailed assessment of the LED manufacturing process and used these findings to provide a comparative LCA taking into consideration a wider range of environmental impacts. Both reports concluded that the life-cycle environmental impact of a given lamp is dominated by the energy used during lamp operation—the upstream generation of electricity drives the total environmental footprint of the product. However, a more detailed understanding of end-of-life disposal considerations for LED products has become increasingly important as their installation base has grown. The Part 3 study (reported herein) was undertaken to augment the LCA findings with chemical analysis of a variety of LED, CFL, and incandescent lamps using standard testing procedures. A total of 22 samples, representing 11 different models, were tested to determine whether any of 17 elements were present at levels exceeding California or Federal regulatory thresholds for hazardous waste. Key findings include: • The selected models were generally found to be below thresholds for Federally regulated elements; • All CFLs and LED lamps and most incandescent lamps exceeded California thresholds for Copper; • Most CFL samples exceeded California thresholds for Antimony and Nickel, and half of the LED samples exceeded California thresholds for Zinc; • The greatest contributors were the screw bases, drivers, ballasts, and wires or filaments; • Overall concentrations in LED lamps were comparable to cell phones and other types of electronic devices, and were generally attributable to components other than the internal LED light sources; • Although the life-cycle environmental impact of the LED lamps is favorable when compared to CFLs and incandescent lamps, recycling will likely gain importance as consumer adoption increases. This study was exploratory in nature and was not intended to provide a definitive indication of regulatory compliance for any specific lamp model or technology. Further study would be needed to more broadly characterize the various light source technologies; to more accurately and precisely characterize a specific model; or to determine whether product redesign would be appropriate.« less

Management's Ecstasy and Disparity Over Job Enrichment

ERIC Educational Resources Information Center

King, Albert S.

1976-01-01

A case study analyzing job enrichment schemes and manager expectations of increased productivity is presented. It was found that it was the managers' expectations of increased productivity, not the reorganization of work, that led to higher productivity. (EC)

Is light-emitting diode phototherapy (LED-LLLT) really effective?

PubMed Central

Kim, Won-Serk; Calderhead, R Glen

2011-01-01

Background: Low level light therapy (LLLT) has attracted attention in many clinical fields with a new generation of light-emitting diodes (LEDs) which can irradiate large targets. To pain control, the first main application of LLLT, have been added LED-LLLT in the accelerated healing of wounds, both traumatic and iatrogenic, inflammatory acne and the patient-driven application of skin rejuvenation. Rationale and Applications: The rationale behind LED-LLLT is underpinned by the reported efficacy of LED-LLLT at a cellular and subcellular level, particularly for the 633 nm and 830 nm wavelengths, and evidence for this is presented. Improved blood flow and neovascularization are associated with 830 nm. A large variety of cytokines, chemokines and macromolecules can be induced by LED phototherapy. Among the clinical applications, non-healing wounds can be healed through restoring the collagenesis/collagenase imbalance in such examples, and ‘normal’ wounds heal faster and better. Pain, including postoperative pain, postoperative edema and many types of inflammation can be significantly reduced. Experimental and clinical evidence: Some personal examples of evidence are offered by the first author, including controlled animal models demonstrating the systemic effect of 830 nm LED-LLLT on wound healing and on induced inflammation. Human patients are presented to illustrate the efficacy of LED phototherapy on treatment-resistant inflammatory disorders. Conclusions: Provided an LED phototherapy system has the correct wavelength for the target cells, delivers an appropriate power density and an adequate energy density, then it will be at least partly, if not significantly, effective. The use of LED-LLLT as an adjunct to conventional surgical or nonsurgical indications is an even more exciting prospect. LED-LLLT is here to stay. PMID:24155530

Enhancement of mosquito trapping efficiency by using pulse width modulated light emitting diodes.

PubMed

Liu, Yu-Nan; Liu, Yu-Jen; Chen, Yi-Chian; Ma, Hsin-Yi; Lee, Hsiao-Yi

2017-01-06

In this study, a light-driving bug zapper is presented for well controlling the diseases brought by insects, such as mosquitoes. In order to have the device efficient to trap the insect pests in off-grid areas, pulse width modulated light emitting diodes (PWM-LED) combined with a solar power module are proposed and implemented. With specific PWM electric signals to drive the LED, it is found that no matter what the ability of catching insects or the consumed power efficiency can be enhanced thus. It is demonstrated that 40% of the UV LED consumed power and 25.9% of the total load power consumption can be saved, and the trapped mosquitoes are about 250% increased when the PWM method is applied in the bug zapper experiments.

Output blue light evaluation for phosphor based smart white LED wafer level packages.

PubMed

Kolahdouz, Zahra; Rostamian, Ali; Kolahdouz, Mohammadreza; Ma, Teng; van Zeijl, Henk; Zhang, Kouchi

2016-02-22

This study presents a blue light detector for evaluating the output light of phosphor based white LED package. It is composed of a silicon stripe-shaped photodiode designed and implemented in a 2 μm BiCMOS process which can be used for wafer level integration of different passive and active devices all in just 5 lithography steps. The final device shows a high selectivity to blue light. The maximum responsivity at 480 nm is matched with the target blue LED illumination. The designed structure have better responsivity compared to simple photodiode structure due to reducing the effect of dead layer formation close to the surface because of implantation. It has also a two-fold increase in the responsivity and quantum efficiency compared to previously similar published sensors.

Enhancement of mosquito trapping efficiency by using pulse width modulated light emitting diodes

NASA Astrophysics Data System (ADS)

Liu, Yu-Nan; Liu, Yu-Jen; Chen, Yi-Chian; Ma, Hsin-Yi; Lee, Hsiao-Yi

2017-01-01

In this study, a light-driving bug zapper is presented for well controlling the diseases brought by insects, such as mosquitoes. In order to have the device efficient to trap the insect pests in off-grid areas, pulse width modulated light emitting diodes (PWM-LED) combined with a solar power module are proposed and implemented. With specific PWM electric signals to drive the LED, it is found that no matter what the ability of catching insects or the consumed power efficiency can be enhanced thus. It is demonstrated that 40% of the UV LED consumed power and 25.9% of the total load power consumption can be saved, and the trapped mosquitoes are about 250% increased when the PWM method is applied in the bug zapper experiments.

The Use of Music Playlists for People with Dementia: A Critical Synthesis.

PubMed

Garrido, Sandra; Dunne, Laura; Chang, Esther; Perz, Janette; Stevens, Catherine J; Haertsch, Maggie

2017-01-01

The use of pre-recorded music to ease behavioral and psychological symptoms associated with dementia is popular in health-care contexts in both formal music therapy settings and in non-therapist led interventions. However, further understanding of how non-therapist led interventions compare to therapist led interventions is needed. This paper reviews 28 studies that used pre-recorded music with people with dementia using a critical interpretive synthesis model. Results revealed that pre-recorded music can be effective in reducing a variety of affective and behavioral symptoms, in particular agitation, even where a trained music therapist is not present. However, the results are not universally positive, suggesting the need for further clarification of protocols for music use and closer investigation of variables that influence individual responseto music.

The Use of Music Playlists for People with Dementia: A Critical Synthesis

PubMed Central

Garrido, Sandra; Dunne, Laura; Chang, Esther; Perz, Janette; Stevens, Catherine J.; Haertsch, Maggie

2017-01-01

The use of pre-recorded music to ease behavioral and psychological symptoms associated with dementia is popular in health-care contexts in both formal music therapy settings and in non-therapist led interventions. However, further understanding of how non-therapist led interventions compare to therapist led interventions is needed. This paper reviews 28 studies that used pre-recorded music with people with dementia using a critical interpretive synthesis model. Results revealed that pre-recorded music can be effective in reducing a variety of affective and behavioral symptoms, in particular agitation, even where a trained music therapist is not present. However, the results are not universally positive, suggesting the need for further clarification of protocols for music use and closer investigation of variables that influence individual responseto music. PMID:28984606

Investigating the origin of efficiency droop by profiling the voltage across the multi-quantum well of an operating light-emitting diode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Taewoong; Seong, Tae-Yeon; School of Materials Science and Engineering, Korea University, Seoul 136-713

Efficiency droop is a phenomenon in which the efficiency of a light-emitting diode (LED) decreases with the increase in current density. To analyze efficiency droop, direct experimental observations on the energy conversion occurring inside the LED is required. Here, we present the measured voltage profiles on the cross section of an operating LED and analyze them with the cross-sectional temperature profiles obtained in a previous study under the same operation conditions. The measured voltage profiles suggest that with increases in the injection current density, electron depletion shifts from the multi-quantum well through an electron blocking layer to the p-GaN region.more » This is because electron leakage increases with increases in current density.« less

Enhancement of mosquito trapping efficiency by using pulse width modulated light emitting diodes

PubMed Central

Liu, Yu-Nan; Liu, Yu-Jen; Chen, Yi-Chian; Ma, Hsin-Yi; Lee, Hsiao-Yi

2017-01-01

In this study, a light-driving bug zapper is presented for well controlling the diseases brought by insects, such as mosquitoes. In order to have the device efficient to trap the insect pests in off-grid areas, pulse width modulated light emitting diodes (PWM-LED) combined with a solar power module are proposed and implemented. With specific PWM electric signals to drive the LED, it is found that no matter what the ability of catching insects or the consumed power efficiency can be enhanced thus. It is demonstrated that 40% of the UV LED consumed power and 25.9% of the total load power consumption can be saved, and the trapped mosquitoes are about 250% increased when the PWM method is applied in the bug zapper experiments. PMID:28059148

A School-Wide Approach to Student-Led Conferences: A Practitioner's Guide.

ERIC Educational Resources Information Center

Kinney, Patti; Munroe, Mary Beth; Sessions, Pam

Noting that the benefits of student-led conferences align well with practices recognized as developmentally appropriate for the middle school years, this book provides a step-by-step guide to implementing student-led conferences at the middle school level. The chapters are: (1) "Setting the Stage," presenting the rationale for student-led…

Enhanced thermaly managed packaging for III-nitride light emitters

NASA Astrophysics Data System (ADS)

Kudsieh, Nicolas

In this Dissertation our work on `enhanced thermally managed packaging of high power semiconductor light sources for solid state lighting (SSL)' is presented. The motivation of this research and development is to design thermally high stable cost-efficient packaging of single and multi-chip arrays of III-nitrides wide bandgap semiconductor light sources through mathematical modeling and simulations. Major issues linked with this technology are device overheating which causes serious degradation in their illumination intensity and decrease in the lifetime. In the introduction the basics of III-nitrides WBG semiconductor light emitters are presented along with necessary thermal management of high power cingulated and multi-chip LEDs and laser diodes. This work starts at chip level followed by its extension to fully packaged lighting modules and devices. Different III-nitride structures of multi-quantum well InGaN/GaN and AlGaN/GaN based LEDs and LDs were analyzed using advanced modeling and simulation for different packaging designs and high thermal conductivity materials. Study started with basic surface mounted devices using conventional packaging strategies and was concluded with the latest thermal management of chip-on-plate (COP) method. Newly discovered high thermal conductivity materials have also been incorporated for this work. Our study also presents the new approach of 2D heat spreaders using such materials for SSL and micro LED array packaging. Most of the work has been presented in international conferences proceedings and peer review journals. Some of the latest work has also been submitted to well reputed international journals which are currently been reviewed for publication. .

Presence of Mind: A Qualitative Study of Meditating Teachers

ERIC Educational Resources Information Center

Irwin, Michèle; Miller, John P.

2016-01-01

This article presents the results of a study into the effects of meditation practice on the lives of professional educators, specifically educators who either began or continued such practice during course work led by Professor Miller at the University of Toronto. The study incorporates semistructured interviews with 12 participants to track their…

Students' Attitudes towards Peers with Disabilities: A Review of the Literature

ERIC Educational Resources Information Center

de Boer, Anke; Pijl, Sip Jan; Minnaert, Alexander

2012-01-01

The trend towards inclusive education has led to an increase of studies focusing on peer attitudes. This review study presents an overview of studies describing attitudes of students, variables relating to students' attitudes, and the relationship between students' attitudes and the social participation of peers with disabilities. Based on a…

Effect of LED irradiation on the expression of MMP-3 and MMP-13 in SW1353 cells in vitro

NASA Astrophysics Data System (ADS)

Zeng, Chang-chun; Guo, Zhou-yi; Zhang, Feng-xue; Deng, Wen-di; Liu, Song-hao

2007-05-01

Matrix Metalloproteinase (MMP) plays an active role in remodeling cartilage in osteoarthritic cartilage. To find an effective method of prevention of osteoclasia, this in vitro study focuses on the expression of MMP-3 and MMP-13 in the SW1353 cells by LED irradiation. The human chondrosarcoma cell line SW1353 were stimulated with the proinflammatory cytokine IL-1beta or tumor necrosis factor-alpha (TNF-alpha), and were received the irradiation of LED (632nm, 4mW/cm2). The cell count was assessed over a 96-hour period by using Trypan blue dye exclusion assay, and the cell activity was evaluated with a Cell Counting Kit-8 Assays. The subsequent expression of MMP-3 and MMP-13 was quantified. Results of this experiment showed that the cultural cell activity was decreased, and the expression of MMP-3 and MMP-13 was increased by being stimulated with IL-1beta or TNF-alpha. After received LED irradiation, the death rate of cultural cell was increased and the expression of MMP-3 and MMP-13 was decreased significantly. The present study concluded that particular LED irradiation stimulates SW1353 cell proliferation activity and inhibit the MMP-3 and MMP-13 enzymatic activity. These findings might be clinically relevant, indicating that the low power laser irradiation treatment is likely to achieve the repair of articular cartilage in clinic.

A new method to manipulate broiler chicken growth and metabolism: Response to mixed LED light system

PubMed Central

Yang, Yefeng; Yu, Yonghua; Pan, Jinming; Ying, Yibin; Zhou, Hong

2016-01-01

Present study introduced a new method to manipulate broiler chicken growth and metabolism by mixing the growth-advantage LED. We found that the green/blue LED mixed light system (G-B and G × B) have the similar stimulatory effect on chick body weight with single green light and single blue light (G and B), compared with normal artificial light (P = 0.028). Moreover, the percentage of carcass was significantly greater in the mixed light (G × B) when compared with the single light (P = 0.003). Synchronized with body weight, the mixed light (G-B and G × B) had a significant improved influence on the feed conversion of birds compared with normal light (P = 0.002). A significant improvement in feed conversion were found in mixed light (G × B) compared with single LED light (P = 0.037). G group resulted in a greater high-density lipoprotein cholesterol level than B group (P = 0.002), whereas B group resulted in a greater low-density lipoprotein cholesterol level than G group (P = 0.017). The mixed light significantly increased the birds’ glucose level in comparison with the single light (P = 0.003). This study might establish an effective strategy for maximizing growth of chickens by mixed LED technology. PMID:27170597

A new method to manipulate broiler chicken growth and metabolism: Response to mixed LED light system.

PubMed

Yang, Yefeng; Yu, Yonghua; Pan, Jinming; Ying, Yibin; Zhou, Hong

2016-05-12

Present study introduced a new method to manipulate broiler chicken growth and metabolism by mixing the growth-advantage LED. We found that the green/blue LED mixed light system (G-B and G × B) have the similar stimulatory effect on chick body weight with single green light and single blue light (G and B), compared with normal artificial light (P = 0.028). Moreover, the percentage of carcass was significantly greater in the mixed light (G × B) when compared with the single light (P = 0.003). Synchronized with body weight, the mixed light (G-B and G × B) had a significant improved influence on the feed conversion of birds compared with normal light (P = 0.002). A significant improvement in feed conversion were found in mixed light (G × B) compared with single LED light (P = 0.037). G group resulted in a greater high-density lipoprotein cholesterol level than B group (P = 0.002), whereas B group resulted in a greater low-density lipoprotein cholesterol level than G group (P = 0.017). The mixed light significantly increased the birds' glucose level in comparison with the single light (P = 0.003). This study might establish an effective strategy for maximizing growth of chickens by mixed LED technology.

A new method to manipulate broiler chicken growth and metabolism: Response to mixed LED light system

NASA Astrophysics Data System (ADS)

Yang, Yefeng; Yu, Yonghua; Pan, Jinming; Ying, Yibin; Zhou, Hong

2016-05-01

Present study introduced a new method to manipulate broiler chicken growth and metabolism by mixing the growth-advantage LED. We found that the green/blue LED mixed light system (G-B and G × B) have the similar stimulatory effect on chick body weight with single green light and single blue light (G and B), compared with normal artificial light (P = 0.028). Moreover, the percentage of carcass was significantly greater in the mixed light (G × B) when compared with the single light (P = 0.003). Synchronized with body weight, the mixed light (G-B and G × B) had a significant improved influence on the feed conversion of birds compared with normal light (P = 0.002). A significant improvement in feed conversion were found in mixed light (G × B) compared with single LED light (P = 0.037). G group resulted in a greater high-density lipoprotein cholesterol level than B group (P = 0.002), whereas B group resulted in a greater low-density lipoprotein cholesterol level than G group (P = 0.017). The mixed light significantly increased the birds’ glucose level in comparison with the single light (P = 0.003). This study might establish an effective strategy for maximizing growth of chickens by mixed LED technology.

Teaching and Learning in a University Classroom: A Norwegian Case Study on Students' Perspectives

ERIC Educational Resources Information Center

Postholm, May Britt

2007-01-01

This article focuses on student activity and how students experience learning. A teaching programme was both led and researched by the one teacher. The article describes a master's level teaching programme and presents the data collection strategies used by the teacher-researcher and presents learning viewed from the students' perspective. The…

Non-imaging Optics of multi-LED light source for hyperspectral imaging

NASA Astrophysics Data System (ADS)

Islam, Kashif; Gosnell, Martin E.; Ploschner, Martin; Anwer, Ayad G.; Goldys, Ewa M.

2016-12-01

The main objective of our work was to design a light source which should be capable to collect and illuminate light of LEDs at the smaller aperture of cone (9mm) which could be either coupled with secondary optics of a microscope or utilized independently for hyperspectral studies. Optimized performance of cone was assessed for different substrates (diffused glass silica, Alumina, Zerodur glass, acrylic plastic) and coating surfaces (white diffused, flat white paint, standard mirror) using a simulation software. The parameters optimized for truncated cone include slanting length and Top Major R (Larger diameter of cone) which were also varied from 10 to 350 mm and 10 to 80 mm respectively. In order to see affect of LED positions on cone efficiency, the positions of LED were varied from central axis to off-axis. Similarly, interLED distance was varied from 2 mm to 6 mm to reckon its effect on the performance of cone. The optimized Slant length (80 mm) and Top Major R (50 mm) were determined for substrates (glass zerodur or acrylic plastic) and coating surface (standard mirror). The output profile of truncated source was found non uniform, which is a typical presentation of non imaging optics problem. The maximum efficiency of cone has been found for LED at the centre and it was found decreasing as LED moves away from the central axis. Moreover, shorter the interLED distance, better is the performance of cone. The primary optics of cone shaped light source is capable to lit visible and UV LEDs in practical design. The optimum parameters obtained through simulations could be implemented in the fabrication procedure if the reflectance of source would have been maintained upto finish level of a standard mirror.

Blue LED induced thermal effects in wound healing: experimental evidence in an in vivo model of superficial abrasions

NASA Astrophysics Data System (ADS)

Rossi, Francesca; Cicchi, Riccardo; Magni, Giada; Tatini, Francesca; Bacci, Stefano; Paroli, Gaia; Alfieri, Domenico; Tripodi, Cristina; De Siena, Gaetano; Pavone, Francesco S.; Pini, Roberto

2017-02-01

A faster healing process was observed in superficial skin wounds after irradiation with a blue LED (EmoLED) photocoagulator. EmoLED is a compact handheld device, used to induce a thermal effect and thus coagulation in superficial abrasions. We present the results of an in vivo study, conducted in a mouse model, to analyze the induced wound healing. Two superficial abrasions were produced on the back of the mice: one area was treated with EmoLED (1.4 W/cm2, 30 s treatment time), while the other one was left naturally recovering. During the treatment, a temperature around 40-45°C was induced on the abrasion surface. Mice back healthy skin was used as a control. The animals underwent a follow up study and were sacrificed at 0, 1, 3, 6, 9, 12, 18, 21, 24 hours p.o. and 6 days p.o.. Samples from the two abraded areas were harvested and examined by histopathological and immunofluorescence analysis, SHG imaging and confocal microscopy. The aim of the study was to investigate the inflammatory infiltrate, mastocyte population, macrophage subpopulation, fibroblasts and myofibroblasts. Our results show that soon after the treatment, both the inflammatory infiltrate and the M1 macrophage subpopulation appear earlier in the treated, compared to a delayed appearance in the untreated samples. There was no alteration in collagen morphology in the recovered wound. This study confirms the preliminary results obtained in a previous study on a rat model: the selective photothermal effect we used for inducing immediate coagulation in superficial wounds seems to be associated to a faster and improved healing process.

Design and construction evaluation of a photovoltaic DC LED lighting system

NASA Astrophysics Data System (ADS)

Bhamidipati, Jyotsna

2008-08-01

The market demand for commercialization of Photovoltaic (PV) systems depends a lot on the reliability, efficiency and performance of various components within the system. PV panels produce DC power when exposed to sunlight, and an inverter converts this to AC power in a typical solar powered building. Though, PV lighting has existed for a long time it hasn't been very effective, as incandescent light sources were commonly used which are inefficient. Today fluorescent fixtures are mostly used with PV's due to its high efficacy. Light-emitting diodes present a new vision to energy efficiency in lighting design with their low energy consumption. Current research predicts improved efficiencies of LED light fixtures and their commercial use is a few years away. LEDs which operate on DC voltages when coupled with photovoltaics can be a simple PV lighting application and a sustainable solution with potential for payback. This research evaluates the design and construction of a photovoltaic DC LED lighting system for a solar house at Pennsylvania State University. A detailed cost and payback analysis of a PV DC LED lighting system is presented in this research. PV output simulations for the solar house are presented. Results presented in this research indicate that the Solid state lighting market is evolving rapidly and that LED's are a choice in stand-alone photovoltaic DC lighting systems. The efficiency and the cost-effectiveness of such systems would however improve in the coming years with research and development now focused on PV systems and on Solid state lighting technologies.

Human-Friendly Light-Emitting Diode Source Stimulates Broiler Growth.

PubMed

Pan, Jinming; Yang, Yefeng; Yang, Bo; Dai, Wenhua; Yu, Yonghua

2015-01-01

Previous study and our laboratory have reported that short-wavelength (blue and green) light and combination stimulate broiler growth. However, short-wavelength stimuli could have negative effects on poultry husbandry workers. The present study was conducted to evaluate the effects of human-friendly yellow LED light, which is acceptable to humans and close to green light, on broiler growth. We also aimed to investigate the potential quantitative relationship between the wavelengths of light used for artificial illumination and growth parameters in broilers. After hatching, 360 female chicks ("Meihuang" were evenly divided into six lighting treatment groups: white LED strips (400-700 nm, WL); red LED strips (620 nm, RL); yellow LED strips (580 nm, YL); green LED strips (514 nm, GL); blue LED strips (455 nm, BL); and fluorescent strips (400-700 nm, FL). From 30 to 72 days of age, broilers reared under YL and GL were heavier than broilers treated with FL (P < 0.05). Broilers reared under YL obtained the similar growth parameters with the broilers reared under GL and BL (P > 0.05). Moreover, YL significantly improved feeding efficiency when compared with GL and BL at 45 and 60 days of age (P < 0.05). In addition, we found an age-dependent effect of light spectra on broiler growth and a quantitative relationship between LED light spectra (455 to 620 nm) and the live body weights of broilers. The wavelength of light (455 to 620 nm) was found to be negatively related (R2 = 0.876) to live body weight at an early stage of development, whereas the wavelength of light (455 to 620 nm) was found to be positively correlated with live body weight (R2 = 0.925) in older chickens. Our results demonstrated that human-friendly yellow LED light (YL), which is friendly to the human, can be applied to the broilers production.

Human-Friendly Light-Emitting Diode Source Stimulates Broiler Growth

PubMed Central

Yang, Bo; Dai, Wenhua; Yu, Yonghua

2015-01-01

Previous study and our laboratory have reported that short-wavelength (blue and green) light and combination stimulate broiler growth. However, short-wavelength stimuli could have negative effects on poultry husbandry workers. The present study was conducted to evaluate the effects of human-friendly yellow LED light, which is acceptable to humans and close to green light, on broiler growth. We also aimed to investigate the potential quantitative relationship between the wavelengths of light used for artificial illumination and growth parameters in broilers. After hatching, 360 female chicks (“Meihuang” were evenly divided into six lighting treatment groups: white LED strips (400–700 nm, WL); red LED strips (620 nm, RL); yellow LED strips (580 nm, YL); green LED strips (514 nm, GL); blue LED strips (455 nm, BL); and fluorescent strips (400–700 nm, FL). From 30 to 72 days of age, broilers reared under YL and GL were heavier than broilers treated with FL (P < 0.05). Broilers reared under YL obtained the similar growth parameters with the broilers reared under GL and BL (P > 0.05). Moreover, YL significantly improved feeding efficiency when compared with GL and BL at 45 and 60 days of age (P < 0.05). In addition, we found an age-dependent effect of light spectra on broiler growth and a quantitative relationship between LED light spectra (455 to 620 nm) and the live body weights of broilers. The wavelength of light (455 to 620 nm) was found to be negatively related (R 2 = 0.876) to live body weight at an early stage of development, whereas the wavelength of light (455 to 620 nm) was found to be positively correlated with live body weight (R 2 = 0.925) in older chickens. Our results demonstrated that human-friendly yellow LED light (YL), which is friendly to the human, can be applied to the broilers production. PMID:26270988

Oxytocin and Migraine Headache.

PubMed

Tzabazis, Alexander; Kori, Shashi; Mechanic, Jordan; Miller, James; Pascual, Conrado; Manering, Neil; Carson, Dean; Klukinov, Michael; Spierings, Egilius; Jacobs, Daniel; Cuellar, Jason; Frey, William H; Hanson, Leah; Angst, Martin; Yeomans, David C

2017-05-01

This article reviews material presented at the 2016 Scottsdale Headache Symposium. This presentation provided scientific results and rationale for the use of intranasal oxytocin for the treatment of migraine headache. Results from preclinical experiments are reviewed, including in vitro experiments demonstrating that trigeminal ganglia neurons possess oxytocin receptors and are inhibited by oxytocin. Furthermore, most of these same neurons contain CGRP, the release of which is inhibited by oxytocin. Results are also presented which demonstrate that nasal oxytocin inhibits responses of trigeminal nucleus caudalis neurons to noxious stimulation using either noxious facial shock or nitroglycerin infusion. These studies led to testing the analgesic effect of intranasal oxytocin in episodic migraineurs-studies which did not meet their primary endpoint of pain relief at 2 h, but which were highly informative and led to additional rat studies wherein inflammation was found to dramatically upregulate the number of oxytocin receptors available on trigeminal neurons. This importance of inflammation was supported by a series of in vivo rat behavioral studies, which demonstrated a clear craniofacial analgesic effect when a pre-existing inflammatory injury was present. The significance of inflammation was further solidified by a small single-dose clinical study, which showed analgesic efficacy that was substantially stronger in chronic migraine patients that had not taken an anti-inflammatory drug within 24 h of oxytocin dosing. A follow-on open label study examining effects of one month of intranasal oxytocin dosing did show a reduction in pain, but a more impressive decrease in the frequency of headaches in both chronic and high frequency episodic migraineurs. This study led to a multicountry double blind, placebo controlled study studying whether, over 2 months of dosing, "as needed" dosing of intranasal oxytocin by chronic and high frequency migraineurs would reduce the frequency of their headaches compared to a 1-month baseline period. This study failed to meet its primary endpoint, due to an extraordinarily high placebo rate in the country of most of the patients (Chile), but was also highly informative, showing strong results in other countries and strong post hoc indications of efficacy. The results provide a strong argument for further development of intranasal oxytocin for migraine prophylaxis. © 2017 American Headache Society.

How Temporal and Spatial Aspects of Presenting Visualizations Affect Learning about Locomotion Patterns

ERIC Educational Resources Information Center

Imhof, Birgit; Scheiter, Katharina; Edelmann, Jorg; Gerjets, Peter

2012-01-01

Two studies investigated the effectiveness of dynamic and static visualizations for a perceptual learning task (locomotion pattern classification). In Study 1, seventy-five students viewed either dynamic, static-sequential, or static-simultaneous visualizations. For tasks of intermediate difficulty, dynamic visualizations led to better…

Carrier lifetimes in polar InGaN-based LEDs

NASA Astrophysics Data System (ADS)

Wang, Lai; Jin, Jie; Hao, Zhibiao; Luo, Yi

2018-02-01

Measurement of carrier lifetime is very important to understand the physics in light-emitting diodes (LEDs), as it builds a link between carrier concentration and excitation power or current density. In this paper, we present our study on optical and electrical characterizations on carrier lifetimes in polar InGaN-based LEDs. First, a carrier rate equation model is proposed to explain the non-exponential nature of time-resolved photoluminescence (TRPL) decay curves, wherein exciton recombination is replaced by bimolecular recombination, considering the influence of polarization field on electron-hole pairs. Then, nonradiative recombination and radiative recombination coefficients can be deduced from fitting and used to calculate the radiative recombination efficiency. By comparing with the temperature-dependent photoluminescence (TDPL) and power-dependent photoluminescence (PDPL), it is found these three methods provide the consistent results. Second, differential carrier lifetimes depending on injection current are measured in commercial near-ultraviolet (NUV), blue and green LEDs. It is found that carrier lifetime is longer in green one and shorter in NUV one, which is attributed to the influence of polarization-induced quantum confined Stark effect (QCSE). This result implies the carrier density is higher in green LED while lower NUV LED, even the injection current is the same. By ignoring Auger recombination and fitting the efficiency-current and carrier lifetime-current curves simultaneously, the dependence of injection efficiency on carrier concentration in different LED samples are plotted. The NUV LED, which has the shallowest InGaN quantum well, actually exhibits the most serious efficiency droop versus carrier concentration. Then, the approaches to overcome the efficiency droop are discussed.

Effect of red and blue light emitting diodes "CRB-LED" on in vitro organogenesis of date palm (Phoenix dactylifera L.) cv. Alshakr.

PubMed

Al-Mayahi, Ahmed Madi Waheed

2016-10-01

The objective of the present study is to determine the effect of light source on enhancement of shoot multiplication, phytochemicals, as well as, antioxidant enzyme activities of in vitro cultures of date palm cv. Alshakr. In vitro-grown buds were cultured on Murashige and Skoog (MS) medium and incubated under a conventional white fluorescent light (control), and combinations of red + blue light emitting diode (18:2) (CRB-LED). Results revealed that the treatment of CRB-LED showed a significant increase in the number of shoots compared with the white florescent light. Total soluble carbohydrate "TSCH" (7.10 mg g(-1) DW.), starch (1.63 mg g(-1) DW.) and free amino acids (2.90 mg g(-1) DW.) were significantly higher in CRB-LED (p < 0.05). Additionally, CRB-LED induced a higher peroxidase activity (25.50 U ml(-1)) compared with the white fluorescent light treatment (19.74 U ml(-1)) as control treatment. Potassium, magnesium and sodium contents in (3.62, 13.99 and 2.76 mg g(-1) DW.) were increased in in vitro shoots under CRB-LED treatment in comparison with fluorescent light (p < 0.05). Protein profile showed the appearance of newly bands with the molecular weight of 38 and 60 kDa at the treatment CRB-LED compared with control treatment. Our results demonstrate the positive effects of CRB-LED light during the course of date palm tissue cultures.

Alterations in enamel remineralization in vitro induced by blue light

NASA Astrophysics Data System (ADS)

Kato, I. T.; Zezell, D. M.; Mendes, F. M.; Wetter, N. U.

2010-06-01

Blue light, especially from LED devices, is a very frequently used tool in dental procedures. However, the investigations of its effects on dental enamel are focused primarily on enamel demineralization and fluoride retention. Despite the fact that this spectral region can inhibit enamel demineralization, the effects of the irradiation on demineralized enamel are not known. For this reason, we evaluated the effects of blue LED on remineralization of dental enamel. Artificial lesions were formed in bovine dental enamel blocks by immersing the samples in undersaturated acetate buffer. The lesions were irradiated with blue LED (455 nm, 1.38 W/cm2, 13.75 J/cm2, and 10 s) and remineralization was induced by pH-cycling process. Cross-sectional hardness was used to asses mineral changes after remineralization. Non-irradiated enamel lesions presented higher mineral content than irradiated ones. Furthermore, the mineral content of irradiated group was not significantly different from the lesion samples that were not submitted to the remineralization process. Results obtained in the present study show that the blue light is not innocuous for the dental enamel and inhibition of its remineralization can occur.

NASA light emitting diode medical applications from deep space to deep sea

NASA Astrophysics Data System (ADS)

Whelan, Harry T.; Buchmann, Ellen V.; Whelan, Noel T.; Turner, Scott G.; Cevenini, Vita; Stinson, Helen; Ignatius, Ron; Martin, Todd; Cwiklinski, Joan; Meyer, Glenn A.; Hodgson, Brian; Gould, Lisa; Kane, Mary; Chen, Gina; Caviness, James

2001-02-01

This work is supported and managed through the NASA Marshall Space Flight Center-SBIR Program. LED-technology developed for NASA plant growth experiments in space shows promise for delivering light deep into tissues of the body to promote wound healing and human tissue growth. We present the results of LED-treatment of cells grown in culture and the effects of LEDs on patients' chronic and acute wounds. LED-technology is also biologically optimal for photodynamic therapy of cancer and we discuss our successes using LEDs in conjunction with light-activated chemotherapeutic drugs. .

Flexible inorganic light emitting diodes based on semiconductor nanowires

PubMed Central

Guan, Nan; Dai, Xing; Babichev, Andrey V.; Julien, François H.

2017-01-01

The fabrication technologies and the performance of flexible nanowire light emitting diodes (LEDs) are reviewed. We first introduce the existing approaches for flexible LED fabrication, which are dominated by organic technologies, and we briefly discuss the increasing research effort on flexible inorganic LEDs achieved by micro-structuring and transfer of conventional thin films. Then, flexible nanowire-based LEDs are presented and two main fabrication technologies are discussed: direct growth on a flexible substrate and nanowire membrane formation and transfer. The performance of blue, green, white and bi-color flexible LEDs fabricated following the transfer approach is discussed in more detail. PMID:29568439

The Value of Clinical Practice in Cadaveric Dissection: Lessons Learned From a Course in Eye and Orbital Anatomy.

PubMed

Schulz, Christopher

To test the hypothesis that there is greater benefit in a dissection-based anatomy course among those participants with clinical experience in the relevant field, and those without. A retrospective comparative study. Brighton and Sussex Medical School Anatomy Department: an educational facility that provides undergraduate and postgraduate anatomy teaching using cadaveric specimens. All attendees (n = 40) to a postgraduate course in eye and orbital anatomy completed course evaluation forms. The course has been attended by delegates from around the country, with experience ranging from that of final year medical students to clinical fellows who have completed their specialist training in ophthalmology. Those participants who were practicing ophthalmology tended to be older than those who were not, with a greater amount of time spent on prior learning. Participants scored both the prosection-led and dissection-led sessions highly, with a mean combined evaluation of 8.9 (out of 10) for dissection-led learning and 9.2 for prosection-led learning. Prosection-led learning was regarded equally by those participants currently practicing in ophthalmology, and those who are not. In contrast, dissection-led learning was scored higher by those participants who were practicing ophthalmology (9.4), when compared with those not in ophthalmic practice (8.5; p = 0.018). The present study supports the hypothesis that the benefits of cadaveric dissection could be maximized during postgraduate surgical training. This has important implications given the trend away from cadaveric dissection in the undergraduate curriculum. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

Effect of NASA light-emitting diode irradiation on molecular changes for wound healing in diabetic mice.

PubMed

Whelan, Harry T; Buchmann, Ellen V; Dhokalia, Apsara; Kane, Mary P; Whelan, Noel T; Wong-Riley, Margaret T T; Eells, Janis T; Gould, Lisa J; Hammamieh, Rasha; Das, Rina; Jett, Marti

2003-04-01

The purpose of this study was to assess the changes in gene expression of near-infrared light therapy in a model of impaired wound healing. Light-Emitting Diodes (LED), originally developed for NASA plant growth experiments in space, show promise for delivering light deep into tissues of the body to promote wound healing and human tissue growth. In this paper we present the effects of LED treatment on wounds in a genetically diabetic mouse model. Polyvinyl acetal (PVA) sponges were subcutaneously implanted in the dorsum of BKS.Cg-m +/+ Lepr(db) mice. LED treatments were given once daily, and at the sacrifice day, the sponges, incision line and skin over the sponges were harvested and used for RNA extraction. The RNA was subsequently analyzed by cDNA array. Our studies have revealed certain tissue regenerating genes that were significantly upregulated upon LED treatment when compared to the untreated sample. Integrins, laminin, gap junction proteins, and kinesin superfamily motor proteins are some of the genes involved during regeneration process. These are some of the genes that were identified upon gene array experiments with RNA isolated from sponges from the wound site in mouse with LED treatment. We believe that the use of NASA light-emitting diodes (LED) for light therapy will greatly enhance the natural wound healing process, and more quickly return the patient to a preinjury/illness level of activity. This work is supported and managed through the Defense Advanced Research Projects Agency (DARPA) and NASA Marshall Space Flight Center-SBIR Program.

Lighting theory and luminous characteristics of white light-emitting diodes

NASA Astrophysics Data System (ADS)

Uchida, Yuji; Taguchi, Tsunemasa

2005-12-01

A near-ultraviolet (UV)-based white light-emitting diode (LED) lighting system linked with a semiconductor InGaN LED and compound phosphors for general lighting applications is proposed. We have developed for the first time a novel type of high-color rendering index (Ra) white LED light source, which is composed of near-UV LED and multiphosphor materials showing orange (O), yellow (Y), green (G), and blue (B) emissions. The white LED shows the superior characteristics of luminous efficacy and high Ra to be about 40 lm/W and 93, respectively. Luminous and chromaticity characteristics, and their spectral distribution of the present white LED can be evaluated using the multipoint LED light source theory. It is revealed that the OYGB white LED can provide better irradiance properties than that of conventional white LEDs. Near-UV white LED technologies, in conjunction with phosphor blends, can offer superior color uniformity, high Ra, and excellent light quality. Consequently we are carrying out a "white LEDs for medical applications" program in the second phase of this national project from 2004 to 2009.

The role of graphene formed on silver nanowire transparent conductive electrode in ultra-violet light emitting diodes

PubMed Central

Seo, Tae Hoon; Lee, Seula; Min, Kyung Hyun; Chandramohan, S.; Park, Ah Hyun; Lee, Gun Hee; Park, Min; Suh, Eun-Kyung; Kim, Myung Jong

2016-01-01

This paper reports a highly reliable transparent conductive electrode (TCE) that integrates silver nanowires (AgNWs) and high-quality graphene as a protecting layer. Graphene with minimized defects and large graphene domains has been successfully obtained through a facile two-step growth approach. Ultraviolet light emitting diodes (UV-LEDs) were fabricated with AgNWs or hybrid electrodes where AgNWs were combined with two-step grown graphene (A-2GE) or conventional one-step grown graphene (A-1GE). The device performance and reliability of the UV-LEDs with three different electrodes were compared. The A-2GE offered high figure of merit owing to the excellent UV transmittance and reduced sheet resistance. As a consequence, the UV-LEDs made with A-2GE demonstrated reduced forward voltage, enhanced electroluminescence (EL) intensity, and alleviated efficiency droop. The effects of joule heating and UV light illumination on the electrode stability were also studied. The present findings prove superior performance of the A-2GE under high current injection and continuous operation of UV LED, compared to other electrodes. From our observation, the A-2GE would be a reliable TCE for high power UV-LEDs. PMID:27387274

The role of graphene formed on silver nanowire transparent conductive electrode in ultra-violet light emitting diodes

NASA Astrophysics Data System (ADS)

Seo, Tae Hoon; Lee, Seula; Min, Kyung Hyun; Chandramohan, S.; Park, Ah Hyun; Lee, Gun Hee; Park, Min; Suh, Eun-Kyung; Kim, Myung Jong

2016-07-01

This paper reports a highly reliable transparent conductive electrode (TCE) that integrates silver nanowires (AgNWs) and high-quality graphene as a protecting layer. Graphene with minimized defects and large graphene domains has been successfully obtained through a facile two-step growth approach. Ultraviolet light emitting diodes (UV-LEDs) were fabricated with AgNWs or hybrid electrodes where AgNWs were combined with two-step grown graphene (A-2GE) or conventional one-step grown graphene (A-1GE). The device performance and reliability of the UV-LEDs with three different electrodes were compared. The A-2GE offered high figure of merit owing to the excellent UV transmittance and reduced sheet resistance. As a consequence, the UV-LEDs made with A-2GE demonstrated reduced forward voltage, enhanced electroluminescence (EL) intensity, and alleviated efficiency droop. The effects of joule heating and UV light illumination on the electrode stability were also studied. The present findings prove superior performance of the A-2GE under high current injection and continuous operation of UV LED, compared to other electrodes. From our observation, the A-2GE would be a reliable TCE for high power UV-LEDs.

Correlating electroluminescence characterization and physics-based models of InGaN/GaN LEDs: Pitfalls and open issues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calciati, Marco; Vallone, Marco; Zhou, Xiangyu

2014-06-15

Electroluminescence (EL) characterization of InGaN/GaN light-emitting diodes (LEDs), coupled with numerical device models of different sophistication, is routinely adopted not only to establish correlations between device efficiency and structural features, but also to make inferences about the loss mechanisms responsible for LED efficiency droop at high driving currents. The limits of this investigative approach are discussed here in a case study based on a comprehensive set of current- and temperature-dependent EL data from blue LEDs with low and high densities of threading dislocations (TDs). First, the effects limiting the applicability of simpler (closed-form and/or one-dimensional) classes of models are addressed,more » like lateral current crowding, vertical carrier distribution nonuniformity, and interband transition broadening. Then, the major sources of uncertainty affecting state-of-the-art numerical device simulation are reviewed and discussed, including (i) the approximations in the transport description through the multi-quantum-well active region, (ii) the alternative valence band parametrizations proposed to calculate the spontaneous emission rate, (iii) the difficulties in defining the Auger coefficients due to inadequacies in the microscopic quantum well description and the possible presence of extra, non-Auger high-current-density recombination mechanisms and/or Auger-induced leakage. In the case of the present LED structures, the application of three-dimensional numerical-simulation-based analysis to the EL data leads to an explanation of efficiency droop in terms of TD-related and Auger-like nonradiative losses, with a C coefficient in the 10{sup −30} cm{sup 6}/s range at room temperature, close to the larger theoretical calculations reported so far. However, a study of the combined effects of structural and model uncertainties suggests that the C values thus determined could be overestimated by about an order of magnitude. This preliminary attempt at uncertainty quantification confirms, beyond the present case, the need for an improved description of carrier transport and microscopic radiative and nonradiative recombination mechanisms in device-level LED numerical models.« less

Degradation modeling of mid-power white-light LEDs by using Wiener process.

PubMed

Huang, Jianlin; Golubović, Dušan S; Koh, Sau; Yang, Daoguo; Li, Xiupeng; Fan, Xuejun; Zhang, G Q

2015-07-27

The IES standard TM-21-11 provides a guideline for lifetime prediction of LED devices. As it uses average normalized lumen maintenance data and performs non-linear regression for lifetime modeling, it cannot capture dynamic and random variation of the degradation process of LED devices. In addition, this method cannot capture the failure distribution, although it is much more relevant in reliability analysis. Furthermore, the TM-21-11 only considers lumen maintenance for lifetime prediction. Color shift, as another important performance characteristic of LED devices, may also render significant degradation during service life, even though the lumen maintenance has not reached the critical threshold. In this study, a modified Wiener process has been employed for the modeling of the degradation of LED devices. By using this method, dynamic and random variations, as well as the non-linear degradation behavior of LED devices, can be easily accounted for. With a mild assumption, the parameter estimation accuracy has been improved by including more information into the likelihood function while neglecting the dependency between the random variables. As a consequence, the mean time to failure (MTTF) has been obtained and shows comparable result with IES TM-21-11 predictions, indicating the feasibility of the proposed method. Finally, the cumulative failure distribution was presented corresponding to different combinations of lumen maintenance and color shift. The results demonstrate that a joint failure distribution of LED devices could be modeled by simply considering their lumen maintenance and color shift as two independent variables.

Radiation-damage-induced phasing: a case study using UV irradiation with light-emitting diodes.

PubMed

de Sanctis, Daniele; Zubieta, Chloe; Felisaz, Franck; Caserotto, Hugo; Nanao, Max H

2016-03-01

Exposure to X-rays, high-intensity visible light or ultraviolet radiation results in alterations to protein structure such as the breakage of disulfide bonds, the loss of electron density at electron-rich centres and the movement of side chains. These specific changes can be exploited in order to obtain phase information. Here, a case study using insulin to illustrate each step of the radiation-damage-induced phasing (RIP) method is presented. Unlike a traditional X-ray-induced damage step, specific damage is introduced via ultraviolet light-emitting diodes (UV-LEDs). In contrast to UV lasers, UV-LEDs have the advantages of small size, low cost and relative ease of use.

Antibacterial activity and antibiotic modulating potential of the essential oil obtained from Eugenia jambolana in association with led lights.

PubMed

Pereira, Nara L F; Aquino, Pedro E A; Júnior, José G A S; Cristo, Janyketchuly S; Vieira Filho, Marcos A; Moura, Flávio F; Ferreira, Najla M N; Silva, Maria K N; Nascimento, Eloiza M; Correia, Fabrina M A; Cunha, Francisco A B; Boligon, Aline A; Coutinho, Henrique D M; Ribeiro-Filho, Jaime; Matias, Edinardo F F; Guedes, Maria I F

2017-09-01

Bacterial resistance has risen as an important health problem with impact on the pharmaceutical industry because many antibiotics have become ineffective, which has affected their commercialization. The Brazilian biodiversity is marked by a vast variety of natural products with significant therapeutic potential, which could bring new perspectives in the treatment of infections caused by resistant microorganisms. The present study aimed to evaluate the antibacterial effect of the essential oil obtained from Eugenia jambolana (EjEO) using the method of microdilution method to determine the Minimum Inhibitory Concentration (MIC). The modulatory effect of this oil on antibiotic activity was determined using both the broth microdilution and gaseous contact methods. The antibacterial effect of the association of the gaseous contact and the use of a LED unit with red and blue lights was also determined. The chemical components of the EjEO were characterized by HPLC, which revealed the presence of α-pinene as a major constituent. The EjEO presented a MIC≥128μg/mL against S. aureus and ≥1024μg/mL against E. coli. The combination of the EjEO with antibiotics presented synergism against E. coli and antagonism against S. aureus. An antagonistic effect was obtained from the association of EjEO with amikacin and erythromycin by the method of gaseous contact. On the other hand, the association of EjEO with ciprofloxacin presented a synergistic effect against S. aureus and E. coli exposed to LED lights. A similar effect was observed in the association of the EjEO with norfloxacin presented synergism against S. aureus in the same conditions. In conclusion, our results demonstrated that the essential oil obtained from Eugenia jambolana interfere with the action of antibiotics against bacteria exposed to LED lights. Thus, further researches are required to elucidate the mechanisms underlying these effects, which could open new perspectives in the development of new antibacterial therapies. Copyright © 2017 Elsevier B.V. All rights reserved.

Historical and Current Perspective on Tobacco use and Nicotine Addiction

PubMed Central

Dani, John A.; Balfour, David J.K.

2011-01-01

Although the addictive influence of tobacco was recognized very early, the modern concepts of nicotine addiction have relied on knowledge of cholinergic neurotransmission and nicotinic acetylcholine receptors (nAChRs). The discovery of the “receptive substance” by Langley, that would turn out to be nAChRs, and “Vagusstoff” (acetylcholine) by Loewi, coincided with an exciting time when the concept of chemical synaptic transmission was being formulated. More recently, the application of more powerful techniques and the study of animal models that replicate key features of nicotine dependence have led to important advancements in our understanding of molecular, cellular, and systems mechanisms of nicotine addiction. In this Review, we present a historical perspective and overview of the research that has led to our present understanding of nicotine addiction. PMID:21696833

Analyses of multi-color plant-growth light sources in achieving maximum photosynthesis efficiencies with enhanced color qualities.

PubMed

Wu, Tingzhu; Lin, Yue; Zheng, Lili; Guo, Ziquan; Xu, Jianxing; Liang, Shijie; Liu, Zhuguagn; Lu, Yijun; Shih, Tien-Mo; Chen, Zhong

2018-02-19

An optimal design of light-emitting diode (LED) lighting that benefits both the photosynthesis performance for plants and the visional health for human eyes has drawn considerable attention. In the present study, we have developed a multi-color driving algorithm that serves as a liaison between desired spectral power distributions and pulse-width-modulation duty cycles. With the aid of this algorithm, our multi-color plant-growth light sources can optimize correlated-color temperature (CCT) and color rendering index (CRI) such that photosynthetic luminous efficacy of radiation (PLER) is maximized regardless of the number of LEDs and the type of photosynthetic action spectrum (PAS). In order to illustrate the accuracies of the proposed algorithm and the practicalities of our plant-growth light sources, we choose six color LEDs and German PAS for experiments. Finally, our study can help provide a useful guide to improve light qualities in plant factories, in which long-term co-inhabitance of plants and human beings is required.

Studying Light Color using White LED Lighting

NASA Astrophysics Data System (ADS)

Yamagishi, Misako; Yamaba, Kazuo; Nagata, Manori; Kubo, Chiho; Nokura, Kunihiro

Recently, white Light Emitting Diodes (LEDs) are receiving attention worldwide as new lighting devices. This study examined effects of a lighting application on performance using white LEDs. The light color—the correlated color temperature (CCT) —was assessed. It affected to psychological states and physiological conditions. Three CCT conditions were respectively set for the experiment: 2500 K, 5000 K, and 8200 K. In all, 20 younger subjects (20-30 years old), 15 middle-aged to elderly subjects (45-60 years old) and 12 elderly subjects (over 65 years-old) participated. They were presented a Numerical Verification (NV) task for performance measurement. The psychological states on performance were evaluated using the lighting assessment questionnaire. The physiological conditions were recorded using an electrocardiograph. Results show that the effects of CCT differ among age groups. Especially, the performance of younger subjects might differ from CCT conditions; elderly subjects are affected by CCT condition because of their visual acuity or response to contrast of objects.

Promoting research and audit at medical school: evaluating the educational impact of participation in a student-led national collaborative study.

PubMed

Chapman, Stephen J; Glasbey, James C D; Khatri, Chetan; Kelly, Michael; Nepogodiev, Dmitri; Bhangu, Aneel; Fitzgerald, J Edward F

2015-03-13

Medical students often struggle to engage in extra-curricular research and audit. The Student Audit and Research in Surgery (STARSurg) network is a novel student-led, national research collaborative. Student collaborators contribute data to national, clinical studies while gaining an understanding of audit and research methodology and ethical principles. This study aimed to evaluate the educational impact of participation. Participation in the national, clinical project was supported with training interventions, including an academic training day, an online e-learning module, weekly discussion forums and YouTube® educational videos. A non-mandatory, online questionnaire assessed collaborators' self-reported confidence in performing key academic skills and their perceptions of audit and research prior to and following participation. The group completed its first national clinical study ("STARSurgUK") with 273 student collaborators across 109 hospital centres. Ninety-seven paired pre- and post-study participation responses (35.5%) were received (male = 51.5%; median age = 23). Participation led to increased confidence in key academic domains including: communication with local research governance bodies (p < 0.001), approaching clinical staff to initiate local collaboration (p < 0.001), data collection in a clinical setting (p < 0.001) and presentation of scientific results (p < 0.013). Collaborators also reported an increased appreciation of research, audit and study design (p < 0.001). Engagement with the STARSurg network empowered students to participate in a national clinical study, which increased their confidence and appreciation of academic principles and skills. Encouraging active participation in collaborative, student-led, national studies offers a novel approach for delivering essential academic training.

A Pilot Study of a Behavioral Parent Training in the Republic of Macedonia

ERIC Educational Resources Information Center

Hansen, Blake D.; Orton, Emma Lucy; Adams, Chase; Knecht, Laura; Rindlisbaker, Sophie; Jurtoski, Filip; Trajkovski, Vladimir

2017-01-01

Parenting children with autism in countries with limited professional and financial resources can be overwhelming. Parent training led by non-governmental organizations may help alleviate some of these burdens. The present pilot study was conducted in the Republic of Macedonia, a country located in Southeastern Europe. The purpose of the study was…

A Case Study of Autonomy and Motivation in a Student-Led Game Development Project

ERIC Educational Resources Information Center

Prigmore, M.; Taylor, R.; De Luca, D.

2016-01-01

This paper presents the findings of an exploratory case study into the relationship between student autonomy and motivation in project based learning, using Self-Determination Theory (SDT) to frame the investigation. The case study explores how different forms of motivation affect the students' response to challenges and their intention to…

Comparison of instructor-led versus peer-led debriefing in nursing students.

PubMed

Roh, Young Sook; Kelly, Michelle; Ha, Eun Ho

2016-06-01

Despite its widespread support, the most effective simulation-based debriefing method has little evidence to support its efficacy. In this study, we compared the effect of peer-led and instructor-led debriefing among nursing students. The study was conducted with a non-equivalent control group using a pretest-post-test design. A convenience sample of third-year nursing students was used for the study, where 65 students enrolled in a 2-week clinical placement rotation were randomly assigned to the instructor-led group or peer-led group. The quality of cardiopulmonary resuscitation skills, satisfaction with simulation, and quality of debriefing in the peer-led group were compared to those in the instructor-led group. Group differences at each testing interval were analyzed using independent t-test. Nursing students in the instructor-led debriefing group showed better subsequent cardiopulmonary resuscitation performance, more satisfaction with simulation experience, and higher debriefing scores compared to the peer-led group. From our study, instructor-led debriefing is an effective method in improving skills performance, inducing favorable satisfaction, and providing better quality of debriefing among nursing students. © 2016 John Wiley & Sons Australia, Ltd.

A blue-LED-based device for selective photocoagulation of superficial abrasions: theoretical modeling and in vivo validation

NASA Astrophysics Data System (ADS)

Rossi, Francesca; Pini, Roberto; De Siena, Gaetano; Massi, Daniela; Pavone, Francesco S.; Alfieri, Domenico; Cannarozzo, Giovanni

2010-02-01

The blue light (~400 nm) emitted by high power Light Emitting Diodes (LED) is selectively absorbed by the haemoglobin content of blood and then converted into heat. This is the basic concept in setting up a compact, low-cost, and easy-to-handle photohaemostasis device for the treatment of superficial skin abrasions. Its main application is in reducing bleeding from superficial capillary vessels during laser induced aesthetic treatments, such as skin resurfacing, thus reducing the treatment time and improving aesthetic results (reduction of scar formation). In this work we firstly present the preliminary modeling study: a Finite Element Model (FEM) of the LED induced photothermal process was set up, in order to estimate the optimal wavelength and treatment time, by studying the temperature dynamics in the tissue. Then, a compact, handheld illumination device has been designed: commercially available high power LEDs emitting in the blue region were mounted in a suitable and ergonomic case. The prototype was tested in the treatment of dorsal excoriations in rats. Thermal effects were monitored by an infrared thermocamera, experimentally evidencing the modest and confined heating effects and confirming the modeling predictions. Objective observations and histopathological analysis performed in a follow-up study showed no adverse reactions and no thermal damage in the treated areas and surrounding tissues. The device was then used in human patients, in order to stop bleeding during Erbium laser skin resurfacing procedure. By inducing LED-based photocoagulation, the overall treatment time was shortened and scar formation was reduced, thus enhancing esthetic effect of the laser procedure.

Constraints on drivers for visible light communications emitters based on energy efficiency.

PubMed

Del Campo-Jimenez, Guillermo; Perez-Jimenez, Rafael; Lopez-Hernandez, Francisco Jose

2016-05-02

In this work we analyze the energy efficiency constraints on drivers for Visible light communication (VLC) emitters. This is the main reason why LED is becoming the main source of illumination. We study the effect of the waveform shape and the modulation techniques on the overall energy efficiency of an LED lamp. For a similar level of illumination, we calculate the emitter energy efficiency ratio η (P_LED/P_TOTAL) for different signals. We compare switched and sinusoidal signals and analyze the effect of both OOK and OFDM modulation techniques depending on the power supply adjustment, level of illumination and signal amplitude distortion. Switched and OOK signals present higher energy efficiency behaviors (0.86≤η≤0.95) than sinusoidal and OFDM signals (0.53≤η≤0.79).

Design of axisymmetrical tailored concentrators for LED light source applications

NASA Astrophysics Data System (ADS)

Van Giel, Bart; Meuret, Youri; Thienpont, Hugo

2006-04-01

In our contribution we present a solution to an important question in the design of a LED-based illumination engine for projection systems: the collimation of the LED light. We tested the principle in the modification of a common device in non-imaging optics, the compound Parabolic Concentrator. This CPC-like achieves a collection of 72% (ideal reflective coating presumed). This CPC-like was tailored by numerically solving an differential equation. This approach has some serious drawbacks. For a compact collection device with high collimation, an other approach is required. A more elegant design strategy will rely fully on geometrical principles. The result of our work is a compound collection lens that achieves a collection efficiency of 87%, assuming an ideal reflective coating and neglecting Fresnel losses. We study the performance of this device in detail. Further enhancements are suggested.

Automated platform for determination of LEDs spatial radiation pattern

NASA Astrophysics Data System (ADS)

Vladescu, Marian; Vuza, Dan Tudor

2015-02-01

Nowadays technologies lead to remarkable properties of the light-emitting diodes (LEDs), making them attractive for more and more applications, such as: interior and exterior lighting, outdoor LED panels, traffic signals, automotive (tail and brake lights, backlighting in dashboard and switches), backlighting of display panels, LCD displays, symbols on switches, keyboards, graphic boards and measuring scales. Usually, LEDs are small light sources consisting of a chip placed into a package, which may bring additional optics to this encapsulated ensemble, resulting in a less or more complex spatial distribution of the light intensity, with particular radiation patterns. This paper presents an automated platform designed to allow a quick and accurate determination of the spatial radiation patterns of LEDs encapsulated in various packages. Keywords: LED, luminous

A Process Evaluation of Project Developmental Continuity. Interim Report II, Part B: Recommendations for Measuring Program Impact.

ERIC Educational Resources Information Center

Love, John M.; And Others

This report presents recommendations for measures to be used in assessing the impact of Project Developmental Continuity (PDC). Chapter I reviews the purpose of the impact study and presents the basic considerations guiding the selection of measures. Chapter II describes the review process that led to the final recommendations. Chapter III…

Combined electrical and resonant optical excitation characterization of multi-quantum well InGaN-based light-emitting diodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Presa, S., E-mail: silvino.presa@tyndall.ie; School of Engineering, University College Cork, Cork; Maaskant, P. P.

We present a comprehensive study of the emission spectra and electrical characteristics of InGaN/GaN multi-quantum well light-emitting diode (LED) structures under resonant optical pumping and varying electrical bias. A 5 quantum well LED with a thin well (1.5 nm) and a relatively thick barrier (6.6 nm) shows strong bias-dependent properties in the emission spectra, poor photovoltaic carrier escape under forward bias and an increase in effective resistance when compared with a 10 quantum well LED with a thin (4 nm) barrier. These properties are due to a strong piezoelectric field in the well and associated reduced field in the thickermore » barrier. We compare the voltage ideality factors for the LEDs under electrical injection, light emission with current, photovoltaic mode (PV) and photoluminescence (PL) emission. The PV and PL methods provide similar values for the ideality which are lower than for the resistance-limited electrical method. Under optical pumping the presence of an n-type InGaN underlayer in a commercial LED sample is shown to act as a second photovoltaic source reducing the photovoltage and the extracted ideality factor to less than 1. The use of photovoltaic measurements together with bias-dependent spectrally resolved luminescence is a powerful method to provide valuable insights into the dynamics of GaN LEDs.« less

A transparent look at the measurement and application of colour rendering in the use of LED light sources

NASA Astrophysics Data System (ADS)

Leuschner, F. W.; Van Der Westhuyzen, J. G. J.

2014-06-01

The technology for the measurement of colour rendering and colour quality is not new, but many parameters related to this issue are currently changing. A number of standard methods were developed and are used by different specialty areas of the lighting industry. CIE 13.3 has been the accepted standard implemented by many users and used for many years. Light-emitting Diode (LED) technology moves at a rapid pace and, as this lighting source finds wider acceptance, it appears that traditional colour-rendering measurement methods produce inconsistent results. Practical application of various types of LEDs yielded results that challenged conventional thinking regarding colour measurement of light sources. Recent studies have shown that the anatomy and physiology of the human eye is more complex than formerly accepted. Therefore, the development of updated measurement methodology also forces a fresh look at functioning and colour perception of the human eye, especially with regard to LEDs. This paper includes a short description of the history and need for the measurement of colour rendering. Some of the traditional measurement methods are presented and inadequacies are discussed. The latest discoveries regarding the functioning of the human eye and the perception of colour, especially when LEDs are used as light sources, are discussed. The unique properties of LEDs when used in practical applications such as luminaires are highlighted.

Quantum-Dot Light-Emitting Diodes with Nitrogen-Doped Carbon Nanodot Hole Transport and Electronic Energy Transfer Layer.

PubMed

Park, Young Ran; Jeong, Hu Young; Seo, Young Soo; Choi, Won Kook; Hong, Young Joon

2017-04-12

Electroluminescence efficiency is crucial for the application of quantum-dot light-emitting diodes (QD-LEDs) in practical devices. We demonstrate that nitrogen-doped carbon nanodot (N-CD) interlayer improves electrical and luminescent properties of QD-LEDs. The N-CDs were prepared by solution-based bottom up synthesis and were inserted as a hole transport layer (HTL) between other multilayer HTL heterojunction and the red-QD layer. The QD-LEDs with N-CD interlayer represented superior electrical rectification and electroluminescent efficiency than those without the N-CD interlayer. The insertion of N-CD layer was found to provoke the Förster resonance energy transfer (FRET) from N-CD to QD layer, as confirmed by time-integrated and -resolved photoluminescence spectroscopy. Moreover, hole-only devices (HODs) with N-CD interlayer presented high hole transport capability, and ultraviolet photoelectron spectroscopy also revealed that the N-CD interlayer reduced the highest hole barrier height. Thus, more balanced carrier injection with sufficient hole carrier transport feasibly lead to the superior electrical and electroluminescent properties of the QD-LEDs with N-CD interlayer. We further studied effect of N-CD interlayer thickness on electrical and luminescent performances for high-brightness QD-LEDs. The ability of the N-CD interlayer to improve both the electrical and luminescent characteristics of the QD-LEDs would be readily exploited as an emerging photoactive material for high-efficiency optoelectronic devices.

Significant reduction in energy for plant-growth lighting in space using targeted LED lighting and spectral manipulation

NASA Astrophysics Data System (ADS)

Poulet, L.; Massa, G. D.; Morrow, R. C.; Bourget, C. M.; Wheeler, R. M.; Mitchell, C. A.

2014-07-01

Bioregenerative life-support systems involving photoautotrophic organisms will be necessary to sustain long-duration crewed missions at distant space destinations. Since sufficient sunlight will not always be available for plant growth at many space destinations, efficient electric-lighting solutions are greatly needed. The present study demonstrated that targeted plant lighting with light-emitting diodes (LEDs) and optimizing spectral parameters for close-canopy overhead LED lighting allowed the model crop leaf lettuce (Lactuca sativa L. cv. 'Waldmann's Green') to be grown using significantly less electrical energy than using traditional electric-lighting sources. Lettuce stands were grown hydroponically in a growth chamber controlling temperature, relative humidity, and CO2 level. Several red:blue ratios were tested for growth rate during the lag phase of lettuce growth. In addition, start of the exponential growth phase was evaluated. Following establishment of a 95% red + 5% blue spectral balance giving the best growth response, the energy efficiency of a targeted lighting system was compared with that of two total coverage (untargeted) LED lighting systems throughout a crop-production cycle, one using the same proportion of red and blue LEDs and the other using white LEDs. At the end of each cropping cycle, whole-plant fresh and dry mass and leaf area were measured and correlated with the amount of electrical energy (kWh) consumed for crop lighting. Lettuce crops grown with targeted red + blue LED lighting used 50% less energy per unit dry biomass accumulated, and the total coverage white LEDs used 32% less energy per unit dry biomass accumulated than did the total coverage red + blue LEDs. An energy-conversion efficiency of less than 1 kWh/g dry biomass is possible using targeted close-canopy LED lighting with spectral optimization. This project was supported by NASA grant NNX09AL99G.

Visual cueing aids for rotorcraft landings

NASA Technical Reports Server (NTRS)

Johnson, Walter W.; Andre, Anthony D.

1993-01-01

The present study used a rotorcraft simulator to examine descents-to-hover at landing pads with one of three approach lighting configurations. The impact of simulator platform motion upon descents to hover was also examined. The results showed that the configuration with the most useful optical information led to the slowest final approach speeds, and that pilots found this configuration, together with the presence of simulator platform motion, most desirable. The results also showed that platform motion led to higher rates of approach to the landing pad in some cases. Implications of the results for the design of vertiport approach paths are discussed.

Simulation of multicomponent light source for optical-electronic system of color analysis objects

NASA Astrophysics Data System (ADS)

Peretiagin, Vladimir S.; Alekhin, Artem A.; Korotaev, Valery V.

2016-04-01

Development of lighting technology has led to possibility of using LEDs in the specialized devices for outdoor, industrial (decorative and accent) and domestic lighting. In addition, LEDs and devices based on them are widely used for solving particular problems. For example, the LED devices are widely used for lighting of vegetables and fruit (for their sorting or growing), textile products (for the control of its quality), minerals (for their sorting), etc. Causes of active introduction LED technology in different systems, including optical-electronic devices and systems, are a large choice of emission color and LED structure, that defines the spatial, power, thermal and other parameters. Furthermore, multi-element and color devices of lighting with adjustable illumination properties can be designed and implemented by using LEDs. However, devices based on LEDs require more attention if you want to provide a certain nature of the energy or color distribution at all the work area (area of analysis or observation) or surface of the object. This paper is proposed a method of theoretical modeling of the lighting devices. The authors present the models of RGB multicomponent light source applied to optical-electronic system for the color analysis of mineral objects. The possibility of formation the uniform and homogeneous on energy and color illumination of the work area for this system is presented. Also authors showed how parameters and characteristics of optical radiation receiver (by optical-electronic system) affect on the energy, spatial, spectral and colorimetric properties of a multicomponent light source.

A Systematic Inventory of Motives for Becoming an Orchestra Conductor: A Preliminary Study

ERIC Educational Resources Information Center

Makris, Ioannis; Mullet, Etienne

2009-01-01

The study examined the various motives (reasons) that may have led an individual to become an orchestra conductor interpreting classical works, using Apter's (2001) Metamotivational Theory framework. Questionnaires derived from the theory, consisting of 92 possible motives for becoming an orchestra conductor, were presented to 101 orchestra…

Are We Facing an Epidemic of Self-Injury?

ERIC Educational Resources Information Center

Brumberg, Joan Jacobs

2006-01-01

This article discusses two Cornell research studies on the prevalence of self-injury or "cutting" in today's youth, led by Janis Whitlock, and presents historical perspectives on the issue. The first study randomly surveyed 3,069 undergraduate and graduate students at Cornell University and Princeton University. Data showed that 17 percent of the…

Auditing and Evaluating University-Community Engagement: Lessons from a UK Case Study

ERIC Educational Resources Information Center

Hart, Angie; Northmore, Simon

2011-01-01

The growing importance of community and public engagement activities in universities has led to an increasing emphasis on auditing and evaluating university-community partnerships. However, the development of effective audit and evaluation tools is still at a formative stage. This article presents a case study of the University of Brighton's…

A new contribution to the study of 22 trisomy.

PubMed

Pérez-Castillo, A; Abrisqueta, J A; Martin-Lucas, M A; Goday, C; Del Mazo, J; Aller, V

1975-09-20

The case of a 2 1/2-month-old male child with intrauterine distrophy features and multiple congenital malformations is presented. Cytogenetic studies of the child and his parents, completed with Q- and G-banding techniques led us to conclude that it is a case of 22 trisomy inherited from his mother.

School Type and Academic Culture: Evidence for the Differentiation-Polarization Theory

ERIC Educational Resources Information Center

Van Houtte, Mieke

2006-01-01

Several decades ago it was shown that the differentiation of pupils into tracks and streams led to a polarization into "anti-school" and "pro-school" cultures. Support for this differentiation-polarization theory is mainly based on case studies. This paper presents findings of a quantitative study in Belgium (Flanders).…

Coronado and Aesop: Fable and Violence on the Sixteenth-Century Plains

ERIC Educational Resources Information Center

Palmer, Daryl W.

2009-01-01

In the spring of 1540, Francisco Vazquez de Coronado led an "entrada" from present-day Mexico into the region we call New Mexico, where the expedition spent a violent winter among pueblo peoples. The following year, after a long march across the Great Plains, Coronado led an elite group of his men north into present-day Kansas where,…

Polymer dispensing and embossing technology for the lens type LED packaging

NASA Astrophysics Data System (ADS)

Chien, Chien-Lin Chang; Huang, Yu-Che; Hu, Syue-Fong; Chang, Chung-Min; Yip, Ming-Chuen; Fang, Weileun

2013-06-01

This study presents a ring-type micro-structure design on the substrate and its corresponding micro fabrication processes for a lens-type light-emitting diode (LED) package. The dome-type or crater-type silicone lenses are achieved by a dispensing and embossing process rather than a molding process. Silicone with a high viscosity and thixotropy index is used as the encapsulant material. The ring-type micro structure is adopted to confine the dispensed silicone encapsulant so as to form the packaged lens. With the architecture and process described, this LED package technology herein has three merits: (1) the flexibility of lens-type LED package designs is enhanced; (2) a dome-type package design is used to enhance the intensity; (3) a crater-type package design is used to enhance the view angle. Measurement results show the ratio between the lens height and lens radius can vary from 0.4 to 1 by changing the volume of dispensed silicone. The view angles of dome-type and crater-type packages can reach 155° ± 5° and 175° ± 5°, respectively. As compared with the commercial plastic leaded chip carrier-type package, the luminous flux of a monochromatic blue light LED is improved by 15% by the dome-type package (improved by 7% by the crater-type package) and the luminous flux of a white light LED is improved by 25% by the dome-type package (improved by 13% by the crater-type package). The luminous flux of monochromatic blue light LED and white light LED are respectively improved by 8% and 12% by the dome-type package as compare with the crater-type package.

Clinician-led, peer-led, and internet-delivered dissonance-based eating disorder prevention programs: Acute effectiveness of these delivery modalities.

PubMed

Stice, Eric; Rohde, Paul; Shaw, Heather; Gau, Jeff M

2017-09-01

Because independent trials have provided evidence for the efficacy and effectiveness of the dissonance-based Body Project eating disorder prevention program, the present trial tested whether clinicians produce the largest intervention effects, or whether delivery can be task-shifted to less expensive undergraduate peer educators or to Internet delivery without effect size attenuation, focusing on acute effects. In this study, 680 young women (M age = 22.2 years, SD = 7.1) recruited at colleges in 2 states were randomized to clinician-led Body Project groups, peer-led Body Project groups, the Internet-based eBody Project, or an educational video control condition. Participants in all 3 variants of the Body Project intervention showed significantly greater reductions in eating disorder risk factors and symptoms than did educational video controls. Participants in clinician-led and peer-led Body Project groups showed significantly greater reductions in risk factors than did eBody Project participants, but effects for the 2 types of groups were similar. Eating disorder onset over 7-month follow-up was significantly lower for peer-led Body Project group participants versus eBody Project participants (2.2% vs. 8.4%) but did not differ significantly between other conditions. The evidence that all 3 dissonance-based prevention programs outperformed an educational video condition, that both group-based interventions outperformed the Internet-based intervention in risk factor reductions, and that the peer-led groups showed lower eating disorder onset over follow-up than did the Internet-based intervention is novel. These acute-effects data suggest that both group-based interventions produce superior eating disorder prevention effects than does the Internet-based intervention and that delivery can be task-shifted to peer leaders. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Effects of the led therapy on the global DNA methylation and the expression of Dnmt1 and Dnmt3a genes in a rat model of skin wound healing.

PubMed

Gomes, Marcus Vinícius de Matos; Manfredo, Marcelo Henrique; Toffoli, Leandro Vaz; Castro-Alves, Daniellen Christine; do Nascimento, Lucas Magnoni; da Silva, Wyllian Rafael; Kashimoto, Roberto Kiyoshi; Rodrigues, Gelson Marcos; Estrada, Viviane Batista; Andraus, Rodrigo Antonio; Pelosi, Gislaine Garcia

2016-09-01

The use of light emitting diodes (LED) as a therapeutic resource for wound healing has increased over the last years; however, little is still known about the molecular pathways associated to LED exposure. In the present study, we verified the effects of LED therapy on DNA methylation and expression of the DNA methyltransferase (Dnmt) genes, Dnmt1 and Dnmt3a, in an in vivo model of epithelial wound healing. Male Wistar rats were submitted to epithelial excision in the dorsal region and subsequently distributed within the experimental groups: group 1, animals that received irradiation of 0.8 J/cm(2) of LED (604 nm); group 2, animals that received 1.6 J/cm(2) of LED (604 nm); control (CTL), animals not submitted to therapeutic intervention. LED applications were performed during 7 days, and tissues from the periphery of the wound area were obtained for molecular analysis. The Image-J software was used for analysis of the wound area. DNA methylation was evaluated by ELISA-based method and gene expressions were quantified by real-time PCR. Decrease on global DNA methylation profile was observed in all experimental groups (CTL, 1, and 2) revealing the participation of DNA methylation in the healing process. Significant decrease in the wound area accompanied by increase in the Dnmt3a expression was associated to group 2. Based on our findings, we propose that DNA methylation is an important molecular mechanism associated to wound healing and that irradiation with 1.6 J/cm(2) of LED evokes an increase in the expression of the Dnmt3a that might associates to the efficiency of the epithelial wound healing.

Pharmacist-led discharge medication counselling: A scoping review.

PubMed

Bonetti, Aline F; Reis, Wálleri C; Lombardi, Natália Fracaro; Mendes, Antonio M; Netto, Harli Pasquini; Rotta, Inajara; Fernandez-Llimos, Fernando; Pontarolo, Roberto

2018-06-01

Discharge medication counselling has produced improved quality of care and health outcomes, especially by reducing medication errors and readmission rates, and improving medication adherence. However, no studies have assembled an evidence-based discharge counselling process for clinical pharmacists. Thus, the present study aims to map the components of the pharmacist-led discharge medication counselling process. We performed a scoping review by searching electronic databases (Pubmed, Scopus, and DOAJ) and conducting a manual search to identify studies published up to July 2017. Studies that addressed pharmacist-led discharge medication counselling, regardless of the population, clinical conditions, and outcomes evaluated, were included. A total of 1563 studies were retrieved, with 75 matching the inclusion criteria. Thirty-two different components were identified, and the most prevalent were the indication of the medications and adverse drug reactions, which were reported in more than 50% of the studies. The components were reported similarly by studies from the USA and the rest of the world, and over the years. However, 2 differences were identified: the use of a dosage schedule, which was more frequent in studies published in 2011 or before and in studies outside the USA; and the teach-back technique, which was used more frequently in the USA. Poor quality reporting was also observed, especially regarding the duration of the counselling, the number of patients, and the medical condition. Mapping the components of the pharmacist-led discharge counselling studies through a scoping review allowed us to reveal how this service is performed around the world. Wide variability in this process and poor reporting were identified. Future studies are needed to define the core outcome set of this clinical pharmacy service to allow the generation of robust evidence and reproducibility in clinical practice. © 2018 John Wiley & Sons, Ltd.

Protein Sequestration of Lipophilic Furanocoumarins in Grapefruit Juice

USDA-ARS?s Scientific Manuscript database

Our previous discoveries of grapefruit furanocoumarin binding to edible fungi led us to investigate the possible roles of dietary factors in this binding phenomenon. In this present study sequestration of grapefruit furanocoumarins by foods was investigated by characterizing the binding between thes...

A Needs-led Framework for Understanding the Impact of Caring for a Family Member With Dementia.

PubMed

Pini, Simon; Ingleson, Emma; Megson, Molly; Clare, Linda; Wright, Penny; Oyebode, Jan R

2018-03-19

Approximately half the care for people with dementia is provided by families. It is therefore imperative that research informs ways of maintaining such care. In this study, we propose that a needs-led approach can provide a useful, novel means of conceptualizing the impact of caring on the lives of family carers. Our aim was to develop and present a needs-led framework for understanding how providing care impacts on carers' fulfilment of needs. In this qualitative study, we conducted 42 semistructured interviews with a purposively diverse sample of family carers to generate nuanced contextualized accounts of how caring impacted on carers' lives. Our inductive thematic analysis focused upon asking: "What need is being impacted here?" in order to generate a needs-led framework for understanding. Nine themes were widely endorsed. Each completed the sentence: "Being a carer impacts on fulfilling my need to/for….": Freedom; feel close to my relative; feel in control of my life; be my own person; protect my relative; share/express my thoughts and feelings; take care of myself; feel connected to the people around me; get things done. These needs echo those from other research areas, with relational needs emerging as particularly central. The needs-led approach offers a perspective that is able to capture both stresses and positive aspects of caregiving. We recommend that clinical interviewing using Socratic questioning to discover human needs that are being impacted by caring would provide a valuable starting point for care planning.

Active play opportunities at child care.

PubMed

Tandon, Pooja S; Saelens, Brian E; Christakis, Dimitri A

2015-06-01

Physical activity (PA) is important for children's health and development, yet preschoolers are not meeting PA recommendations. The objective of this study was to examine different PA opportunities at child care and how variation in indoor versus outdoor and free versus teacher-led opportunities relate to children's PA. An observational study of 98 children (mean age 4.5 years, 49% girls) from 10 child care centers. Classrooms were observed for at least 4 full days per center (total 50 days) to categorize time into (1) not an active play opportunity (APO); (2) naptime; (3) APO, outdoor free play; (4) APO, outdoor teacher-led; (5) APO, indoor free play; and (6) APO, indoor teacher-led. Children wore accelerometers during observations. Linear regression models examined the influence of APO categories on moderate-vigorous physical activity (MVPA) and sedentary time. Children's activity was 73% sedentary, 13% light, and 14% MVPA. For 88% of time children did not have APOs, including 26% time as naptime. On average, 48 minutes per day were APOs (41% sedentary, 18% light, and 41% MVPA), 33 minutes per day were outdoors. The most frequent APO was outdoor free play (8% of time); outdoor teacher-led time was <1%. Children were more active and less sedentary outdoors versus indoors and during the child-initiated APOs (indoors and outdoors) versus teacher-led APOs. Preschoolers were presented with significantly fewer than recommended opportunities for PA at child care. More APOs are needed for children to meet recommendations, particularly those that encourage more outdoor time, more teacher-led and child-initiated active play, and flexibility in naptime for preschoolers. Copyright © 2015 by the American Academy of Pediatrics.

Comparative performance analysis of shunt and series passive filter for LED lamp

NASA Astrophysics Data System (ADS)

Sarwono, Edi; Facta, Mochammad; Handoko, Susatyo

2018-03-01

Light Emitting Diode lamp or LED lamp nowadays is widely used by consumers as a new innovation in the lighting technologies due to its energy saving for low power consumption lamps for brighter light intensity. How ever, the LED lamp produce an electric pollutant known as harmonics. The harmonics is generated by rectifier as part of LED lamp circuit. The present of harmonics in current or voltage has made the source waveform from the grid is distorted. This distortion may cause inacurrate measurement, mall function, and excessive heating for any element at the grid. This paper present an analysis work of shunt and series filters to suppress the harmonics generated by the LED lamp circuit. The work was initiated by conducting several tests to investigate the harmonic content of voltage and currents. The measurements in this work were carried out by using HIOKI Power Quality Analyzer 3197. The measurement results showed that the harmonics current of tested LED lamps were above the limit of IEEE standard 519-2014. Based on the measurement results shunt and series filters were constructed as low pass filters. The bode analysis were appled during construction and prediction of the filters performance. Based on experimental results, the application of shunt filter at input side of LED lamp has reduced THD current up to 88%. On the other hand, the series filter has significantly reduced THD current up to 92%.

Energy efficient LED layout optimization for near-uniform illumination

NASA Astrophysics Data System (ADS)

Ali, Ramy E.; Elgala, Hany

2016-09-01

In this paper, we consider the problem of designing energy efficient light emitting diodes (LEDs) layout while satisfying the illumination constraints. Towards this objective, we present a simple approach to the illumination design problem based on the concept of the virtual LED. We formulate a constrained optimization problem for minimizing the power consumption while maintaining a near-uniform illumination throughout the room. By solving the resulting constrained linear program, we obtain the number of required LEDs and the optimal output luminous intensities that achieve the desired illumination constraints.

Efficient calculation of luminance variation of a luminaire that uses LED light sources

NASA Astrophysics Data System (ADS)

Goldstein, Peter

2007-09-01

Many luminaires have an array of LEDs that illuminate a lenslet-array diffuser in order to create the appearance of a single, extended source with a smooth luminance distribution. Designing such a system is challenging because luminance calculations for a lenslet array generally involve tracing millions of rays per LED, which is computationally intensive and time-consuming. This paper presents a technique for calculating an on-axis luminance distribution by tracing only one ray per LED per lenslet. A multiple-LED system is simulated with this method, and with Monte Carlo ray-tracing software for comparison. Accuracy improves, and computation time decreases by at least five orders of magnitude with this technique, which has applications in LED-based signage, displays, and general illumination.

Design, development, testing and validation of a Photonics Virtual Laboratory for the study of LEDs

NASA Astrophysics Data System (ADS)

Naranjo, Francisco L.; Martínez, Guadalupe; Pérez, Ángel L.; Pardo, Pedro J.

2014-07-01

This work presents the design, development, testing and validation of a Photonic Virtual Laboratory, highlighting the study of LEDs. The study was conducted from a conceptual, experimental and didactic standpoint, using e-learning and m-learning platforms. Specifically, teaching tools that help ensure that our students perform significant learning have been developed. It has been brought together the scientific aspect, such as the study of LEDs, with techniques of generation and transfer of knowledge through the selection, hierarchization and structuring of information using concept maps. For the validation of the didactic materials developed, it has been used procedures with various assessment tools for the collection and processing of data, applied in the context of an experimental design. Additionally, it was performed a statistical analysis to determine the validity of the materials developed. The assessment has been designed to validate the contributions of the new materials developed over the traditional method of teaching, and to quantify the learning achieved by students, in order to draw conclusions that serve as a reference for its application in the teaching and learning processes, and comprehensively validate the work carried out.

Fuselage mounted anti-collision lights utilizing high power LEDs

NASA Astrophysics Data System (ADS)

Lundberg, John; Machi, Nicolo; Mangum, Scott; Singer, Jeffrey

2005-09-01

As LEDs continue to improve in efficacy and total light output, they are increasingly finding their way in to new applications in the aviation industry as well as adjacent markets. One function that is particularly challenging and may reap substantial benefits from this new technology is the fuselage mounted anti-collision light. Anti-collision lights provide conspicuity for the aircraft by periodically emitting bright flashes of light. The color, light distribution and intensity levels for these lights are all closely regulated through Federal Aviation Regulation (FAR) documents. These lighting requirements, along with thermal, environmental and aerodynamic requirements, drive the overall design. In this paper, we will discuss the existing technologies used in anti-collision lights and the advantages and challenges associated with an LED solution. Particular attention will be given to the optical, thermal, electrical and aerodynamic aspects associated with an LED approach. A specific case study will be presented along with some of the challenges that have arisen during the design process. These challenges include the addition of an integrated covert anti-collision lighting.

High-aggregate-capacity visible light communication links using stacked multimode polymer waveguides and micro-pixelated LED arrays

NASA Astrophysics Data System (ADS)

Bamiedakis, N.; McKendry, J. J. D.; Xie, E.; Gu, E.; Dawson, M. D.; Penty, R. V.; White, I. H.

2018-02-01

In recent years, light emitting diodes (LEDs) have gained renewed interest for use in visible light communication links (VLC) owing to their potential use as both high-quality power-efficient illumination sources as well as low-cost optical transmitters in free-space and guided-wave links. Applications that can benefit from their use include optical wireless systems (LiFi and Internet of Things), in-home and automotive networks, optical USBs and short-reach low-cost optical interconnects. However, VLC links suffer from the limited LED bandwidth (typically 100 MHz). As a result, a combination of novel LED devices, advanced modulation formats and multiplexing methods are employed to overcome this limitation and achieve high-speed (>1 Gb/s) data transmission over such links. In this work, we present recent advances in the formation of high-aggregate-capacity low cost guided wave VLC links using stacked polymer multimode waveguides and matching micro-pixelated LED (μLED) arrays. μLEDs have been shown to exhibit larger bandwidths (>200 MHz) than conventional broad-area LEDs and can be formed in large array configurations, while multimode polymer waveguides enable the formation of low-cost optical links onto standard PCBs. Here, three- and four-layered stacks of multimode waveguides, as well as matching GaN μLED arrays, are fabricated in order to generate high-density yet low-cost optical interconnects. Different waveguide topologies are implemented and are investigated in terms of loss and crosstalk performance. The initial results presented herein demonstrate good intrinsic crosstalk performance and indicate the potential to achieve >= 0.5 Tb/s/mm2 aggregate interconnection capacity using this low-cost technology.

The Impact of Semantic Impairment on Verbal Short-Term Memory in Stroke Aphasia and Semantic Dementia: A Comparative Study

ERIC Educational Resources Information Center

Jefferies, Elizabeth; Hoffman, Paul; Jones, Roy; Lambon Ralph, Matthew A.

2008-01-01

This study presents the first direct comparison of immediate serial recall in semantic dementia (SD) and transcortical sensory aphasia (TSA). Previous studies of the effect of semantic impairment on verbal short-term memory (STM) have led to important theoretical advances. However, different conclusions have been drawn from these two groups. This…

Effectiveness of nurse-led cardiac clinics in adult patients with a diagnosis of coronary heart disease.

PubMed

Page, Tamara; Lockwood, Craig; Conroy-Hiller, Tiffany

2005-02-01

Background  Coronary heart disease is the major cause of illness and death in Western countries and this is likely to increase as the average age of the population rises. Consumers with established coronary heart disease are at the highest risk of experiencing further coronary events. Lifestyle measures can contribute significantly to a reduction in cardiovascular mortality in established coronary heart disease. Improved management of cardiac risk factors by providing education and referrals as required has been suggested as one way of maintaining quality care in patients with established coronary heart disease. There is a need to ascertain whether or not nurse-led clinics would be an effective adjunct for patients with coronary heart disease to supplement general practitioner advice and care. Objectives  The objective of this review was to present the best available evidence related to nurse-led cardiac clinics. Inclusion criteria  This review considered any randomised controlled trials that evaluated cardiac nurse-led clinics. In the absence of randomised controlled trials, other research designs such as non-randomised controlled trials and before and after studies were considered for inclusion. Participants were adults (18 years and older) with new or existing coronary heart disease. The interventions of interest to the review included education, assessment, consultation, referral and administrative structures. Outcomes measured included adverse event rates, readmissions, admissions, clinical and cost effectiveness, consumer satisfaction and compliance with therapy. Results  Based on the search terms used, 80 papers were initially identified and reviewed for inclusion; full reports of 24 of these papers were retrieved. There were no papers included that addressed cost effectiveness or adverse events; and none addressed the outcome of referrals. A critical appraisal of the 24 remaining papers identified a total of six randomised controlled trials that met the inclusion criteria. Two studies addressed nurse-led clinics for patients diagnosed with angina, one looked at medication administration and the other looked at educational plans. A further four studies compared secondary preventative care with a nurse-led clinic and general practitioner clinic. One specifically compared usual care versus shared care introduced by nurses for patients awaiting coronary artery bypass grafting. Of the remaining three studies, two have been combined in the results section, as they are an interim report and a final report of the same study. Because of inconsistencies in reporting styles and outcome measurements, meta-analysis could not be performed on all outcomes. However, a narrative summary of each study and comparisons of specific outcomes assessed from within each study has been developed. Although not all outcomes obtained statistical significance, nurse-led clinics were at least as effective as general practitioner clinics for most outcomes. Recommendations  The following recommendations are made: • The use of nurse-led clinics is recommended for patients with coronary heart disease (Level II). • Utilise nurse-led clinics to increase clinic attendance and follow-up rates (Level II). • Nurse-led clinics are recommended for patients who require lifestyle changes to decrease their risk of adverse outcomes associated with coronary heart disease (Level II).

Prevention of bloodstream infections by photodynamic inactivation of multiresistant Pseudomonas aeruginosa in burn wounds

NASA Astrophysics Data System (ADS)

Hashimoto, M. C. E.; Prates, R. A.; Toffoli, D. J.; Courrol, L. C.; Ribeiro, M. S.

2010-02-01

Bloodstream infections are potentially life-threatening diseases. They can cause serious secondary infections, and may result in endocarditis, severe sepsis or toxic-shock syndrome. Pseudomonas aeruginosa is an opportunistic pathogen and one of the most important etiological factors responsible for nosocomial infections, mainly in immuno-compromissed hosts, characteristic of patients with severe burns. Its multiresistance to antibiotics produces many therapeutic problems, and for this reason, the development of an alternative method to antibiotic therapy is needed. Photodynamic inactivation (PDI) may be an effective and alternative therapeutic option to prevent bloodstream infections in patients with severe burns. In this study we report the use of PDI to prevent bloodstream infections in mice with third-degree burns. Burns were produced on the back of the animals and they were infected with 109 cfu/mL of multi-resistant (MR) P. aeruginosa. Fifteen animals were divided into 3 groups: control, PDT blue and PDT red. PDT was performed thirty minutes after bacterial inoculation using 10μM HB:La+3 and a light-emitting diode (LED) emitting at λ=460nm+/-20nm and a LED emitting at λ=645 nm+/-10nm for 120s. Blood of mice were colected at 7h, 10h, 15h, 18h and 22h pos-infection (p.i.) for bacterial counting. Control group presented 1×104 cfu/mL in bloodstream at 7h p.i. increasing to 1×106 at 22h, while mice PDT-treated did not present any bacteria at 7h; only at 22h p.i. they presented 1×104cfu/mL. These results suggest that HB:La+3 associated to blue LED or red LED is effective to delay and diminish MR P.aeruginosa bloodstream invasion in third-degree-burned mice.

Solid state switch panel. [determination of optimum transducer type for required switches

NASA Technical Reports Server (NTRS)

Beenfeldt, E.

1973-01-01

An intensive study of various forms of transducers was conducted with application towards hermetically sealing the transducer and all electronics. The results of the study indicated that the Hall effect devices and a LED/phototransistor combination were the most practical for this type of application. Therefore, hardware was developed utilizing a magnet/Hall effect transducer for single action switches and LED/phototransistor transducers for rotary multiposition or potentiometer applications. All electronics could be housed in a hermetically sealed compartment. A number of switches were built and models were hermetically sealed to prove the feasibility of this type of fabrication. One of each type of switch was subjected to temperature cycling, vibration, and EMI tests. The results of these tests are presented.

Serendipitous findings while researching oxygen free radicals.

PubMed

Floyd, Robert A

2009-04-15

This review is based on the honor of receiving the Discovery Award from the Society of Free Radical Biology and Medicine. The review is reflective and presents our thinking that led to experiments that yielded novel observations. Critical questioning of our understanding of oxygen free radicals in biomedical problems led us to use and develop more direct and extremely sensitive methods. This included nitrone free radical spin trapping and HPLC-electrochemical detection. This technology led to the pioneering use of salicylate to trap hydroxyl free radicals and show increased flux in ischemia/reperfused brain regions and also to first sensitively detect 8-hydroxyl-2-deoxyguanosine in oxidatively damaged DNA and help assess its role in cancer development. We demonstrated that methylene blue (MB) photoinduces formation of 8-hydroxyguanine in DNA and RNA and discovered that MB sensitively photoinactivates RNA viruses, including HIV and the West Nile virus. Studies in experimental stroke led us serendipitously to discover that alpha-phenyl-tert-butylnitrone (PBN) was neuroprotective if given after the stroke. This led to extensive commercial development of NXY-059, a PBN derivative, for the treatment of stroke. More recently we discovered that PBN nitrones have potent anti-cancer activity and are active in preventing hearing loss caused by acute acoustical trauma.

Wafer bonding process for building MEMS devices

NASA Astrophysics Data System (ADS)

Pabo, Eric F.; Meiler, Josef; Matthias, Thorsten

2014-06-01

The technology for the measurement of colour rendering and colour quality is not new, but many parameters related to this issue are currently changing. A number of standard methods were developed and are used by different specialty areas of the lighting industry. CIE 13.3 has been the accepted standard implemented by many users and used for many years. Light-emitting Diode (LED) technology moves at a rapid pace and, as this lighting source finds wider acceptance, it appears that traditional colour-rendering measurement methods produce inconsistent results. Practical application of various types of LEDs yielded results that challenged conventional thinking regarding colour measurement of light sources. Recent studies have shown that the anatomy and physiology of the human eye is more complex than formerly accepted. Therefore, the development of updated measurement methodology also forces a fresh look at functioning and colour perception of the human eye, especially with regard to LEDs. This paper includes a short description of the history and need for the measurement of colour rendering. Some of the traditional measurement methods are presented and inadequacies are discussed. The latest discoveries regarding the functioning of the human eye and the perception of colour, especially when LEDs are used as light sources, are discussed. The unique properties of LEDs when used in practical applications such as luminaires are highlighted.

Effects of White Leds on Growth and Phytonutrients of Outredgeous Romaine Lettuce When Supplemented with Various Monochromatic Wavelengths

NASA Technical Reports Server (NTRS)

Mickens, Matthew; Skoog, Emilie J.; Barnwell, Payton; Massa, Gioia; Wheeler, Raymond

2017-01-01

Growing plants in space will be an essential part of sustaining astronauts during long-range missions. To drive photosynthesis, light-emitting diodes (LEDs) are becoming superior because of their efficiency, longevity, small size, safety, and wavelength versatility. Isolating the effects of certain wavelengths on plant growth when combined with white light is attracting attention. To optimize crop production/quality in space, this study has aimed to configure novel light recipes for the Advanced Plant Habitat currently aboard the International Space Station (ISS). By using white light as a background to maintain normal growth, the addition of monochromatic wavelengths provides a clearer understanding of how each part of the visible spectrum affects plant growth. By growing Outredgeous lettuce under six treatments of White (W) LEDs, W + blue (B), W+ green (G), W + red (R), W + far red (FR), and RGB + FR LEDs with ratios similar to natural sunlight, this investigation has assessed differences in biomass, morphology, chlorophyll, and the synthesis of key phytonutrients. The potential for Outredgeous to produce anthocyanin, lutein, potassium, magnesium, and iron is paramount to maintaining astronaut health. The crop responses to each treatment have been evaluated and the optimal LED combination for both plant yield and nutrient content will be presented.

Serendipitous Findings While Researching Oxygen Free Radicals

PubMed Central

Floyd, Robert A.

2009-01-01

This review is based on the honor of receiving the Discovery Award from the Society of Free Radical Biology and Medicine. The review is reflective and presents our thinking which led to experiments that yielded novel observations. Critical questioning of our understanding of oxygen free radicals in biomedical problems led us to use and develop more direct and extremely sensitive methods. This included nitrone free radical spin-trapping and HPLC-electrochemical detection. This technology led to the pioneering use of salicylate to trap hydroxyl free radicals and show increased flux in ischemia/reperfused brain regions and to also first sensitively detect 8-hydroxy-droxyguanosine (8-OHdG) in oxidative-damaged DNA and help assess its role in cancer development. We demonstrated that Methylene Blue (MB) photo-induced formation of 8-hydroxy-guanine in DNA and RNA and discovered that MB sensitively photo-inactivated RNA viruses including HIV and the West Nile Virus. Studies in experimental stroke led us to serendipitously discover that α-phenyl-tert-butylnitrone (PBN) was neuroprotective if given after the stroke. This led to extensive commercial development of NXY-059, a PBN derivative, for the treatment of stroke. More recently we discovered that PBN-nitrones have potent anti-cancer activity and are active in preventing hearing loss caused by acute acoustical trauma. PMID:19439210

Peer-led and professional-led group interventions for people with co-occurring disorders: a qualitative study.

PubMed

Pallaveshi, Luljeta; Balachandra, Krishna; Subramanian, Priya; Rudnick, Abraham

2014-05-01

This pilot study evaluated the experience of people with co-occurring disorders (mental illness and addiction) in relation to peer-led and professional-led group interventions. The study used a qualitative (phenomenological) approach to evaluate the experience of a convenience sample of 6 individuals with co-occurring disorders who participated in up to 8 sessions each of both peer-led and professional-led group interventions (with a similar rate of attendance in both groups). The semi-structured interview data were coded and thematically analyzed. We found 5 themes within and across the 2 interventions. In both groups, participants experienced a positive environment and personal growth, and learned, albeit different things. They were more comfortable in the peer-led group and acquired more knowledge and skills in the professional-led group. Offering both peer-led and professional-led group interventions to people with co-occurring disorders may be better than offering either alone.

Gluing silicon with silicone

NASA Astrophysics Data System (ADS)

Abt, I.; Fox, H.; Moshous, B.; Richter, R. H.; Riechmann, K.; Rietz, M.; Riedl, J.; Denis, R. St; Wagner, W.

1998-02-01

Problems and solutions concerning the gluing of silicon detectors are discussed. The R & D work for the HERA- B vertex detector system led to gluing studies with epoxy and silicone-based adhesives used on ceramics and carbon fibre. The HERA- B solution using a silicone glue is presented.

Beyond conventional c-plane GaN-based light emitting diodes: A systematic exploration of LEDs on semi-polar orientations

NASA Astrophysics Data System (ADS)

Monavarian, Morteza

Despite enormous efforts and investments, the efficiency of InGaN-based green and yellow-green light emitters remains relatively low, and that limits progress in developing full color display, laser diodes, and bright light sources for general lighting. The low efficiency of light emitting devices in the green-to-yellow spectral range, also known as the "Green Gap", is considered a global concern in the LED industry. The polar c-plane orientation of GaN, which is the mainstay in the LED industry, suffers from polarization-induced separation of electrons and hole wavefunctions (also known as the "quantum confined Stark effect") and low indium incorporation efficiency that are the two main factors that contribute to the Green Gap phenomenon. One possible approach that holds promise for a new generation of green and yellow light emitting devices with higher efficiency is the deployment of nonpolar and semi-polar crystallographic orientations of GaN to eliminate or mitigate polarization fields. In theory, the use of other GaN planes for light emitters could also enhance the efficiency of indium incorporation compared to c-plane. In this thesis, I present a systematic exploration of the suitable GaN orientation for future lighting technologies. First, in order to lay the groundwork for further studies, it is important to discuss the analysis of processes limiting LED efficiency and some novel designs of active regions to overcome these limitations. Afterwards, the choice of nonpolar orientations as an alternative is discussed. For nonpolar orientation, the (1100)-oriented (mo-plane) structures on patterned Si (112) and freestanding m-GaN are studied. The semi-polar orientations having substantially reduced polarization field are found to be more promising for light-emitting diodes (LEDs) owing to high indium incorporation efficiency predicted by theoretical studies. Thus, the semi-polar orientations are given close attention as alternatives for future LED technology. (Abstract shortened by ProQuest.).

Comparative Field Evaluation of Different Traps for Collecting Adult Phlebotomine Sand Flies (Diptera: Psychodidae) in an Endemic Area of Cutaneous Leishmaniasis in Quintana Roo, Mexico.

PubMed

Rodríguez-Rojas, Jorge J; Arque-Chunga, Wilfredo; Fernández-Salas, Ildefonso; Rebollar-Téllez, Eduardo A

2016-06-01

Phlebotominae are the vectors of Leishmania parasites. It is important to have available surveillance and collection methods for the sand fly vectors. The objectives of the present study were to evaluate and compare traps for the collection of sand fly species and to analyze trap catches along months and transects. Field evaluations over a year were conducted in an endemic area of leishmaniasis in the state of Quintana Roo, Mexico. A randomized-block design was implemented in study area with tropical rainforest vegetation. The study design utilized 4 transects with 11 trap types: 1) Centers for Disease Control and Prevention (CDC) light trap with incandescent bulb (CDC-I), 2) CDC light trap with blue light-emitting diodes (LEDs) (CDC-B), 3) CDC light trap with white LEDs (CDC-W), 4) CDC light trap with red LEDs (CDC-R), 5) CDC light trap with green LEDs (CDC-G), 6) Disney trap, 7) Disney trap with white LEDs, 8) sticky panels, 9) sticky panels with white LEDs, 10) delta-like trap, and 11) delta-like trap with white LEDs. A total of 1,014 specimens of 13 species and 2 genera (Lutzomyia and Brumptomyia) were collected. There were significant differences in the mean number of sand flies caught with the 11 traps; CDC-I was (P  =  0.0000) more effective than the other traps. Other traps exhibited the following results: CDC-W (17.46%), CDC-B (15.68%), CDC-G (14.89%), and CDC-R (14.30%). The relative abundance of different species varied according to trap types used, and the CDC-I trap attracted more specimens of the known vectors of Leishmania spp., such as like Lutzomyia cruciata, Lu. shannoni, and Lu. ovallesi. Disney trap captured more specimens of Lu. olmeca olmeca. Based on abundance and number of species, CDC light traps and Disney traps appeared to be good candidates for use in vector surveillance programs in this endemic area of Mexico.

LEDs as light source: examining quality of acquired images

NASA Astrophysics Data System (ADS)

Bachnak, Rafic; Funtanilla, Jeng; Hernandez, Jose

2004-05-01

Recent advances in technology have made light emitting diodes (LEDs) viable in a number of applications, including vehicle stoplights, traffic lights, machine-vision-inspection, illumination, and street signs. This paper presents the results of comparing images taken by a videoscope using two different light sources. One of the sources is the internal metal halide lamp and the other is a LED placed at the tip of the insertion tube. Images acquired using these two light sources were quantitatively compared using their histogram, intensity profile along a line segment, and edge detection. Also, images were qualitatively compared using image registration and transformation. The gray-level histogram, edge detection, image profile and image registration do not offer conclusive results. The LED light source, however, produces good images for visual inspection by an operator. The paper will present the results and discuss the usefulness and shortcomings of various comparison methods.

Color digital lensless holographic microscopy: laser versus LED illumination.

PubMed

Garcia-Sucerquia, Jorge

2016-08-20

A comparison of the performance of color digital lensless holographic microscopy (CDLHM) as utilized for illumination of RGB lasers or a super-bright white-light LED with a set of spectral filters is presented. As the use of lasers in CDLHM conceals the possibility of having a compact, lightweight, portable, and low cost microscope, and additionally the limited available laser radiation wavelengths limit a real multispectral imaging microscope, here we present the use of super-bright white-light LED and spectral filters for illuminating the sample. The performance of RGB laser-CDLHM and LED-CDLHM is evaluated on imaging a section of the head of a Drosophila melanogaster fly. This comparison shows that there is trade-off between the spatial resolution of the microscope and the light sources utilized, which can be understood with regard to the coherence properties of the illuminating light. Despite the smaller spatial coherence features of LED-CDLHM in comparison with laser-CDLHM, the former shows promise as a portable RGB digital lensless holographic microscope that could be extended to other wavelengths by the use of different spectral filters.

Clinical study on orofacial photonic hydration using phototherapy and biomaterials

NASA Astrophysics Data System (ADS)

Lizarelli, Rosane F. Z.; Grandi, Natália D. P.; Florez, Fernando L. E.; Grecco, Clovis; Lopes, Luciana A.

2015-06-01

Skin hydration is important to prevent aging and dysfunction of orofacial system. Nowadays, it is known that cutaneous system is linked to muscle system, then every dentist need to treat healthy facial skin, as lips, keeping orofacial functions healthy. Thirty-two patients were treated using laser and led therapy single or associated to biomaterials (dermo-cosmetics) searching for the best protocol to promote skin hydration. Using a peace of equipment to measure electric impedance, percentage of water and oil from skin, before and after different treatments were analyzed. Statistic tests using 5% and 0.1% of significance were applied and results showed that light could improve hydration of epidermis layer of facial skin. Considering just light effect, using infrared laser followed by blue led system is more effective to hydration than just blue led system application. Considering dermo-cosmetic and light, the association between both presented the best result.

A nurse led model of chronic disease care - an interim report.

PubMed

Eley, Diann S; Del Mar, Chris B; Patterson, Elizabeth; Synnott, Robyn L; Baker, Peter G; Hegney, Desley

2008-12-01

Chronic condition management in general practice is projected to account for 50% of all consultations by 2051. General practices under present workforce conditions will be unable to meet this demand. Nurse led collaborative care models of chronic disease management have been successful overseas and are proposed as one solution. This article provides an interim report on a prospective randomised trial to investigate the acceptability, cost effectiveness and feasibility of a nurse led model of care for chronic conditions in Australian general practice. A qualitative study focused on the impact of this model of care through the perceptions of practice staff from one urban and one regional practice in Queensland, and one Victorian rural practice. Primary benefits of the collaborative care model focused on increased efficiency and communication between practice staff and patients. The increased degree of patient self responsibility was noted by all and highlights the motivational aspect of chronic disease management.

Broadband radiometric LED measurements

NASA Astrophysics Data System (ADS)

Eppeldauer, G. P.; Cooksey, C. C.; Yoon, H. W.; Hanssen, L. M.; Podobedov, V. B.; Vest, R. E.; Arp, U.; Miller, C. C.

2016-09-01

At present, broadband radiometric LED measurements with uniform and low-uncertainty results are not available. Currently, either complicated and expensive spectral radiometric measurements or broadband photometric LED measurements are used. The broadband photometric measurements are based on the CIE standardized V(λ) function, which cannot be used in the UV range and leads to large errors when blue or red LEDs are measured in its wings, where the realization is always poor. Reference irradiance meters with spectrally constant response and high-intensity LED irradiance sources were developed here to implement the previously suggested broadband radiometric LED measurement procedure [1, 2]. Using a detector with spectrally constant response, the broadband radiometric quantities of any LEDs or LED groups can be simply measured with low uncertainty without using any source standard. The spectral flatness of filtered-Si detectors and low-noise pyroelectric radiometers are compared. Examples are given for integrated irradiance measurement of UV and blue LED sources using the here introduced reference (standard) pyroelectric irradiance meters. For validation, the broadband measured integrated irradiance of several LED-365 sources were compared with the spectrally determined integrated irradiance derived from an FEL spectral irradiance lamp-standard. Integrated responsivity transfer from the reference irradiance meter to transfer standard and field UV irradiance meters is discussed.

Multiwavelength pulse oximetry in the measurement of hemoglobin fractions

NASA Astrophysics Data System (ADS)

Manzke, Bernd; Schwider, Johannes; Lutter, Norbert O.; Engelhardt, Kai; Stork, Wilhelm

1996-04-01

The two wavelength design of the majority of pulse oximeters assumes only two absorbing hemoglobin fractions, oxyhemoglobin (O2Hb), and reduced hemoglobin (HHb) irrespective of the presence of methemoglobin (MetHb) and carboxyhemoglobin (COHb). If MetHb or COHb is present, it contributes to the pulse-added absorbance signal and will be interpreted as either HHb or O2Hb or some combination of the two. In this paper we describe a noninvasive multi-wavelength pulse oximeter measuring O2Hb, HHb, MetHb, and COHb at a specified accuracy of 1.0%. The system was designed with respect to the results of numerical simulations. It consists of 9 laserdiodes (LDs) and 7 light emitting diodes (LEDs), a 16-bit analog-digital converter (ADC) and has a sampling rate of 16 kHz. The laser didoes and LEDs were coupled into multi-mode fibers and led with a liquid lightguide to the finger clip and then the photodiode. It also presents the results of a clinical study, including a setup with a quartz tungsten halogen lamp (with fiber output) and a diode array spectrometer, a standard pulse oximeter and two in-vitro oximeters (radiometer OSM3 and radiometer ABL 520) as references.

System Constraints on Efficacious Teacher Behaviours in School-Based Suicide Prevention Initiatives; A Qualitative Study of Teacher Views and Experiences

ERIC Educational Resources Information Center

McConnellogue, Sheila; Storey, Lesley

2017-01-01

International concern about youth suicide has led to a growing consensus that schools are a potentially important location for suicide prevention efforts. The present study investigated the experiences and perceptions of teachers regarding a role in youth suicide prevention through semi-structured interviews which were analysed using…

Why Some Stay: A Study of Factors Contributing to Persistence in Undergraduate Physics.

ERIC Educational Resources Information Center

Vazquez-Abad, Jesus; Winer, Laura R.; Derome, Jean-Robert

1997-01-01

Relates that concerns about the dropout rate among physics majors at the University of Montreal (Canada) led to a study of student persistence. Indicates that those who dropped out and those who stayed differed in their perceptions of their skills and knowledge, and their confidence in finishing the program. Presents preliminary recommendations.…

Attending and Responding to Student Thinking in Science

ERIC Educational Resources Information Center

Levin, Daniel M.; Grant, Terrence; Hammer, David

2012-01-01

We present a class discussion that took place in the second author's high school biology class. Working from video data that we transcribed, studied, and analyzed closely, we recount how the question "Is air matter?" posed at the beginning of a unit on photosynthesis led to student-driven inquiry and learning. This case study illustrates what we…

Ascent control studies of the 049 and ATP parallel burn solid rocket motor shuttle configurations

NASA Technical Reports Server (NTRS)

Ryan, R. S.; Mowery, D. K.; Hammer, M.; Weisler, A. C.

1972-01-01

The control authority approach is discussed as a major problem of the parallel burn soil shuttle configuration due to the many resulting system impacts regardless of the approach. The major trade studies and their results, which led to the recommendation of an SRB TVC control authority approach are presented.

Do Transmasculine Speakers Present with Gender-Related Voice Problems? Insights from a Participant-Centered Mixed-Methods Study

ERIC Educational Resources Information Center

Azul, David; Arnold, Aron; Neuschaefer-Rube, Christiane

2018-01-01

Purpose: The purpose of this study was to investigate whether there are indications of gender-related voice problems in our transmasculine participants and to analyze how discrepancies between participant self-evaluations and researcher-led examinations can be best negotiated to ensure a participant-centered interpretation. Method: We conducted a…

Value Types in Higher Education--Students' Perspective

ERIC Educational Resources Information Center

Dziewanowska, Katarzyna

2017-01-01

The purpose of the paper is to propose the service-dominant logic in marketing as a framework for analysing the value co-creation process in the higher education sector and present the results of a quantitative study (a survey) conducted among business students from four Polish public universities. The results of the study led to identification of…

A Qualitative Study of Factors Influencing Racial Diversity in Environmental Education: Preliminary Results

Treesearch

Kathy James; Leo H. McAvoy

1992-01-01

This study presents preliminary result interviews with people of color working in environmental education and interpretation throughout the United States. The three primary questions asked were these? (1) What path led each individual to a career in environmental education; (2) How does each individual define environmentalism? and (3) What are the primary issues this...

Critical Incidents of Transnational Student-Teachers in Central Mexico

ERIC Educational Resources Information Center

Serna-Gutiérrez, José Irineo Omar; Mora-Pablo, Irasema

2018-01-01

This study is an exploration of the life-changing decisions and changes which the participants underwent, and which led them to pursue an education in English language teaching (or languages). The foremost objective of this study was to highlight the critical incidents from the past, present, and teaching practice of transnational students in a BA…

Structural, electrical and optical characterization of high brightness phosphor-free white light emitting diodes

NASA Astrophysics Data System (ADS)

Omiya, Hiromasa

Much interest currently exists in GaN and related materials for applications such as light-emitting devices operating in the amber to ultraviolet range. Solid-state lighting (SSL) using these materials is widely being investigated worldwide, especially due to their high-energy efficiency and its impact on environmental issues. A new approach for solid-state lighting uses phosphor-free white light emitting diodes (LEDs) that consist of blue, green, and red quantum wells (QW), all in a single device. This approach leads to improved color rendering, and directionality, compared to the conventional white LEDs that use yellow phosphor on blue or ultraviolet emitters. Improving the brightness of these phosphor-free white LEDs should enhance and accelerate the development of SSL technology. The main objective of the research reported in this dissertation is to provide a comprehensive understanding of the nature of the multiple quantum wells used in phosphor-free white LEDs. This dissertation starts with an introduction to lighting history, the fundamental concepts of nitride semiconductors, and the evolution of LED technology. Two important challenges in LED technology today are metal-semiconductor contacts and internal piezoelectric fields present in quantum well structures. Thus, the main portion of this dissertation consists of three parts dealing with metal-semiconductor interfaces, single quantum well structures, and multiple quantum well devices. Gold-nickel alloys are widely used as contacts to the p-region of LEDs. We have performed a detailed study for its evolution under standard annealing steps. The atomic arrangement of gold at its interface with GaN gives a clear explanation for the improved ohmic contact performance. We next focus on the nature of InGaN QWs. The dynamic response of the QWs was studied with electron holography and time-resolved cathodoluminescence. Establishing the correlation between energy band structure and the light emission spectra elucidated the nature of light emission. Finally, we studied a more complex device, consisting of two red, one green, and two blue emitting quantum wells. A correlation between structural, electrical and optical measurements allows us to understand the dynamic performance of this device. The collective results of this dissertation lead to an improved understanding of the performance of high-brightness, phosphor-free, white LEDs.

Spatial layout optimization design of multi-type LEDs lighting source based on photoelectrothermal coupling theory

NASA Astrophysics Data System (ADS)

Xue, Lingyun; Li, Guang; Chen, Qingguang; Rao, Huanle; Xu, Ping

2018-03-01

Multiple LED-based spectral synthesis technology has been widely used in the fields of solar simulator, color mixing, and artificial lighting of plant factory and so on. Generally, amounts of LEDs are spatially arranged with compact layout to obtain the high power density output. Mutual thermal spreading among LEDs will produce the coupled thermal effect which will additionally increase the junction temperature of LED. Affected by the Photoelectric thermal coupling effect of LED, the spectrum of LED will shift and luminous efficiency will decrease. Correspondingly, the spectral synthesis result will mismatch. Therefore, thermal management of LED spatial layout plays an important role for multi-LEDs light source system. In the paper, the thermal dissipation network topology model considering the mutual thermal spreading effect among the LEDs is proposed for multi-LEDs system with various types of power. The junction temperature increment cased by the thermal coupling has the great relation with the spatial arrangement. To minimize the thermal coupling effect, an optimized method of LED spatial layout for the specific light source structure is presented and analyzed. The results showed that layout of LED with high-power are arranged in the corner and low-power in the center. Finally, according to this method, it is convenient to determine the spatial layout of LEDs in a system having any kind of light source structure, and has the advantages of being universally applicable to facilitate adjustment.

Smart LED lighting for major reductions in power and energy use for plant lighting in space

NASA Astrophysics Data System (ADS)

Poulet, Lucie

Launching or resupplying food, oxygen, and water into space for long-duration, crewed missions to distant destinations, such as Mars, is currently impossible. Bioregenerative life-support systems under development worldwide involving photoautotrophic organisms offer a solution to the food dilemma. However, using traditional Earth-based lighting methods, growth of food crops consumes copious energy, and since sunlight will not always be available at different space destinations, efficient electric lighting solutions are badly needed to reduce the Equivalent System Mass (ESM) of life-support infrastructure to be launched and transported to future space destinations with sustainable human habitats. The scope of the present study was to demonstrate that using LEDs coupled to plant detection, and optimizing spectral and irradiance parameters of LED light, the model crop lettuce (Lactuca sativa L. cv. Waldmann's Green) can be grown with significantly lower electrical energy for plant lighting than using traditional lighting sources. Initial experiments aimed at adapting and troubleshooting a first-generation "smart" plant-detection system coupled to LED arrays resulted in optimizing the detection process for plant position and size to the limits of its current design. Lettuce crops were grown hydroponically in a growth chamber, where temperature, relative humidity, and CO2 level are controlled. Optimal irradiance and red/blue ratio of LED lighting were determined for plant growth during both lag and exponential phases of crop growth. Under optimizing conditions, the efficiency of the automatic detection system was integrated with LED switching and compared to a system in which all LEDs were energized throughout a crop-production cycle. At the end of each cropping cycle, plant fresh and dry weights and leaf area were measured and correlated with the amount of electrical energy (kWh) consumed. Preliminary results indicated that lettuce plants grown under optimizing conditions with red and blue LED lighting required 12 times less energy than with a traditional high-intensity discharge lighting system. This study paves the way for refinement of the smart lighting system and further, major reductions in ESM for space life-support systems and for ground-based controlled-environment agriculture. Project supported by NASA grant number NNX09AL99G.

A modal approach to the prediction of the sound reduction index

NASA Astrophysics Data System (ADS)

Tisseyre, Alain; Courné, Cécile; Buzzy, Thomas; Moulinier, André

2003-04-01

The calculation of the sound reduction index in modal analysis is presented in a general way; different possible approaches are described. These calculations are done in two steps: a vibratory study to determine the transverse displacement of the plate and a study of radiation. The specificity of orthotropic plates is presented. This study led to programming a calculation algorithm. Initial hypotheses are indicated, as well as results obtained for various plates or partitions. Modal analysis calculation results are then compared to the Cremer-Sewell approach results.

A light-emitting diode- (LED-) based absorption sensor for simultaneous detection of carbon monoxide and carbon dioxide

DOE PAGES

Thurmond, Kyle; Loparo, Zachary; Partridge, Jr., William P.; ...

2016-04-18

Here, a sensor was developed for simultaneous measurements of carbon monoxide (CO) and carbon dioxide (CO 2) fluctuations in internal combustion engine exhaust gases. This sensor utilizes low-cost and compact light-emitting diodes (LEDs) that emit in the 3–5 µm wavelength range. An affordable, fast response sensor that can measure these gases has a broad application that can lead to more efficient, fuel-flexible engines and regulation of harmful emissions. Light emission from LEDs is spectrally broader and more spatially divergent when compared to that of lasers, which presented many design challenges. Optical design studies addressed some of the non-ideal characteristics ofmore » the LED emissions. Measurements of CO and CO 2 were conducted using their fundamental absorption bands centered at 4.7 µm and 4.3 µm, respectively, while a 3.6 µm reference LED was used to account for scattering losses (due to soot, window deposits, etc.) common to the three measurement LEDs. Instrument validation and calibration was performed using a laboratory flow cell and bottled-gas mixtures. The sensor was able to detect CO 2 and CO concentration changes as small as 30 ppm and 400 ppm, respectively. Because of the many control and monitor species with infra-red absorption features, which can be measured using the strategy described, this work demonstrates proof of concept for a wider range of fast (250 Hz) and low-cost sensors for gas measurement and process monitoring.« less

The Discourse of the Literacy Hour.

ERIC Educational Resources Information Center

Mroz, Maria; Smith, Fay; Hardman, Frank

2000-01-01

Presents a study in which ten teachers from England were observed teaching literacy skills to primary age children to determine if they were teaching in a manner that provided for class discussion. Finds that teacher-led question and answer sessions were the most frequently used form of interaction. (DAJ)

Conceptualizing Youth Empowerment within Tobacco Control

ERIC Educational Resources Information Center

Holden, Debra J.; Messeri, Peter; Evans, W. Douglas; Crankshaw, Erik; Ben-Davies, Maureen

2004-01-01

This article presents a conceptual framework that was developed to guide a national evaluation of the American Legacy Foundation's (Legacy) Statewide Youth Movement Against Tobacco Use (SYMATU) program. This program was designed to develop youth-led, youth-directed initiatives within local communities. Two evaluation studies were designed and…

Accurate chromatic control and color rendering optimization in LED lighting systems using junction temperature feedback

NASA Astrophysics Data System (ADS)

Sisto, Marco Michele; Gauvin, Jonny

2014-09-01

Accurate color control of LED lighting systems is a challenging task: noticeable chromaticity shifts are commonly observed in mixed-color and phosphor converted LEDs due to intensity dimming. Furthermore, the emitted color varies with the LED temperature. We present a novel color control method for tri-chromatic and tetra-chromatic LEDs, which enable to set and maintain the LED emission at a target color, or combination of correlated color temperature (CCT) and intensity. The LED color point is maintained over variations in the LED junctions' temperatures and intensity dimming levels. The method does not require color feedback sensors, so to minimize system complexity and cost, but relies on estimation of the LED junctions' temperatures from the junction voltages. If operated with tetra-chromatic LEDs, the method allows meeting an additional optimization criterion: for example, the maximization of a color rendering metric like the Color Rendering Index (CRI) or the Color Quality Scale (CQS), thus providing a high quality and clarity of colors on the surface illuminated by the LED. We demonstrate the control of a RGBW LED at target D65 white point with CIELAB color difference metric triangle;a,bE < 1 for simultaneous variations of flux from approximately 30 lm to 100 lm and LED heat sink temperature from 25°C to 58°C. In the same conditions, we demonstrate a CCT error <1%. Furthermore, the method allows varying the LED CCT from 5500K to 8000K while maintaining luminance within 1% of target. Further work is ongoing to evaluate the stability of the method over LED aging.

Comparative studies on dimming capabilities of retrofit LED lamps

NASA Astrophysics Data System (ADS)

Ionescu, Ciprian; Vasile, Alexandru; Codreanu, Norocel; Negroiu, Rodica

2016-12-01

These days many variants for lighting systems are available on the market, and new solutions are about to emerge. Most of the new lamps are offered in form to be retrofitted to existing sockets and luminaires. In this paper, are presented some systematically investigations on different lamps as LEDs, Compact Fluorescent Lamps (CFLs), tungsten, and new available Cold Cathode Fluorescent Lamps (CCFLs), regarding the light level, dimming performances and also the resulting flicker and power distortion performances. The light level was expressed by the illuminance level, measured for all lamps in the same conditions, at the same distance and on the same surface represented by the photometer probe.

[Erythromycin in therapy of cyclic vomiting syndrome].

PubMed

Pavlović, Momcilo; Radlović, Nedeljko; Leković, Zoran; Berenji, Karolina

2007-01-01

Cyclic vomiting syndrome is an insufficiently understood disorder which manifests itself in stereotypical episodes of vomiting with no detectable organic cause. Considering its unknown aetiology, drugs borrowed from various medication classes are applied in the therapy of this disorder, with variable success. Among other medicaments, erythromycin is also used in treatment of cyclic vomiting syndrome. This is a case study in which the application of erythromycin led to the prevention of attacks of cyclic vomiting syndrome. Our case report presents how periodical erythromycin therapy in two-week intervals at expected attack periods in a girl led to disappearance of cyclic vomiting. Adverse effects of erythromycin did not show up.

Analysis of LED arrangement in an array with respect to lens geometry

NASA Astrophysics Data System (ADS)

Ley, Peer-Phillip; Held, Marcel Philipp; Lachmayer, Roland

2018-02-01

Highly adaptive light sources such as LED arrays have been surpassing conventional light sources (halogen, xenon) for automotive applications. Individual LED arrangements within the array, high durability and low energy consumption of the LEDs are some of the reasons. With the introduction of Audi's Matrix beam system, efforts to increase the quantity of pixels were already underway and the stage was practically set for pixel light systems. Current efforts are focused towards the exploration of an optimal LED array density and the use of spatial light modulators. In both cases, one question remains - What arrangement of LEDs is the most suitable in terms of light output efficiency for a given lens geometry? The radiation characteristics of an LED usually shows a Lambertian pattern. Following from the definition of luminous efficacy, this characteristic property of LEDs has a decisive impact on the lens geometry in a given array. Due to the proportional correlation between the lens diameter and the distance of LEDs emission surface to the lens surface. Assuming a constant viewing angle an increase of the distance leads to an increase of the lens diameter. In this paper, two different approaches for an optimized LED array with regards to the LED arrangement will be presented. The introduced designs result from one imaging and one non-imaging optical system, which will be investigated. The paper is concluded with a comparative analysis of the LED array design as a function of the LED pitch and the luminous efficacy.

Assessment of students' satisfaction with a student-led team-based learning course.

PubMed

Bouw, Justin W; Gupta, Vasudha; Hincapie, Ana L

2015-01-01

To date, no studies in the literature have examined student delivery of team-based learning (TBL) modules in the classroom. We aimed to assess student perceptions of a student-led TBL elective. Third-year pharmacy students were assigned topics in teams and developed learning objectives, a 15-minute mini-lecture, and a TBL application exercise and presented them to student colleagues. Students completed a survey upon completion of the course and participated in a focus group discussion to share their views on learning. The majority of students (n=23/30) agreed that creating TBL modules enhanced their understanding of concepts, improved their self-directed learning skills (n=26/30), and improved their comprehension of TBL pedagogy (n=27/30). However, 60% disagreed with incorporating student-generated TBL modules into core curricular classes. Focus group data identified student-perceived barriers to success in the elective, in particular the development of TBL application exercises. This study provides evidence that students positively perceived student-led TBL as encouraging proactive learning from peer-to-peer teaching.

A device for multimodal imaging of skin

NASA Astrophysics Data System (ADS)

Spigulis, Janis; Garancis, Valerijs; Rubins, Uldis; Zaharans, Eriks; Zaharans, Janis; Elste, Liene

2013-03-01

A compact prototype device for diagnostic imaging of skin has been developed and tested. Polarized LED light at several spectral regions is used for illumination, and round skin spot of diameter 30mm is imaged by a CMOS sensor via crossoriented polarizing filter. Four consecutive imaging series are performed: (1) RGB image at white LED illumination for revealing subcutaneous structures; (2) four spectral images at narrowband LED illumination (450nm, 540nm, 660nm, 940nm) for mapping of the main skin chromophores; (3) video-imaging under green LED illumination for mapping of skin blood perfusion; (4) autofluorescence video-imaging under UV (365nm) LED irradiation for mapping of the skin fluorophores. Design details of the device as well as preliminary results of clinical tests are presented.

Accelerated Stress Testing of Multi-Source LED Products: Horticulture Lamps and Tunable-White Modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, Lynn; Rountree, Kelley; Mills, Karmann

This report discusses the use of accelerated stress testing (AST) to provide insights into the long-term behavior of commercial products utilizing different types of mid-power LEDs (MP-LEDs) integrated into the same LED module. Test results are presented from two commercial lamps intended for use in horticulture applications and one tunable-white LED module intended for use in educational and office lighting applications. Each of these products is designed to provide a custom spectrum for their targeted applications and each achieves this goal in different ways. Consequently, a comparison of the long-term stability of these devices will provide insights regarding approaches thatmore » could be used to possibly lengthen the lifetime of SSL products.« less

Current crowding and self-heating effects in AlGaN-based flip-chip deep-ultraviolet light-emitting diodes

NASA Astrophysics Data System (ADS)

Hao, Guo-Dong; Taniguchi, Manabu; Tamari, Naoki; Inoue, Shin-ichiro

2018-01-01

We thoroughly explored the physical origin of the efficiency decrease with increasing injection current and current crowding effect in 280 nm AlGaN-based flip-chip deep-ultraviolet (DUV) light-emitting diodes (LEDs). The current spreading length was experimentally determined to be much smaller in DUV LEDs than that in conventional InGaN-based visible LEDs. The severe self-heating caused by the low power conversion efficiency of DUV LEDs should be mainly responsible for the considerable decrease of efficiency when current crowding is present. The wall-plug efficiency of the DUV LEDs was markedly enhanced by using a well-designed p-electrode pattern to improve the current distribution.

A Needs-led Framework for Understanding the Impact of Caring for a Family Member With Dementia

PubMed Central

Pini, Simon; Ingleson, Emma; Megson, Molly; Wright, Penny; Oyebode, Jan R

2018-01-01

Abstract Background and Objectives Approximately half the care for people with dementia is provided by families. It is therefore imperative that research informs ways of maintaining such care. In this study, we propose that a needs-led approach can provide a useful, novel means of conceptualizing the impact of caring on the lives of family carers. Our aim was to develop and present a needs-led framework for understanding how providing care impacts on carers’ fulfilment of needs. Design and Methods In this qualitative study, we conducted 42 semistructured interviews with a purposively diverse sample of family carers to generate nuanced contextualized accounts of how caring impacted on carers’ lives. Our inductive thematic analysis focused upon asking: “What need is being impacted here?” in order to generate a needs-led framework for understanding. Results Nine themes were widely endorsed. Each completed the sentence: “Being a carer impacts on fulfilling my need to/for….”: Freedom; feel close to my relative; feel in control of my life; be my own person; protect my relative; share/express my thoughts and feelings; take care of myself; feel connected to the people around me; get things done. Discussion and Implications These needs echo those from other research areas, with relational needs emerging as particularly central. The needs-led approach offers a perspective that is able to capture both stresses and positive aspects of caregiving. We recommend that clinical interviewing using Socratic questioning to discover human needs that are being impacted by caring would provide a valuable starting point for care planning. PMID:29562360

Solution processable inverted structure ZnO-organic hybrid heterojuction white LEDs

NASA Astrophysics Data System (ADS)

Bano, N.; Hussain, I.; Soomro, M. Y.; EL-Naggar, A. M.; Albassam, A. A.

2018-05-01

Improving luminance efficiency and colour purity are the most important challenges for zinc oxide (ZnO)-organic hybrid heterojunction light emitting diodes (LEDs), affecting their large area applications. If ZnO-organic hybrid heterojunction white LEDs are fabricated by a hydrothermal method, it is difficult to obtain pure and stable blue emission from PFO due to the presence of an undesirable green emission. In this paper, we present an inverted-structure ZnO-organic hybrid heterojunction LED to avoid green emission from PFO, which mainly originates during device processing. With this configuration, each ZnO nanorod (NR) forms a discrete p-n junction; therefore, large-area white LEDs can be designed without compromising the junction area. The configuration used for this novel structure is glass/ZnO NRs/PFO/PEDOT:PSS/L-ITO, which enables the development of efficient, large-area and low-cost hybrid heterojunction LEDs. Inverted-structure ZnO-organic hybrid heterojunction white LEDs offer several improvements in terms of brightness, size, colour, external quantum efficiency and a wider applicability as compared to normal architecture LEDs.

A new approach to preparation of standard LEDs for luminous intensity and flux measurement of LEDs

NASA Astrophysics Data System (ADS)

Park, Seung-Nam; Park, Seongchong; Lee, Dong-Hoon

2006-09-01

This work presents an alternative approach for preparing photometric standard LEDs, which is based on a novel functional seasoning method. The main idea of our seasoning method is simultaneously monitoring the light output and the junction voltage to obtain quantitative information on the temperature dependence and the aging effect of the LED emission. We suggested a general model describing the seasoning process by taking junction temperature variation and aging effect into account and implemented a fully automated seasoning facility, which is capable of seasoning 12 LEDs at the same time. By independent measurements of the temperature dependence, we confirmed the discrepancy of the theoretical model to be less than 0.5 % and evaluate the uncertainty contribution of the functional seasoning to be less than 0.5 % for all the seasoned samples. To demonstrate assigning the reference value to a standard LED, the CIE averaged LED intensity (ALI) of the seasoned LEDs was measured with a spectroradiometer-based instrument and the measurement uncertainty was analyzed. The expanded uncertainty of the standard LED prepared by the new approach amounts to be 4 % ~ 5 % (k=2) depending on color without correction of spectral stray light in the spectroradiometer.

Improved Cognitive Function After Transcranial, Light-Emitting Diode Treatments in Chronic, Traumatic Brain Injury: Two Case Reports

PubMed Central

Saltmarche, Anita; Krengel, Maxine H.; Hamblin, Michael R.; Knight, Jeffrey A.

2011-01-01

Abstract Objective: Two chronic, traumatic brain injury (TBI) cases, where cognition improved following treatment with red and near-infrared light-emitting diodes (LEDs), applied transcranially to forehead and scalp areas, are presented. Background: Significant benefits have been reported following application of transcranial, low-level laser therapy (LLLT) to humans with acute stroke and mice with acute TBI. These are the first case reports documenting improved cognitive function in chronic, TBI patients treated with transcranial LED. Methods: Treatments were applied bilaterally and to midline sagittal areas using LED cluster heads [2.1″ diameter, 61 diodes (9 × 633 nm, 52 × 870 nm); 12–15 mW per diode; total power: 500 mW; 22.2 mW/cm2; 13.3 J/cm2 at scalp (estimated 0.4 J/cm2 to cortex)]. Results: Seven years after closed-head TBI from a motor vehicle accident, Patient 1 began transcranial LED treatments. Pre-LED, her ability for sustained attention (computer work) lasted 20 min. After eight weekly LED treatments, her sustained attention time increased to 3 h. The patient performs nightly home treatments (5 years); if she stops treating for more than 2 weeks, she regresses. Patient 2 had a history of closed-head trauma (sports/military, and recent fall), and magnetic resonance imaging showed frontoparietal atrophy. Pre-LED, she was on medical disability for 5 months. After 4 months of nightly LED treatments at home, medical disability discontinued; she returned to working full-time as an executive consultant with an international technology consulting firm. Neuropsychological testing after 9 months of transcranial LED indicated significant improvement (+1, +2SD) in executive function (inhibition, inhibition accuracy) and memory, as well as reduction in post-traumatic stress disorder. If she stops treating for more than 1 week, she regresses. At the time of this report, both patients are continuing treatment. Conclusions: Transcranial LED may improve cognition, reduce costs in TBI treatment, and be applied at home. Controlled studies are warranted. PMID:21182447

LED Lighting – Modification of Growth, Metabolism, Yield and Flour Composition in Wheat by Spectral Quality and Intensity

PubMed Central

Monostori, István; Heilmann, Márk; Kocsy, Gábor; Rakszegi, Marianna; Ahres, Mohamed; Altenbach, Susan B.; Szalai, Gabriella; Pál, Magda; Toldi, Dávid; Simon-Sarkadi, Livia; Harnos, Noémi; Galiba, Gábor; Darko, Éva

2018-01-01

The use of light-emitting diode (LED) technology for plant cultivation under controlled environmental conditions can result in significant reductions in energy consumption. However, there is still a lack of detailed information on the lighting conditions required for optimal growth of different plant species and the effects of light intensity and spectral composition on plant metabolism and nutritional quality. In the present study, wheat plants were grown under six regimens designed to compare the effects of LED and conventional fluorescent lights on growth and development, leaf photosynthesis, thiol and amino acid metabolism as well as grain yield and flour quality of wheat. Benefits of LED light sources over fluorescent lighting were manifested in both yield and quality of wheat. Elevated light intensities made possible with LEDs increased photosynthetic activity, the number of tillers, biomass and yield. At lower light intensities, blue, green and far-red light operated antagonistically during the stem elongation period. High photosynthetic activity was achieved when at least 50% of red light was applied during cultivation. A high proportion of blue light prolonged the juvenile phase, while the shortest flowering time was achieved when the blue to red ratio was around one. Blue and far-red light affected the glutathione- and proline-dependent redox environment in leaves. LEDs, especially in Blue, Pink and Red Low Light (RedLL) regimens improved flour quality by modifying starch and protein content, dough strength and extensibility as demonstrated by the ratios of high to low molecular weight glutenins, ratios of glutenins to gliadins and gluten spread values. These results clearly show that LEDs are efficient for experimental wheat cultivation, and make it possible to optimize the growth conditions and to manipulate metabolism, yield and quality through modification of light quality and quantity. PMID:29780400

LED Lighting - Modification of Growth, Metabolism, Yield and Flour Composition in Wheat by Spectral Quality and Intensity.

PubMed

Monostori, István; Heilmann, Márk; Kocsy, Gábor; Rakszegi, Marianna; Ahres, Mohamed; Altenbach, Susan B; Szalai, Gabriella; Pál, Magda; Toldi, Dávid; Simon-Sarkadi, Livia; Harnos, Noémi; Galiba, Gábor; Darko, Éva

2018-01-01

The use of light-emitting diode (LED) technology for plant cultivation under controlled environmental conditions can result in significant reductions in energy consumption. However, there is still a lack of detailed information on the lighting conditions required for optimal growth of different plant species and the effects of light intensity and spectral composition on plant metabolism and nutritional quality. In the present study, wheat plants were grown under six regimens designed to compare the effects of LED and conventional fluorescent lights on growth and development, leaf photosynthesis, thiol and amino acid metabolism as well as grain yield and flour quality of wheat. Benefits of LED light sources over fluorescent lighting were manifested in both yield and quality of wheat. Elevated light intensities made possible with LEDs increased photosynthetic activity, the number of tillers, biomass and yield. At lower light intensities, blue, green and far-red light operated antagonistically during the stem elongation period. High photosynthetic activity was achieved when at least 50% of red light was applied during cultivation. A high proportion of blue light prolonged the juvenile phase, while the shortest flowering time was achieved when the blue to red ratio was around one. Blue and far-red light affected the glutathione- and proline-dependent redox environment in leaves. LEDs, especially in Blue, Pink and Red Low Light (RedLL) regimens improved flour quality by modifying starch and protein content, dough strength and extensibility as demonstrated by the ratios of high to low molecular weight glutenins, ratios of glutenins to gliadins and gluten spread values. These results clearly show that LEDs are efficient for experimental wheat cultivation, and make it possible to optimize the growth conditions and to manipulate metabolism, yield and quality through modification of light quality and quantity.

A Randomized Trial of Peer-Delivered Self-Management Support for Hypertension

PubMed Central

Schapira, Marilyn M.; Fletcher, Kathlyn E.; Hayes, Avery; Morzinski, Jeffrey; Laud, Purushottam; Eastwood, Dan; Ertl, Kristyn; Patterson, Leslie; Mosack, Katie E.

2014-01-01

BACKGROUND Peer-led interventions to improve chronic disease self-management can improve health outcomes but are not widely used. Therefore, we tested a peer-led hypertension self-management intervention delivered at regular meetings of community veterans’ organizations. METHODS We randomized 58 organizational units (“posts”) of veterans’ organizations in southeast Wisconsin to peer-led vs. professionally delivered self-management education. Volunteer peer leaders at peer-led posts delivered monthly presentations regarding hypertension self-management during regular post meetings. Volunteer post representatives at seminar posts encouraged post members to attend 3 didactic seminars delivered by health professionals at a time separate from the post meeting. Volunteers in both groups encouraged members to self-monitor using blood pressure cuffs, weight scales, and pedometers. Our primary outcome was change in systolic blood pressure (SBP) at 12 months. RESULTS We measured SBP in 404 participants at baseline and in 379 participants at 12 months. SBP decreased significantly (4.4mm Hg; P < 0.0001) overall; the decrease was similar in peer-led and seminar posts (3.5mm Hg vs. 5.4mm Hg; P = 0.24). Among participants with uncontrolled BP at baseline, SBP decreased by 10.1mm Hg from baseline to 12 months but was again similar in the 2 groups. This pattern was also seen at 6 months and with diastolic blood pressure. CONCLUSIONS Our peer-led educational intervention was not more effective than didactic seminars for SBP control. Although peer-led educational programs have had important impacts in a number of studies, we did not find our intervention superior to a similar intervention delivered by healthcare professionals. Clinical trial registration ClinicalTrials.gov NCT00571038. PMID:24755206

The Technical and Performance Characteristics of a Low-Cost, Simply Constructed, Black Light Moth Trap

PubMed Central

White, Peter J. T.; Glover, Katharine; Stewart, Joel; Rice, Amanda

2016-01-01

The universal mercury vapor black light trap is an effective device used for collecting moth specimens in a wide variety of habitats; yet, they can present challenges for researchers. The mercury vapor trap is often powered by a heavy automotive battery making it difficult to conduct extensive surveys in remote regions. The mercury vapor trap also carries a considerable financial cost per trap unit, making trapping challenging with low research budgets. Here, we describe the development and trapping properties of a lighter, simply constructed, and less expensive trap. The LED funnel trap consists of a funnel, soda bottles with plastic vanes, and is powered by rechargeable 9-V batteries. Two strips of low-wavelength LEDs are used as attractants. We tested the trapping parameters of this trap design compared to a standard mercury vapor trap over 10 trap nights in a suburban woodlot in the summer of 2015. The mercury vapor trap caught significantly more moth individuals than the LED trap (average of 78 vs 40 moths per trap night; P < 0.05), and significantly more species than the LED trap (23 vs 15 per trap night; P < 0.05); the mercury vapor trap caught a total of 104 macromoth species over the duration of the study, compared to a total of 87 by the LED trap. Despite the lower yields, the low cost of the LED trap (<$30 ea.) makes it superior to the mercury vapor trap in cost-acquisition per moth species and per moth individual trapped. The LED trap may be a viable alternative to the standard mercury vapor trap, facilitating insect trapping in more diverse settings. PMID:26936923

Cross-Evaluation of Degree Programmes in Higher Education

ERIC Educational Resources Information Center

Kettunen, Juha

2010-01-01

Purpose: This study seeks to develop and describe the benchmarking approach of enhancement-led evaluation in higher education and to present a cross-evaluation process for degree programmes. Design/methodology/approach: The benchmarking approach produces useful information for the development of degree programmes based on self-evaluation,…

Learning from Fellow Engineering Students Who Have Current Professional Experience

ERIC Educational Resources Information Center

Davies, John W.; Rutherford, Ursula

2012-01-01

This paper presents an investigation of how experience-led content in an engineering degree can be strengthened by creating opportunities for engineering students to benefit from the knowledge, skills and resources of students with current professional experience. Students who study civil engineering part-time at Coventry University (while also…

GAS PERMEATION PROPERTIES OF POLY(LACTIC ACID). (R826733)

EPA Science Inventory

Abstract

The need for the development of polymeric materials based on renewable resources has led to the development of poly(lactic acid) (PLA) which is being produced from a feedstock of corn rather than petroleum. The present study examines the permeation of nitrogen...

Einstein Revisited

ERIC Educational Resources Information Center

Fine, Leonard

2005-01-01

A brief description on the work and life of the great physicist scientist Albert Einstein is presented. The photoelectric paper written by him in 1905 led him to the study of fluctuations in the energy density of radiation and from there to the incomplete nature of the equipartition theorem of classical mechanics, which failed to account for…

Critical Experiences for Field Geologists: Emergent Themes in Interest Development

ERIC Educational Resources Information Center

LaDue, Nicole D.; Pacheco, Heather A.

2013-01-01

Geoscience education researchers are working to understand how we can most effectively increase our overall geoscience workforce capacity. The present study employed an inductive approach to explore the critical experiences that led to the persistence of successful field geologists in this STEM field. Interviews with 29 professional field…

Self-Regulation across Different Contexts: Findings in Young Albanian Children

ERIC Educational Resources Information Center

von Suchodoletz, Antje; Uka, Fitim; Larsen, Ross A. A. A.

2015-01-01

Research Findings: The importance of self-regulation for children's successful academic performance has led to greatly increased interest in this topic in recent years. However, less is known about the interrelations among self-regulatory processes across different contexts. The present study investigated the structure of self-regulation in young…

Effects of Distributed Practice on the Proceduralization of Morphology

ERIC Educational Resources Information Center

Suzuki, Yuichi; DeKeyser, Robert

2017-01-01

The present study aimed to examine whether distributed practice works better than massed practice for proceduralization of grammatical knowledge. Learners of Japanese as a second language were trained on an element of Japanese morphology under either massed or distributed practice conditions. Results showed that massed practice led to accurate…

A Brief History of the Resting State: the Washington University Perspective

PubMed Central

Snyder, Abraham Z.; Raichle, Marcus E.

2012-01-01

We present a history of the concepts and developments that have led us to focus on the resting state as an object of study. We then discuss resting state research performed in our laboratory since 2005 with an emphasis on papers of particular interest. PMID:22266172

Mandated Preparation Program Redesign: Kentucky Case

ERIC Educational Resources Information Center

Browne-Ferrigno, Tricia

2013-01-01

This case study presents a chronicle of events spanning a decade in Kentucky that led to state policy changes for principal preparation and details the response to those mandated changes by professors at the University of Kentucky. Professors' collaborative efforts resulted in a new teacher leadership program and redesigned principal certification…

Evaluation of an LED (Light-Emitting Diode) high-mounted signal lamp

NASA Astrophysics Data System (ADS)

Olson, P. L.

1987-02-01

Two studies are described evaluating high-mounted stoplights using light-emitting diodes (LEDs) compared with conventional incandescent units. The first of these studies obtained ratings from subjects who drove one car and followed another car that was equipped with the test lamps. The results indicate that the subjects generally preferred the LEDs to the conventional lamp. The second study was a laboratory evaluation of the attention-getting capabilities of LED and incandescent stoplights. Under all conditions tested subjects responded faster to the LED units. The response time advantage for the LED units increased with more difficult viewing conditions, such as high levels of illumination and long viewing distance. The results of these investigations are discussed in terms of the applicability of the LED technology to high mounted stoplights on motor vehicles.

Broadband Radiometric LED Measurements

PubMed Central

Eppeldauer, G. P.; Cooksey, C. C.; Yoon, H. W.; Hanssen, L. M.; Podobedov, V. B.; Vest, R. E.; Arp, U.; Miller, C. C.

2017-01-01

At present, broadband radiometric measurements of LEDs with uniform and low-uncertainty results are not available. Currently, either complicated and expensive spectral radiometric measurements or broadband photometric LED measurements are used. The broadband photometric measurements are based on the CIE standardized V(λ) function, which cannot be used in the UV range and leads to large errors when blue or red LEDs are measured in its wings, where the realization is always poor. Reference irradiance meters with spectrally constant response and high-intensity LED irradiance sources were developed here to implement the previously suggested broadband radiometric LED measurement procedure [1, 2]. Using a detector with spectrally constant response, the broadband radiometric quantities of any LEDs or LED groups can be simply measured with low uncertainty without using any source standard. The spectral flatness of filtered-Si detectors and low-noise pyroelectric radiometers are compared. Examples are given for integrated irradiance measurement of UV and blue LED sources using the here introduced reference (standard) pyroelectric irradiance meters. For validation, the broadband measured integrated irradiance of several LED-365 sources were compared with the spectrally determined integrated irradiance derived from an FEL spectral irradiance lamp-standard. Integrated responsivity transfer from the reference irradiance meter to transfer standard and field UV irradiance meters is discussed. PMID:28649167

Broadband Radiometric LED Measurements.

PubMed

Eppeldauer, G P; Cooksey, C C; Yoon, H W; Hanssen, L M; Podobedov, V B; Vest, R E; Arp, U; Miller, C C

2016-01-01

At present, broadband radiometric measurements of LEDs with uniform and low-uncertainty results are not available. Currently, either complicated and expensive spectral radiometric measurements or broadband photometric LED measurements are used. The broadband photometric measurements are based on the CIE standardized V(λ) function, which cannot be used in the UV range and leads to large errors when blue or red LEDs are measured in its wings, where the realization is always poor. Reference irradiance meters with spectrally constant response and high-intensity LED irradiance sources were developed here to implement the previously suggested broadband radiometric LED measurement procedure [1, 2]. Using a detector with spectrally constant response, the broadband radiometric quantities of any LEDs or LED groups can be simply measured with low uncertainty without using any source standard. The spectral flatness of filtered-Si detectors and low-noise pyroelectric radiometers are compared. Examples are given for integrated irradiance measurement of UV and blue LED sources using the here introduced reference (standard) pyroelectric irradiance meters. For validation, the broadband measured integrated irradiance of several LED-365 sources were compared with the spectrally determined integrated irradiance derived from an FEL spectral irradiance lamp-standard. Integrated responsivity transfer from the reference irradiance meter to transfer standard and field UV irradiance meters is discussed.

Changes in electrical and thermal parameters of led packages under different current and heating stresses

NASA Astrophysics Data System (ADS)

Jayawardena, Adikaramge Asiri

The goal of this dissertation is to identify electrical and thermal parameters of an LED package that can be used to predict catastrophic failure real-time in an application. Through an experimental study the series electrical resistance and thermal resistance were identified as good indicators of contact failure of LED packages. This study investigated the long-term changes in series electrical resistance and thermal resistance of LED packages at three different current and junction temperature stress conditions. Experiment results showed that the series electrical resistance went through four phases of change; including periods of latency, rapid increase, saturation, and finally a sharp decline just before failure. Formation of voids in the contact metallization was identified as the underlying mechanism for series resistance increase. The rate of series resistance change was linked to void growth using the theory of electromigration. The rate of increase of series resistance is dependent on temperature and current density. The results indicate that void growth occurred in the cap (Au) layer, was constrained by the contact metal (Ni) layer, preventing open circuit failure of contact metal layer. Short circuit failure occurred due to electromigration induced metal diffusion along dislocations in GaN. The increase in ideality factor, and reverse leakage current with time provided further evidence to presence of metal in the semiconductor. An empirical model was derived for estimation of LED package failure time due to metal diffusion. The model is based on the experimental results and theories of electromigration and diffusion. Furthermore, the experimental results showed that the thermal resistance of LED packages increased with aging time. A relationship between thermal resistance change rate, with case temperature and temperature gradient within the LED package was developed. The results showed that dislocation creep is responsible for creep induced plastic deformation in the die-attach solder. The temperatures inside the LED package reached the melting point of die-attach solder due to delamination just before catastrophic open circuit failure. A combined model that could estimate life of LED packages based on catastrophic failure of thermal and electrical contacts is presented for the first time. This model can be used to make a-priori or real-time estimation of LED package life based on catastrophic failure. Finally, to illustrate the usefulness of the findings from this thesis, two different implementations of real-time life prediction using prognostics and health monitoring techniques are discussed.

Improvement of GaN light-emitting diodes with surface-treated Al-doped ZnO transparent Ohmic contacts by holographic photonic crystal

NASA Astrophysics Data System (ADS)

Yang, W. F.; Liu, Z. G.; Xie, Y. N.; Cai, J. F.; Liu, S.; Gong, H.; Wu, Z. Y.

2012-06-01

This letter presents a holographic photonic crystal (H-PhC) Al-doped ZnO (AZO) transparent Ohmic contact layer on p-GaN to increase the light output of GaN-based LEDs without destroying the p-GaN. The operating voltage of the PhC LEDs at 20 mA was almost the same as that of the typical planar AZO LEDs. While the resultant PhC LED devices exhibited significant improvements in light extraction, up to 1.22 times that of planar AZO LEDs without PhC integration. Temperature dependence of the integrated photoluminescence intensity indicates that this improvement can be attributed to the increased extraction efficiency due to the surface modification. These results demonstrate that the surface-treated AZO layer by H-PhCs is suitable for fabricating high-brightness GaN-based LEDs.

Cognitive Control of a Simple Mental Image in Patients with Obsessive-Compulsive Disorder

ERIC Educational Resources Information Center

Kocak, Orhan Murat; Ozpolat, Aysegul Yilmaz; Atbasoglu, Cem; Cicek, Metehan

2011-01-01

The nature of obsessions has led researchers to try to determine if the main problem in obsessive-compulsive disorder (OCD) is impaired inhibitory control. Previous studies report that the effort to suppress is one of the factors that increase the frequency of obsessive thoughts. Based on these results and those of the present study that suggest…

The Influences of Social Collaboration on Web 2.0 Self-Efficacy for Higher Education

ERIC Educational Resources Information Center

Turky, Mohamed Abdullah

2016-01-01

The present study tries to research the relationship between Social Collaboration Activity and Web 2.0 Self-Efficacy for Higher Education student. It additionally looks to decide how Social Collaboration adds to the forecast of their sense Web 2.0 Self-Efficacy. The study reported in this paper was led to inspect the relationship Social…

The Relationship between Individual Characteristics and Ideation Behavior: An Empirical Study of Storyboards

ERIC Educational Resources Information Center

Teng, Pei-Shan; Cai, Dengchuan; Yu, Tai-Kuei

2014-01-01

The development of digital technology tool and the progress of animation design activities have led to great progress in the animation field. The storyboard is a type of media used to present animator ideas. Therefore, it is commonly viewed as fundamental to the animation industry. This study aims to discuss cognitive style- and gender-based…

A Case Study of Two Rural Secondary Schools in New Mexico: Perspectives on Leadership

ERIC Educational Resources Information Center

Iron Moccasin, Shawl D.

2012-01-01

The present study was designed to examine factors that led to the academic success of two rural secondary schools in New Mexico. The primary focus was on the characteristics and behaviors of leaders in two high-achieving rural schools and how these factors might have contributed to achievement of Adequate Yearly Progress (AYP) in school year…

Re-evaluation of cosmic ray cutoff terminology

NASA Technical Reports Server (NTRS)

Cooke, D. J.; Humble, J. E.; Shea, M. A.; Smart, D. F.; Lund, N.; Rasmussen, I. L.; Byrnak, B.; Goret, P.; Petrou, N.

1985-01-01

The study of cosmic ray access to locations inside the geomagnetic field has evolved in a manner that has led to some misunderstanding and misapplication of the terminology originally developed to describe particle access. This paper presents what is believed to be a useful set of definitions for cosmic ray cutoff terminology for use in theoretical and experimental cosmic ray studies.

A Comparative Study of Paper-Based and Computer-Based Contextualization in Vocabulary Learning of EFL Students

ERIC Educational Resources Information Center

Ahmadian, Mousa; Amerian, Majid; Goodarzi, Ahmad

2015-01-01

Vocabulary acquisition is one of the largest and most important tasks in language classes. New technologies, such as computers, have helped a lot in this way. The importance of the issue led the researchers to do the present study which concerns the comparison of contextualized vocabulary learning on paper and through Computer Assisted Language…

Teachers' Academic Appraisals and Referral Decisions: The Effect of Sharing Health Information when Diabetes Is Present

ERIC Educational Resources Information Center

Cunningham, Melissa M.; Wodrich, David L.

2012-01-01

Two prior studies showed that giving teachers more information about a student's illness led them to make better attributions about that student's classroom problems and better classroom accommodations. In this study, 235 teachers appraised academic competence and judged whether to seek help or make a referral for a hypothetical student with type…

Using a Theory-guided Learning Collaborative Model to Improve Implementation of EBPs in a State Children’s Mental Health System: A Pilot Study

PubMed Central

Nadeem, Erum; Weiss, Dara; Olin, S. Serene; Hoagwood, Kimberly E.; Horwitz, Sarah M.

2016-01-01

Learning collaboratives (LCs) are used widely to promote implementation of evidence-based practices (EBPs). However, there has been limited research on the effectiveness of LCs and models vary widely in their structure, focus and components. The goal of the present study was to develop and field test a theory-based LC model to augment a state-led, evidence-based training program for clinicians providing mental health services to children. Analysis of implementation outcomes contrasted LC sites to matched comparison sites that participated in the clinical training program alone. Results suggested that clinicians from sites participating in the LC were more highly engaged in the state-led clinical training program and were more likely to complete program requirements. PMID:27167744

Using a Theory-Guided Learning Collaborative Model to Improve Implementation of EBPs in a State Children's Mental Health System: A Pilot Study.

PubMed

Nadeem, Erum; Weiss, Dara; Olin, S Serene; Hoagwood, Kimberly E; Horwitz, Sarah M

2016-11-01

Learning collaboratives (LCs) are used widely to promote implementation of evidence-based practices. However, there has been limited research on the effectiveness of LCs and models vary widely in their structure, focus and components. The goal of the present study was to develop and field test a theory-based LC model to augment a state-led, evidence-based training program for clinicians providing mental health services to children. Analysis of implementation outcomes contrasted LC sites to matched comparison sites that participated in the clinical training program alone. Results suggested that clinicians from sites participating in the LC were more highly engaged in the state-led clinical training program and were more likely to complete program requirements.

A comparative study on effect of e-learning and instructor-led methods on nurses' documentation competency.

PubMed

Abbaszadeh, Abbas; Sabeghi, Hakimeh; Borhani, Fariba; Heydari, Abbas

2011-01-01

Accurate recording of the nursing care indicates the care performance and its quality, so that, any failure in documentation can be a reason for inadequate patient care. Therefore, improving nurses' skills in this field using effective educational methods is of high importance. Since traditional teaching methods are not suitable for communities with rapid knowledge expansion and constant changes, e-learning methods can be a viable alternative. To show the importance of e-learning methods on nurses' care reporting skills, this study was performed to compare the e-learning methods with the traditional instructor-led methods. This was a quasi-experimental study aimed to compare the effect of two teaching methods (e-learning and lecture) on nursing documentation and examine the differences in acquiring competency on documentation between nurses who participated in the e-learning (n = 30) and nurses in a lecture group (n = 31). The results of the present study indicated that statistically there was no significant difference between the two groups. The findings also revealed that statistically there was no significant correlation between the two groups toward demographic variables. However, we believe that due to benefits of e-learning against traditional instructor-led method, and according to their equal effect on nurses' documentation competency, it can be a qualified substitute for traditional instructor-led method. E-learning as a student-centered method as well as lecture method equally promote competency of the nurses on documentation. Therefore, e-learning can be used to facilitate the implementation of nursing educational programs.

Evaluation of the effect of photodynamic antimicrobial therapy in dentin caries: a pilot in vivo study

NASA Astrophysics Data System (ADS)

Borges, F. M. C.; de-Melo, M. A. S.; Lima, J. M. P.; Zanin, I. C. J.; Rodrigues, L. K. A.; Nobre-dos-Santos, M.

2010-02-01

In vitro and in situ studies have demonstrated that the photodynamic antimicrobial therapy (PACT) is effective in reducing Streptococcus mutans population in artificially carious dentin. This pilot in vivo study evaluated the antimicrobial effect of PACT using toluidine blue O (TBO) and a light-emitting diode (LED) in carious dentin lesions. Five healthy adult volunteers (19-36 yr), with at least 4 active carious cavities each, participated in this study. Teeth of each volunteer were randomly divided into four groups: (1) without TBO and without light (Control); (2) with TBO alone (TBO); (3) with LED at 94/J cm2 alone (LED); and (4) with TBO plus LED at 94 J/cm2 (PACT). Each cavity was divided into two halves. The baseline carious dentin sample was collected from half of each cavity. Following, the treatments were performed using a random distribution of tooth into treatments. Then, the second collection of carious dentin samples was performed. Before and after treatments, dentin samples were analyzed with regard to the counts of total viable microorganisms, total streptococci, mutans streptococci, and lactobacilli. The data were statistically analyzed by Kruskal-Wallis and Student-Newman-Keuls tests (α=5%). Log reductions ranged from -0.12 to 2.68 and significant reductions were observed for PACT (group 4) when compared to the other groups (1, 2, and 3) for total streptococci and mutans streptococci. Concluding, PACT was effective in killing oral microorganisms present in in vivo carious dentin lesions and may be a promising technique for eliminating bacteria from dentin before restoration.

A comparative study on effect of e-learning and instructor-led methods on nurses’ documentation competency

PubMed Central

Abbaszadeh, Abbas; Sabeghi, Hakimeh; Borhani, Fariba; Heydari, Abbas

2011-01-01

BACKGROUND: Accurate recording of the nursing care indicates the care performance and its quality, so that, any failure in documentation can be a reason for inadequate patient care. Therefore, improving nurses’ skills in this field using effective educational methods is of high importance. Since traditional teaching methods are not suitable for communities with rapid knowledge expansion and constant changes, e-learning methods can be a viable alternative. To show the importance of e-learning methods on nurses’ care reporting skills, this study was performed to compare the e-learning methods with the traditional instructor-led methods. METHODS: This was a quasi-experimental study aimed to compare the effect of two teaching methods (e-learning and lecture) on nursing documentation and examine the differences in acquiring competency on documentation between nurses who participated in the e-learning (n = 30) and nurses in a lecture group (n = 31). RESULTS: The results of the present study indicated that statistically there was no significant difference between the two groups. The findings also revealed that statistically there was no significant correlation between the two groups toward demographic variables. However, we believe that due to benefits of e-learning against traditional instructor-led method, and according to their equal effect on nurses’ documentation competency, it can be a qualified substitute for traditional instructor-led method. CONCLUSIONS: E-learning as a student-centered method as well as lecture method equally promote competency of the nurses on documentation. Therefore, e-learning can be used to facilitate the implementation of nursing educational programs. PMID:22224113

Multicolor white light-emitting diodes for illumination applications

NASA Astrophysics Data System (ADS)

Chi, Solomon W. S.; Chen, Tzer-Perng; Tu, Chuan-Cheng; Chang, Chih-Sung; Tsai, Tzong-Liang; Hsieh, Mario C. C.

2004-01-01

Semiconductor light emitting diode (LED) has become a promising device for general-purpose illumination applications. LED has the features of excellent durability, long operation life, low power consumption, no mercury containing and potentially high efficiency. Several white LED technologies appear capable of meeting the technical requirements of illumination. In this paper we present a new multi-color white (MCW) LED as a high luminous efficacy, high color rendering index and low cost white illuminator. The device consists of two LED chips, one is AlInGaN LED for emitting shorter visible spectra, another is AlInGaP LED for emitting longer visible spectra. At least one chip in the MCW-LED has two or more transition energy levels used for emitting two or more colored lights. The multiple colored lights generated from the MCW-LED can be mixed into a full-spectral white light. Besides, there is no phosphors conversion layer used in the MCW-LED structure. Therefore, its color rendering property and illumination efficiency are excellent. The Correlated Color Temperature (CCT) of the MCW-LED may range from 2,500 K to over 10,000 K. The theoretical General Color Rendering Index (Ra) could be as high as 94, which is close to the incandescent and halogen sources, while the Ra of binary complementary white (BCW) LED is about 30 ~ 45. Moreover, compared to the expensive ternary RGB (Red AlInGaP + Green AlInGaN + Blue AlInGaN) white LED sources, the MCW-LED uses only one AlInGaN chip in combination with one cheap AlInGaP chip, to form a low cost, high luminous performance white light source. The MCW-LED is an ideal light source for general-purpose illumination applications.

LED instrument approach instruction display

NASA Technical Reports Server (NTRS)

Meredith, B. D.; Kelly, W. L., IV; Crouch, R. K.

1979-01-01

A display employing light emitting diodes (LED's) was developed to demonstrate the feasibility of such displays for presenting landing and navigation information to reduce the workload of general aviation pilots during IFR flight. The display consists of a paper tape reader, digital memory, control electronics, digital latches, and LED alphanumeric displays. A presentable digital countdown clock-timer is included as part of the system to provide a convenient means of monitoring time intervals for precise flight navigation. The system is a limited capability prototype assembled to test pilot reaction to such a device under simulated IFR operation. Pilot opinion indicates that the display is helpful in reducing the IFR pilots workload when used with a runway approach plate. However, the development of a compact, low power second generation display was recommended which could present several instructions simultaneously and provide information update capability. A microprocessor-based display could fulfill these requirements.

Multispectral digital lensless holographic microscopy: from femtosecond laser to white light LED

NASA Astrophysics Data System (ADS)

Garcia-Sucerquia, J.

2015-04-01

The use of femtosecond laser radiation and super bright white LED in digital lensless holographic microscopy is presented. For the ultrafast laser radiation two different configurations of operation of the microscope are presented and the dissimilar performance of each one analyzed. The microscope operating with a super bright white light LED in combination with optical filters shows very competitive performance as it is compared with more expensive optical sources. The broadband emission of both radiation sources allows the multispectral imaging of biological samples to obtain spectral responses and/or full color images of the microscopic specimens; sections of the head of a Drosophila melanogaster fly are imaged in this contribution. The simple, solid, compact, lightweight, and reliable architecture of digital lensless holographic microscopy operating with broadband light sources to image biological specimens exhibiting micrometer-sized details is evaluated in the present contribution.

Processing and characterization of high resolution GaN/InGaN LED arrays at 10 micron pitch for micro display applications

NASA Astrophysics Data System (ADS)

Dupré, Ludovic; Marra, Marjorie; Verney, Valentin; Aventurier, Bernard; Henry, Franck; Olivier, François; Tirano, Sauveur; Daami, Anis; Templier, François

2017-02-01

We report the fabrication process and characterization of high resolution 873 x 500 pixels emissive arrays based on blue or green GaN/InGaN light emitting diodes (LEDs) at a reduced pixel pitch of 10 μm. A self-aligned process along with a combination of damascene metallization steps is presented as the key to create a common cathode which is expected to provide good thermal dissipation and prevent voltage drops between center and side of the micro LED matrix. We will discuss the challenges of a self-aligned technology related to the choice of a good P contact metal and will present our solutions for the realization of the metallic interconnections between the GaN contacts and the higher levels of metallization at such a small pixel pitch. Enhanced control of each technological step allows scalability of the process up to 4 inch LED wafers and production of high quality LED arrays. The very high brightness (up to 107 cd.m-2) and good external quantum efficiency (EQE) of the resulting device make these kind of micro displays suitable for augmented reality or head up display applications.

AlGaN UV LED and Photodiodes Radiation Hardness and Space Qualifications and Their Applications in Space Science and High Energy Density Physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, K. X.

2011-05-31

This presentation provides an overview of robust, radiation hard AlGaN optoelectronic devices and their applications in space exploration & high energy density physics. Particularly, deep UV LED and deep UV photodiodes are discussed with regard to their applications, radiation hardness and space qualification. AC charge management of UV LED satellite payload instruments, which were to be launched in late 2012, is covered.

Potential of Sm3+ doped LiSrVO4 nanophosphor to fill amber gap in LEDs

NASA Astrophysics Data System (ADS)

Biswas, P.; Kumar, Vinay; Sharma, Vishal; Bedyal, A. K.; Padha, Naresh; Swart, H. C.

2018-04-01

The LiSrVO4:Sm3+ phosphor powders were synthesized by the combustion method by varying the concentration of the Sm3+ ions from 0.25 mol% to 2.5 mol%. The powder X-ray diffraction (XRD) studies confirmed that the phosphors were crystallized as monoclinic structure belonging to space group P2/m and the transmission electron microscopy (TEM) revealed nanosized grains of the powders. The Fourier transform infrared studies (FTIR) established the formation of non-hygroscopic vanadate powders. The photoluminescence (PL) and diffused reflectance studies (DRS) were also carried out and discussed. Under 401 nm excitation, the optimized phosphor exhibited the characteristic 568, 600, 646 and 704 nm emissions of Sm3+ which corresponded to the orange-red (amber) color with (0.59, 0.41) Commission Internationale de' Eclairage (CIE) chromaticity coordinates. Concentration quenching of phosphor intensity on account of non-radiative energy transfer was ascribed to dipole-dipole interaction between activators. DRS study reveals that the host of the phosphor is a wide bandgap material which accommodates the dopant successfully. The present results signify that the LiSrVO4:Sm3+ phosphor can suitably be excited by the GaN family of UV-LEDs chips for efficient amber LEDs applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thurmond, Kyle; Loparo, Zachary; Partridge, Jr., William P.

Here, a sensor was developed for simultaneous measurements of carbon monoxide (CO) and carbon dioxide (CO 2) fluctuations in internal combustion engine exhaust gases. This sensor utilizes low-cost and compact light-emitting diodes (LEDs) that emit in the 3–5 µm wavelength range. An affordable, fast response sensor that can measure these gases has a broad application that can lead to more efficient, fuel-flexible engines and regulation of harmful emissions. Light emission from LEDs is spectrally broader and more spatially divergent when compared to that of lasers, which presented many design challenges. Optical design studies addressed some of the non-ideal characteristics ofmore » the LED emissions. Measurements of CO and CO 2 were conducted using their fundamental absorption bands centered at 4.7 µm and 4.3 µm, respectively, while a 3.6 µm reference LED was used to account for scattering losses (due to soot, window deposits, etc.) common to the three measurement LEDs. Instrument validation and calibration was performed using a laboratory flow cell and bottled-gas mixtures. The sensor was able to detect CO 2 and CO concentration changes as small as 30 ppm and 400 ppm, respectively. Because of the many control and monitor species with infra-red absorption features, which can be measured using the strategy described, this work demonstrates proof of concept for a wider range of fast (250 Hz) and low-cost sensors for gas measurement and process monitoring.« less

Laser/LED phototherapy on the repair of tibial fracture treated with wire osteosynthesis evaluated by Raman spectroscopy.

PubMed

Pinheiro, Antônio L B; Soares, Luiz G P; da Silva, Aline C P; Santos, Nicole R S; da Silva, Anna Paula L T; Neves, Bruno Luiz R C; Soares, Amanda P; Silveira, Landulfo

2018-04-23

The aim of the present study was to assess, by means of Raman spectroscopy, the repair of complete surgical tibial fractures fixed with wire osteosynthesis (WO) treated or not with infrared laser (λ780 nm) or infrared light emitting diode (LED) (λ850 ± 10 nm) lights, 142.8 J/cm 2 per treatment, associated or not to the use of mineral trioxide aggregate (MTA) cement. Surgical tibial fractures were created on 18 rabbits, and all fractures were fixed with WO and some groups were grafted with MTA. Irradiated groups received lights at every other day during 15 days, and all animals were sacrificed after 30 days, being the tibia removed. The results showed that only irradiation with either laser or LED influenced the peaks of phosphate hydroxyapatite (~ 960 cm -1 ). Collagen (~ 1450 cm -1 ) and carbonated hydroxyapatite (~ 1070 cm -1 ) peaks were influenced by both the use of MTA and the irradiation with either laser or LED. It is concluded that the use of either laser or LED phototherapy associated to MTA cement was efficacious on improving the repair of complete tibial fractures treated with wire osteosynthesis by increasing the synthesis of collagen matrix and creating a scaffold of calcium carbonate (carbonated hydroxyapatite-like) and the subsequent deposition of phosphate hydroxyapatite.

Defect-induced infrared electroluminescence from radial GaInP/AlGaInP quantum well nanowire array light- emitting diodes

NASA Astrophysics Data System (ADS)

Hussain, Laiq; Karimi, Mohammad; Berg, Alexander; Jain, Vishal; Borgström, Magnus T.; Gustafsson, Anders; Samuelson, Lars; Pettersson, Håkan

2017-12-01

Radial GaInP/AlGaInP nanowire array light-emitting diodes (LEDs) are promising candidates for novel high-efficiency solid state lighting due to their potentially large strain-free active emission volumes compared to planar LEDs. Moreover, by proper tuning of the diameter of the nanowires, the fraction of emitted light extracted can be significantly enhanced compared to that of planar LEDs. Reports so far on radial growth of nanowire LED structures, however, still point to significant challenges related to obtaining defect-free radial heterostructures. In this work, we present evidence of optically active growth-induced defects in a fairly broad energy range in vertically processed radial GaInP/AlGaInP quantum well nanowire array LEDs using a variety of complementary experimental techniques. In particular, we demonstrate strong infrared electroluminescence in a spectral range centred around 1 eV (1.2 μm) in addition to the expected red light emission from the quantum well. Spatially resolved cathodoluminescence studies reveal a patchy red light emission with clear spectral features along the NWs, most likely induced by variations in QW thickness, composition and barriers. Dark areas are attributed to infrared emission generated by competing defect-assisted radiative transitions, or to trapping mechanisms involving non-radiative recombination processes. Possible origins of the defects are discussed.

Supplemental Upward Lighting from Underneath to Obtain Higher Marketable Lettuce (Lactuca sativa) Leaf Fresh Weight by Retarding Senescence of Outer Leaves

PubMed Central

Zhang, Geng; Shen, Shanqi; Takagaki, Michiko; Kozai, Toyoki; Yamori, Wataru

2015-01-01

Recently, the so-called “plant factory with artificial lighting” (PFAL) approach has been developed to provide safe and steady food production. Although PFALs can produce high-yielding and high-quality plants, the high plant density in these systems accelerates leaf senescence in the bottom (or outer) leaves owing to shading by the upper (or inner) leaves and by neighboring plants. This decreases yield and increases labor costs for trimming. Thus, the establishment of cultivation methods to retard senescence of outer leaves is an important research goal to improve PFAL yield and profitability. In the present study, we developed an LED lighting apparatus that would optimize light conditions for PFAL cultivation of a leafy vegetable. Lettuce (Lactuca sativa L.) was hydroponically grown under white, red, or blue LEDs, with light provided from above (downward), with or without supplemental upward lighting from underneath the plant. White LEDs proved more appropriate for lettuce growth than red or blue LEDs, and the supplemental lighting retarded the senescence of outer leaves and decreased waste (i.e., dead or low-quality senescent leaves), leading to an improvement of the marketable leaf fresh weight. PMID:26697055

Effect of LED light spectra on starvation-induced oxidative stress in the cinnamon clownfish Amphiprion melanopus.

PubMed

Choi, Cheol Young; Shin, Hyun Suk; Choi, Young Jae; Kim, Na Na; Lee, Jehee; Kil, Gyung-Suk

2012-11-01

The present study aimed to test starvation-induced oxidative stress in the cinnamon clownfish Amphiprion melanopus illuminated by light-emitting diodes (LEDs): red (peak at 630 nm), green (peak at 530 nm), and blue (peak at 450 nm) within a visible light. We investigated the oxidative stress induced by starvation for 12 days during illumination with 3 LED light spectra through measuring antioxidant enzyme (superoxide dismutase [SOD] and catalase [CAT]) mRNA expression and activity; CAT western blotting; and measuring lipid peroxidation [LPO]), plasma H(2)O(2), lysozyme, glucose, alanine aminotransferase (AlaAT), aspartate aminotransferase (AspAT), and melatonin levels. In green and blue lights, expression and activity of antioxidant enzyme mRNA were significantly lower than those of other light spectra, results that are in agreement with CAT protein expression level by western blot analysis. Also, in green and blue lights, plasma H(2)O(2), lysozyme, glucose, AlaAT, AspAT, and melatonin levels were significantly lower than those in other light spectra. These results indicate that green and blue LEDs inhibit oxidative stress and enhance immune function in starved cinnamon clownfish. Copyright © 2012 Elsevier Inc. All rights reserved.

Supplemental Upward Lighting from Underneath to Obtain Higher Marketable Lettuce (Lactuca sativa) Leaf Fresh Weight by Retarding Senescence of Outer Leaves.

PubMed

Zhang, Geng; Shen, Shanqi; Takagaki, Michiko; Kozai, Toyoki; Yamori, Wataru

2015-01-01

Recently, the so-called "plant factory with artificial lighting" (PFAL) approach has been developed to provide safe and steady food production. Although PFALs can produce high-yielding and high-quality plants, the high plant density in these systems accelerates leaf senescence in the bottom (or outer) leaves owing to shading by the upper (or inner) leaves and by neighboring plants. This decreases yield and increases labor costs for trimming. Thus, the establishment of cultivation methods to retard senescence of outer leaves is an important research goal to improve PFAL yield and profitability. In the present study, we developed an LED lighting apparatus that would optimize light conditions for PFAL cultivation of a leafy vegetable. Lettuce (Lactuca sativa L.) was hydroponically grown under white, red, or blue LEDs, with light provided from above (downward), with or without supplemental upward lighting from underneath the plant. White LEDs proved more appropriate for lettuce growth than red or blue LEDs, and the supplemental lighting retarded the senescence of outer leaves and decreased waste (i.e., dead or low-quality senescent leaves), leading to an improvement of the marketable leaf fresh weight.

LIGHT-EMITTING DIODE TECHNOLOGY IMPROVES INSECT TRAPPING

PubMed Central

GILLEN, JONATHON I.; MUNSTERMANN, LEONARD E.

2008-01-01

In a climate of increased funding for vaccines, chemotherapy, and prevention of vector-borne diseases, fewer resources have been directed toward improving disease and vector surveillance. Recently developed light-emitting diode (LED) technology was applied to standard insect-vector traps to produce a more effective lighting system. This approach improved phlebotomine sand fly capture rates by 50%, and simultaneously reduced the energy consumption by 50–60%. The LEDs were incorporated into 2 lighting designs, 1) a LED combination bulb for current light traps and 2) a chip-based LED design for a modified Centers for Disease Control and Prevention light trap. Detailed descriptions of the 2 designs are presented. PMID:18666546

Best practices : bus signage for persons with visual impairments : light-emitting diode (LED) signs

DOT National Transportation Integrated Search

2004-01-01

This best-practices report provides key information regarding the use of Light-Emitting Diode (LED) sign technologies to present destination and route information on transit vehicles. It will assist managers and engineers in the acquisition and use o...

Long-term Testing Results for the 2008 Installation of LED Luminaires at the I-35 West Bridge in Minneapolis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kinzey, Bruce R.; Davis, Robert G.

2014-09-30

This document reports the long-term testing results from an extended GATEWAY project that was first reported in “Demonstration Assessment of Light-Emitting Diode (LED) Roadway Lighting at the I-35W Bridge, in Minneapolis, MN,” August 2009. That original report presented the results of lighting the newly reconstructed I 35W Bridge using LEDs in place of conventional high-pressure sodium (HPS) roadway luminaires, comparing energy use and illuminance levels with a simulated baseline condition. That installation was an early stage implementation of LED lighting and remains one of the oldest installations in continued operation today. This document provides an update of the LED system’smore » performance since its installation in September 2008.« less

Selective-area nanoheteroepitaxy for light emitting diode (LED) applications

NASA Astrophysics Data System (ADS)

Wildeson, Isaac H.

Over 20% of the electricity in the United States is consumed for lighting, and the majority of this energy is wasted as heat during the lighting process. A solid-state (or light emitting diode (LED)-based) light source has the potential of saving the United States billions of dollars in electricity and reducing megatons of global CO2 emissions annually. While white light LEDs are currently on the market with efficiencies that are superior to incandescent and fluorescent light sources, their high up-front cost is inhibiting mass adoption. One reason for the high cost is the inefficiency of green and amber LEDs that can used to make white light. The inefficiency of green and amber LEDs results in more of these chips being required, and thus a higher cost. Improvements in the performance of green and amber LEDs is also required in order to realize the full potential of solid-state lighting. Nanoheteroepitaxy is an interesting route towards achieving efficient green and amber LEDs as it resolves major challenges that are currently plaguing III-nitride LEDs such as high dislocation densities and limited active region critical thicknesses. A method for fabricating III-nitride nanopyramid LEDs is presented that employs conventional processing used in industry. The present document begins with an overview of the current challenges in III-nitride LEDs and the benefits of nanoheteroepitaxy. A process for controlled selective-area growth of nanopyramid LEDs by organometallic vapor phase epitaxy has been developed throughout the course of this work. Dielectric templates used for the selective-area growth are patterned by two methods, namely porous anodic alumina and electron-beam lithography. The dielectric templates serve as efficient dislocation filters; however, planar defects are initiated during lower temperature growth on the nanopyramids. The quantum wells outline six semipolar planes that form each hexagonal pyramid. Quantum wells grown on these semipolar planes generate built-in electric fields with magnitudes that are one-tenth those on the polar c-plane with the same (In,Ga)N composition. The lateral strain relaxation innate in the nanoheterostructures allows greater coherent InN incorporation in the nanopyramids as compared to thin-film heterostructures, as confirmed by electroluminescence and transmission electron microscopy. In addition to applications for light emitting diodes, selective area growth of GaN nanostructures is also important for biological and sensing applications. A process for fabricating porous GaN nanorods is presented that also relies on selective-area organometallic vapor phase epitaxy. The nanopore walls are primarily outlined by nonpolar planes, and the diameter of the nanopore can be controlled by the diameter of the opening in the dielectric template and the growth time. The lining of the nanopore walls is comprised of crystalline GaN, which makes these structures interesting for sensing, electrical and optical applications.

Efficient electroluminescent cooling with a light-emitting diode coupled to a photovoltaic cell (Conference Presentation)

NASA Astrophysics Data System (ADS)

Xiao, Tianyao P.; Chen, Kaifeng; Santhanam, Parthiban; Fan, Shanhui; Yablonovitch, Eli

2017-02-01

The new breakthrough in photovoltaics, exemplified by the slogan "A great solar cell has to be a great light-emitting diode (LED)", has led to all the major new solar cell records, while also leading to extraordinary LED efficiency. As an LED becomes very efficient in converting its electrical input into light, the device cools as it operates because the photons carry away entropy as well as energy. If these photons are absorbed in a photovoltaic (PV) cell, the generated electricity can be used to provide part of the electrical input that drives the LED. Indeed, the LED/PV cell combination forms a new type of heat engine with light as the working fluid. The electroluminescent refrigerator requires only a small amount of external electricity to provide cooling, leading to a high coefficient of performance. We present the theoretical performance of such a refrigerator, in which the cool side (LED) is radiatively coupled to the hot side (PV) across a vacuum gap. The coefficient of performance is maximized by using a highly luminescent material, such as GaAs, together with device structures that optimize extraction of the luminescence. We consider both a macroscopic vacuum gap and a sub-wavelength gap; the latter allows for evanescent coupling of photons between the devices, potentially providing a further enhancement to the efficiency of light extraction. Using device assumptions based on the current record-efficiency solar cells, we show that electroluminescent cooling can, in certain regimes of cooling power, achieve a higher coefficient of performance than thermoelectric cooling.

A Light-Emitting Diode- (LED-) Based Absorption Sensor for Simultaneous Detection of Carbon Monoxide and Carbon Dioxide.

PubMed

Thurmond, Kyle; Loparo, Zachary; Partridge, William; Vasu, Subith S

2016-06-01

A sensor was developed for simultaneous measurements of carbon monoxide (CO) and carbon dioxide (CO2) fluctuations in internal combustion engine exhaust gases. This sensor utilizes low-cost and compact light-emitting diodes (LEDs) that emit in the 3-5 µm wavelength range. An affordable, fast response sensor that can measure these gases has a broad application that can lead to more efficient, fuel-flexible engines and regulation of harmful emissions. Light emission from LEDs is spectrally broader and more spatially divergent when compared to that of lasers, which presented many design challenges. Optical design studies addressed some of the non-ideal characteristics of the LED emissions. Measurements of CO and CO2 were conducted using their fundamental absorption bands centered at 4.7 µm and 4.3 µm, respectively, while a 3.6 µm reference LED was used to account for scattering losses (due to soot, window deposits, etc.) common to the three measurement LEDs. Instrument validation and calibration was performed using a laboratory flow cell and bottled-gas mixtures. The sensor was able to detect CO2 and CO concentration changes as small as 30 ppm and 400 ppm, respectively. Because of the many control and monitor species with infra-red absorption features, which can be measured using the strategy described, this work demonstrates proof of concept for a wider range of fast (250 Hz) and low-cost sensors for gas measurement and process monitoring. © The Author(s) 2016.

Developing Successful International Faculty Led Program

ERIC Educational Resources Information Center

Fabregas Janeiro, Maria G.; Fabre, Ricardo Lopez; Rosete, Rodrigo Tello

2012-01-01

Faculty Led Programs are study abroad experiences led by university professors. Faculty Led Programs are considered as an opportunity for college students, especially in the United States to attend a short-term international experience (Mills, 2010). Faculty Led Program is an international experience which is different from the traditional…

Navigating future uncertainty in marine protected area governance: Lessons from the Scottish MPA network

NASA Astrophysics Data System (ADS)

Hopkins, Charlotte Rachael; Bailey, David Mark; Potts, Tavis

2018-07-01

As international pressure for marine protection has increased, Scotland has increased spatial protection through the development of a Marine Protected Area (MPA) network. Few MPA networks to date have included specific considerations of climate change in the design, monitoring or management of the network. The Scottish MPA network followed a feature-led approach to identify a series of MPAs across the Scottish marine area and incorporated the diverse views of many different stakeholders. This feature led approach has led to wide ranging opinions and understandings regarding the success of the MPA network. Translating ideas of success into a policy approach whilst also considering how climate change may affect these ideas of success is a complex challenge. This paper presents the results of a Delphi process that aimed to facilitate clear communication between academics, policy makers and stakeholders in order to identify specific climate change considerations applicable to the Scottish MPA network. This study engaged a group of academic and non-academic stakeholders to discuss potential options that could be translated into an operational process for management of the MPA network. The results of Delphi process discussion are presented with the output of a management matrix tool, which could aid in future decisions for MPA management under scenarios of climate change.

Evaluation of Small Student-Led Discussion Groups as an Adjunct to a Course in Abnormal Psychology

ERIC Educational Resources Information Center

White, Geoffry D.

1978-01-01

Presents data related to student involvement in biweekly student-led discussion groups in an undergraduate abnormal psychology course. Evaluates the degree to which students felt they benefited from discussion groups composed of similar and dissimilar students. (Author/AV)

LED's in Physics Demos: A Handful of Examples.

ERIC Educational Resources Information Center

Lottis, Dan; Jaeger, Herbert

1996-01-01

Describes the use of light-emitting diodes (LED) instead of incandescent bulbs in experiments that generally use battery and bulbs to enable students to explore and understand fundamental electrical phenomena. Presents the following examples: Faraday's Law demonstration, conductors and insulators, and rectifying action of a diode. (JRH)

Three consecutive days of application of LED therapy is necessary to inhibit experimentally induced root resorption in rats: a microtomographic study.

PubMed

Higashi, Dayla Thyeme; Andrello, Avacir Casanova; Tondelli, Pedro Marcelo; de Oliveira Toginho Filho, Dari; de Paula Ramos, Solange

2017-01-01

Previous studies have suggested that phototherapy may modulate orthodontic tooth movement and the incidence of root resorption. We aimed to identify a minimal dose-response relationship to LED therapy with regard to orthodontic tooth movement (OTM) and root resorption in rats. Forty-eight male Wistar rats were divided into six groups with equal and random distribution: control (C) no intervention; three daily LED irradiation (CLED); submitted only to OTM (RR); OTM and LED irradiation on the first day (LED1); OTM and two LED irradiation on the first and second days (LED2); and OTM and three LED irradiation on the first, second, and third days (LED3). Orthodontic appliance was installed in groups RR, LED1, LED2, and LED3 to promote OTM. Animals from groups CLED, LED1, LED2, and LED3 received LED therapy (940 nm, 4 J, 4 J/cm2) according to each group of treatment. After 7 days, all the animals were sacrificed. The jaws were fixed and scanned with microtomography (micro-CT). The micro-CT images were reconstructed on 2D and 3D models. These models were used to identify and measure root resorption number and dimensions (diameter, depth, and volume). The distance between the first and second molars was used to verify tooth displacement. The results showed that LED3 group had significantly lower number of root resorption. The root resorption dimensions (diameter and depth) had no significant differences among the experimental groups. LED3 group had significant tooth displacement in relation to C and CLED groups. In conclusion, three daily LED therapy doses are required to inhibit root resorption after appliance of orthodontic forces.

The design of optical module of LED street lamp with non-axial symmetrical reflector

NASA Astrophysics Data System (ADS)

Lu, Ming-Jun; Chen, Chi-An; Chen, Yi-Yung; Whang, Allen Jong-Woei

2010-05-01

In recently, many research focus on the LED applications for environmental protection so a number of LED street lamps are presented. Although LED has many advantages for environmental protection, its special optical characteristics, such as intensity distribution, always limit the advantages in many applications. Therefore, we always need to do the secondary optical design for LED street lamp to replace the traditional optical designs that are designed for high-pressure sodium lamps and mercury lamps. According to the situation, we design an optical module of LED street lamp with LEDs and secondary optical design. First, the LEDs are placed on freeform reflector for the specific illuminated conditions. We design the optical module of street lamp with the two conditions that include the uniformity and the ratio of length to width in the illuminated area and without any light pollution. According to the simulation with the designed optical module, the uniformity in the illuminated area is about 0.6 that is better than the general condition, 0.3, and the ratio of length to width in the illuminated area is 3:1 in which the length is 30 meters and the width is 10 meters. Therefore, the design could let LED street lamp fits the two conditions, uniformity and ratio in the illuminated area.

[Nurse-Led Care Models in the Context of Community Elders With Chronic Disease Management: A Systematic Review].

PubMed

Hsieh, Pei-Lun; Chen, Ching-Min

2016-08-01

Longer average life expectancies have caused the rapid growth of the elderly as a percentage of Taiwan's population and, as a result of the number of elders with chronic diseases and disability. Providing continuing-care services in community settings for elderly with multiple chronic conditions has become an urgent need. To review the nurse-led care models that are currently practiced among elders with chronic disease in the community and to further examine the effectiveness and essential components of these models using a systematic review method. Twelve original articles on chronic disease-care planning for the elderly or on nurse-led care management interventions that were published between 2000 and 2015 in any of five electronic databases: MEDLINE, PubMed, CINAHL (Cumulative Index to Nursing and Allied Health Literature) Plus with Full Text, Cochrane Library, and CEPS (Chinese Electronic Periodicals Service）were selected and analyzed systematically. Four types of nurse-led community care models, including primary healthcare, secondary prevention care, cross-boundary models, and case management, were identified. Chronic disease-care planning, case management, and disease self-management were found to be the essential components of the services that were provided. The care models used systematic processes to conduct assessment, planning, implementation, coordination, and follow-up activities as well as to deliver services and to evaluate disease status. The results revealed that providing continuing-care services through the nurse-led community chronic disease-care model and cross-boundary model enhanced the ability of the elderly to self-manage their chronic diseases, improved healthcare referrals, provided holistic care, and maximized resource utilization efficacy. The present study cross-referenced all reviewed articles in terms of target clients, content, intervention, measurements, and outcome indicators. Study results may be referenced in future implementations of nurse-led community care models as well as in future research.

Solid-state turn coordinator display

NASA Technical Reports Server (NTRS)

Meredith, B. D.; Crouch, R. K.; Kelly, W. L., IV

1975-01-01

A solid state turn coordinator display which employs light emitting diodes (LED's) as the display medium was developed to demonstrate the feasibility of such displays for aircraft applications. The input to the display is supplied by a fluidic inertial rate sensor used in an aircraft wing leveler system. The display is composed of the LED radial display face and the electronics necessary to address and drive the individual lines of LED's. Three levels of brightness are provided to compensate for the different amounts of ambient light present in the cockpit.

Spectral design flexibility of LED brings better life

NASA Astrophysics Data System (ADS)

Ou, Haiyan; Corell, Dennis; Ou, Yiyu; Poulsen, Peter B.; Dam-Hansen, Carsten; Petersen, Paul-Michael

2012-03-01

Light-emitting diodes (LEDs) are penetrating into the huge market of general lighting because they are energy saving and environmentally friendly. The big advantage of LED light sources, compared to traditional incandescent lamps and fluorescent light tubes, is the flexible spectral design to make white light using different color mixing schemes. The spectral design flexibility of white LED light sources will promote them for novel applications to improve the life quality of human beings. As an initial exploration to make use of the spectral design flexibility, we present an example: 'no blue' white LED light source for sufferers of disease Porphyria. An LED light source prototype, made of high brightness commercial LEDs applying an optical filter, was tested by a patient suffering from Porphyria. Preliminary results have shown that the sufferer could withstand the light source for much longer time than the standard light source. At last future perspectives on spectral design flexibility of LED light sources improving human being's life will be discussed, with focus on the light and health. The good health is ensured by the spectrum optimized so that vital hormones (melatonin and serotonin) are produced during times when they support human daily rhythm.

Energy-Saving Tunnel Illumination System Based on LED's Intelligent Control

NASA Astrophysics Data System (ADS)

Guo, Shanshan; Gu, Hanting; Wu, Lan; Jiang, Shuixiu

2011-02-01

At present there is a lot of electric energy wastage in tunnel illumination, whose design is based on the maximum brightness outside and the maximum vehicle speed all year round. LED's energy consumption is low, and the control of its brightness is simple and effective. It can be quickly adjusted between 0-100% of its maximum brightness, and will not affect the service life. Therefore, using LED as tunnel's illumination source, we can achieve a good energy saving effect. According to real-time data acquisition of vehicle speed, traffic flow and brightness outside the tunnel, the auto real-time control of tunnel illumination can be achieved. And the system regulated the LED luminance by means of combination of LED power module and intelligent control module. The tunnel information was detected by inspection equipments, which included luminometer, vehicle detector, and received by RTU(Remote Terminal Unit), then synchronously transmitted to PC. After data processing, RTU emitted the dimming signal to the LED driver to adjust the brightness of LED. Despite the relatively high cost of high-power LED lights, the enormous energy-saving effect and the well-behaved controllability is beyond compare to other lighting devices.

PREGNANCY LOSS ASSOCIATED WITH EXPOSURE TO PERFLUOROOCTANOIC ACID IN THE MOUSE

EPA Science Inventory

Pregnancy loss in the mouse due to perfluorooctanoic acids (PFOA) was investigated in this present study. Daily administration of PFOA (20 or 40 mg/kg) by oral gavage to pregnant CD-1 mice from GD 1-17 led to 75% and 100% incidence respectively, of total resorption at term with c...

Performance Stress and the Very Young Musician

ERIC Educational Resources Information Center

Boucher, Helene; Ryan, Charlene A.

2011-01-01

Performance anxiety is a common experience among musicians. Recent studies have found it to be an issue not only for adult performers but also for developing musicians as early as third grade. The question as to its developed or innate nature led to the present inquiry pertaining to young children's responses to performance situations. Sixty-six…

Maternal ADHD: Parent-Child Interactions and Relations with Child Disruptive Behavior

ERIC Educational Resources Information Center

Zisser, Alison R.; Eyberg, Sheila M.

2012-01-01

This study examined how ADHD symptoms in mothers of children with ADHD relate to their behavior during parent-child interactions and to their children's disruptive behavior. Findings indicated that mothers' retrospective self-ratings of ADHD symptoms were related to their present negativity during parent-led play. Mothers' self-ratings of current…

Making Student Learning Evidence Transparent: The State of the Art

ERIC Educational Resources Information Center

Jankowski, Natasha A.; Provezis, Staci J.

2011-01-01

This publication presents a series of studies that the National Institute for Learning Outcomes Assessment (NILOA) staff, led by Staci Provezis and Natasha Jankowski, conducted over the past couple of years. It may be the most comprehensive examination yet of institutional transparency in terms of student learning outcomes and the assessment…

Teacher Led School Improvement: Teacher Leadership in the UK

ERIC Educational Resources Information Center

Muijs, Daniel; Harris, Alma

2006-01-01

Teacher leadership is increasingly being seen as a key vehicle for school improvement and renewal. However, research on this phenomenon is limited, especially outside of the US. This article presents findings from an empirical study of teacher leadership in the UK, aimed at exploring both the ways in which teacher leadership can influence school…

In Search of Leadership: What Happened to Management?

ERIC Educational Resources Information Center

Mertkan, Sefika

2014-01-01

Significant changes have taken place in the governance of education systems around the world. Shifts in education policy have led to a focus towards reform through leadership development and away from school management analysis. This shift in policy from management to leadership has fostered a large number of academic studies presenting a…

Monitoring and Fostering Elementary School Students' Life Satisfaction: A Case Study

ERIC Educational Resources Information Center

Wingate, Emily J.; Suldo, Shannon M.; Peterson, Rebekah K. S.

2018-01-01

Research on the importance of complete mental health has led to increased focus on students' subjective well-being (i.e., happiness and life satisfaction) coupled with the traditional attention to psychopathology. Although screeners for psychopathology abound, the present project is novel in applying best practices in universal screening to grade…

Lean Six Sigma and Assurance of Learning: Challenges and Opportunities

ERIC Educational Resources Information Center

Rexeisen, Richard J.; Owens, Ernest L., Jr.; Garrison, Michael J.

2018-01-01

The importance, and associated challenges, of faculty ownership and engagement in the assurance of learning (AoL) process are well documented in the literature. The authors demonstrate how schools can further their AoL objectives by encouraging and subsequently supporting organic, faculty-led initiatives. Specifically, we present a case study of a…

Preparing Principals to Improve Student Achievement

ERIC Educational Resources Information Center

Corcoran, Roisin P.

2017-01-01

Background: The growing interest in principal effectiveness as a means of improving teaching and student learning has led to a focus on the quality of principal preparation programs (PPPs) with calls for the adoption of PPP accountability systems similar to those of teacher preparation programs. Objective: The purpose of the present study is to…

Organizational Development in Transition: The Schooling Perspective.

ERIC Educational Resources Information Center

Snyder, Karolyn J.; And Others

This paper presents the initial findings of a comprehensive 28-school multi-site case study, which sought to identify patterns in schools that are changing bureaucratic work patterns to those found in quality-management systems. The schools are located in Florida, Virginia, Minnesota, and Louisiana; all are led by principals who are trainers in…

ACED IT: A Tool for Improved Ethical and Moral Decision-Making

ERIC Educational Resources Information Center

Kreitler, Crystal Mata; Stenmark, Cheryl K.; Rodarte, Allen M.; Piñón DuMond, Rebecca

2014-01-01

Numerous examples of unethical organizational decision-making highlighted in the media have led many to question the general moral perception and ethical judgments of individuals. The present study examined two forms of a straightforward ethical decision-making (EDM) tool (ACED IT cognitive map) that could be a relatively simple instrument for…

Carbon allocation and morphology of cherrybark oak seedlings and sprouts under three light regimes

Treesearch

Brian Roy Lockhart; Emile S. Gardiner; John D. Hodges; Andrew W. Ezell

2008-01-01

Continued problems in regenerating oak forests has led to a need for more basic infomation on oak seedling biology.In the present study, carbon allocation and morphology were compared between cherrybark oak (Quercus pagoda Raf.) seedlings and sprouts at I -Lag grown in full, 47%, and 20% sunlight....

Perception of the Capabilities and Personality of a Blind Interviewer by Hong Kong Chinese Teachers.

ERIC Educational Resources Information Center

Stratford, Brian; Mei, Lan Au

1986-01-01

Presents the results of a study which examined the attitudes of 46 experienced teachers toward a blind Cantonese speaking interviewer. Experimental group teachers (n=23) were led to believe the interviewer was blind. Results showed that the blind interviewer was perceived more positively than the sighted individual. (JDH)

Thriving in the Classroom

ERIC Educational Resources Information Center

Schreiner, Laurie A.

2010-01-01

In the last issue of "About Campus," the author outlined the research studies that she presented with Eric J. McIntosh, Denise Nelson, and Shannon Pothovenin in 2009, which led to the creation of the Thriving Quotient, a reliable and valid 35-item instrument that measures the changeable psychological qualities in students that affect their ability…

Using Action Research to Investigate Social Networking Technologies

ERIC Educational Resources Information Center

Worrall, Lisa; Harris, Katy

2013-01-01

This article outlines the first cycle of an Action Research (AR) investigation into why professional learners are not using the Social Networking Technologies (SNTs) of their bespoke website. It presents the rationale of how this study came about, the ontological and epistemological stance of the authors and how this led to the particular choice…

Complexity-Based Learning and Teaching: A Case Study in Higher Education

ERIC Educational Resources Information Center

Fabricatore, Carlo; López, María Ximena

2014-01-01

This paper presents a learning and teaching strategy based on complexity science and explores its impacts on a higher education game design course. The strategy aimed at generating conditions fostering individual and collective learning in educational complex adaptive systems, and led the design of the course through an iterative and adaptive…

Large-area sheet task advanced dendritic web growth development

NASA Technical Reports Server (NTRS)

Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.

1983-01-01

Modeling in the development of low stress configurations for wide web growth is presented. Parametric sensitivity to identify design features which can be used for dynamic trimming of the furnace element was studied. Temperature measurements of experimental growth behavior led to modification in the growth system to improve lateral temperature distributions.

Investigation of lubricants under boundary friction

NASA Technical Reports Server (NTRS)

Heidebroek, E; Pietsch, E

1942-01-01

Numerous observations of such lubrication processes within range of boundary friction on journal bearings and gear tooth profiles have strengthened the supposition that it should be possible to study the attendant phenomena with engineering methods and equipment. These considerations formed the basis of the present studies, which have led to the discovery of relations governing the suitability of bearing surfaces and the concept of "lubricating quality."

Making Sense of Social Justice Leadership: A Case Study of a Principal's Experiences to Create a More Inclusive School

ERIC Educational Resources Information Center

DeMatthews, David

2015-01-01

Social justice leadership in high-poverty urban schools is complex. Principals experience a range of feelings and emotions while practicing social justice leadership with implications on their leadership. This article presents a qualitative case study of an elementary school principal in an urban setting and how she led to create a more inclusive…

Optimized optical wireless channel for indoor and intra-vehicle communications: power distribution and SNR analysis

NASA Astrophysics Data System (ADS)

Shaaban, Rana; Faruque, Saleh

2018-01-01

Light emitting diodes - LEDs are modernizing the indoor illumination and replacing current incandescent and fluorescent lamps rapidly. LEDs have multiple advantages such as extremely high energy efficient, longer lifespan, and lower heat generation. Due to the ability to switch to different light intensity at a very fast rate, LED has given rise to a unique communication technology (visible light communication - VLC) used for high speed data transmission. By studying various kinds of commonly used VLC channel analysis: diffuse and line of sight channels, we presented a simply improved indoor and intra-vehicle visible light communication transmission model. Employing optical wireless communications within the vehicle, not only enhance user mobility, but also alleviate radio frequency interference, and increase efficiency by lowering the complexity of copper cabling. Moreover, a solution to eliminate ambient noise caused by environmental conditions is examined by using optical differential receiver. The simulation results show the improved received power distribution and signal to noise ratio - SNR.

240 nm UV LEDs for LISA test mass charge control

NASA Astrophysics Data System (ADS)

Olatunde, Taiwo; Shelley, Ryan; Chilton, Andrew; Serra, Paul; Ciani, Giacomo; Mueller, Guido; Conklin, John

2015-05-01

Test Masses inside the LISA Gravitational Reference Sensor must maintain almost pure geodesic motion for gravitational waves to be successfully detected. LISA requires residual test mass accelerations below 3 fm/s2/√Hz at all frequencies between 0.1 and 3 mHz. One of the well-known noise sources is associated with the charges on the test masses which couple to stray electrical potentials and external electromagnetic fields. LISA Pathfinder will use Hg-discharge lamps emitting mostly around 254 nm to discharge the test masses via photoemission in its 2015/16 flight. A future LISA mission launched around 2030 will likely replace the lamps with newer UV-LEDs. Presented here is a preliminary study of the effectiveness of charge control using latest generation UV-LEDs which produce light at 240 nm with energy above the work function of pure Au. Their lower mass, better power efficiency and small size make them an ideal replacement for Hg lamps.

DMD-based LED-illumination super-resolution and optical sectioning microscopy.

PubMed

Dan, Dan; Lei, Ming; Yao, Baoli; Wang, Wen; Winterhalder, Martin; Zumbusch, Andreas; Qi, Yujiao; Xia, Liang; Yan, Shaohui; Yang, Yanlong; Gao, Peng; Ye, Tong; Zhao, Wei

2013-01-01

Super-resolution three-dimensional (3D) optical microscopy has incomparable advantages over other high-resolution microscopic technologies, such as electron microscopy and atomic force microscopy, in the study of biological molecules, pathways and events in live cells and tissues. We present a novel approach of structured illumination microscopy (SIM) by using a digital micromirror device (DMD) for fringe projection and a low-coherence LED light for illumination. The lateral resolution of 90 nm and the optical sectioning depth of 120 μm were achieved. The maximum acquisition speed for 3D imaging in the optical sectioning mode was 1.6×10(7) pixels/second, which was mainly limited by the sensitivity and speed of the CCD camera. In contrast to other SIM techniques, the DMD-based LED-illumination SIM is cost-effective, ease of multi-wavelength switchable and speckle-noise-free. The 2D super-resolution and 3D optical sectioning modalities can be easily switched and applied to either fluorescent or non-fluorescent specimens.

DMD-based LED-illumination Super-resolution and optical sectioning microscopy

PubMed Central

Dan, Dan; Lei, Ming; Yao, Baoli; Wang, Wen; Winterhalder, Martin; Zumbusch, Andreas; Qi, Yujiao; Xia, Liang; Yan, Shaohui; Yang, Yanlong; Gao, Peng; Ye, Tong; Zhao, Wei

2013-01-01

Super-resolution three-dimensional (3D) optical microscopy has incomparable advantages over other high-resolution microscopic technologies, such as electron microscopy and atomic force microscopy, in the study of biological molecules, pathways and events in live cells and tissues. We present a novel approach of structured illumination microscopy (SIM) by using a digital micromirror device (DMD) for fringe projection and a low-coherence LED light for illumination. The lateral resolution of 90 nm and the optical sectioning depth of 120 μm were achieved. The maximum acquisition speed for 3D imaging in the optical sectioning mode was 1.6×107 pixels/second, which was mainly limited by the sensitivity and speed of the CCD camera. In contrast to other SIM techniques, the DMD-based LED-illumination SIM is cost-effective, ease of multi-wavelength switchable and speckle-noise-free. The 2D super-resolution and 3D optical sectioning modalities can be easily switched and applied to either fluorescent or non-fluorescent specimens. PMID:23346373

Chemical ecology of the emerald ash borer Agrilus planipennis.

PubMed

Crook, Damon J; Mastro, Victor C

2010-01-01

The emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) is a serious invasive pest that has caused devastating mortality of ash trees (Fraxinus sp., Oleaceae) since it was first identified in North America in 2002. Shortly after its discovery, surveys were conducted, based on the visual inspection of trees. The shortcomings of visual surveys have led to a critical research need to find an efficient survey method for detecting A. planipennis infestations. Here, we present a review of research that has led to the development of effective trapping methods for A. planipennis. Studies on the insect's biology and behavior have led to the identification of several potential attractants as well as the design of a visually attractive trap. The ongoing challenge in developing an optimally efficient trapping methodology for A. planipennis will involve finding the best combination of variables, such as trap shape, trap color (or other visual properties), trap placement, lure components, as well as the ratios and release rates of those components.

Compact collimators designed with a modified point approximation for light-emitting diodes

NASA Astrophysics Data System (ADS)

Luo, Tao; Wang, Gang

2017-09-01

We present a novel freeform lens design method for an application to LED collimating illumination. The method is derived from a basic geometric-optics analysis and construction approach. By using this method, a compact collimated lenses with Aspect Ratio = 0.219 is presented. Moreover, the utility efficiency (UE) inside the angle defined by ideal concentrator hypothesis with different lens-to-LED size ratios for both this lens and TIR lens are presented. A prototype of the collimator lens is also made to verify the practical performance of the lens, which has light distribution very compatible with the simulation results.

Sclerodermatomyositis, ocular manifestations.

PubMed

Pedroza-Seres, M; Serna-Ojeda, J C; Flores-Suárez, L F

2017-07-01

Sclerodermatomyositis is an overlap syndrome of myositis and scleroderma, with dermatological, muscular and joint involvement, but may also present with ocular manifestations. A 57 year-old woman presented with ophthalmological manifestations, including scleral thinning 360°, and the presence of cells in the anterior and posterior chamber. Oriented physical examination and laboratory studies led to the diagnosis, with the need for systemic treatment. Sclerodermatomyositis is a rare disease. Its diagnosis needs thorough clinical and laboratory studies, and its management should be multidisciplinary when inflammatory ocular manifestations may be present. Copyright © 2016 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

EDITORIAL: LED light sources (light for the future) LED light sources (light for the future)

NASA Astrophysics Data System (ADS)

Grandjean, N.

2010-09-01

Generating white light from electricity with maximum efficacy has been a long quest since the first incandescent lamp was invented by Edison at the end of the 19th century. Nowadays, semiconductors are making reality the holy grail of converting electrons into photons with 100% efficiency and with colours that can be mixed for white light illumination. The revolution in solid-state lighting (SSL) dates to 1994 when Nakamura reported the first high-brightness blue LED based on GaN semiconductors. Then, white light was produced by simply combining a blue dye with a yellow phosphor. After more than a decade of intensive research the performance of white LEDs is quite impressive, beating by far the luminous efficacy of compact fluorescent lamps. We are likely close to replacing our current lighting devices by SSL lamps. However, there are still technological and fabrication cost issues that could delay large market penetration of white LEDs. Interestingly, SSL may create novel ways of using light that could potentially limit electricity saving. Whatever the impact of SSL, it will be significant on our daily life. The purpose of this special cluster issue is to produce a snapshot of the current situation of SSL from different viewing angles. In an introductory paper, Tsao and co-workers from Sandia National Laboratories, present an energy-economics perspective of SSL considering societal changes and SSL technology evolution. In a second article, Narukawa et al working at Nichia Corporation—the pioneer and still the leading company in SSL—describe the state of the art of current research products. They demonstrate record performance with white LEDs exhibiting luminous efficacy of 183 lm W-1 at high-current injection. Then, a series of topical papers discuss in detail various aspects of the physics and technology of white LEDs Carrier localization in InGaN quantum wells has been considered the key to white LEDs' success despite the huge density of defects. A comprehensive review of the different localization mechanisms and their implication for internal quantum efficiency (IQE) is proposed by Oliver and co-workers from Cambridge University. When discussing IQE in InGaN-based LEDs, the efficiency droop at high-current injection always emerges, which is a major concern for the future of SSL technology. Here, a collaborative work between Samsung and the Gwangju Institute of Science and Technology (Korea) proves that a specific design of the active region can limit this detrimental effect. Once the issue of the IQE is solved, one still has to let the photons out of the chip. Matioli and Weisbuch from the University of California at Santa Barbara introduce the use of photonic crystals (PhCs) to improve light extraction efficiency. They describe different approaches to overcoming the main limitation of LEDs when implementing surface PhCs. The technology of SSL, and in particular of colour rendering, is tackled by Zukauskas et al who studied in detail different white light sources. They show that extreme colour-fidelity indices need to cover the entire spectrum, with a broad-band at 530-610 nm and a component beyond 610 nm. Then, the reliability of GaN-based LEDs is discussed in the paper of Meneghesso and co-workers. The authors consider the most important physical mechanisms that are (i) the degradation of the active layer of LEDs, (ii) the degradation of the package/phosphor system, (iii) the failure of GaN-based LEDs against electrostatic discharge. Finally, GaN LEDs on silicon developed in the group of Egawa at the Nagoya Institute of Technology are presented. This technology could allow a significant decrease in the fabrication cost of white LEDs.

Biochemical, photosynthetic and productive parameters of Chinese cabbage grown under blue-red LED assembly designed for space agriculture

NASA Astrophysics Data System (ADS)

Avercheva, Olga; Berkovich, Yuliy A.; Smolyanina, Svetlana; Bassarskaya, Elizaveta; Pogosyan, Sergey; Ptushenko, Vasiliy; Erokhin, Alexei; Zhigalova, Tatiana

2014-06-01

Currently light emitting diodes (LEDs) are considered to be most preferable source for space plant growth facilities. We performed a complex study of growth and photosynthesis in Chinese cabbage plants (Brassica chinensis L.) grown with continuous LED lighting based on red (650 nm) and blue (470 nm) LEDs with a red to blue photon ratio of 7:1. Plants grown with high-pressure sodium (HPS) lamps were used as a control. PPF levels used were about 100 μmol/(m2 s) (PPF 100) and nearly 400 μmol/(m2 s) (PPF 400). One group of plants was grown with PPF 100 and transferred to PPF 400 at the age of 12 days. Plants were studied at the age of 15 and 28 days (harvest age); some plants were left to naturally end their life cycle. We studied a number of parameters reflecting different stages of photosynthesis: photosynthetic pigment content; chlorophyll fluorescence parameters (photosystem II quantum yield, photochemical and non-photochemical chlorophyll fluorescence quenching); electron transport rate, proton gradient on thylakoid membranes (ΔpH), and photophosphorylation rate in isolated chloroplasts. We also tested parameters reflecting plant growth and productivity: shoot and root fresh and dry weight, sugar content and ascorbic acid content in shoots. Our results had shown that at PPF 100, plants grown with LEDs did not differ from control plants in shoot fresh weight, but showed substantial differences in photophosphorylation rate and sugar content. Differences observed in plants grown with PPF 100 become more pronounced in plants grown with PPF 400. Most parameters characterizing the plant photosynthetic performance, such as photosynthetic pigment content, electron transport rate, and ΔpH did not react strongly to light spectrum. Photophosphorylation rate differed strongly in plants grown with different spectrum and PPF level, but did not always reflect final plant yield. Results of the present work suggest that narrow-band LED lighting caused changes in Chinese cabbage plants on levels of the photosynthetic apparatus and the whole plant, concerning its development and adaptation to a varying PPF level.

Advanced LED warning system for rural intersections : phase 2 (ALERT-2) : final report.

DOT National Transportation Integrated Search

2014-02-01

This report presents findings of the second phase of the Advanced LED Warning System for Rural : Intersections (ALERT) project. Since it is the next generation of the same system, the second phase : system is referred to as the ALERT-2 system while t...

Investigating Bandgap Energies, Materials, and Design of Light-Emitting Diodes

ERIC Educational Resources Information Center

Wagner, Eugene P., II

2016-01-01

A student laboratory experiment to investigate the intrinsic and extrinsic bandgaps, dopant materials, and diode design in light-emitting diodes (LEDs) is presented. The LED intrinsic bandgap is determined by passing a small constant current through the diode and recording the junction voltage variation with temperature. A second visible…

The High-efficiency LED Driver for Visible Light Communication Applications.

PubMed

Gong, Cihun-Siyong Alex; Lee, Yu-Chen; Lai, Jyun-Liang; Yu, Chueh-Hao; Huang, Li Ren; Yang, Chia-Yen

2016-08-08

This paper presents a LED driver for VLC. The main purpose is to solve the low data rate problem used to be in switching type LED driver. The GaN power device is proposed to replace the traditional silicon power device of switching LED driver for the purpose of increasing switching frequency of converter, thereby increasing the bandwidth of data transmission. To achieve high efficiency, the diode-connected GaN power transistor is utilized to replace the traditional ultrafast recovery diode used to be in switching type LED driver. This work has been experimentally evaluated on 350-mA output current. The results demonstrate that it supports the data of PWM dimming level encoded in the PPM scheme for VLC application. The experimental results also show that system's efficiency of 80.8% can be achieved at 1-Mb/s data rate.

The effect of the photobiomodulation in the treatment of Bell's palsy: clinical experience

NASA Astrophysics Data System (ADS)

Colombo, Fabio; Marques, Aparecida Maria C.; Carvalho, Carolina M.; Paraguassu, Gardenia M.; de Sousa, José A. C.; Magalhaes, Edival; Cangussu, Maria Cristina T.; de A. Reis, Silvia Regina; Pinheiro, Antonio Luiz B.

2012-03-01

The Bell's palsy (G51) consists of a unilateral face paralysis that sudden begins with unknown cause and can result in complete mimic loss or partial paralysis of the face. Damage to the VII cranial nerve can be found in the pathology, promoting mussel's inactivity. The light Photobiomodulation (LPBM) has presented ability of rush the tissue repair, favoring the regeneration of neural structures. The present study aimed to assess the effectiveness use of the 780nm laser and 850nm LED (light-emitting diode) in the treatment of the face paralysis. Were evaluated 14 patients that suffer of Bell's palsy whom were submitted to the light administration, on the Laser Clinic of the UFBA between 2005 and 2010. The treatment was performed by infrared Laser in 11 patients (78.57%), and by LED in 3 patients (21.42%). At the end of the 12 sections, 11 patients (78.57%) had presented themselves cure or with substantial improvement of the initial picture, however 3 patients (21.42%) dealt with infra-red Laser λ780nm had not evolution. The light presented as an effective method for the treatment of Bell's palsy, but the association with the physiotherapy and medications is important.

Context before implementation: a qualitative study of decision makers' views of a peer-led healthy lifestyle intervention for people with serious mental illness in supportive housing.

PubMed

Cabassa, Leopoldo J; Stefancic, Ana

2018-04-04

People with serious mental illness die at an earlier age than people in the general population largely due to cardiovascular disease. Healthy lifestyle interventions can help reduce this health inequity. In this qualitative study, we examined the perceptions that decision makers in supportive housing agencies had toward a peer-led healthy lifestyle intervention and their views of contextual factors that could shape implementation at these agencies. A purposive sample of 12 decision makers from three supportive housing agencies was recruited. We presented participants a vignette describing our peer-led intervention and used semistructured qualitative interviews to examine their views. Interviews were recorded, professionally transcribed, and analyzed using directed content analysis. Participants reported positive views toward the intervention with the most valued intervention attributes being relative advantage over existing services, compatibility to clients' needs, ability to pilot the intervention, and cost. A model emerged from our data depicting multilevel contextual factors believed to shape the implementation of our intervention at these agencies, including system- (funding, marketability, and external regulations), organization- (leadership support, fit with organization, staff buy-in and burden), and client-level (adaptability to clients' needs, and clients' buy-in) factors. Study findings illustrate the importance of understanding the context of practice before implementation. This examination can help identify critical views from decision makers that could undermine or advance the integration of peer-led interventions in supportive housing agencies and help identify structures, policies, and organizational practices that can inform the implementation process.

A Difference in Cutaneous Pigmentary Response to LED Versus Halogen Incandescent Visible Light: A Case Report from a Single Center, Investigational Clinical Trial Determining a Minimal Pigmentary Visible Light Dose.

PubMed

Soleymani, Teo; Soter, Nicholas A; Folan, Lorcan M; Elbuluk, Nada; Okereke, Uchenna R; Cohen, David E

2017-04-01

BACKGROUND: While most of the attention regarding skin pigmentation has focused on the effects on ultraviolet radiation, the cutaneous effects of visible light (400 to 700nm) are rarely reported. In this report, we describe a case of painful erythema and induration that resulted from direct irradiation of UV-naïve skin with visible LED light in a patient with Fitzpatrick type II skin.

METHODS AND RESULTS: A 24-year-old healthy woman with Fitzpatrick type II skin presented to our department to participate in a clinical study. As part of the study, the subject underwent visible light irradiation with an LED and halogen incandescent visible light source. After 5 minutes of exposure, the patient complained of appreciable pain at the LED exposed site. Evaluation demonstrated erythema and mild induration. There were no subjective or objective findings at the halogen incandescent irradiated site, which received equivalent fluence (0.55 Watts / cm2). The study was halted as the subject was unable to tolerate the full duration of visible light irradiation.

CONCLUSION: This case illustrates the importance of recognizing the effects of visible light on skin. While the vast majority of investigational research has focused on ultraviolet light, the effects of visible light have been largely overlooked and must be taken into consideration, in all Fitzpatrick skin types.

J Drugs Dermatol. 2017;16(4):388-392.

Preparation of nanocomposites resin from seed Pterodon emarginatus doped maghemite nanoparticles.

PubMed

Silveira, L B; Martins, Q S; Maia, J C; Santos, J G

2012-06-01

Electrical characterization and magnetic nanocomposite resin seeds Pterodon emarginatus (PE) doped with nanoparticles of maghemite and treated by different chemical processes is reported in this paper. The pure PE resin showed semiconducting characteristics probably the presence of natural iron oxide in its molecular structure. The analysis of Mössbauer spectra pure resin showed two magnetic sites presented on measurements made at temperature of 300 K. Six "LEDs" to have been doped maghemite nanoparticles forming concentrations of 2.6 x 10(15) to 1.56 x 10(16) particles/cm2 forming the LED-PEMN. In the presence of the applied current versus voltage (0 to 0.9 V) LED-PEMN shown semiconducting properties. In the presence of frequency versus voltage sample of pure resin and LED features small decrease. While samples of LED-PEMN suffers loss frequency linearly with concentration and voltage. The pure PE resin shows high resistance to the applied voltage while the LED-PEMN is observed linear increase with the strength and concentration of nanoparticles of maghemite.

ELiXIR—Solid-State Luminaire With Enhanced Light Extraction by Internal Reflection

NASA Astrophysics Data System (ADS)

Allen, Steven C.; Steckl, Andrew J.

2007-06-01

A phosphor-converted light-emitting diode (pcLED) luminaire featuring enhanced light extraction by internal reflection (ELiXIR) with efficacy of 60 lm/W producing 18 lumens of yellowish green light at 100 mA is presented. The luminaire consists of a commercial blue high power LED, a polymer hemispherical shell lens with interior phosphor coating, and planar aluminized reflector. High extraction efficiency of the phosphor-converted light is achieved by separating the phosphor from the LED and using internal reflection to steer the light away from lossy reflectors and the LED package and out of the device. At 10 and 500 mA, the luminaire produces 2.1 and 66 lumens with efficacies of 80 and 37 lm/W, respectively. Technological improvements over existing commercial LEDs, such as more efficient pcLED packages or, alternatively, higher efficiency green or yellow for color mixing, will be essential to achieving 150 200 lm/W solid-state lighting. Advances in both areas are demonstrated.

Accidental mydriasis from blue nightshade "lipstick".

PubMed

Rubinfeld, R S; Currie, J N

1987-03-01

A 7-year-old girl presented with bilaterally dilated pupils, nausea, and vomiting 2 days after head trauma. Pilocarpine pupil testing led to the correct diagnosis of pharmacologic pupillary dilation from an unexpected and unusual source of plant poisoning, Solanum dulcamara (blue nightshade). In patients with internal ophthalmoplegia, awareness of the possibility of pharmacologic mydriasis and correct use of topical pilocarpine testing can preclude the necessity for neuroradiologic and invasive diagnostic studies, even in cases with atypical or complex presentations.

New illuminations approaches with single-use micro LEDs endoilluminators for the pars plana vitrectomy

NASA Astrophysics Data System (ADS)

Koelbl, Philipp Simon; Koch, Frank H. J.; Lingenfelder, Christian; Hessling, Martin

2018-02-01

The illumination of the intraocular space during pars plana vitrectomy always bears the risk of retina damage by irradiation. Conventional illumination systems consist of an external light source and an optical fiber to transfer the visible light (radiation) into the eye. Often xenon arc and halogen lamps are employed for this application with some disadvantageous properties like high phototoxicity and low efficiency. Therefore, we propose to generate the light directly within the eye by inserting a white micro LED with a diameter of 0.6 mm. The LED offers a luminous flux of 0.6 lm of white light with a blue peak @ 450 nm and a yellow peak @ 555 nm. The presented prototypes fit through a standard 23 G trocar and are the first intraocular light sources worldwide. Two different single-use approaches have already been developed: a handguided and a chandelier device. The hand-guided applicator enables a directly navigation and illumination up to a working distance of 6 mm. The chandelier device is much smaller and does not need an active navigation of the light cone. The brightness and homogeneity of the illumination of these LED devices have been successfully tested on porcine eyes. Presented measurements and calculations prove that even for high LED currents and small distances to the retina these intraocular micro LED devices expose the retina to less hazard than conventional illumination sources like fiber based xenon systems. Even under the worst circumstances application durations of 180 hours would be justifiable.

Color Maintenance of LEDs in Laboratory and Field Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Royer, Michael P.; Tuttle, Ralph; Rosenfeld, Scott M.

Synopsis: To date, consideration for parametric failure of LED products has largely been focused on lumen maintenance. However, color shift is a cause of early failure for some products, and is especially important to consider in certain applications, like museums, where visual appearance is critical. Example data collected by the GATEWAY program for LED lamps installed in museums shows that many have changed color beyond a reasonable tolerance well before their rated lifetime was reached, necessitating replacement. Similar data collected by the CALiPER program between 2008 and 2010 reveals that many early products shifted beyond acceptable tolerances in as littlemore » as a few thousand hours. In contrast, data from the L Prize program illustrates that commercially available LED products can have exemplary color stability that is unmatched by traditional light sources. Beyond presenting data from the aforementioned DOE programs, this report discusses the metrics used for communicating color shift—namely MacAdam ellipses and Δu'v'—as well as providing guidance for end users on how to monitor color shift and what to look for in manufacturer warranties. Also included are descriptions of the physical changes that have been documented as leading to color shift in some example types of LED packages. As with complete products, the data presented herein for LED packages shows that a wide variety of products are available; in order for specifiers and consumers to make educated choices, more detailed and standardized information should be made available.« less

Replicative manufacturing of complex lighting optics by non-isothermal glass molding

NASA Astrophysics Data System (ADS)

Kreilkamp, Holger; Vu, Anh Tuan; Dambon, Olaf; Klocke, Fritz

2016-09-01

The advantages of LED lighting, especially its energy efficiency and the long service life have led to a wide distribution of LED technology in the world. However, in order to make fully use of the great potential that LED lighting offers, complex optics are required to distribute the emitted light from the LED efficiently. Nowadays, many applications use polymer optics which can be manufactured at low costs. However, due to ever increasing luminous power, polymer optics reach their technological limits. Due to its outstanding properties, especially its temperature resistance, resistance against UV radiation and its long term stability, glass is the alternative material of choice for the use in LED optics. This research is introducing a new replicative glass manufacturing approach, namely non-isothermal glass molding (NGM) which is able to manufacture complex lighting optics in high volumes at competitive prices. The integration of FEM simulation at the early stage of the process development is presented and helps to guarantee a fast development cycle. A coupled thermo-mechanical model is used to define the geometry of the glass preform as well as to define the mold surface geometry. Furthermore, simulation is used to predict main process outcomes, especially in terms of resulting form accuracy of the molded optics. Experiments conducted on a commercially available molding machine are presented to validate the developed simulation model. Finally, the influence of distinct parameters on important process outcomes like form accuracy, surface roughness, birefringence, etc. is discussed.

"Bounded" empowerment: analyzing tensions in the practice of youth-led participatory research in urban public schools.

PubMed

Ozer, Emily J; Newlan, Sami; Douglas, Laura; Hubbard, Elizabeth

2013-09-01

This multi-method study examines tensions in the practice of youth-led participatory research (YPAR) in urban high schools among 15 semester-cohorts. Student participants in the present study were 77 ethnically diverse youth from four high schools in a major metropolitan school district. Data were gathered using systematic classroom observations, interviews with teachers and students involved in the projects, and participant observation. The two most commonly-constrained phases of the YPAR project were issue selection and action steps. A central tension in the issue selection phase for projects enacted across multiple semester cohorts was the tension between original inquiry and "traction:" Sticking with the same topic enabled sustained building of strategic alliances and expertise for making change, but limited the incoming cohort's power to define the problem to be addressed. In further analyses, we identified processes that promoted student power despite continuity-related constraints-teachers' framing and buy-in strategies, "micro-power" compensation, and alignment of students' interests with the prior cohort-as well as constraints in other phases of the projects. This study's findings regarding the promotion of youth power in the face of constraints advance the integration of theory and practice in youth-led research and have implications for participatory research more broadly.

Development and future of ultraviolet light-emitting diodes: UV-LED will replace the UV lamp

NASA Astrophysics Data System (ADS)

Muramoto, Yoshihiko; Kimura, Masahiro; Nouda, Suguru

2014-06-01

Ultraviolet light-emitting diodes (UV-LEDs) have started replacing UV lamps. The power per LED of high-power LED products has reached 12 W (14 A), which is 100 times the values observed ten years ago. In addition, the cost of these high-power LEDs has been decreasing. In this study, we attempt to understand the technologies and potential of UV-LEDs.

Development and testing of a homogenous multi-wavelength LED light source

NASA Astrophysics Data System (ADS)

Bolton, Frank J.; Bernat, Amir; Jacques, Steven L.; Levitz, David

2017-03-01

Multispectral imaging of human tissue is a powerful method that allows for quantify scattering and absorption parameters of the tissue and differentiate tissue types or identify pathology. This method requires imaging at multiple wavelengths and then fitting the measured data to a model based on light transport theory. Earlier, a mobile phone based multi-spectral imaging system was developed to image the uterine cervix from the colposcopy geometry, outside the patient's body at a distance of 200-300 mm. Such imaging of a distance object has inherent challenges, as bright and homogenous illumination is required. Several solutions addressing this problem were developed, with varied degrees of success. In this paper, several multi-spectral illumination setups were developed and tested for brightness and uniformity. All setups were specifically designed with low cost in mind, utilizing a printed circuit board with surface-mounted LEDs. The three setups include: LEDs illuminating the target directly, LEDs illuminating focused by a 3D printed miniature lens array, and LEDs coupled to a mixing lens and focusing optical system. In order to compare the illumination uniformity and intensity performance two experiments were performed. Test results are presented, and various tradeoffs between the three system configurations are discussed. Test results are presented, and various tradeoffs between the three system configurations are discussed.

Photomatrix LED therapy of extensive cutaneous pathology

NASA Astrophysics Data System (ADS)

Zharov, Vladimir P.; Menyaev, Yulian A.; Zharova, I. Z.; Leviev, Dmitry O.; Tsarev, V. N.; Sarantsev, V. P.; Krusic, Joze

2000-05-01

Standard sources of radiation have not sufficient efficiency at treating spatially extended pathology, especially when pathologic areas involve opposite sides of the human being's body or when they are uneven in shape. The typical examples of such pathology are extensive burns, oedema, inflammatory processes, infectious wounds, actinic keratosis, psoriasis, arthritis and neurological diseases. Superbright LEDs gathered in a matrix and grasping the area of irradiation are the most suitable sources of radiation. This article presents the result of investigation of the effectiveness of various types of the blue-to-infrared spectrum range LED array that allow irradiating a surface with an area from several cm2 to several thousand cm2 including the whole human being's body with the intensity varying from 1 to 100 mW/cm2. Besides the matrixes, composed of separate light diodes, modular systems with separate monolithic hybrid chips with a high density of positioning the sources of radiation are considered. The peculiarities and results of applying such systems to treat oedema, cancer, weight regulation, neurological diseases, different infections diseases in combination with PDT, stomatitis and paradontosis are analyzed. The parameters of the photomatrix LED for different spectral regions and different geometry from flat shape to semispherical and cylindrical are presented. The perspective combination photomatrix LED with another therapeutical devices including photovacuum and photomagnetic therapy are considered.

Comparison of UV-LED and low pressure UV for water disinfection: Photoreactivation and dark repair of Escherichia coli.

PubMed

Li, Guo-Qiang; Wang, Wen-Long; Huo, Zheng-Yang; Lu, Yun; Hu, Hong-Ying

2017-12-01

Studies on ultraviolet light-emitting diode (UV-LED) water disinfection have shown advantages, such as safety, flexible design, and lower starting voltages. However, information about reactivation after UV-LED disinfection is limited, which is an important issue of UV light-based technology. In this study, the photoreactivation and dark repair of Escherichia coli after UV-LEDs and low pressure (LP) UV disinfection were compared. Four UV-LED units, 265 nm, 280 nm, the combination of 265 + 280 (50%), and 265 + 280 (75%) were tested. 265 nm LEDs was more effective than 280 nm LEDs and LP UV lamps for E. coli inactivation. No synergic effect for disinfection was observed from the combination of 265 and 280 nm LEDs. 265 nm LEDs had no different reactivation performances with that of LP UV, while 280 nm LEDs could significantly repress photoreactivation and dark repair at a low irradiation intensity of 6.9 mJ/cm 2 . Furthermore, the UV-induced damage of 280 nm LEDs was less repaired which was determined by endonuclease sensitive site (ESS) assay. The impaired protein activities by 280 nm LEDs might be one of the reasons that inhibited reactivation. A new reactivation rate constant, K max , was introduced into the logistic model to simulate the reactivation data, which showed positive relationship with the maximum survival ratio and was more reasonable to interpret the results of photoreactivation and dark repair. This study revealed the distinct roles of different UV lights in disinfection and reactivation, which is helpful for the future design of UV-LED equipment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multiobjective generalized extremal optimization algorithm for simulation of daylight illuminants

NASA Astrophysics Data System (ADS)

Kumar, Srividya Ravindra; Kurian, Ciji Pearl; Gomes-Borges, Marcos Eduardo

2017-10-01

Daylight illuminants are widely used as references for color quality testing and optical vision testing applications. Presently used daylight simulators make use of fluorescent bulbs that are not tunable and occupy more space inside the quality testing chambers. By designing a spectrally tunable LED light source with an optimal number of LEDs, cost, space, and energy can be saved. This paper describes an application of the generalized extremal optimization (GEO) algorithm for selection of the appropriate quantity and quality of LEDs that compose the light source. The multiobjective approach of this algorithm tries to get the best spectral simulation with minimum fitness error toward the target spectrum, correlated color temperature (CCT) the same as the target spectrum, high color rendering index (CRI), and luminous flux as required for testing applications. GEO is a global search algorithm based on phenomena of natural evolution and is especially designed to be used in complex optimization problems. Several simulations have been conducted to validate the performance of the algorithm. The methodology applied to model the LEDs, together with the theoretical basis for CCT and CRI calculation, is presented in this paper. A comparative result analysis of M-GEO evolutionary algorithm with the Levenberg-Marquardt conventional deterministic algorithm is also presented.

Modified scoring criteria for the RBANS figures.

PubMed

Duff, Kevin; Leber, W R; Patton, Doyle E; Schoenberg, Mike R; Mold, James W; Scott, James G; Adams, Russell L

2007-01-01

Visual construction and memory tasks are routinely used in neuropsychological assessment, but their subjective scoring criteria can negatively affect the reliability of these instruments. The current study examined the standard scoring criteria for the Figure Copy and Recall subtests of the RBANS and compared them to a modified set of scoring criteria in two samples. In both a large community dwelling sample of older adults and in a mixed clinical sample, the original scoring criteria consistently led to lower scores than the modified criteria. Inter-rater reliability was high for the modified scoring criteria, and no age effects were found with the modified scoring criteria. In both samples, the modified scoring criteria led to Figure Copy scores that more closely approximated other performances on the RBANS compared to the standard criteria, whereas both scoring systems led to plausible Figure Recall scores. Despite these results, the present study cannot identify one scoring criterion as the "better," but only points out the significant differences between them. Such differences can have important clinical implications, and practitioners and researchers who utilize the RBANS with patient samples should be cautious when interpreting low scores on Figure Copy and Recall if the standard criteria are used.

Online and offline peer led models against bullying and cyberbullying.

PubMed

Palladino, Benedetta Emanuela; Nocentini, Annalaura; Menesini, Ersilia

2012-11-01

The aim of the present study is to describe and evaluate an ongoing peer-led model against bullying and cyberbullying carried out with Italian adolescents. The evaluation of the project was made through an experimental design consisting of a pre-test and a post-test. Participants in the study were 375 adolescents (20.3% males), enrolled in 9th to 13th grades. The experimental group involved 231 students with 42 peer educators, and the control group involved 144 students. Results showed a significant decrease in the experimental group as compared to the control group for all the variables except for cyberbullying. Besides, in the experimental group we found a significant increase in adaptive coping strategies like problem solving and a significant decrease in maladaptive coping strategies like avoidance: these changes mediate the changes in the behavioural variables. In particular, the decrease in avoidance predicts the decrease in victimization and cybervictimization for peer educators and for the other students in the experimental classes whereas the increase in problem solving predicts the decrease in cyberbullying only in the peer educators group. Results are discussed following recent reviews on evidence based efficacy of peer led models.

The prospective effects of workplace violence on physicians' job satisfaction and turnover intentions: the buffering effect of job control.

PubMed

Heponiemi, Tarja; Kouvonen, Anne; Virtanen, Marianna; Vänskä, Jukka; Elovainio, Marko

2014-01-17

Health care professionals, including physicians, are at high risk of encountering workplace violence. At the same time physician turnover is an increasing problem that threatens the functioning of the health care sector worldwide. The present study examined the prospective associations of work-related physical violence and bullying with physicians' turnover intentions and job satisfaction. In addition, we tested whether job control would modify these associations. The present study was a 4-year longitudinal survey study, with data gathered in 2006 and 2010.The present sample included 1515 (61% women) Finnish physicians aged 25-63 years at baseline. Analyses of covariance (ANCOVA) were conducted while adjusting for gender, age, baseline levels, specialisation status, and employment sector. The results of covariance analyses showed that physical violence led to increased physician turnover intentions and that both bullying and physical violence led to reduced physician job satisfaction even after adjustments. We also found that opportunities for job control were able to alleviate the increase in turnover intentions resulting from bullying. Our results suggest that workplace violence is an extensive problem in the health care sector and may lead to increased turnover and job dissatisfaction. Thus, health care organisations should approach this problem through different means, for example, by giving health care employees more opportunities to control their own work.

The prospective effects of workplace violence on physicians’ job satisfaction and turnover intentions: the buffering effect of job control

PubMed Central

2014-01-01

Background Health care professionals, including physicians, are at high risk of encountering workplace violence. At the same time physician turnover is an increasing problem that threatens the functioning of the health care sector worldwide. The present study examined the prospective associations of work-related physical violence and bullying with physicians’ turnover intentions and job satisfaction. In addition, we tested whether job control would modify these associations. Methods The present study was a 4-year longitudinal survey study, with data gathered in 2006 and 2010.The present sample included 1515 (61% women) Finnish physicians aged 25–63 years at baseline. Analyses of covariance (ANCOVA) were conducted while adjusting for gender, age, baseline levels, specialisation status, and employment sector. Results The results of covariance analyses showed that physical violence led to increased physician turnover intentions and that both bullying and physical violence led to reduced physician job satisfaction even after adjustments. We also found that opportunities for job control were able to alleviate the increase in turnover intentions resulting from bullying. Conclusions Our results suggest that workplace violence is an extensive problem in the health care sector and may lead to increased turnover and job dissatisfaction. Thus, health care organisations should approach this problem through different means, for example, by giving health care employees more opportunities to control their own work. PMID:24438449

Improved predictive modeling of white LEDs with accurate luminescence simulation and practical inputs with TracePro opto-mechanical design software

NASA Astrophysics Data System (ADS)

Tsao, Chao-hsi; Freniere, Edward R.; Smith, Linda

2009-02-01

The use of white LEDs for solid-state lighting to address applications in the automotive, architectural and general illumination markets is just emerging. LEDs promise greater energy efficiency and lower maintenance costs. However, there is a significant amount of design and cost optimization to be done while companies continue to improve semiconductor manufacturing processes and begin to apply more efficient and better color rendering luminescent materials such as phosphor and quantum dot nanomaterials. In the last decade, accurate and predictive opto-mechanical software modeling has enabled adherence to performance, consistency, cost, and aesthetic criteria without the cost and time associated with iterative hardware prototyping. More sophisticated models that include simulation of optical phenomenon, such as luminescence, promise to yield designs that are more predictive - giving design engineers and materials scientists more control over the design process to quickly reach optimum performance, manufacturability, and cost criteria. A design case study is presented where first, a phosphor formulation and excitation source are optimized for a white light. The phosphor formulation, the excitation source and other LED components are optically and mechanically modeled and ray traced. Finally, its performance is analyzed. A blue LED source is characterized by its relative spectral power distribution and angular intensity distribution. YAG:Ce phosphor is characterized by relative absorption, excitation and emission spectra, quantum efficiency and bulk absorption coefficient. Bulk scatter properties are characterized by wavelength dependent scatter coefficients, anisotropy and bulk absorption coefficient.

Progress in extremely high brightness LED-based light sources

NASA Astrophysics Data System (ADS)

Hoelen, Christoph; Antonis, Piet; de Boer, Dick; Koole, Rolf; Kadijk, Simon; Li, Yun; Vanbroekhoven, Vincent; Van De Voorde, Patrick

2017-09-01

Although the maximum brightness of LEDs has been increasing continuously during the past decade, their luminance is still far from what is required for multiple applications that still rely on the high brightness of discharge lamps. In particular for high brightness applications with limited étendue, e.g. front projection, only very modest luminance values in the beam can be achieved with LEDs compared to systems based on discharge lamps or lasers. With dedicated architectures, phosphor-converted green LEDs for projection may achieve luminance values up to 200-300 Mnit. In this paper we report on the progress made in the development of light engines based on an elongated luminescent concentrator pumped by blue LEDs. This concept has recently been introduced to the market as ColorSpark High Lumen Density LED technology. These sources outperform the maximum brightness of LEDs by multiple factors. In LED front projection, green LEDs are the main limiting factor. With our green modules, we now have achieved peak luminance values of 2 Gnit, enabling LED-based projection systems with over 4000 ANSI lm. Extension of this concept to yellow and red light sources is presented. The light source efficiency has been increased considerably, reaching 45-60 lm/W for green under practical application conditions. The module architecture, beam shaping, and performance characteristics are reviewed, as well as system aspects. The performance increase, spectral range extensions, beam-shaping flexibility, and cost reductions realized with the new module architecture enable a breakthrough in LED-based projection systems and in a wide variety of other high brightness applications.

Topical and Intradermal Efficacy of Photodynamic Therapy with Methylene Blue and Light-Emitting Diode in the Treatment of Cutaneous Leishmaniasis Caused by Leishmania braziliensis

PubMed Central

Sbeghen, Mônica Raquel; Voltarelli, Evandra Maria; Campois, Tácito Graminha; Kimura, Elza; Aristides, Sandra Mara Alessi; Hernandes, Luzmarina; Caetano, Wilker; Hioka, Noboru; Lonardoni, Maria Valdrinez Campana; Silveira, Thaís Gomes Verzignassi

2015-01-01

Introduction: The topical and intradermal photodynamic therapy (PDT) effect of methylene blue (MB) using light-emitting diode (LED) as light source (MB/LED-PDT) in the treatment of lesions of American cutaneous leishmaniasis (ACL) caused by Leishmania braziliensis in hamsters were investigated. Methods: Hamsters were infected in the footpad with 4×107 promastigotes of L. braziliensis and divided in 4 groups: Control group was not treated, AmB group was treated with amphotericin B, MB-Id group received intradermal MB at the edge of the lesion and MB-Tp group received MB topic. After treatment with MB, the animals were illuminated using red LEDs at the 655 nm wavelength for 1 hour. The MB/LED-PDT was carried out three times a week for 12 weeks. Results: Animals of MB-Tp group presented lesion healing with significant diminution in extent of the lesion, and reduced parasite burden compared to control group; however, no significant difference was seen compared to the AmB group. MB-Tp group also showed reconstitution of the epithelium, the formation of collagen fibers, organization in the epidermis, a little disorganization and inflammation in the dermis. MB-Id was ineffective in all parameters evaluated, and it was comparable to the control group results. Conclusion: These data show that PDT with the use of MB-Tp and LED may be an alternative for the treatment of ACL. However, additional studies are being conducted to assess the potential of MB/LED-PDT, alone or in combination with conventional therapy, for the treatment of ACL. PMID:26464777

The Impact of Multiple Master Patient Index Records on the Business Performance of Health Care Organizations: A Qualitative Grounded Theory Study

ERIC Educational Resources Information Center

Banton, Cynthia L.

2014-01-01

The purpose of this qualitative grounded theory study was to explore and examine the factors that led to the creation of multiple record entries, and present a theory on the impact the problem has on the business performance of health care organizations. A sample of 59 health care professionals across the United States participated in an online…

Managed Care Peer-Led Teaching: An Innovative Learning Approach Outside the College of Pharmacy Core Curriculum.

PubMed

Tang, SyHui; Smith, Julia; Lau, Wilson; Tse, Isaac; Tan, Christine; Cotten, Ryan; Pittenger, Amy

2017-07-01

Managed care pharmacy is a growing field, but there are still limited educational opportunities available in pharmacy school core curricula. Students often seek self-directed learning opportunities to further explore the field. To (a) evaluate practicality and effectiveness of a student-designed managed care pharmacy elective and (b) determine emerging best practices for design and sustainability of peer-led, self-directed courses. A managed care elective course was designed as a student, peer-led course during the 2012-2013 school year at the University of Minnesota College of Pharmacy. As the course evolved, coordinators evaluated the effectiveness and sustainability of a student-led elective. The course required students to select a managed care topic of interest and deliver a discussion-based presentation. Teleconferencing was used to maximize participation and flexibility of pharmacist delegates from local managed care organizations who provided industry insight and expert mentorship. Data sources were gathered via course evaluation surveys, peer evaluations of presentations, and postgraduation surveys. Data were used to guide course improvement, gain insight into motivation for student participation, and evaluate the effect on career choices. During the fall and spring semesters of 2014-2015, 45 students participated and completed surveys: 28 in the fall and 17 in the spring. Seventy percent of enrollees took the course because of interest in managed care; 12% took the course because of referrals from past students; and 12% enrolled to explore topics outside of the pharmacy core curriculum. After completion of the course, 50% of students felt "somewhat comfortable" in discussing managed care topics, and 31% felt "very comfortable." None of the 17 students from the spring semester class answered "not comfortable" or "somewhat not comfortable." Suggestions for improvement from the fall semester class led to smaller class size, a roundtable setting, and new meeting times. In a survey of 6 graduates, 1 student pursued a fellowship; 2 students obtained managed care residencies; and 1 student worked as a managed care pharmacist. Data collected from students enrolled in the managed care elective indicated increased exposure and enhanced knowledge on topics discussed. Data also indicated value and support for the addition of peerled courses to the College of Pharmacy's curriculum. Graduates who took the course have pursued managed care careers and confirmed the benefits of peer-led learning. No outside funding supported this study. The authors have nothing to disclose. Study concept and design were contributed by Tang, Smith, Tse, Tan, and Pittenger. Lau took the lead in data collection, along with Tang and Smith. Data interpretation was performed primarily by Lau, along with Tang, Smith, and Pittenger. The manuscript was written by all the authors and revised primarily by Tang, along with Smith, Lau, Pittenger, and Tan. This research was presented as a poster at the Academy of Managed Care Pharmacy Nexus 2015; October 26-29, 2015; Orlando, Florida.

Neuronal correlates of visual and auditory alertness in the DMT and ketamine model of psychosis.

PubMed

Daumann, J; Wagner, D; Heekeren, K; Neukirch, A; Thiel, C M; Gouzoulis-Mayfrank, E

2010-10-01

Deficits in attentional functions belong to the core cognitive symptoms in schizophrenic patients. Alertness is a nonselective attention component that refers to a state of general readiness that improves stimulus processing and response initiation. The main goal of the present study was to investigate cerebral correlates of alertness in the human 5HT(2A) agonist and N-methyl-D-aspartic acid (NMDA) antagonist model of psychosis. Fourteen healthy volunteers participated in a randomized double-blind, cross-over event-related functional magnetic resonance imaging (fMRI) study with dimethyltryptamine (DMT) and S-ketamine. A target detection task with cued and uncued trials in both the visual and the auditory modality was used. Administration of DMT led to decreased blood oxygenation level-dependent response during performance of an alertness task, particularly in extrastriate regions during visual alerting and in temporal regions during auditory alerting. In general, the effects for the visual modality were more pronounced. In contrast, administration of S-ketamine led to increased cortical activation in the left insula and precentral gyrus in the auditory modality. The results of the present study might deliver more insight into potential differences and overlapping pathomechanisms in schizophrenia. These conclusions must remain preliminary and should be explored by further fMRI studies with schizophrenic patients performing modality-specific alertness tasks.

Sexperts! Disrupting Injustice through HIV Prevention and Legal Rights Education with Transgenders in Thailand

ERIC Educational Resources Information Center

Walsh, Christopher S.; Chaiyajit, Nada

2012-01-01

In addition to growing epidemics of HIV transgenders in Thailand, a low awareness of how to access justice increases their vulnerability to HIV infection. This paper presents a unique case study of how one community-based and led organisations used social networking and instant messaging to address this problem among transgender community in…

Drawing Firmer Conclusions: Autistic Children Show No Evidence of a Local Processing Bias in a Controlled Copying Task

ERIC Educational Resources Information Center

Smith, Alastair D.; Kenny, Lorcan; Rudnicka, Anna; Briscoe, Josie; Pellicano, Elizabeth

2016-01-01

Drawing tasks are frequently used to test competing theories of visuospatial skills in autism. Yet, methodological differences between studies have led to inconsistent findings. To distinguish between accounts based on local bias or global deficit, we present a simple task that has previously revealed dissociable local/global impairments in…

The Student Voice in Higher Education Curriculum Design: Is There Value in Listening?

ERIC Educational Resources Information Center

Brooman, S.; Darwent, S.; Pimor, A.

2015-01-01

This article presents a case study illustrating the potential value of enhanced student participation in higher education (HE) curriculum development, in response to an absence of research in this area. Lecturers and students had divergent views of the effectiveness of a staff-led redesign of a module curriculum. Focus groups were used to…

Using a Naturalistic Ecological Approach to Examine the Factors Influencing Youth Physical Activity across Grades 7 to 12

ERIC Educational Resources Information Center

Humbert, M. Louise; Chad, Karen E.; Bruner, Mark W.; Spink, Kevin S.; Muhajarine, Nazeem; Anderson, Kristal D.; Girolami, Tammy M.; Odnokon, Patrick; Gryba, Catherine R.

2008-01-01

High levels of inactivity in youth have led researchers and practitioners to focus on identifying the factors that influence physical activity behaviors in young people. The present study employed a qualitative ecological framework to examine the intrapersonal, social, and environmental factors influencing youth physical activity. In…

Loneliness, Depressive Symptomatology, and Suicide Ideation in Adolescence: Cross-Sectional and Longitudinal Analyses

ERIC Educational Resources Information Center

Lasgaard, Mathias; Goossens, Luc; Elklit, Ask

2011-01-01

The paper presents the first known longitudinal study of the relationship between loneliness, depressive symptoms, and suicide ideation in adolescence, in a stratified sample of high school students (Time 1 N = 1009; 57% female; Time 2 N = 541; 60% female). Cross-lagged structural equation modeling indicated that depressive symptoms led to more…

Creating a Culture of Student Philanthropy to Address Financial Challenges in Universities

ERIC Educational Resources Information Center

Pottick, Kathleen J.; Giordano, Stephanie; Chirico, Danielle E.

2015-01-01

Concerns about the cost of higher education and student loan debt have resulted in increasing efforts by policymakers and university administrators to find alternative ways to support the financing of higher education for students. The authors present a case study of a student-led philanthropy campaign to generate funding for social work student…

Designing, Developing and Implementing a Software Tool for Scenario Based Learning

ERIC Educational Resources Information Center

Norton, Geoff; Taylor, Mathew; Stewart, Terry; Blackburn, Greg; Jinks, Audrey; Razdar, Bahareh; Holmes, Paul; Marastoni, Enrique

2012-01-01

The pedagogical value of problem-based and inquiry-based learning activities has led to increased use of this approach in many courses. While scenarios or case studies were initially presented to learners as text-based material, the development of modern software technology provides the opportunity to deliver scenarios as e-learning modules,…

Enhance Academic Study in Vocational Education in China

ERIC Educational Resources Information Center

Sun, Ling

2010-01-01

The increase in international trade and the information technology boom led us to begin to face the previously unthinkable of academic shortage towards vocational education. The main objective of this paper is to present the problem and find ways to solve it. The main finding included lack of investment from society and high degree involvement of…

Fluorescence spectroscopy of dental calculus

NASA Astrophysics Data System (ADS)

Bakhmutov, D.; Gonchukov, S.; Sukhinina, A.

2010-05-01

The aim of the present study was to investigate the fluorescence properties of dental calculus in comparison with the properties of adjacent unaffected tooth structure using both lasers and LEDs in the UV-visible range for fluorescence excitation. The influence of calculus color on the informative signal is demonstrated. The optimal spectral bands of excitation and registration of the fluorescence are determined.

A Nice Way To Make a Living: Reflections on the Career of an Experienced Theatre Teacher.

ERIC Educational Resources Information Center

Brown, Cynthia L.

1999-01-01

Presents a case study examining the personal characteristics and external support systems which may have led to longevity in the career of a specific high school theatre arts teacher. Discusses internal support systems (including organizational skills, being adaptable to change, and respecting students) and external support systems (including the…

Exploring Secondary Science Teachers' Perceptions on the Goals of Earth Science Education in Taiwan

ERIC Educational Resources Information Center

Chang, Chun-Yen; Chang, Yueh-Hsia; Yang, Fang-Ying

2009-01-01

The educational reform movement since the 1990s has led the secondary earth science curriculum in Taiwan into a stage of reshaping. The present study investigated secondary earth science teachers' perceptions on the Goals of Earth Science Education (GESE). The GESE should express the statements of philosophy and purpose toward which educators…

Ecology and management of the spotted owl in the Pacific Northwest.

Treesearch

Ralph J. Gutierrez; Andrew B. tech. eds. Carey

1985-01-01

The spotted owl (Strix occidentalis caurina) has been listed as a sensitive species by the Pacific Southwest Region USDA Forest Service. Past and present-studies-and surveys have led to the development of a region-wide network of owl territories to comply with the maintenance of viable populations as required by the National Forest Management Act....

The Case for Teacher Leadership: Towards Definition and Development.

ERIC Educational Resources Information Center

Fay, Carolyn

The first part of this paper presents the findings of a study of the leadership needs of five practicing teacher leaders. Findings identified an expressed need for specific teacher development and training, which led to the creation of a Leadership Institute for the Future of Teaching (LIFT). The second part of the paper describes the LIFT…

Predicting Success Using HESI A2 Entrance Tests in an Associate Degree Nursing Program

ERIC Educational Resources Information Center

Bodman, Susan

2012-01-01

A challenge presented to nurse educators is retention of nursing students. This has led nursing faculty to review admission requirements and question how well entrance tests predict success in Associate Degree Nursing Programs. The purpose of this study was to investigate the relationship between the HESI Admission Assessment Exam (HESI A2) and…

Annual Research Review: Attachment Disorders in Early Childhood--Clinical Presentation, Causes, Correlates, and Treatment

ERIC Educational Resources Information Center

Zeanah, Charles H.; Gleason, Mary Margaret

2015-01-01

Background: Though noted in the clinical literature for more than 50 years, attachment disorders have been studied systematically only recently. In part because of the ubiquity of attachments in humans, determining when aberrant behavior is best explained as an attachment disorder as opposed to insecure attachment has led to some confusion. In…

Adsorption of Oxy-Anions in the Teaching Laboratory: An Experiment to Study a Fundamental Environmental Engineering Problem

ERIC Educational Resources Information Center

D'Arcy, Mitch; Bullough, Florence; Moffat, Chris; Borgomeo, Edoardo; Teh, Micheal; Vilar, Ramon; Weiss, Dominik J.

2014-01-01

Synthesizing and testing bicomposite adsorbents for the removal of environmentally problematic oxy-anions is high on the agenda of research-led universities. Here we present a laboratory module successfully developed at Imperial College London that introduces the advanced undergraduate student in engineering (chemical, civil, earth) and science…

The Cooperative Sharing of Audiovisual Materials in Medical Schools; a Network Approach. Case Study 1.

ERIC Educational Resources Information Center

National Medical Audiovisual Center of the National Library of Medicine, Atlanta, GA.

The evolution of medical schools from their post-Renaissance Italian prototypes to present modern facilities has been marked by a variety of philosophies, methodologies, and pedagogical styles. Pressures to improve medical curriculum led to the educational media movement of the 1950's. By 1970, the Association of Professors of Gynecology and…

Flipping an Algebra Classroom: Analyzing, Modeling, and Solving Systems of Linear Equations

ERIC Educational Resources Information Center

Kirvan, Rebecca; Rakes, Christopher R.; Zamora, Regie

2015-01-01

The present study investigated whether flipping an algebra classroom led to a stronger focus on conceptual understanding and improved learning of systems of linear equations for 54 seventh- and eighth-grade students using teacher journal data and district-mandated unit exam items. Multivariate analysis of covariance was used to compare scores on…

L2 Effects on L1 Event Conceptualization

ERIC Educational Resources Information Center

Bylund, Emanuel; Jarvis, Scott

2011-01-01

The finding that speakers of aspect languages encode event endpoints to a lesser extent than do speakers of non-aspect languages has led to the hypothesis that there is a relationship between grammatical aspect and event conceptualization (e.g., von Stutterheim and Nuse, 2003). The present study concerns L1 event conceptualization in 40 L1…

Language Change in the Wake of Empire: Syriac in Its Greco-Roman Context

ERIC Educational Resources Information Center

Butts, Aaron Michael

2013-01-01

Greek-Aramaic bilingualism was wide-spread throughout Late Antique Syria and Mesopotamia. Among the various Aramaic dialects, Syriac underwent a particularly intense and prolonged period of contact with Greek. This contact led to changes in both languages. The present study provides a new analysis of contact-induced changes in Syriac due to Greek,…

Interactive Whiteboards in State School Settings: Teacher Responses to Socio-Constructivist Hegemonies

ERIC Educational Resources Information Center

Schmid, Euline Cutrim; Whyte, Shona

2012-01-01

Recent CALL research suggests that the arrival of new technologies in the language classroom has led to an increased dominance of the socio-constructivist paradigm (Felix, 2006). Borg (2006) suggests, however, that the hegemony of this paradigm may not extend beyond well-researched university and private ESL contexts. The present study tests this…

Accuracy Improvement for Light-Emitting-Diode-Based Colorimeter by Iterative Algorithm

NASA Astrophysics Data System (ADS)

Yang, Pao-Keng

2011-09-01

We present a simple algorithm, combining an interpolating method with an iterative calculation, to enhance the resolution of spectral reflectance by removing the spectral broadening effect due to the finite bandwidth of the light-emitting diode (LED) from it. The proposed algorithm can be used to improve the accuracy of a reflective colorimeter using multicolor LEDs as probing light sources and is also applicable to the case when the probing LEDs have different bandwidths in different spectral ranges, to which the powerful deconvolution method cannot be applied.

A new integrating sphere design for spectral radiant flux determination of light-emitting diodes

NASA Astrophysics Data System (ADS)

Hanselaer, P.; Keppens, A.; Forment, S.; Ryckaert, W. R.; Deconinck, G.

2009-09-01

Light-emitting diode (LED) technology is developing very quickly and may be considered an alternative for traditional light sources. However, at this moment, manufacturers and end users of LEDs are facing a rather basic but major problem. The lack of standardization regarding optical and electrical characterization of LEDs appears to compromise a successful implementation. In particular, numbers quoted for the luminous flux, and consequently for the efficacy of LEDs, are very sensitive data because they are used to impress and push the LED market. In this paper, the most was made of the typical hemispherical radiation of high-power LEDs to increase the accuracy of the flux determination using a custom-made integrating sphere. Recently developed measurement techniques such as the use of an external spectral irradiance standard and an optimized spectral irradiance detection head are combined with a very particular port geometry and a minimized baffle area. This results in a uniform spatial response distribution function (SRDF), which guarantees an accurate radiant and luminous flux determination, irrespective of the spatial intensity distribution of the LED package or luminaire. The effect of the directional response of the detector head on the SRDF has been explored. Measurements on LED devices with and without external optics are presented, illustrating the possibilities of the measurement setup.

Water Scarcity, Food Insecurity and Drought Induced Displacement in an Arid Ecosystem: A Case Study in Indian Desert

NASA Astrophysics Data System (ADS)

Rehman Siddiqui, Azizur

2017-04-01

Indian Arid Ecosystem is characterised by scare as well as seasonal precipitation that have led to long term stress in a fragile ecosystem. In addition to this, over the years, Indian desert has experienced varying magnitude of drought, which have considerably influenced food and fodder production and led to the depletion of surface and ground water table. All these factors mean that the production potential of land is hardly sufficient to feed human as well as livestock population of the desert and this has led to extensive rural to urban migration in Indian Desert. In the present study, satellite data from Landsat TM, AWiFS, NOAA AVHRR have been used to detect the intensity and severity of drought condition, and data collected through primary survey has been used to measure the impact of water scarcity on food insecurity and drought induced migration. Rainfall trend analysis of the study area has been done with the help of Man Kendall Method to assess the meteorological vulnerability. In addition to these, NDVI, VCI, TCI, and VHI have also been used to find out the long term vegetation health in the study area. With the help of these scientific techniques, the paper focuses on the moisture deficiency during growing period and its effect on human population and livestock population. Keywords: Arid Ecosystem, Indian Desert, Drought, Migration

White LEDs and modules in chip-on-board technology for general lighting

NASA Astrophysics Data System (ADS)

Hartmann, Paul; Wenzl, Franz P.; Sommer, Christian; Pachler, Peter; Hoschopf, Hans; Schweighart, Marko; Hartmann, Martin; Kuna, Ladislav; Jakopic, Georg; Leising, Guenther; Tasch, Stefan

2006-08-01

At present, light-emitting diode (LED) modules in various shapes are developed and designed for the general lighting, advertisement, emergency lighting, design and architectural markets. To compete with and to surpass the performance of traditional lighting systems, enhancement of Lumen output and the white light quality as well as the thermal management and the luminary integration are key factors for success. Regarding these issues, white LEDs based on the chip-on-board (COB) technology show pronounced advantages. State-of-the-art LEDs exploiting this technology are now ready to enter the general lighting segments. We introduce and discuss the specific properties of the Tridonic COB technology dedicated for general lighting. This technology, in combination with a comprehensive set of tools to improve and to enhance the Lumen output and the white light quality, including optical simulation, is the scaffolding for the application of white LEDs in emerging areas, for which an outlook will be given.

The High-efficiency LED Driver for Visible Light Communication Applications

PubMed Central

Gong, Cihun-Siyong Alex; Lee, Yu-Chen; Lai, Jyun-Liang; Yu, Chueh-Hao; Huang, Li Ren; Yang, Chia-Yen

2016-01-01

This paper presents a LED driver for VLC. The main purpose is to solve the low data rate problem used to be in switching type LED driver. The GaN power device is proposed to replace the traditional silicon power device of switching LED driver for the purpose of increasing switching frequency of converter, thereby increasing the bandwidth of data transmission. To achieve high efficiency, the diode-connected GaN power transistor is utilized to replace the traditional ultrafast recovery diode used to be in switching type LED driver. This work has been experimentally evaluated on 350-mA output current. The results demonstrate that it supports the data of PWM dimming level encoded in the PPM scheme for VLC application. The experimental results also show that system’s efficiency of 80.8% can be achieved at 1-Mb/s data rate. PMID:27498921

Improved LED backlight with unique color and intensity control and NVIS capability

NASA Astrophysics Data System (ADS)

Herman, Robert; Zagar, Pete; Ulijasz, Ted; Hansen, Hans C.; Ellner, Fred

2006-05-01

Currently deployed conventional flat panel AMLCD displays employ fluorescent lamp backlights to achieve the required lighting levels for cockpits in high performance aircraft. Advances have been made in backlighting technology by replacing fluorescent lamps with high performance LEDs. However, these new LED-based backlights are lacking in control of color and luminance intensity especially when related to NVIS requirements in a cockpit. This paper describes a unique integration of LED, electronic, and optical components to meet the requirements of high performance aircraft over their extreme range of operating environments. The LED-based backlight utilizes state-of-art components to enable daylight, night, and NVIS requirements to be implemented in a simple cost-effective package. The performance results presented highlight the advantages of this new design when compared to currently available backlighting designs. Techniques as described in section 2 of this paper are covered under patent application to the US and International Patent Offices.

A new light emitting diode-light emitting diode portable carbon dioxide gas sensor based on an interchangeable membrane system for industrial applications.

PubMed

de Vargas-Sansalvador, I M Pérez; Fay, C; Phelan, T; Fernández-Ramos, M D; Capitán-Vallvey, L F; Diamond, D; Benito-Lopez, F

2011-08-12

A new system for CO(2) measurement (0-100%) based on a paired emitter-detector diode arrangement as a colorimetric detection system is described. Two different configurations were tested: configuration 1 (an opposite side configuration) where a secondary inner-filter effect accounts for CO(2) sensitivity. This configuration involves the absorption of the phosphorescence emitted from a CO(2)-insensitive luminophore by an acid-base indicator and configuration 2 wherein the membrane containing the luminophore is removed, simplifying the sensing membrane that now only contains the acid-base indicator. In addition, two different instrumental configurations have been studied, using a paired emitter-detector diode system, consisting of two LEDs wherein one is used as the light source (emitter) and the other is used in reverse bias mode as the light detector. The first configuration uses a green LED as emitter and a red LED as detector, whereas in the second case two identical red LEDs are used as emitter and detector. The system was characterised in terms of sensitivity, dynamic response, reproducibility, stability and temperature influence. We found that configuration 2 presented a better CO(2) response in terms of sensitivity. Copyright © 2011 Elsevier B.V. All rights reserved.

Hydrothermally Grown In-doped ZnO Nanorods on p-GaN Films for Color-tunable Heterojunction Light-emitting-diodes

PubMed Central

Park, Geun Chul; Hwang, Soo Min; Lee, Seung Muk; Choi, Jun Hyuk; Song, Keun Man; Kim, Hyun You; Kim, Hyun-Suk; Eum, Sung-Jin; Jung, Seung-Boo; Lim, Jun Hyung; Joo, Jinho

2015-01-01

The incorporation of doping elements in ZnO nanostructures plays an important role in adjusting the optical and electrical properties in optoelectronic devices. In the present study, we fabricated 1-D ZnO nanorods (NRs) doped with different In contents (0% ~ 5%) on p-GaN films using a facile hydrothermal method, and investigated the effect of the In doping on the morphology and electronic structure of the NRs and the electrical and optical performances of the n-ZnO NRs/p-GaN heterojunction light emitting diodes (LEDs). As the In content increased, the size (diameter and length) of the NRs increased, and the electrical performance of the LEDs improved. From the electroluminescence (EL) spectra, it was found that the broad green-yellow-orange emission band significantly increased with increasing In content due to the increased defect states (oxygen vacancies) in the ZnO NRs, and consequently, the superposition of the emission bands centered at 415 nm and 570 nm led to the generation of white-light. These results suggest that In doping is an effective way to tailor the morphology and the optical, electronic, and electrical properties of ZnO NRs, as well as the EL emission property of heterojunction LEDs. PMID:25988846

Hydrothermally Grown In-doped ZnO Nanorods on p-GaN Films for Color-tunable Heterojunction Light-emitting-diodes.

PubMed

Park, Geun Chul; Hwang, Soo Min; Lee, Seung Muk; Choi, Jun Hyuk; Song, Keun Man; Kim, Hyun You; Kim, Hyun-Suk; Eum, Sung-Jin; Jung, Seung-Boo; Lim, Jun Hyung; Joo, Jinho

2015-05-19

The incorporation of doping elements in ZnO nanostructures plays an important role in adjusting the optical and electrical properties in optoelectronic devices. In the present study, we fabricated 1-D ZnO nanorods (NRs) doped with different In contents (0% ~ 5%) on p-GaN films using a facile hydrothermal method, and investigated the effect of the In doping on the morphology and electronic structure of the NRs and the electrical and optical performances of the n-ZnO NRs/p-GaN heterojunction light emitting diodes (LEDs). As the In content increased, the size (diameter and length) of the NRs increased, and the electrical performance of the LEDs improved. From the electroluminescence (EL) spectra, it was found that the broad green-yellow-orange emission band significantly increased with increasing In content due to the increased defect states (oxygen vacancies) in the ZnO NRs, and consequently, the superposition of the emission bands centered at 415 nm and 570 nm led to the generation of white-light. These results suggest that In doping is an effective way to tailor the morphology and the optical, electronic, and electrical properties of ZnO NRs, as well as the EL emission property of heterojunction LEDs.

Light colour and intensity alters reproductive/seasonal responses in Japanese quail.

PubMed

Yadav, Suneeta; Chaturvedi, Chandra Mohini

2015-08-01

An extensive literature is available on the photoperiodic responses of avian species but studies on light colour and wavelength from light emitting diode (LED) sources on reproduction are limited. Hence, an experiment was designed to study the effect of different colours and intensities of light on the reproductive responses of Japanese quail. Three-week old quail were exposed to five different light conditions with a long photoperiod (LD 16:8): WT (white fluorescent light 100 lux as control), W LED (white light emitting diode, 30 lux), B LED (blue LED, 30 lux), G LED (green LED, 30 lux) and R-LED (red LED, 30 lux). The cloacal gland size, an indicator of androgenic activity, was monitored weekly. The results indicated an early initiation of gonadal growth in WT quail which continued and maintained a plateau throughout the period of study. On the other hand, in general low intensity light, there was a decreased amplitude of the reproductive cycle and the quail exposed to different colour lights (green, red and blue lights) used different incubation times to initiate their gonadal growth and exhibited a gonadal cycle of a different duration up to 15.5 weeks. Thereafter, the gonad of quail of all the LED groups started developing again (including the blue LED exposed quail which remained undeveloped until this age) and attained the increased degree of growth until 26.5 weeks of age. During the second cycle, gonads of green and red light exposed quail continued to increase and maintained a plateau of development similar to WT exposed control while white and blue LED exposed quail exhibited spontaneous regression and attained complete sexual quiescence. Based on our study, it is suggested that long term exposure to blue LED light of low intensity may induce gonadal regression even under long-day conditions (LD 16:8), while exposure to green and red lights appears to maintain a constant photosensitivity after one complete gonadal cycle. Copyright © 2015 Elsevier Inc. All rights reserved.

A randomized trial of peer-delivered self-management support for hypertension.

PubMed

Whittle, Jeff; Schapira, Marilyn M; Fletcher, Kathlyn E; Hayes, Avery; Morzinski, Jeffrey; Laud, Purushottam; Eastwood, Dan; Ertl, Kristyn; Patterson, Leslie; Mosack, Katie E

2014-11-01

Peer-led interventions to improve chronic disease self-management can improve health outcomes but are not widely used. Therefore, we tested a peer-led hypertension self-management intervention delivered at regular meetings of community veterans' organizations. We randomized 58 organizational units ("posts") of veterans' organizations in southeast Wisconsin to peer-led vs. professionally delivered self-management education. Volunteer peer leaders at peer-led posts delivered monthly presentations regarding hypertension self-management during regular post meetings. Volunteer post representatives at seminar posts encouraged post members to attend 3 didactic seminars delivered by health professionals at a time separate from the post meeting. Volunteers in both groups encouraged members to self-monitor using blood pressure cuffs, weight scales, and pedometers. Our primary outcome was change in systolic blood pressure (SBP) at 12 months. We measured SBP in 404 participants at baseline and in 379 participants at 12 months. SBP decreased significantly (4.4mm Hg; P < 0.0001) overall; the decrease was similar in peer-led and seminar posts (3.5mm Hg vs. 5.4mm Hg; P = 0.24). Among participants with uncontrolled BP at baseline, SBP decreased by 10.1mm Hg from baseline to 12 months but was again similar in the 2 groups. This pattern was also seen at 6 months and with diastolic blood pressure. Our peer-led educational intervention was not more effective than didactic seminars for SBP control. Although peer-led educational programs have had important impacts in a number of studies, we did not find our intervention superior to a similar intervention delivered by healthcare professionals. ClinicalTrials.gov NCT00571038. © Published by Oxford University Press on behalf of American Journal of Hypertension Ltd 2014. This work is written by (a) US Government employees(s) and is in the public domain in the US.

Interaction of LED light with coinitiator-containing composite resins: effect of dual peaks.

PubMed

Sim, Jae-Seong; Seol, Hyo-Joung; Park, Jeong-Kil; Garcia-Godoy, Franklin; Kim, Hyung-Il; Kwon, Yong Hoon

2012-10-01

Recently the colour stability of composite resins has been an issue due to the emphasis on the aesthetics of restored teeth. The purpose of the present study was to investigate how dual-peak LED units affect the polymerization of coinitiator-containing composite resins. Five composite resins [coinitiator-containing: Aelite LS Posterior (AL), Tetric EvoCeram (TE), and Vit-l-escence (VI); only CQ-containing: Grandio (GD) and Filtek Z350 (Z3)] were light cured using four different light-curing units (LCUs). Among them, Bluephase G2 (BP) and G-light (GL) were dual-peak LED LCUs. Microhardness, polymerization shrinkage, flexural, and compressive properties were measured. BP and GL had no consistent effect on the microhardness of AL, TE, and VI on the top and bottom surfaces of resin specimens. Among the specimens, AL and VI showed the least (9.86-10.41 μm) and greatest (17.58-19.21 μm) polymerization shrinkage, respectively. However, the effect of BP and GL on the shrinkage of specimens was not consistent. Among the specimens, GD showed the greatest flexural properties [strength (FS) and modulus (FM)] and TE showed the lowest flexural and compressive properties [strength (CS) and modulus (CM)]. In same resin product, maximum FS and CS differences due to the different LCUs were 10.3-21.0% and 3.6-9.2%, respectively. Furthermore, the influences of BP and GL on FS and CS were not consistent. The tested dual-peak LED LCUs had no consistent synergic effect on the polymerization of coinitiator-containing composite resins as compared with QTH and single-peak LED LCUs. The dual-peak LED LCUs achieve a similar degree of polymerization in coinitiator-composite resins as QTH and single-peak LED LCUs did. Choice of LCU does not appear to be a determinant of the light curing of coinitiator-composite resins. Copyright © 2012 Elsevier Ltd. All rights reserved.

High-power modular LED-based illumination systems for mask-aligner lithography.

PubMed

Bernasconi, Johana; Scharf, Toralf; Vogler, Uwe; Herzig, Hans Peter

2018-04-30

Mask-aligner lithography is traditionally performed using mercury arc lamps with wavelengths ranging from 250 nm to 600 nm with intensity peaks at the i, g and h lines. Since mercury arc lamps present several disadvantages, it is of interest to replace them with high power light emitting diodes (LEDs), which recently appeared on the market at those wavelengths. In this contribution, we present a prototype of an LED-based mask-aligner illumination. An optical characterization is made and the prototype is tested in a mask-aligner. Very good performances are demonstrated. The measured uniformity in the mask plane is 2.59 ± 0.24 % which is within the uniformity of the standard lamp. Print tests show resolution of 1 micron in contact printing and of 3 microns in proximity printing with a proximity gap of 30 microns.

Study on effective thermal conductivity of silicone/phosphor composite and its size effect by Lattice Boltzmann method

NASA Astrophysics Data System (ADS)

Li, Lan; Zheng, Huai; Yuan, Chao; Hu, Run; Luo, Xiaobing

2016-12-01

The silicone/phosphor composite is widely used in light emitting diode (LED) packaging. The composite thermal properties, especially the effective thermal conductivity, strongly influence the LED performance. In this paper, a lattice Boltzmann model was presented to predict the silicone/phosphor composite effective thermal conductivity. Based on the present lattice Boltzmann model, a random generation method was established to describe the phosphor particle distribution in composite. Benchmarks were conducted by comparing the simulation results with theoretical solutions for simple cases. Then the model was applied to analyze the effective thermal conductivity of the silicone/phosphor composite and its size effect. The deviations between simulation and experimental results are <7 %, when the phosphor volume fraction varies from 0.038 to 0.45. The simulation results also indicate that effective thermal conductivity of the composite with larger particles is higher than that with small particles at the same volume fraction. While mixing these two sizes of phosphor particles provides an extra enhancement for the effective thermal conductivity.

British Observations of the 18 August 1868 Total Solar Eclipse from Guntoor, India

NASA Astrophysics Data System (ADS)

Orchiston, Wayne; Lee, Eun-Hee; Ahn, Young-Sook

The total solar eclipse of 18 August 1868 was observed in Aden, India, Siam (present-day Thailand) and the Dutch East Indies (present-day Indonesia). One Indian expedition was sponsored by the Royal Astronomical Society, and led by Major J.F. Tennant. In this chapter we describe the observing team and instruments, discuss their observations, and conclude with some remarks on the place of the 1868 eclipse in solar studies and later nineteenth century European astronomical expeditions to India.

The 30/20 GHz flight experiment system, phase 2. Volume 2: Experiment system description

NASA Technical Reports Server (NTRS)

Bronstein, L.; Kawamoto, Y.; Ribarich, J. J.; Scope, J. R.; Forman, B. J.; Bergman, S. G.; Reisenfeld, S.

1981-01-01

A detailed technical description of the 30/20 GHz flight experiment system is presented. The overall communication system is described with performance analyses, communication operations, and experiment plans. Hardware descriptions of the payload are given with the tradeoff studies that led to the final design. The spacecraft bus which carries the payload is discussed and its interface with the launch vehicle system is described. Finally, the hardwares and the operations of the terrestrial segment are presented.

LEDs based upon AlGaInP heterostructures with multiple quantum wells: comparison of fast neutrons and gamma-quanta irradiation

NASA Astrophysics Data System (ADS)

Gradoboev, A. V.; Orlova, K. N.; Simonova, A. V.

2018-05-01

The paper presents the research results of watt and volt characteristics of LEDs based upon AlGaInP heterostructures with multiple quantum wells in the active region. The research is completed for LEDs (emission wavelengths 624 nm and 590 nm) under irradiation by fast neutron and gamma-quanta in passive powering mode. Watt-voltage characteristics in the average and high electron injection areas are described as a power function of the operating voltage. It has been revealed that the LEDs transition from average electron injection area to high electron injection area occurs by overcoming the transition area. It disappears as it get closer to the limit result of the irradiation LEDs that is low electron injection mode in the entire supply voltage range. It has been established that the gamma radiation facilitates initial defects restructuring only 42% compared to 100% when irradiation is performed by fast neutrons. Ratio between measured on the boundary between low and average electron injection areas current value and the contribution magnitude of the first stage LEDs emissive power reducing is established. It is allows to predict LEDs resistance to irradiation by fast neutrons and gamma rays.

Semantic e-Science in Space Physics - A Case Study

NASA Astrophysics Data System (ADS)

Narock, T.; Yoon, V.; Merka, J.; Szabo, A.

2009-05-01

Several search and retrieval systems for space physics data are currently under development in NASA's heliophysics data environment. We present a case study of two such systems, and describe our efforts in implementing an ontology to aid in data discovery. In doing so we highlight the various aspects of knowledge representation and show how they led to our ontology design, creation, and implementation. We discuss advantages that scientific reasoning allows, as well as difficulties encountered in current tools and standards. Finally, we present a space physics research project conducted with and without e-Science and contrast the two approaches.

Nurse-led versus doctor-led care for bronchiectasis.

PubMed

Lawton, Kathryn; Royals, Karen; Carson-Chahhoud, Kristin V; Campbell, Fiona; Smith, Brian J

2018-06-20

Specialist nursing roles to manage stable disease populations are being used to meet the needs of both patients and health services. With increasing cost pressures on health departments, alternative models such as nurse-led care are gaining momentum as a substitute for traditional doctor-led care. This review evaluates the safety, effectiveness, and health outcomes of nurses practising in autonomous roles while using advanced practice skills, within the context of bronchiectasis management in subacute, ambulatory, and/or community care. To compare the effectiveness of nurse-led care versus doctor-led care in the management of stable bronchiectasis. We searched the Cochrane Airways Group Specialised Register and bibliographies of selected papers in addition to grey literature such as electronic clinical trials registries. Searches were current as of March 2018. Randomised controlled trials were eligible for inclusion in the review. Two reviewers extracted and entered data from included studies. Primary outcomes were numbers of exacerbations requiring treatment with antibiotics, hospital admissions, and emergency department attendances. We included one United Kingdom (UK) study in the review. In this randomised controlled trial, a total of 80 participants, with a mean age of 58 years, were treated for 12 months by a specialist nurse or doctor, then were crossed over to the other clinician for the next 12 months. Two participants died during the study period. Six participants failed to cross over to nurse-led care because of unstable bronchiectasis. Overall, the level of study completion was high.Data show no difference in the numbers of exacerbations requiring treatment with antibiotics (rate ratio 1.09, 95% confidence interval (CI) 0.91 to 1.30, 80 participants, moderate-certainty evidence). Investigators reported more hospital admissions in the nurse-led care group (rate ratio 1.52, 95% CI 1.04 to 2.23, 80 participants, moderate-certainty evidence) and did not report emergency department attendance.For secondary outcomes, participants in the nurse-led care group used more healthcare resources during the first year of the trial. Increased admissions and greater use of resources made treatment costs for nurse-led groups' higher. Total costs for both years of the study were £8,464 and £5,228 for nurse-led care compared with doctor-led care. However, by the second year, treatment costs were almost equitable between the two groups, which may reflect the nurses' learning of how to better treat people with bronchiectasis. No statistically significant changes were observed in quality of life, exercise capacity, mortality, or lung function. Wide confidence intervals led to uncertainty regarding these results. Adverse events were not an outcome for this review. This update of the review shows that only one trial met review criteria. Review authors were unable to demonstrate effectiveness of nurse-led care compared with doctor-led care on the basis of findings of a single study. The included study reported no significant differences, but limited evidence means that differences in clinical outcomes between nurse-led care and usual care within the setting of a specialist clinic remain unclear. Further research is required to determine whether nurse-led care is cost-effective, if guidelines and protocols for bronchiectasis management are followed does this increases costs and how effective nurse-led management of bronchiectasis is in other clinical settings such as inpatient and outreach.

Protocol for Determining Ultraviolet Light Emitting Diode (UV-LED) Fluence for Microbial Inactivation Studies.

PubMed

Kheyrandish, Ataollah; Mohseni, Madjid; Taghipour, Fariborz

2018-06-15

Determining fluence is essential to derive the inactivation kinetics of microorganisms and to design ultraviolet (UV) reactors for water disinfection. UV light emitting diodes (UV-LEDs) are emerging UV sources with various advantages compared to conventional UV lamps. Unlike conventional mercury lamps, no standard method is available to determine the average fluence of the UV-LEDs, and conventional methods used to determine the fluence for UV mercury lamps are not applicable to UV-LEDs due to the relatively low power output, polychromatic wavelength, and specific radiation profile of UV-LEDs. In this study, a method was developed to determine the average fluence inside a water suspension in a UV-LED experimental setup. In this method, the average fluence was estimated by measuring the irradiance at a few points for a collimated and uniform radiation on a Petri dish surface. New correction parameters were defined and proposed, and several of the existing parameters for determining the fluence of the UV mercury lamp apparatus were revised to measure and quantify the collimation and uniformity of the radiation. To study the effect of polychromatic output and radiation profile of the UV-LEDs, two UV-LEDs with peak wavelengths of 262 and 275 nm and different radiation profiles were selected as the representatives of typical UV-LEDs applied to microbial inactivation. The proper setup configuration for microorganism inactivation studies was also determined based on the defined correction factors.

Significance of autobiographical episodes and spacing effects in incidental memory.

PubMed

Toyota, Hiroshi

2013-10-01

Participants were presented with target words on two occasions, and were asked each time to generate a memory of a past episode associated with the targets. Participants were also instructed to rate the importance (significance elaboration) or pleasantness of the pisode (pleasantness elaboration) in an orienting task, followed by an unexpect d recall test. Significance elaboration led to better recall than pleasantness elaboration, but only in the spaced presentation. The spaced presentation led to better tree recall than massed presentation with significance elaboration, but the difference between the two types of presentation was not observed with pleasantness elaboration. These results suggest that the significance of an episode is more critical than the pleasantness of an episode in determining the effectiveness of autobiographical elaboration in facilitating recall.

[Functional state of the visual analyzer in the conditions of the use of traditional and LED light sources].

PubMed

Kaptsov, V A; Sosunov, N N; Shishchenko, I I; Viktorov, V S; Tulushev, V N; Deynego, V N; Bukhareva, E A; Murashova, M A; Shishchenko, A A

2014-01-01

There was performed the experimental work on the study of the possibility of the application of LED lighting (LED light sources) in rail transport for traffic safety in related professions. Results of 4 series of studies involving 10 volunteers for the study and a comparative evaluation of the functional state of the visual analyzer, the general functional state and mental capacity under the performing the simulated operator activity in conditions of traditional light sources (incandescent, fluorescent lamp) and the new LED (LED lamp, LED panel) light sources have revealed changes in the negative direction. This was pronounced in a some decrease of functional stability to color discrimination between green and red cone signals, as well as an increase in response time in complex visual--motor response and significant reduction in readiness for emergency action of examinees.

NANOSCALE BIOSENSORS IN ECOSYSTEM EXPOSURE RESEARCH

EPA Science Inventory

This powerpoint presentation presented information on nanoscale biosensors in ecosystem exposure research. The outline of the presentation is as follows: nanomaterials environmental exposure research; US agencies involved in nanosensor research; nanoscale LEDs in biosensors; nano...

Mathematical Models for Immunology: Current State of the Art and Future Research Directions.

PubMed

Eftimie, Raluca; Gillard, Joseph J; Cantrell, Doreen A

2016-10-01

The advances in genetics and biochemistry that have taken place over the last 10 years led to significant advances in experimental and clinical immunology. In turn, this has led to the development of new mathematical models to investigate qualitatively and quantitatively various open questions in immunology. In this study we present a review of some research areas in mathematical immunology that evolved over the last 10 years. To this end, we take a step-by-step approach in discussing a range of models derived to study the dynamics of both the innate and immune responses at the molecular, cellular and tissue scales. To emphasise the use of mathematics in modelling in this area, we also review some of the mathematical tools used to investigate these models. Finally, we discuss some future trends in both experimental immunology and mathematical immunology for the upcoming years.

Residents examine factors associated with 30-day, same-cause hospital readmissions on an internal medicine service.

PubMed

Moran, Jennifer; Colbert, Colleen Y; Song, Juhee; Hull, Joshua; Rajan, Sabitha; Varghees, Sunita; Arroliga, Alejandro C; Reddy, Santosh P

2013-01-01

In recent years, there has been increased interest in stemming the tide of hospital readmissions in an attempt to improve quality of care. This study presents the Phase I results of a resident-led quality improvement initiative to determine the percentage of and risk factors for same-cause readmissions (SCRs; defined as hospital readmission within 30 days of hospital discharge for treatment of the same condition) to the internal medicine service of a multispecialty teaching hospital in central Texas. Results indicate that patients diagnosed with chronic obstructive pulmonary disease/asthma or anemia may be at increased risk for SCRs. Those patients who are insured by Medicaid and those who require assistance from social services also demonstrated an increased risk for SCRs. This study appears to be the first resident-led initiative in the field to examine 30-day SCRs to an internal medicine service for demographic and clinical risk factors.

Retrofitting the Williams Energy Services Ignacio Plant for higher throughput and recovery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lynch, J.T.; Pitman, R.N.

1999-07-01

The Ignacio Plant located near Durango, Colorado was originally designed to process 346 MMscfd of feed gas and to recover approximately 82% of the contained ethane. Based on increasing volumes of available feed gas, Williams Energy Services (WES) undertook a study to investigate alternatives for increasing plant capacity and ethane recovery. This study led to the selection of Ortloff's Recycle Split-Vapor (RSV) process for retrofitting the existing facility because it offered several very important advantages: maximum utilization of existing equipment, a 30% increase in plant feed handling capacity and an increase in average ethane recovery to 94% without adding residuemore » compressors. This paper presents the comparative case analysis that led to the selection of the RSV design. It also describes the modifications required for the retrofit, all of which can be accomplished with minimum plant down time. The modified Ignacio Plant is scheduled for startup in March 1999.« less

[The neurological and embryological studies of Santiago Ramon y Cajal].

PubMed

Baratas Diaz, L A

1997-01-01

The neurological and embryological work of Santiago Ramon y Cajal appeared in three stages: a) Between 1888 and 1893 observations on the development of neuron prolongations led to the observation of the growth cone and formulation of the neurotropic hypothesis. b) Between 1905 and 1908 the study of regenerative phenomena in nerves and nervours centers presented a large body of evidence consistent with the neurotropic hypothesis. c)Between 1910 and 1914 an experimental program was undertaken to test the neurotropic hypothesis; this program led to conclusions on the origin and chemical nature of the growth stimulating factor. These contributions initiated an important line of research that none of Ramon y Cajal's disciples could continue. In the nineteen fifties a group of researchers from three disciplines (biochemistry, embryology and neurohistology) discovered the existence of nerve growth factor (NGF), thus initiating a fertile new field of knowledge in cell biology.

Modifying interpretation biases in body dysmorphic disorder: Evaluation of a brief computerized treatment.

PubMed

Summers, Berta J; Cougle, Jesse R

2016-12-01

Individuals meeting diagnostic criteria for body dysmorphic disorder (BDD; N = 40) were enrolled in a randomized, four-session trial comparing interpretation bias modification (IBM) training designed to target social evaluation- and appearance-related interpretation biases with a placebo control training condition (PC). Sessions took place over the course of two weeks (two sessions per week). Analyses indicated that, relative to the PC condition, IBM led to a significant increase in benign biases and reduction in threat biases at post-treatment. IBM also led to greater reductions in BDD symptoms compared to PC, though this effect was present at high but not low levels of pre-treatment BDD symptoms. Additionally, compared to PC, IBM led to lower urge to check and lower fear in response to an in vivo appearance-related stressor (having their picture taken from different angles), though the latter effect was present only among those reporting elevated fear at pre-treatment. The effects of treatment on interpretation biases and BDD symptoms were largely maintained at a one-month follow-up assessment. Moderated-mediation analyses showed that change in threat bias mediated the effect of condition on post-treatment symptoms for individuals high in pre-treatment BDD symptoms. The current study provides preliminary support for the efficacy of IBM for BDD. Copyright © 2016 Elsevier Ltd. All rights reserved.

Degradation mechanism of cyanide in water using a UV-LED/H2O2/Cu2+ system.

PubMed

Kim, Tae-Kyoung; Kim, Taeyeon; Jo, Areum; Park, Suhyun; Choi, Kyungho; Zoh, Kyung-Duk

2018-06-01

In this study, we developed a UV-LED/H 2 O 2 /Cu 2+ system to remove cyanide, which is typically present in metal electroplating wastewater. The results showed the synergistic effects of UV-LED, H 2 O 2 , and Cu 2+ ions on cyanide removal in comparison with UV-LED photolysis, H 2 O 2 oxidation, UV-LED/H 2 O 2 , and H 2 O 2 /Cu 2+ systems. Cyanide was removed completely in 30 min in the UV-LED/H 2 O 2 /Cu 2+ system, and its loss followed pseudo-first order kinetics. Statistically, both H 2 O 2 and Cu 2+ ions showed positive effects on cyanide removal, but Cu 2+ ions exhibited a greater effect. The highest cyanide removal rate constant (k = 0.179 min -1 ) was achieved at pH 11, but the lowest was achieved at pH 12.5 (k = 0.064 min -1 ) due to the hydrolysis of H 2 O 2 (pK a of H 2 O 2  = 11.75). The presence of dissolved organic matter (DOM) inhibited cyanide removal, and the removal rate constant exhibited a negative linear correlation with DOM (R 2  = 0.987). The removal rate of cyanide was enhanced by the addition of Zn 2+ ions (from 0.179 to 0.457 min -1 ), while the co-existence of Ni 2+ or Cr +6 ion with Cu 2+ ion reduced cyanide removal. The formation of OH radicals in the UV-LED/H 2 O 2 /Cu 2+ system was verified using an aminophenyl fluorescence (APF) probe. Cyanate ions and ammonia were detected as the byproducts of cyanide decomposition. Finally, an acute toxicity reduction of 64.6% was achieved in the system within 1 h, despite a high initial cyanide concentration (100 mg/L). In terms of removal efficiency and toxicity reduction, the UV-LED/H 2 O 2 /Cu 2+ system may be an alternative method of cyanide removal from wastewaters. Copyright © 2018 Elsevier Ltd. All rights reserved.

US-UK Collaboration on Fossil Energy Advanced Materials: Task 1—Steam Oxidation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holcomb, Gordon R.; Tylczak, Joseph; Carney, Casey

This presentation goes over the following from the US-UK collaboration on Fossil Energy Advanced Materials: Task 1, Steam Oxidation: US-led or co-led deliverables, Phase II products (US), 2011-present, Phase III products, Phase III Plan, an explanation of sCO 2 compared with sH 2O, an explanation of Ni-base Alloys, an explanation of 300 Series (18Cr-8Ni)/E-Brite, an explanation of the typical Microchannel HX Fabrication process, and an explanation of diffusion bonded Ni-base superalloys.

Modular, Microprocessor-Controlled Flash Lighting System

NASA Technical Reports Server (NTRS)

Kiefer, Dwayne; Gray, Elizabeth; Skupinski, Robert; Stachowicz, Arthur; Birchenough, William

2006-01-01

A microprocessor-controlled lighting system generates brief, precisely timed, high-intensity flashes of light for scientific imaging at frame rates up to about 1 kHz. The system includes an array of light-emitting diodes (LEDs) that are driven in synchronism with an externally generated timing signal (for example, a timing signal generated by a video camera). The light output can be varied in peak intensity, pulse duration, pulse delay, and pulse rate, all depending on the timing signal and associated externally generated control signals. The array of LEDs comprises as many as 16 LED panels that can be attached together. Each LED panel is a module consisting of a rectangular subarray of 10 by 20 LEDs of advanced design on a printed-circuit board in a mounting frame with a power/control connector. The LED panels are controlled by an LED control module that contains an AC-to-DC power supply, a control board, and 8 LED-panel driver boards. In prior LED panels, the LEDs are packaged at less than maximum areal densities in bulky metal housings that reduce effective active areas. In contrast, in the present LED panels, the LEDs are packed at maximum areal density so as to afford 100-percent active area and so that when panels are joined side by side to form the array, there are no visible seams between them and the proportion of active area is still 100 percent. Each panel produces an illuminance of .5 x 10( exp 4) lux at a distance of 5.8 in. (approx.1.6 cm). The LEDs are driven according to a pulse-width-modulation control scheme that makes it safe to drive the LEDs beyond their rated steady-state currents in order to generate additional light during short periods. The drive current and the pulse-width modulation for each LED panel can be controlled independently of those of the other 15 panels. The maximum allowable duration of each pulse of drive current is a function of the amount of overdrive, the total time to be spent in overdrive operation, and the limitations of the LEDs. The system is configured to limit the overdrive according to values specific to each type of LED in the array. These values are coded into firmware to prevent inadvertent damage to the LED panels.

Promoting Exercise as Part of a Physiotherapy-Led Falls Pathway Service for Adults with Intellectual Disabilities: A Service Evaluation

ERIC Educational Resources Information Center

Crockett, Jennifer; Finlayson, Janet; Skelton, Dawn A.; Miller, Gillian

2015-01-01

Background: People with intellectual disabilities experience high rates of falls. Balance and gait problems are common in people with intellectual disabilities, increasing the likelihood of falls; thus, tailored exercise interventions to improve gait and balance are recommended. The present authors set up a physiotherapy-led falls pathway service…

Moving towards Optimising Demand-Led Learning: The 2005-2007 ECUANET Leonardo Da Vinci Project

ERIC Educational Resources Information Center

Dealtry, Richard; Howard, Keith

2008-01-01

Purpose: The purpose of this paper is to present the key project learning points and outcomes as a guideline for the future quality management of demand-led learning and development. Design/methodology/approach: The research methodology was based upon a corporate university blueprint architecture and browser toolkit developed by a member of the…

Peer-Led Nutrition Education Programs for School-Aged Youth: A Systematic Review of the Literature

ERIC Educational Resources Information Center

Yip, Calvin; Gates, Michelle; Gates, Allison; Hanning, Rhona M.

2016-01-01

To date, the impacts of school-based, peer-led nutrition education initiatives have not been summarized or assessed collectively. This review presents the current evidence, identifies knowledge gaps, and provides recommendations for future research. PubMed, Scopus, ERIC and Google Scholar were searched for refereed Canadian and American primary…

LED surgical lighting system with multiple free-form surfaces for highly sterile operating theater application.

PubMed

Liu, Peng; Zhang, Yaqin; Zheng, Zhenrong; Li, Haifeng; Liu, Xu

2014-06-01

Although the ventilation system is widely employed in the operating theater, a strictly sterile surgical environment still cannot be ensured because of laminar disturbance, which is mainly caused by the surgical lighting system. Abandoning traditional products, we propose an LED surgical lighting system, which can alleviate the laminar disturbance and provide an appropriate lighting condition for surgery. It contains a certain amount of LED lens units, which are embedded in the ceiling and arranged around the air supply smallpox. The LED lens unit integrated with an LED light source and a free-form lens is required to produce a uniform circular illumination with a large tolerance to the change of lighting distance. To achieve such a dedicated lens, two free-form refractive surfaces, which are converted into two ordinary differential equations by the design method presented in this paper, are used to deflect the rays. The results show that the LED surgical lighting system can provide an excellent illumination environment for surgery, and, apparently, the laminar disturbance also can be relieved.

LED phototherapy on midpalatal suture after rapid maxilla expansion: a Raman spectroscopic study

NASA Astrophysics Data System (ADS)

Rosa, Cristiane B.; Habib, Fernando Antonio L.; de Araújo, Telma M.; dos Santos, Jean N.; Cangussu, Maria Cristina T.; Barbosa, Artur Felipe S.; de Castro, Isabele Cardoso V.; Soares, Luiz Guilherme P.; Pinheiro, Antonio L. B.

2015-03-01

A quick bone formation after maxillary expansion would reduce treatment timeand the biomodulating effects of LED light could contribute for it. The aim of this study was to analyze the effect of LED phototherapy on the acceleration of bone formation at the midpalatal suture after maxilla expansion. Thirty rats divided into 6 groups were used on the study at 2 time points - 7 days: Control; Expansion; and Expansion + LED; and 14 days: Expansion; Expansion + LED in the first week; Expansion and LED in the first and second weeks. LED irradiation occurred at every 48 h during 2 weeks. Expansion was accomplished using a spatula and maintained with a triple helicoid of 0.020" stainless steel orthodontic wire. A LED light (λ850 ± 10nm, 150mW ± 10mW, spot of 0.5cm2, t=120 sec, SAEF of 18J/cm2) was applied in one point in the midpalatal suture immediately behind the upper incisors. Near infrared Raman spectroscopic analysis of the suture region was carried and data submitted to statistical analyzes (p≤0.05). Raman spectrum analysis demonstrated that irradiation increased hydroxyapatite in the midpalatal suture after expansion. The results of this indicate that LED irradiation; have a positive biomodulation contributing to the acceleration of bone formation in the midpalatal suture after expansion procedure.

Polar and semipolar GaN/Al0.5Ga0.5N nanostructures for UV light emitters

NASA Astrophysics Data System (ADS)

Brault, J.; Rosales, D.; Damilano, B.; Leroux, M.; Courville, A.; Korytov, M.; Chenot, S.; Vennéguès, P.; Vinter, B.; De Mierry, P.; Kahouli, A.; Massies, J.; Bretagnon, T.; Gil, B.

2014-06-01

AlxGa1-xN-based ultra-violet (UV) light emitting diodes (LEDs) are seen as the best solution for the replacement of traditional mercury lamp technology. By adjusting the Al concentration, a large emission spectrum range from 360 nm (GaN) down to 200 nm (AlN) can be covered. Owing to the large density of defects typically present in AlxGa1-xN materials usually grown on sapphire substrates, LED efficiencies still need to be improved. Taking advantage of the 3D carrier confinement, quantum dots (QDs) are among the solutions currently under investigation to improve the performances of UV LEDs. The objectives of this work are to present and discuss the morphological and optical properties of GaN nanostructures grown by molecular beam epitaxy on the (0 0 0 1) and the (11-22) orientations of Al0.5Ga0.5N. In particular, the dependence of the morphological properties of the nanostructures on the growth conditions and the surface orientation will be presented. The optical characteristics as a function of the nanostructure design (size, shape and dimensionality) will also be shown and discussed. The electroluminescence characteristics of a first series of QD-based GaN/Al0.5Ga0.5N LEDs grown on the polar (0 0 0 1) plane will be investigated.

Solution of multi-element LED light sources development automation problem

NASA Astrophysics Data System (ADS)

Chertov, Aleksandr N.; Gorbunova, Elena V.; Korotaev, Valery V.; Peretyagin, Vladimir S.

2014-09-01

The intensive development of LED technologies resulted in the creation of multicomponent light sources in the form of controlled illumination devices based on usage of mentioned LED technologies. These light sources are used in different areas of production (for example, in the food industry for sorting products or in the textile industry for quality control, etc.). The use of LED lighting products in the devices used in specialized lighting, became possible due to wide range of colors of light, LED structures (which determines the direction of radiation, the spatial distribution and intensity of the radiation, electrical, heat, power and other characteristics), and of course, the possibility of obtaining any shade in a wide dynamic range of brightness values. LED-based lighting devices are notable for the diversity of parameters and characteristics, such as color radiation, location and number of emitters, etc. Although LED technologies have several advantages, however, they require more attention if you need to ensure a certain character of illumination distribution and/or distribution of the color picture at a predetermined distance (for example, at flat surface, work zone, area of analysis or observation). This paper presents software designed for the development of the multicomponent LED light sources. The possibility of obtaining the desired color and energy distribution at the zone of analysis by specifying the spatial parameters of the created multicomponent light source and using of real power, spectral and color parameters and characteristics of the LEDs is shown as well.

Integrated Nanoscale Antenna-LED for On-Chip Optical Communication

NASA Astrophysics Data System (ADS)

Fortuna, Seth

Traditional semiconductor light emitting diodes (LEDs) have low modulation speed because of long spontaneous emission lifetime. Spontaneous emission in semiconductors (and indeed most light emitters) is an inherently slow process owing to the size mismatch between the dipole length of the optical dipole oscillators responsible for light emission and the wavelength of the emitted light. More simply stated: semiconductors behave as a poor antenna for its own light emission. By coupling a semiconductor at the nanoscale to an external antenna, the spontaneous emission rate can be dramatically increased alluding to the exciting possibility of an antenna-LED that can be directly modulated faster than the laser. Such an antenna-LED is well-suited as a light source for on-chip optical communication where small size, fast speed, and high efficiency are needed to achieve the promised benefit of reduced power consumption of on-chip optical interconnect links compared with less efficient electrical interconnect links. Despite the promise of the antenna-LED, significant challenges remain to implement an antenna-coupled device in a monolithically integrated manner. Notably, most demonstrations of antenna-enhanced spontaneous emission have relied upon optical pumping of the light emitting material which is useful for fundamental studies; however, an electrical injection scheme is required for practical implementation of an antenna-LED. In this dissertation, demonstration of an electrically-injected III-V antenna-LED is reported: an important milestone toward on-chip optical interconnects. In the first part of this dissertation, the general design principles of enhancing the spontaneous emission rate of a semiconductor with an optical antenna is discussed. The cavity-backed slot antenna is shown to be uniquely suited for an electrically-injected antenna-LED because of large spontaneous emission enhancement, simple fabrication, and directional emission of light. The design, fabrication, and experimental results of the electrically-injected III-V antenna-LED is then presented. Clear evidence of antenna-enhanced electroluminescence is demonstrated including a large increase in the emitted light intensity with respect to an LED without antenna. Furthermore, it is shown that the active region emission wavelength is influenced by the antenna resonance and the emitted light is polarized; consistent with the expected behavior of the cavity-backed slot antenna. An antenna-LED consisting of a InGaAs quantum well active region is shown to have a large 200-fold enhancement of the spontaneous emission rate. In the last half of this dissertation, the performance of the antenna-LED is discussed. Remarkably, despite the high III-V surface recombination velocity, it is shown that an efficient antenna-LED consisting of an InGaAs active region is possible with an antenna-enhanced spontaneous emission rate. This is true provided the active region surface quality is preserved through the entire device process. A novel technique to preserve and clean InGaAs surfaces is reported. Finally, a rate-equation analysis shows that the optimized antenna-LED with cavity-backed slot antenna is fundamentally capable of achieving greater than 100 GHz direct modulation rate at high efficiency thus showing that an antenna-LED faster than the laser is achievable with this device architecture.

Heat dissipation investigation of the internal heat sink geometry of a commercial available LED lamp

NASA Astrophysics Data System (ADS)

Lai, S. L.; Ong, N. R.; Kirtsaeng, S.; Sakuntasathien, S.; Alcain, J. B.; Sauli, Z.; Thangsi, K.; Retnasamy, V.

2017-09-01

Thermal issue is still the bottleneck of the LED to sustain their operational performance. LED lamp is vastly commercialized and has become the next generation of lighting source to substitute the conventional incandescent lamp. Thus, thermal management issue on LED lamp is important to maintain the device reliability. This study focuses on the modification of internal heat sink of the LED lamp which was considered and the thermal performance was investigated. Open source software, Salome and Elmer were used for this study. The result shows that larger surface area of heat sink has better heat dissipation performance.

Where Have All the Robins Gone? Power, Discourse, and the Closing of Robbinsdale High School

ERIC Educational Resources Information Center

Mertens, Mark E.

2013-01-01

This descriptive historical case study, presented as a sort of means of coming to terms with the past, details a 1980 to 1982 declining-enrollment decision-making process which led to the closure of one of three high schools in the suburban, midwestern Robbinsdale Area Schools. Following the district's expansion from a first-ring suburbia with…

Transnational Experiences, Language Competences and Worldviews: Contrasting Language Policies in Two Recently Migrated Greek Families in Luxembourg

ERIC Educational Resources Information Center

Kirsch, Claudine; Gogonas, Nikolaos

2018-01-01

Against the backdrop of the ongoing crisis-led migration from Southern to Northwestern Europe, the present paper reports on a case study of two families who have recently migrated from Greece to Luxembourg. Luxembourg has a trilingual education system and many pupils of migrant background face difficulties on this account. Drawing on the framework…

Young Sex-Workers in Ho Chi Minh City Telling Their Life Stories

ERIC Educational Resources Information Center

Rubenson, Birgitta; Hanh, Le Thi; Hojer, Bengt; Johansson, Eva

2005-01-01

In this study the life stories of 22 sex-workers (age 15-18 years) in Vietnam are organized into three thematic narratives depicting how the girls presented their lives. Poverty, lack of job alternatives and the responsibility to share in the support of their families led the girls into prostitution. Strong family ties gave many girls…

Using Constructivist Case Study Methodology to Understand Community Development Processes: Proposed Methodological Questions to Guide the Research Process

ERIC Educational Resources Information Center

Lauckner, Heidi; Paterson, Margo; Krupa, Terry

2012-01-01

Often, research projects are presented as final products with the methodologies cleanly outlined and little attention paid to the decision-making processes that led to the chosen approach. Limited attention paid to these decision-making processes perpetuates a sense of mystery about qualitative approaches, particularly for new researchers who will…

Meet-Up for Success: The Story of a Peer Led Program's Journey

ERIC Educational Resources Information Center

Kimmins, Lindy R.

2013-01-01

Technological advancements have forced space and time to evolve to present a virtual university that allows increasing numbers of students to study from a university rather than at university. The best people to guide and advise students through their university journey are experienced students. As Longfellow, May, Burke, and Marks-Maran (2008, p.…

A Multi-Faceted Analysis of a New Therapeutic Model of Linking Appraisals to Affective Experiences.

ERIC Educational Resources Information Center

McCarthy, Christopher; And Others

I. Roseman, M. Spindel, and P. Jose (1990) had previously demonstrated that specific appraisals of events led to discrete emotional responses, but this model has not been widely tested by other research teams using alternative research methods. The present study utilized four qualitative research methods, taught by Patti Lather at the 1994…

Children's Reactions to Television Advertising for Toys.

ERIC Educational Resources Information Center

Gorn, Gerald J.; Goldberg, Marvin E.

This study investigated both the effects of expectancy and TV commercials using an expectancy-value model. In a 3 x 5 factorial design, eight- to ten-year-old boys (N=133) were presented with low, moderate or high expectancies of winning a toy, followed by exposure to 0, 1 or 3 repetitions of a TV commercial for the toy. High expectancy led to…

Thoughts on How to Regulate Behaviours: An Overview of the Current Debate

ERIC Educational Resources Information Center

Etienne, Julien

2013-01-01

The article intends to present the debate on behaviour modification in the regulation studies literature, at a time of renewed interest among regulators for new ideas and strategies. As the financial crisis has led to the most public critique yet of the rational choice view of individuals that has informed regulation in the last few decades, other…

How Equivalent Are the Action Execution, Imagery, and Observation of Intransitive Movements? Revisiting the Concept of Somatotopy during Action Simulation

ERIC Educational Resources Information Center

Lorey, Britta; Naumann, Tim; Pilgramm, Sebastian; Petermann, Carmen; Bischoff, Matthias; Zentgraf, Karen; Stark, Rudolf; Vaitl, Dieter; Munzert, Jorn

2013-01-01

Jeannerod (2001) hypothesized that action execution, imagery, and observation are functionally equivalent. This led to the major prediction that these motor states are based on the same action-specific and even effector-specific motor representations. The present study examined whether hand and foot movements are represented in a somatotopic…

Supporting Students Who Are Deaf or Hard of Hearing in General Education Classrooms: A Washington State Case Study

ERIC Educational Resources Information Center

Berndsen, Maura; Luckner, John

2012-01-01

The majority of students who are deaf or hard of hearing currently receive educational services in general education settings. Trends that have led to this shift in placement as well as potential benefits and barriers are presented. A unique partnership between the Washington State Center for Childhood Deafness and Hearing Loss (formerly the…

The Moral Frontiers of English Education Policy: Governmentality and Ethics within an Alternative Provision Free School

ERIC Educational Resources Information Center

Farrell, Francis; Duckworth, Vicky; Reece, Monika; Rigby, Philip

2017-01-01

This article is a critical poststructuralist analysis of Conservative led free school policy in England focussing on claims made by the New Schools Network and in the 2010 White Paper that free school provision promotes social justice. The article presents an empirical study of an alternative provision free school as a lens through which these…

Emotions and Sensemaking: A Consideration of a Community College Presidential Transition

ERIC Educational Resources Information Center

Kearney, Kerri S.

2013-01-01

A change in primary leadership for a community college presents distinct challenges for its employees. The case study research reported in this article is based on emotions and sensemaking data that were collected at an urban community college in the midst of a presidential transition. Analysis of the data led to a primary focus on the period of…

New closed tube loop mediated isothermal amplification assay for prevention of product cross-contamination

PubMed Central

Karthik, K.; Rathore, Rajesh; Thomas, Prasad; Arun, T.R.; Viswas, K.N.; Dhama, Kuldeep; Agarwal, R.K.

2014-01-01

Loop mediated isothermal amplification (LAMP) assay, a promising diagnostic test, has been developed for detection of different pathogens of human as well as animals. Various positive points support its use as a field level test but the major problem is product cross contamination leading to false positive results. Different methods were adopted by various researchers to control this false positive amplification due to cross contamination but all have their own advantages and disadvantages. A new closed tube LAMP assay based on agar dye capsule was developed in the present study and this technique has some advantages over the other closed tube technique.•Agar at the concentration of 1.5% was used to sandwich SYBR green dye I with the aid of intradermal syringe. This agar dye capsule was placed over the LAMP reaction mixture before it was amplified.•To eliminate the hazardous nature of Ultra Violet (UV) light during result visualization of LAMP products, the present study demonstrates the use of Light Emitting Diode (LED) lights for result visualization.•LAMP was carried out for Brucella species detection using this modified techniques yielding good results without any cross contamination and LED showed similar fluorescence compared to UV. PMID:26150945

New closed tube loop mediated isothermal amplification assay for prevention of product cross-contamination.

PubMed

Karthik, K; Rathore, Rajesh; Thomas, Prasad; Arun, T R; Viswas, K N; Dhama, Kuldeep; Agarwal, R K

2014-01-01

Loop mediated isothermal amplification (LAMP) assay, a promising diagnostic test, has been developed for detection of different pathogens of human as well as animals. Various positive points support its use as a field level test but the major problem is product cross contamination leading to false positive results. Different methods were adopted by various researchers to control this false positive amplification due to cross contamination but all have their own advantages and disadvantages. A new closed tube LAMP assay based on agar dye capsule was developed in the present study and this technique has some advantages over the other closed tube technique.•Agar at the concentration of 1.5% was used to sandwich SYBR green dye I with the aid of intradermal syringe. This agar dye capsule was placed over the LAMP reaction mixture before it was amplified.•To eliminate the hazardous nature of Ultra Violet (UV) light during result visualization of LAMP products, the present study demonstrates the use of Light Emitting Diode (LED) lights for result visualization.•LAMP was carried out for Brucella species detection using this modified techniques yielding good results without any cross contamination and LED showed similar fluorescence compared to UV.

Patient-led versus physician-led titration of insulin glargine in patients with uncontrolled type 2 diabetes: a randomized multinational ATLAS study.

PubMed

Garg, Satish K; Admane, Karim; Freemantle, Nick; Odawara, Masato; Pan, Chang-Yu; Misra, Anoop; Jarek-Martynowa, Iwona R; Abbas-Raza, Syed; Mirasol, Roberto C; Perfetti, Riccardo

2015-02-01

Self-adjustment of insulin dose is commonly practiced in Western patients with type 2 diabetes but is usually not performed in Asian patients. This multinational, 24-week, randomized study compared patient-led with physician-led titration of once-daily insulin glargine in Asian patients with uncontrolled type 2 diabetes who were on 2 oral glucose-lowering agents. Patient-led (n = 275) or physician-led (n = 277) subjects followed the same dose-titration algorithm guided by self-monitored fasting blood glucose (FBG; target, 110 mg/dL [6.1 mmol/L]). The primary endpoint was change in mean glycated hemoglobin (HbA1c) at week 24 in the patient-led versus physician-led titration groups. Patient-led titration resulted in a significantly higher drop in HbA1c value at 24 weeks when compared with physician-led titration (-1.40% vs. -1.25%; mean difference, -0.15; 95% confidence interval, -0.29 to 0.00; P = .043). Mean decrease in FBG was greatest in the patient-led group (-2.85 mmol/L vs. -2.48 mmol/L; P = .001). The improvements in HbA1c and FBG were consistent across countries, with similar improvements in treatment satisfaction in both groups. Mean daily insulin dose was higher in the patient-led group (28.9 units vs. 22.2 units; P<.001). Target HbA1c of <7.0% without severe hypoglycemia was achieved in 40.0% and 32.9% in the patient-led and physician-led groups, respectively (P = .086). Severe hypoglycemia was not different in the 2 groups (0.7%), with an increase in nocturnal and symptomatic hypoglycemia in the patient-led arm. Patient-led insulin glargine titration achieved near-target blood glucose levels in Asian patients with uncontrolled type 2 diabetes who were on 2 oral glucose-lowering drugs, demonstrating that Asian patients can self-uptitrate insulin dose effectively when guided.

The Beginning of the Physics of Leptons

NASA Astrophysics Data System (ADS)

Ting, Samuel C. C.

Over the last 30 years the study of lepton pairs from both hadron and electron accelerators and colliders has led to the discovery of J, ϒ, Z and W particles. The study of acoplanar eμ pairs + missing energy has led to the discovery of the heavy lepton, now called τ lepton. Indeed, the study of lepton pairs with and without missing energy has become the main method in high energy colliders for searching new particles. This paper presents some of the important contributions made by Antonino Zichichi over a 10 year period at CERN and Frascati in opening this new field of physics. This includes the development of instrumentation to distinguish leptons from hadrons, the first experiment on lepton pair production from hadron machines, the precision tests of electrodynamics at very small distances, the production of hadrons from e+e- collisions and most importantly his invention of a new method e+e- → eμ + missing momenta, experimentally proving that, thanks to his new electron and muon detection technology, these signals have very little background.

Development and Testing of an LED-Based Near-Infrared Sensor for Human Kidney Tumor Diagnostics

PubMed Central

Zabarylo, Urszula; Kirsanov, Dmitry; Belikova, Valeria; Ageev, Vladimir; Usenov, Iskander; Galyanin, Vladislav; Minet, Olaf; Sakharova, Tatiana; Danielyan, Georgy; Feliksberger, Elena; Artyushenko, Viacheslav

2017-01-01

Optical spectroscopy is increasingly used for cancer diagnostics. Tumor detection feasibility in human kidney samples using mid- and near-infrared (NIR) spectroscopy, fluorescence spectroscopy, and Raman spectroscopy has been reported (Artyushenko et al., Spectral fiber sensors for cancer diagnostics in vitro. In Proceedings of the European Conference on Biomedical Optics, Munich, Germany, 21–25 June 2015). In the present work, a simplification of the NIR spectroscopic analysis for cancer diagnostics was studied. The conventional high-resolution NIR spectroscopic method of kidney tumor diagnostics was replaced by a compact optical sensing device constructively represented by a set of four light-emitting diodes (LEDs) at selected wavelengths and one detecting photodiode. Two sensor prototypes were tested using 14 in vitro clinical samples of 7 different patients. Statistical data evaluation using principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) confirmed the general applicability of the LED-based sensing approach to kidney tumor detection. An additional validation of the results was performed by means of sample permutation. PMID:28825612

Midwives' experiences of facilitating normal birth in an obstetric-led unit: a feminist perspective.

PubMed

Keating, Annette; Fleming, Valerie E M

2009-10-01

to explore midwives' experiences of facilitating normal birth in an obstetric-led unit. a feminist approach using semi-structured interviews focusing on midwives' perceptions of normal birth and their ability to facilitate this birth option in an obstetric-led unit. Ireland. a purposeful sample of 10 midwives with 6-30 years of midwifery experience. All participants had worked for a minimum of 6 years in a labour ward setting, and had been in their current setting for the previous 2 years. the midwives' narratives related to the following four concepts of patriarchy: 'hierarchical thinking', 'power and prestige', 'a logic of domination' and 'either/or thinking' (dualisms). Two themes, 'hierarchical thinking' and 'either/or thinking', (dualisms) along with their subthemes are presented in this paper. this study identified some of the reasons why midwives find it difficult to facilitate normal birth in an obstetric unit setting, and identified a need for further research in this area. Midwifery education and supportive management structures are required if midwives are to become confident practitioners of normal birth.

[Evaluation of health system decentralization and reform of the Social Security system in Colombia].

PubMed

Jaramillo, I

2002-01-01

The aim of this study is to present the results of the reforms in the health sector that have taken place in Colombia since 1990. These reforms replaced the previous national health system and the so-called Bismarkian social security system. The new system has three basic characteristics: a) the public subsidies are decentralized in the municipalities and territorial departments; b) the public hospitals have been converted into state social enterprises, which has led them towards a management model, and c) the health and social security system monopoly has been abolished and a system of health subsidies has been created for the poorest citizens. This article systematically collects secondary information extracted from the most important studies evaluating the health sector reforms in Colombia. The present author participated in some of these studies. The reforms have increased financial resources, which, has led to an increase in public system staff and their salaries. The availability of hospitals' budgetary resources has increased and the social security system has become wider, including 20% of the poorest population who have benefited from subsidies on demand. Ease of access and equity in the health system have significantly improved. However, indicators of public health have fallen and health professionals are critical of a system based on mediation, which increases transaction costs.

Session 21.1 - Observations, Advances in LED Technology, and Dark Sky Protection

NASA Astrophysics Data System (ADS)

Duriscoe, Dan M.

2016-10-01

The importance of dark sky protection, potential threats to further degradation from LED technology, the announcement of a new world atlas of artificial night sky brightness, and the use of color images from the orbiting International Space Station for monitoring potential sources of light pollution were discussed in the six talks of this session. It was clear from the presentations that the work of professional astronomy depends upon continued restraint in the use of outdoor lighting, especially new LED technology, which relies upon blue-rich sources to support the advantages of high luminous efficacy and resulting energy savings.

A New Individually Addressable Micro-LED Array for Photogenetic Neural Stimulation.

PubMed

McGovern, B; Berlinguer Palmini, R; Grossman, N; Drakakis, E; Poher, V; Neil, M A A; Degenaar, P

2010-12-01

Here, we demonstrate the use of a micro light emitting diode (LED) array as a powerful tool for complex spatiotemporal control of photosensitized neurons. The array can generate arbitrary, 2-D, excitation patterns with millisecond and micrometer resolution. In particular, we describe an active matrix control address system to allow simultaneous control of 256 individual micro LEDs. We present the system optically integrated into a microscope environment and patch clamp electrophysiology. The results show that the emitters have sufficient radiance at the required wavelength to stimulate neurons expressing channelrhodopsin-2 (ChR2).

Freeform lens design for LED collimating illumination.

PubMed

Chen, Jin-Jia; Wang, Te-Yuan; Huang, Kuang-Lung; Liu, Te-Shu; Tsai, Ming-Da; Lin, Chin-Tang

2012-05-07

We present a simple freeform lens design method for an application to LED collimating illumination. The method is derived from a basic geometric-optics analysis and construction approach. By using this method, a highly collimating lens with LED chip size of 1.0 mm × 1.0 mm and optical simulation efficiency of 86.5% under a view angle of ± 5 deg is constructed. To verify the practical performance of the lens, a prototype of the collimator lens is also made, and an optical efficiency of 90.3% with a beam angle of 4.75 deg is measured.

Deep ultraviolet semiconductor light sources for sensing and security

NASA Astrophysics Data System (ADS)

Shatalov, Max; Bilenko, Yuri; Yang, Jinwei; Gaska, Remis

2009-09-01

III-Nitride based deep ultraviolet (DUV) light emitting diodes (LEDs) rapidly penetrate into sensing market owing to several advantages over traditional UV sources (i.e. mercury, xenon and deuterium lamps). Small size, a wide choice of peak emission wavelengths, lower power consumption and reduced cost offer flexibility to system integrators. Short emission wavelength offer advantages for gas detection and optical sensing systems based on UV induced fluorescence. Large modulation bandwidth for these devices makes them attractive for frequency-domain spectroscopy. We will review present status of DUV LED technology and discuss recent advances in short wavelength emitters and high power LED lamps.

Lamp of adjustable spectrum for photographic usage

NASA Astrophysics Data System (ADS)

Mazikowski, Adam; Feldzensztajn, Mateusz

2017-08-01

Photography is a unique rapidly growing interdisciplinary field encompassing aspects of science, art and technology. Expectations of photographers are steadily increasing with the development of technology. One of the areas playing a crucial role in photography is lighting. Consequently, several types of light sources for photographic use have been developed. The ongoing research in this field concentrates on lamps with tunable CCT (Correlated Color Temperature). In this paper, we present a lamp, which emission spectrum can be tailored without affecting the output luminous ux. Intended for photographic uses, the lamp is based on an integrating sphere and a selection of LEDs. As the LED drivers, DC-DC converters controlled by a Raspberry PI were applied. Design process, including the selection of LED wavelengths, is presented. Output characteristics of the lamp were measured using the setup containing the spectrometer. The results of these experiments show good agreement with the spectrum set on the microcomputer.

Ecological-geomorphological assessment of the suburban area of Astana

NASA Astrophysics Data System (ADS)

Akiyanova, F. Zh; Zinabdin, N. B.; Kenzhebayeva, A. Zh; Adilbekova, F. G.; Ilyassova, A. T.; Karakulov, E. M.

2018-01-01

The results of ecological-geomorphological assessment of the suburban zone of Astana is presented in the paper. Climatic and hydrological factors, which are the agents of pollutants’ transport and caused the development of exogenous processes in the suburban area of Astana were studied and mapped. On the base of the geoinformation technologies and field studies the geomorphologic structure and morphogenetic processes were studied. The analysis of the data complex led to assess ecological-geomorphological conditions of the suburban area of Astana.

Effect of light-emitting diode vs. fluorescent lighting on laying hens in aviary hen houses: Part 1 - Operational characteristics of lights and production traits of hens.

PubMed

Long, H; Zhao, Y; Wang, T; Ning, Z; Xin, H

2016-01-01

Light-emitting diode (LED) lights are becoming more affordable for agricultural applications. Despite many lab-scale studies concerning impact of LED on poultry, little research has been documented under field production conditions, especially for laying hens. This 15-month field study was carried out to evaluate the effects of LED vs. fluorescent (FL) lights on laying hens (Dekalb white breed) using 4 (2 pairs) aviary hen houses each at a nominal capacity of 50,000 hens. The evaluation was done regarding operational characteristics of the lights and hen production traits. The results show that spatial distribution of the LED light was less uniform than that of the FL light. Light intensity of the LED light decreased by 27% after 3,360 h use but remained quite steady from 3,360 to 5,760 h use. Eleven out of 762 (1.44%) LED lamps (new at onset of the study) in the 2 houses failed during the 15-month experiment period. The neck area of the LED lamp was hottest, presumably the primary reason for the lamp failure as cracks were noticed in the neck region of all failed LED lamps. No differences were observed in egg weight, hen-day egg production, feed use, and mortality rate between LED and FL regimens. However, hens under the FL had higher eggs per hen housed and better feed conversion than those under the LED during 20 to 70 wk production (P < 0.05). Hens under the LED tended to have less feather uniformity and insulation than those under the FL (P < 0.05). Moreover, hens under the LED showed a larger median avoidance distance than those under the FL at 36 wk age (P < 0.05), indicating that hens under the LED were more alert; but no difference at 60 wk age. More comparative research to quantify behavioral and production responses of different breeds of hens to LED vs. FL lighting seems warranted. © 2015 Poultry Science Association Inc.

Evaluating the outcomes of a podiatry-led assessment service in a public hospital orthopaedic unit.

PubMed

Bonanno, Daniel R; Medica, Virginia G; Tan, Daphne S; Spring, Anita A; Bird, Adam R; Gazarek, Jana

2014-01-01

In Australia, the demand for foot and ankle orthopaedic services in public health settings currently outweighs capacity. Introducing experienced allied health professionals into orthopaedic units to initiate the triage, assessment and management of patients has been proposed to help meet demand. The aim of this study was to evaluate the effect of introducing a podiatry-led assessment service in a public hospital orthopaedic unit. The outcomes of interest were determining: the proportion of patients discharged without requiring an orthopaedic appointment, agreement in diagnosis between the patient referral and the assessing podiatrist, the proportion of foot and ankle conditions presenting to the service, and the proportion of each condition to require an orthopaedic appointment. This study audited the first 100 patients to receive an appointment at a new podiatry-led assessment service. The podiatrist triaged 'Category 3' referrals consisting of musculoskeletal foot and ankle conditions and appointments were provided for those considered likely to benefit from non-surgical management. Following assessment, patients were referred to an appropriate healthcare professional or were discharged. At the initial appointment or following a period of care, patients were discharged if non-surgical management was successful, surgery was not indicated, patients did not want surgery, and if patient's failed to attend their appointments. All other patients were referred for an orthopaedic consultation as indicated. Ninety-five of the 100 patients (69 females and 31 males; mean age 51.9, SD 16.4 years) attended their appointment at the podiatry-led assessment service. The 95 referrals contained a total of 107 diagnoses, of which the podiatrist agreed with the diagnosis stated on the referral in 56 cases (Kappa =0.49, SE = 0.05). Overall, 34 of the 100 patients were referred to an orthopaedic surgeon and the remaining 66 patients were discharged from the orthopaedic waiting list without requiring an orthopaedic consultation. Two-thirds of patients who had an appointment at the podiatry-led assessment service were discharged without requiring a surgical consultation. The introduction of a podiatry-led service assists with timely provision of patient care and ensures those with the greatest need for orthopaedic surgery have improved access to specialist care.

Analysis of Light Emitting Diode Technology for Aerospace Suitability in Human Space Flight Applications

NASA Astrophysics Data System (ADS)

Treichel, Todd H.

Commercial space designers are required to manage space flight designs in accordance with parts selections made from qualified parts listings approved by Department of Defense and NASA agencies for reliability and safety. The research problem was a government and private aerospace industry problem involving how LEDs cannot replace existing fluorescent lighting in manned space flight vehicles until such technology meets DOD and NASA requirements for reliability and safety, and effects on astronaut cognition and health. The purpose of this quantitative experimental study was to determine to what extent commercial LEDs can suitably meet NASA requirements for manufacturer reliability, color reliability, robustness to environmental test requirements, and degradation effects from operational power, while providing comfortable ambient light free of eyestrain to astronauts in lieu of current fluorescent lighting. A fractional factorial experiment tested white and blue LEDs for NASA required space flight environmental stress testing and applied operating current. The second phase of the study used a randomized block design, to test human factor effects of LEDs and a qualified ISS fluorescent for retinal fatigue and eye strain. Eighteen human subjects were recruited from university student members of the American Institute of Aeronautics and Astronautics. Findings for Phase 1 testing showed that commercial LEDs met all DOD and NASA requirements for manufacturer reliability, color reliability, robustness to environmental requirements, and degradation effects from operational power. Findings showed statistical significance for LED color and operational power variables but degraded light output levels did not fall below the industry recognized <70%. Findings from Phase 2 human factors testing showed no statistically significant evidence that the NASA approved ISS fluorescent lights or blue or white LEDs caused fatigue, eye strain and/or headache, when study participants perform detailed tasks of reading and assembling mechanical parts for an extended period of two uninterrupted hours. However, human subjects self-reported that blue LEDs provided the most white light and the favored light source over the white LED and the ISS fluorescent as a sole artificial light source for space travel. According to NASA standards, findings from this study indicate that LEDs meet criteria for the NASA TRL 7 rating, as study findings showed that commercial LED manufacturers passed the rigorous testing standards of suitability for space flight environments and human factor effects. Recommendations for future research include further testing for space flight using the basis of this study for replication, but reduce study limitations by 1) testing human subjects exposure to LEDs in a simulated space capsule environment over several days, and 2) installing and testing LEDs in space modules being tested for human spaceflight.

A review of passive thermal management of LED module

NASA Astrophysics Data System (ADS)

Huaiyu, Ye; Koh, Sau; van Zeijl, Henk; Gielen, A. W. J.; Guoqi, Zhang

2011-01-01

Recently, the high-brightness LEDs have begun to be designed for illumination application. The increased electrical currents used to drive LEDs lead to thermal issues. Thermal management for LED module is a key design parameter as high operation temperature directly affects their maximum light output, quality, reliability and life time. In this review, only passive thermal solutions used on LED module will be studied. Moreover, new thermal interface materials and passive thermal solutions applied on electronic equipments are discussed which have high potential to enhance the thermal performance of LED Module.

Mechanical properties and polymerization shrinkage of composite resins light-cured using two different lasers.

PubMed

Kim, Tae-Wan; Lee, Jang-Hoon; Jeong, Seung-Hwa; Ko, Ching-Chang; Kim, Hyung-Il; Kwon, Yong Hoon

2015-04-01

The purpose of the present study was to investigate the usefulness of 457 and 473 nm lasers for the curing of composite resins during the restoration of damaged tooth cavity. Monochromaticity and coherence are attractive features of laser compared with most other light sources. Better polymerization of composite resins can be expected. Eight composite resins were light cured using these two lasers and a light-emitting diode (LED) light-curing unit (LCU). To evaluate the degrees of polymerization achieved, polymerization shrinkage and flexural and compressive properties were measured and compared. Polymerization shrinkage values by 457 and 473 nm laser, and LED ranged from 10.9 to 26.8, from 13.2 to 26.1, and from 11.5 to 26.3 μm, respectively. The values by 457 nm laser was significantly different from those by 473 and LED LCU (p<0.05). However, there was no statistical difference between values by 473 and LED LCU. Before immersion in distilled water, flexural strength (FS) and compressive modulus (CM) of the specimens were inconsistently influenced by LCUs. On the other hand, flexural modulus (FM) and compressive strength (CS) were not significantly different for the three LCUs (p>0.05). For the tested LCUs, no specific LCU could consistently achieve highest strength and modulus from the specimens tested. Two lasers (457 and 473 nm) can polymerize composite resins to the level that LED LCU can achieve despite inconsistent trends of polymerization shrinkage and flexural and compressive properties of the tested specimens.

Design of compact freeform LED flashlight capable of two different light distributions

NASA Astrophysics Data System (ADS)

Isaac, Annie Shalom; Neumann, Cornelius

2016-04-01

Free-form optical surfaces are designed for desired intensity requirements for applications ranging from general to automotive lighting. But a single compact free-form optics which satisfies two different intensity distributions is not presented so far. In this work, a compact LED flashlight fulfilling two different intensity requirements that could be used in potentially explosive atmospheres is designed and validated. The first target is selected after a study on visibility analysis in fog, dust, and smoke environments. Studies showed that a ring-like distribution (5°- 10°) have better visual recognition for short distances in smoky environments. The second target is selected to have a maximum intensity at the peak to provide visibility for longer distances. We realized these two different intensity requirements by moving the LED with respect to the optics along the optical axis. To fulfill the above- required intensity distributions, hybrid TIR optics was designed as free-form curves calculated by combining several geometric optic methods. We validated the free-form TIR hybrid optics using Monte Carlo ray trace simulation. The overall diameter of the optics is 29 mm and 10 mm in thickness. The simulated results showed an optical efficiency of about 84% to realize both target light distributions in a single optics. Then we designed a whole flashlight consisting of LED, PMMA hybrid optics, PC glass casing and a housing including the critical thermal management for explosive environments. To validate the results, a prototype for the designed optics was made. The measured results showed an overall agreement with the simulated results.

Simulation of multi-element multispectral UV radiation source for optical-electronic system of minerals luminescence analysis

NASA Astrophysics Data System (ADS)

Peretyagin, Vladimir S.; Korolev, Timofey K.; Chertov, Aleksandr N.

2017-02-01

The problems of dressability the solid minerals are attracted attention of specialists, where the extraction of mineral raw materials is a significant sector of the economy. There are a significant amount of mineral ore dressability methods. At the moment the radiometric dressability methods are considered the most promising. One of radiometric methods is method photoluminescence. This method is based on the spectral analysis, amplitude and kinetic parameters luminescence of minerals (under UV radiation), as well as color parameters of radiation. The absence of developed scientific and methodological approaches of analysis irradiation area to UV radiation as well as absence the relevant radiation sources are the factors which hinder development and use of photoluminescence method. The present work is devoted to the development of multi-element UV radiation source designed for the solution problem of analysis and sorting minerals by their selective luminescence. This article is presented a method of theoretical modeling of the radiation devices based on UV LEDs. The models consider such factors as spectral component, the spatial and energy parameters of the LEDs. Also, this article is presented the results of experimental studies of the some samples minerals.

Analysis of condition for uniform lighting generated by array of light emitting diodes with large view angle.

PubMed

Qin, Zong; Wang, Kai; Chen, Fei; Luo, Xiaobing; Liu, Sheng

2010-08-02

In this research, the condition for uniform lighting generated by array of LEDs with large view angle was studied. The luminous intensity distribution of LED is not monotone decreasing with view angle. A LED with freeform lens was designed as an example for analysis. In a system based on LEDs designed in house with a thickness of 20mm and rectangular arrangement, the condition for uniform lighting was derived and the analytical results demonstrated that the uniformity was not decreasing monotonously with the increasing of LED-to-LED spacing. The illuminance uniformities were calculated with Monte Carlo ray tracing simulations and the uniformity was found to increase with the increasing of certain LED-to-LED spacings anomalously. Another type of large view angle LED and different arrangements were discussed in addition. Both analysis and simulation results showed that the method is available for LED array lighting system design on the basis of large view angle LED..

Peer-led versus teacher-led AIDS education for female high-school students in Yazd, Islamic Republic of Iran.

PubMed

Baghianimoghadam, M H; Forghani, H; Zolghadr, R; Rahaei, Z; Khani, P

2012-04-01

Peer-led programmes on AIDS prevention have shown a good level of effectiveness when tested among high-risk populations. This study compared peer-led and teacher-led methods of education about HIV/AIDS among female high-school students in Yazd city, Islamic Republic of Iran. In 2009 students in 3 high schools were trained by their classmates (peer-led), by the research team (teacher-led) or had no education (controls); 180 students completed a specially designed questionnaire based on the health belief model, before and after the intervention. Post-intervention mean knowledge scores increased 2-fold in the peer-led group, and this was significantly higher than the increase in the teacher-led group scores (1.5-fold). Control group scores were unchanged. In the peer-led programme all of the components of the model were significantly improved whereas in the teacher-led programme, only perceived severity and perceived barriers scored significantly higher after the intervention.

A Simple Photometer to Study Skylight

ERIC Educational Resources Information Center

McIntosh Gordon

2006-01-01

A simple photometer constructed from an LED and an op amp can be used to measure light in a number of physical situations. A variety of LEDs exist to investigate different wavelength ranges. Combined with an inexpensive transit, the LED photometer can be used to carry out skylight studies and atmospheric optical depth measurements. The activities…

Engaging Students in Learning: Findings from a Study of Project-Led Education

ERIC Educational Resources Information Center

Fernandes, Sandra; Mesquita, Diana; Flores, Maria Assunção; Lima, Rui M.

2014-01-01

This paper reports on findings from a three-year study of project-based learning implemented in the first year of the Industrial Engineering and Management programme, at the University of Minho, Portugal. This particular model was inspired on project-led education (PLE), following Powell and Weenk's [2003. "Project-Led Engineering…

Teacher Perceptions and Benefits of Student-Led Conferencing in Southern and Central Illinois Elementary Schools

ERIC Educational Resources Information Center

West, Kelly L.

2017-01-01

Student-led conferences are an alternative method of reporting progress to parents. This qualitative phenomenological research study was conducted in order to examine elementary teachers' perceptions of student-led conferences in comparison to traditional parent-teacher conferences in Central and Southern Illinois. Additionally, the study examined…

Effectiveness of a LED flashlight technique in reducing livestock depredation by lions (Panthera leo) around Nairobi National Park, Kenya.

PubMed

Lesilau, Francis; Fonck, Myrthe; Gatta, Maria; Musyoki, Charles; van 't Zelfde, Maarten; Persoon, Gerard A; Musters, Kees C J M; de Snoo, Geert R; de Iongh, Hans H

2018-01-01

The global lion (Panthera leo) population decline is partly a result of retaliatory killing in response to livestock depredation. Nairobi National Park (NNP) is a small protected area in Kenya surrounded by a human-dominated landscape. Communities around the park use flashlights to deter lions from their livestock bomas. We investigated the response by lions to the installation of a LED flashlight technique during 2007-2016.We interviewed 80 owners of livestock bomas with flashlights (n = 43) and without (n = 37) flashlights in the surroundings of NNP and verified reported attacks on bomas against predation data over10 years. The frequency of attacks on bomas equipped with flashlights was significantly lower compared to bomas without flashlights. We also found that after flashlight installation at livestock bomas, lion attacks took place further away from the park edge, towards areas where bomas without flashlights were still present. With increased numbers of flashlight installations at bomas in recent years, we further noticed a shift from nocturnal to more diurnal predation incidences. Our study shows that the LED flashlight technique is effective in reducing nocturnal livestock predation at bomas by lions. Long term studies on the effects as well as expansion of this technique into other communities around NNP are recommended.

Effectiveness of a LED flashlight technique in reducing livestock depredation by lions (Panthera leo) around Nairobi National Park, Kenya

PubMed Central

Fonck, Myrthe; Gatta, Maria; Musyoki, Charles; van 't Zelfde, Maarten; Persoon, Gerard A.; Musters, Kees C. J. M.; de Snoo, Geert R.; de Iongh, Hans H.

2018-01-01

The global lion (Panthera leo) population decline is partly a result of retaliatory killing in response to livestock depredation. Nairobi National Park (NNP) is a small protected area in Kenya surrounded by a human-dominated landscape. Communities around the park use flashlights to deter lions from their livestock bomas. We investigated the response by lions to the installation of a LED flashlight technique during 2007–2016.We interviewed 80 owners of livestock bomas with flashlights (n = 43) and without (n = 37) flashlights in the surroundings of NNP and verified reported attacks on bomas against predation data over10 years. The frequency of attacks on bomas equipped with flashlights was significantly lower compared to bomas without flashlights. We also found that after flashlight installation at livestock bomas, lion attacks took place further away from the park edge, towards areas where bomas without flashlights were still present. With increased numbers of flashlight installations at bomas in recent years, we further noticed a shift from nocturnal to more diurnal predation incidences. Our study shows that the LED flashlight technique is effective in reducing nocturnal livestock predation at bomas by lions. Long term studies on the effects as well as expansion of this technique into other communities around NNP are recommended. PMID:29385146

Changes in the Mg profile and in dislocations induced by high temperature annealing of blue LEDs

NASA Astrophysics Data System (ADS)

Meneghini, M.; Trivellin, N.; Berti, M.; Cesca, T.; Gasparotto, A.; Vinattieri, A.; Bogani, F.; Zhu, D.; Humphreys, C. J.; Meneghesso, G.; Zanoni, E.

2013-03-01

The efficiency of the injection and recombination processes in InGaN/GaN LEDs is governed by the properties of the active region of the devices, which strongly depend on the conditions used for the growth of the epitaxial material. To improve device quality, it is very important to understand how the high temperatures used during the growth process can modify the quality of the epitaxial material. With this paper we present a study of the modifications in the properties of InGaN/GaN LED structures induced by high temperature annealing: thermal stress tests were carried out at 900 °C, in nitrogen atmosphere, on selected samples. The efficiency and the recombination dynamics were evaluated by photoluminescence measurements (both integrated and time-resolved), while the properties of the epitaxial material were studied by Secondary Ion Mass Spectroscopy (SIMS) and Rutherford Backscattering (RBS) channeling measurements. Results indicate that exposure to high temperatures may lead to: (i) a significant increase in the photoluminescence efficiency of the devices; (ii) a decrease in the parasitic emission bands located between 380 nm and 400 nm; (iii) an increase in carrier lifetime, as detected by time-resolved photoluminescence measurements. The increase in device efficiency is tentatively ascribed to an improvement in the crystallographic quality of the samples.

Modeling the effects of phosphor converted LED lighting to the night sky of the Haleakala Observatory, Hawaii

NASA Astrophysics Data System (ADS)

Aubé, M.; Simoneau, A.; Wainscoat, R.; Nelson, L.

2018-05-01

The goal of this study is to evaluate the current level of light pollution in the night sky at the Haleakala Observatory on the island of Maui in Hawaii. This is accomplished with a numerical model that was tested in the first International Dark Sky Reserve located in Mont-Mégantic National Park in Canada. The model uses ground data on the artificial light sources present in the region of study, geographical data, and remotely sensed data for: 1) the nightly upward radiance; 2) the terrain elevation; and, 3) the ground spectral reflectance of the region. The results of the model give a measure of the current state of the sky spectral radiance at the Haleakala Observatory. Then, using the current state as a reference point, multiple light conversion plans are elaborated and evaluated using the model. We can thus estimate the expected impact of each conversion plan on the night sky radiance spectrum. A complete conversion to white (LEDs) with (CCT) of 4000K and 3000K are contrasted with a conversion using (PC) amber (LEDs). We include recommendations concerning the street lamps to be used in sensitive areas like the cities of Kahului and Kihei and suggest best lighting practices related to the color of lamps used at night.

Belief in supernatural agents in the face of death.

PubMed

Norenzayan, Ara; Hansen, Ian G

2006-02-01

Four studies examined whether awareness of mortality intensifies belief in supernatural agents among North Americans. In Studies 1 and 2, mortality salience led to more religiosity, stronger belief in God, and in divine intervention. In Studies 3 and 4, mortality salience increased supernatural agent beliefs even when supernatural agency was presented in a culturally alien context (divine Buddha in Study 3, Shamanic spirits in Study 4). The latter effects occurred primarily among the religiously affiliated, who were predominantly Christian. Implications for the role of supernatural agent beliefs in assuaging mortality concerns are discussed.

Developing the First Generally-Available openEHR Archetypes and Templates for Physiotherapy: An Example of Building Clinical Models and Modelling Capacity via Student-Led Academic-Industrial Collaboration.

PubMed

Chihab, Jamila; Franke, Hildegard; McNicoll, Ian; Darlison, Matthew W

2017-01-01

We present the first public openEHR archetypes and templates for physiotherapy, and the context of multidisciplinary academic-industry partnership that has enabled their production by a team led by a clinically trained student on the UCL health informatics MSc programme.

Application of blue laser diodes and LEDs in phototherapy for neonatal jaundice

NASA Astrophysics Data System (ADS)

Hamza, Mostafa; Sayed El-Ahl, Mohammad H.; Hamza, Ahmad M.; Hamza, Aya M.; Hamza, Yahya M.

2003-10-01

The authors introduce the design of a compact phototherapy unit capable of fulfilling the recommendations of the clinical use of lasers and LEDs in phototherapy for the treatment of neonatal jaundice. The system keeps the duration of phototherapy to the minimum required for efficient treatment. Our leading clinical experience as well as the wavelength selection rules will be presented.

Characterization of electrically-active defects in ultraviolet light-emitting diodes with laser-based failure analysis techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Mary A.; Tangyunyong, Paiboon; Cole, Edward I.

2016-01-14

Laser-based failure analysis techniques demonstrate the ability to quickly and non-intrusively screen deep ultraviolet light-emitting diodes (LEDs) for electrically-active defects. In particular, two laser-based techniques, light-induced voltage alteration and thermally-induced voltage alteration, generate applied voltage maps (AVMs) that provide information on electrically-active defect behavior including turn-on bias, density, and spatial location. Here, multiple commercial LEDs were examined and found to have dark defect signals in the AVM indicating a site of reduced resistance or leakage through the diode. The existence of the dark defect signals in the AVM correlates strongly with an increased forward-bias leakage current. This increased leakage ismore » not present in devices without AVM signals. Transmission electron microscopy analysis of a dark defect signal site revealed a dislocation cluster through the pn junction. The cluster included an open core dislocation. Even though LEDs with few dark AVM defect signals did not correlate strongly with power loss, direct association between increased open core dislocation densities and reduced LED device performance has been presented elsewhere [M. W. Moseley et al., J. Appl. Phys. 117, 095301 (2015)].« less

Internal Quantum Efficiency of Led Structures at Various Charge Carrier Distributions Over InGaN/GaN Quantum Wells

NASA Astrophysics Data System (ADS)

Romanov, I. S.; Prudaev, I. A.; Kopyev, V. V.

2018-06-01

The results of studying the effect of the thickness of GaN barrier layers in the active region of LED structures with InGaN/GaN quantum wells on the internal quantum efficiency (IQE) of photoluminescence are presented. It is shown that a decrease in the thickness of the GaN barrier layers from 15 to 3 nm leads to an increase in the maximum value of IQE and to a shift of the maximum to the region of high excitation powers. The result obtained is explained with consideration for the decrease in the Auger recombination rate due to a more uniform distribution of charge carriers over the active region in structures with a barrier thickness of 3 nm.

Information presentation format moderates the unconscious-thought effect: The role of recollection.

PubMed

Abadie, Marlène; Waroquier, Laurent; Terrier, Patrice

2016-09-01

The unconscious-thought effect occurs when distraction improves complex decision-making. In two experiments using the unconscious-thought paradigm, we investigated the effect of presentation format of decision information (i) on memory for decision-relevant information and (ii) on the quality of decisions made after distraction, conscious deliberation or immediately. We used the process-dissociation procedure to measure recollection and familiarity. The two studies showed that presenting information blocked per criterion led participants to recollect more decision-relevant details compared to a presentation by option. Moreover, a Bayesian meta-analysis of the two studies provided strong evidence that conscious deliberation resulted in better decisions when the information was presented blocked per criterion and substantial evidence that distraction improved decision quality when the information was presented blocked per option. Finally, Study 2 revealed that the recollection of decision-relevant details mediated the effect of presentation format on decision quality in the deliberation condition. This suggests that recollection contributes to conscious deliberation efficacy.

Progress in LED technology for solid-state lighting

NASA Astrophysics Data System (ADS)

Bhardwaj, Jy; Guth, Greg; Cesaratto, John M.; Shchekin, Oleg B.; Soer, Wouter A.; Götz, Werner; Bonné, Ron; Song, Zhihua F.; den Breejen, Jeroen

2017-02-01

As solid-state lighting adoption moves from bulb socket replacement to lighting system engineering, luminaire manufacturers are beginning to actualize far greater cost savings through luminaire optimization rather than the simplistic process of component cost pareto management. Indeed, there are an increasing number of applications in which we see major shifts in the value chain in terms of increasing the L1 (LED) and L2 (LED array on PCB) value. The L1 value increase stems from a number of factors ranging from simply higher performing LEDs reducing the LED count, to L1 innovation such as high voltage LEDs, optimizing driver efficiency or to the use of high luminance LEDs enabling compact optics, allowing not only more design freedom but also cost reduction through space and weight savings. The L2 value increase is realized predominantly through increasing L2 performance with the use of algorithms that optimize L1 selection and placement and/or through L2 integration of drivers, control electronics, sensors, secondary lens and/or environmental protection, which is also initiating level collapse in the value chain. In this paper we will present the L1 and L2 innovations that are enabling this disruption as well as provide examples of fixture/luminaire level benefits.

A 1024-channel 6 mW/mm2 optical stimulator for in-vitro neuroscience experiments.

PubMed

Cai, Lei; Wang, Baitong; Huang, Xiuxiang; Yang, Zhi

2014-01-01

Recent optical stimulation technologies allow improved selectivity and have been widely used in neuroscience research. This paper presents an optical stimulator based on high power LEDs. It has 1024 channels and can produce flexible stimulation patterns in each frame, refreshed at above 20 Hz. To increase the light intensity, each LED has an optical package that directs the light into a small angle. To ensure the light of each LED can reach the lens, the LEDs have been specially placed and oriented to the lens. With these efforts, the achieved power efficiency (defined as the mount of LED light power passing through the lens divided by the LED total power consumption) is 5 × 10(-5). In our current prototype, an individual LED unit can source 60 mW electrical power, where the induced irradiance on neural tissues is 6 mW/mm(2) integrating from 460 nm to 480 nm. The light spot is tunable in size from 18 μm to 40 μm with an extra 5-10 μm separation for isolating two adjacent spots. Through both bench-top measurement and finite element simulation, we found the cross channel interference is below 10%. A customized software interface has been developed to control and program the stimulator operation.

Study on method to simulate light propagation on tissue with characteristics of radial-beam LED based on Monte-Carlo method.

PubMed

Song, Sangha; Elgezua, Inko; Kobayashi, Yo; Fujie, Masakatsu G

2013-01-01

In biomedical, Monte-carlo simulation is commonly used for simulation of light diffusion in tissue. But, most of previous studies did not consider a radial beam LED as light source. Therefore, we considered characteristics of a radial beam LED and applied them on MC simulation as light source. In this paper, we consider 3 characteristics of radial beam LED. The first is an initial launch area of photons. The second is an incident angle of a photon at an initial photon launching area. The third is the refraction effect according to contact area between LED and a turbid medium. For the verification of the MC simulation, we compared simulation and experimental results. The average of the correlation coefficient between simulation and experimental results is 0.9954. Through this study, we show an effective method to simulate light diffusion on tissue with characteristics for radial beam LED based on MC simulation.

Infrastructure for Planetary Sciences: Universal planetary database development project

NASA Astrophysics Data System (ADS)

Kasaba, Yasumasa; Capria, M. T.; Crichton, D.; Zender, J.; Beebe, R.

The International Planetary Data Alliance (IPDA), formally formed under COSPAR (Formal start: from the COSPAR 2008 at Montreal), is a joint international effort to enable global access and exchange of high quality planetary science data, and to establish archive stan-dards that make it easier to share the data across international boundaries. In 2008-2009, thanks to the many players from several agencies and institutions, we got fruitful results in 6 projects: (1) Inter-operable Planetary Data Access Protocol (PDAP) implementations [led by J. Salgado@ESA], (2) Small bodies interoperability [led by I. Shinohara@JAXA N. Hirata@U. Aizu], (3) PDAP assessment [led by Y. Yamamoto@JAXA], (4) Architecture and standards definition [led by D. Crichton@NASA], (5) Information model and data dictionary [led by S. Hughes@NASA], and (6) Venus Express Interoperability [led by N. Chanover@NMSU]. 'IPDA 2009-2010' is important, especially because the NASA/PDS system reformation is now reviewed as it develops for application at the international level. IPDA is the gate for the establishment of the future infrastructure. We are running 8 projects: (1) IPDA Assessment of PDS4 Data Standards [led by S. Hughes (NASA/JPL)], (2) IPDA Archive Guide [led by M.T. Capria (IASF/INAF) and D. Heather (ESA/PSA)], (3) IPDA Standards Identification [led by E. Rye (NASA/PDS) and G. Krishna (ISRO)], (4) Ancillary Data Standards [led by C. Acton (NASA/JPL)], (5) IPDA Registries Definition [led by D. Crichton (NASA/JPL)], (6) PDAP Specification [led by J. Salgado (ESA/PSA) and Y. Yamamoto (JAXA)], (7) In-teroperability Assessment [R. Beebe (NMSU) and D. Heather (ESA/PSA)], and (8) PDAP Geographic Information System (GIS) extension [N. Hirata (Univ. Aizu) and T. Hare (USGS: thare@usgs.gov)]. This paper presents our achievements and plans summarized in the IPDA 5th Steering Com-mittee meeting at DLR in July 2010. We are now just the gate for the establishment of the Infrastructure.

Single-exposure quantitative phase imaging in color-coded LED microscopy.

PubMed

Lee, Wonchan; Jung, Daeseong; Ryu, Suho; Joo, Chulmin

2017-04-03

We demonstrate single-shot quantitative phase imaging (QPI) in a platform of color-coded LED microscopy (cLEDscope). The light source in a conventional microscope is replaced by a circular LED pattern that is trisected into subregions with equal area, assigned to red, green, and blue colors. Image acquisition with a color image sensor and subsequent computation based on weak object transfer functions allow for the QPI of a transparent specimen. We also provide a correction method for color-leakage, which may be encountered in implementing our method with consumer-grade LEDs and image sensors. Most commercially available LEDs and image sensors do not provide spectrally isolated emissions and pixel responses, generating significant error in phase estimation in our method. We describe the correction scheme for this color-leakage issue, and demonstrate improved phase measurement accuracy. The computational model and single-exposure QPI capability of our method are presented by showing images of calibrated phase samples and cellular specimens.

Green perovskite light emitting diodes based on the ITO/Al2O3/CsPbBr3 heterojunction structure

NASA Astrophysics Data System (ADS)

Zhuang, Shiwei; Ma, Xue; Hu, Daqiang; Dong, Xin; Zhang, Yuantao; Zhang, Baolin

2018-03-01

Perovskite light emitting diodes (PeLEDs) now emerge as a promising new optoelectronic application field for these amazing semiconductors. For the purpose of investigating the device structures and light emission mechanisms of PeLEDs, we have fabricated green PeLEDs based on the ITO/Al2O3/CsPbBr3 heterojunction structure. The emission layer inorganic perovskite CsPbBr3 film with small grain sizes (∼28.9 nm) was prepared using a two-step method. The device exhibits a typical rectification behavior with turn-on voltage of ∼6 V. The EL emission band is narrow with the FWHM of ∼25 nm. The peak EQE of the device was ∼0.09%. The working mechanism of the device is also discussed. The result of the present work provides a feasible innovation idea of PeLEDs fabrication and great potentials for the development of perovskite based LEDs.

Modeling of light-emitting diode wavefronts for the optimization of transmission holograms.

PubMed

Karthaus, Daniela; Giehl, Markus; Sandfuchs, Oliver; Sinzinger, Stefan

2017-06-20

The objective of applying transmission holograms in automotive headlamp systems requires the adaptation of holograms to divergent and polychromatic light sources like light-emitting diodes (LEDs). In this paper, four different options to describe the scalar light waves emitted by a typical automotive LED are regarded. This includes a new approach to determine the LED's wavefront from interferometric measurements. Computer-generated holograms are designed considering the different LED approximations and recorded into a photopolymer. The holograms are reconstructed with the LED and the resulting images are analyzed to evaluate the quality of the wave descriptions. In this paper, we show that our presented new approach leads to better results in comparison to other wave descriptions. The enhancement is evaluated by the correlation between reconstructed and ideal images. In contrast to the next best approximation, a spherical wave, the correlation coefficient increased by 0.18% at 532 nm, 1.69% at 590 nm, and 0.75% at 620 nm.

Theoretical and experimental luminous characteristics of white LEDs composed of multiphosphors and near-UV LED for lighting

NASA Astrophysics Data System (ADS)

Uchida, Yuji; Taguchi, Tsunemasa

2003-07-01

We have performed theoretical studies on the luminous characeristics of white LED light source which composed of multi phosphors and near ultraviolet (UV) LED for general lighting. White LED source for general lighting applications requires the conditions that have high-flux, high luminous efficacy of radiation (> 100 lm/W) in addition to high color rendering index (Ra > 90) and variable color temperatures. Recently, we have proposed a novel type white LED based on multi phosphors and near UV LED system in order to high-Ra (>93). We will describe the excellent luminescence properties of white LED consisting of orange (O), yellow (Y), green (G) and blue (B) phosphor materials, and near UV LED. The color spectral contributions of individual phosphor-coated LED are theoretically analyzed using our multi LED lighting theory calculated the maximum luminous efficacy can be estimated to be approximately 300 lm/W having a high Ra of about 90 taking into account individual radiation spectrum. Illuminance distribution of white LED is in fairly good agreement with the experimental data.

A multi-centre randomised trial to compare the effectiveness of geriatrician-led admission avoidance hospital at home versus inpatient admission.

PubMed

Shepperd, Sasha; Cradduck-Bamford, Andrea; Butler, Chris; Ellis, Graham; Godfrey, Mary; Gray, Alastair; Hemsley, Anthony; Khanna, Pradeep; Langhorne, Peter; McCaffrey, Patricia; Mirza, Lubena; Pushpangadan, Maj; Ramsay, Scott; Schiff, Rebekah; Stott, David; Young, John; Yu, Ly-Mee

2017-10-23

There is concern that existing models of acute hospital care will become unworkable as the health service admits an increasing number of frail older people with complex health needs, and that there is inadequate evidence to guide the planning of acute hospital level services. We aim to evaluate whether geriatrician-led admission avoidance to hospital at home is an effective alternative to hospital admission. We are conducting a multi-site randomised open trial of geriatrician-led admission avoidance hospital at home, compared with admission to hospital. We are recruiting older people with markers of frailty or prior dependence who have been referred to admission avoidance hospital at home for an acute medical event. This includes patients presenting with delirium, functional decline, dependence, falls, immobility or a background of dementia presenting with physical disease. Participants are randomised using a computerised random number generator to geriatrician-led admission avoidance hospital at home or a control group of inpatient admission in a 2:1 ratio in favour of the intervention. The primary endpoint 'living at home' (the inverse of death or living in a residential care setting) is measured at 6 months follow-up, and we also collect data on this outcome at 12 months. Secondary outcomes include the incidence of delirium, mortality, new long-term residential care, cognitive impairment, activities of daily living, quality of life and quality-adjusted survival, length of stay, readmission or transfer to hospital. We will conduct a parallel economic evaluation, and a process evaluation that includes an interview study to explore the experiences of patients and carers. Health systems around the world are examining how to provide acute hospital-level care to older adults in greater numbers with a fixed or shrinking hospital resource. This trial is the first large multi-site randomised trial of geriatrician-led admission avoidance hospital at home, and will provide evidence on alternative models of healthcare for older people who require hospital admission. ISRCTN60477865 : Registered on 10 March 2014. Trial Sponsor: University of Oxford. Version 3.1, 14/06/2016.

Transcranial LED therapy for cognitive dysfunction in chronic, mild traumatic brain injury: two case reports

NASA Astrophysics Data System (ADS)

Naeser, Margaret A.; Saltmarche, Anita; Krengel, Maxine H.; Hamblin, Michael R.; Knight, Jeffrey A.

2010-02-01

Two chronic, traumatic brain injury (TBI) cases are presented, where cognitive function improved following treatment with transcranial light emitting diodes (LEDs). At age 59, P1 had closed-head injury from a motor vehicle accident (MVA) without loss of consciousness and normal MRI, but unable to return to work as development specialist in internet marketing, due to cognitive dysfunction. At 7 years post-MVA, she began transcranial LED treatments with cluster heads (2.1" diameter with 61 diodes each - 9x633nm, 52x870nm; 12-15mW per diode; total power, 500mW; 22.2 mW/cm2) on bilateral frontal, temporal, parietal, occipital and midline sagittal areas (13.3 J/cm2 at scalp, estimated 0.4 J/cm2 to brain cortex per area). Prior to transcranial LED, focused time on computer was 20 minutes. After 2 months of weekly, transcranial LED treatments, increased to 3 hours on computer. Performs nightly home treatments (now, 5 years, age 72); if stops treating >2 weeks, regresses. P2 (age 52F) had history of closed-head injuries related to sports/military training and recent fall. MRI shows fronto-parietal cortical atrophy. Pre-LED, was not able to work for 6 months and scored below average on attention, memory and executive function. Performed nightly transcranial LED treatments at home (9 months) with similar LED device, on frontal and parietal areas. After 4 months of LED treatments, returned to work as executive consultant, international technology consulting firm. Neuropsychological testing (post- 9 months of transcranial LED) showed significant improvement in memory and executive functioning (range, +1 to +2 SD improvement). Case 2 reported reduction in PTSD symptoms.

Effects of near-infrared LED therapy on experimental tooth replantation in rats.

PubMed

Pigatto Mitihiro, Débora; de Paula Ramos, Solange; Corazza Montero, Janaína; Alves Campos, Aline; de Oliveira Toginho Filho, Dari; Dezan Garbelini, Cassia Cilene

2017-02-01

Dental avulsion damages periodontal tissues and may induce dentoalveolar ankylosis and root resorption after replantation. The aim of this work was to evaluate the effects of light-emitting diode (LED) therapy after tooth replantation. The upper right incisors of 36 male Wistar rats were extracted and replanted after 15 min. The control group (Co, n = 18) was submitted to replantation and the LED group (n = 18) was submitted to replantation and LED therapy (940 nm, 4 J cm -2 ) for three consecutive days (0, 24, and 48 h). Six animals from each group were euthanized at 7, 14, and 21 days for histological analysis. The upper left incisors were used as a negative control. Data were compared using the Fisher exact test, considering P < 0.05. After 7 days, the Co (73.3%) and LED (72.2%) groups presented areas of periodontal ligament necrosis. However, periodontal ligament necrosis was more frequent in the LED group at 14 (70%, P < 0.05) and 21 days (43.2%, P < 0.05) in relation to the Co group (33 and 21.6%). Inflammatory cell infiltration was more frequent in the Co group at 7 days (100%) than the LED group (24.4%, P < 0.05), but increased in the LED group after 21 days (83.3%, P < 0.05). Bone necrosis was more frequent in the LED group after 14 (79%, P < 0.05) and 21 days (60%, P < 0.005) than in the Co group (45% and 20%). Bone repair was evident in the Co group at 14 days. All of the replanted teeth had pulp necrosis. The results suggest that the application of LED therapy up to 48 h after tooth replantation may delay periodontal ligament repair. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Beacon system based on light-emitting diode sources for runways lighting

NASA Astrophysics Data System (ADS)

Montes, Mario González; Vázquez, Daniel; Fernandez-Balbuena, Antonio A.; Bernabeu, Eusebio

2014-06-01

New aeronautical ground lighting techniques are becoming increasingly important to ensure the safety and reduce the maintenance costs of the plane's tracks. Until recently, tracks had embedded lighting systems whose sources were based on incandescent lamps. But incandescent lamps have several disadvantages: high energy consumption and frequent breakdowns that result in high maintenance costs (lamp average life-time is ˜1500 operating hours) and the lamp's technology has a lack of new lighting functions, such as signal handling and modification. To solve these problems, the industry has developed systems based on light-emitting diode (LED) technology with improved features: (1) LED lighting consumes one tenth the power, (2) it improves preventive maintenance (an LED's lifetime range is between 25,000 and 100,000 hours), and (3) LED lighting technology can be controlled remotely according to the needs of the track configuration. LEDs have been in use for more than three decades, but only recently, around 2002, have they begun to be used as visual aids, representing the greatest potential change for airport lighting since their inception in the 1920s. Currently, embedded LED systems are not being broadly used due to the specific constraints of the rules and regulations of airports (beacon dimensions, power system technology, etc.). The fundamental requirements applied to embedded lighting systems are to be hosted on a volume where the dimensions are usually critical and also to integrate all the essential components for operation. An embedded architecture that meets the lighting regulations for airport runways is presented. The present work is divided into three main tasks: development of an optical system to optimize lighting according to International Civil Aviation Organization, manufacturing prototype, and model validation.

Evaluation of the efficacy of photodynamic antimicrobial therapy using a phenothiazine compound and LED (red-orange) on the interface: macrophage vs S. aureus

NASA Astrophysics Data System (ADS)

Sampaio, Fernando José P.; de Oliveira, Susana C. P. S.; Monteiro, Juliana S. C.; Pires-Santos, Gustavo M.; Gesteira, Maria F. M.; Pinheiro, Antônio L. B.

2015-03-01

Antimicrobial Photodynamic therapy is a technique in which microorganisms are exposed to a photosensitizing drug and then irradiated with low-intensity visible light of the appropriate wavelength. The resulting photochemical reaction generates cytotoxic reactive oxygen species, such as singlet oxygen and free radicals, which are able to exert bactericidal effect. Much is already known about the photodynamic inactivation of microorganisms: both antibiotic-sensitive and - resistant strains can be successfully photo inactivated, and there is the additional advantage that repeated photosensitization of bacterial cells does not induce a selection of resistant strains. Recently, a series of studies have shown that it is possible to kill bacteria with a light source after the microorganisms have been sensitized with low concentration of dye, such as phenothiazines. The aim of this study was to evaluate the phagocytic function of macrophages J774 against S. aureus in the presence and absence of AmPDT with phenothiazine compound (12.5 μg/mL) and red-orange LED. Experimental groups: Control Group (L-F-), Phenothiazine group (L-F+) LED group (L+F-), Photodynamic therapy group (L+F+). The tests presented in this study were carried out in triplicate. This study demonstrated that AmPDT is able to increase about twice the phagocytic ability of macrophages; however, the bactericidal capacity of these cells did not show a substantial improvement, probably because the oxidative burst was less intense.

Side-emitting illuminators using LED sources

NASA Astrophysics Data System (ADS)

Zhao, Feng; Van Derlofske, John F.

2003-11-01

This study investigates illuminators composed of light emitting diode (LED) array sources and side-emitting light guides to provide efficient general illumination. Specifically, new geometries are explored to increase the efficiency of current systems while maintaining desired light distribution. LED technology is already successfully applied in many illumination applications, such as traffic signals and liquid crystal display (LCD) backlighting. It provides energy-efficient, small-package, long-life, and color-adjustable illumination. However, the use of LEDs in general illumination is still in its early stages. Current side-emitting systems typically use a light guide with light sources at one end, an end-cap surface at the other end, and light releasing sidewalls. This geometry introduces efficiency loss that can be as high as 40%. The illuminators analyzed in this study use LED array sources along the longitude of a light guide to increase the system efficiency. These new geometries also provide the freedom of elongating the system without sacrificing system efficiency. In addition, alternative geometries can be used to create white light with monochromatic LED sources. As concluded by this study, the side-emitting illuminators using LED sources gives the possibility of an efficient, distribution-controllable linear lighting system.

The diffusion of youth-led participatory research in urban schools: the role of the prevention support system in implementation and sustainability.

PubMed

Ozer, Emily J; Cantor, Jeremy P; Cruz, Gary W; Fox, Brian; Hubbard, Elizabeth; Moret, Lauren

2008-06-01

This article discusses the dissemination of a process of youth-led participatory research in urban secondary schools within the Interactive Systems Framework for Dissemination and Implementation (ISF) developed in collaboration with the CDC and its university partners (Wandersman et al. American Journal of Community Psychology, 41(3-4) 2008). The focus here is on the development of the Prevention Support System with respect to general and innovation-specific capacity building. The specific process under study involves youth-led needs assessment and research to inform the planning of prevention programs and policies to address students' health and developmental needs. The article first briefly describes the youth-led research process, its potential benefits, and a case example in two urban secondary schools. It then describes challenges and responses in providing support for the diffusion of this model in 6 secondary schools. The settings are urban public schools with a majority of students of color from diverse ethnic groups: Asian-American, Latino, and African-American. This project constitutes a collaborative partnership with a university school of public health and community-based organizations (CBOs) to build capacity for long-term, sustainable implementation of this innovative process within the local school system. The perspectives of the university-based researcher and the CBO partners on the development and effectiveness of the Prevention Support System are presented.

Comparison of hardness of three temporary filling materials cured by two light-curing devices.

PubMed

Bodrumlu, E; Koçak, M M; Hazar Bodrumlu, E; Ozcan, S; Koçak, S

2014-01-01

Polymerization ability of light-curing devices can affect the light-cured material hardness. The purpose of the present study was to evaluate and compare the hardness of three temporary filling materials that had been light-cured by either a light emitting diode (LED) or a halogen light-curing unit. The temporary filling materials, First Fill, Voco Clip and Bioplic, were placed in wells in a Teflon plate. The 24 specimens of each material were divided into two groups (N.=12/group) for photo-activation by either of the two light-curing units. The LED or halogen device was applied for 40s to the top surface of each specimen. A Knoop hardness test was performed on the top and bottom surface of each specimen, with five measurements per specimen. The highest hardness values for both the LED and halogen treated groups were observed for First Fill and the lowest values were for Voco Clip in top and bottom surfaces. The hardness obtained for the three materials with the halogen unit were significantly higher than the values obtained with the LED unit in both surfaces (P<0.05). First Fill light-cured temporary material exhibited the highest hardness values on the top and bottom surfaces than Voco Clip and Bioplic temporary materials. The hardness of light-cured temporary filling materials can be affected by the type of light-curing unit.

Nonprescription medication use and literacy among New Hampshire eighth graders.

PubMed

Abel, Cheryl; Johnson, Kerri; Waller, Dustin; Abdalla, Maha; Goldsmith, Carroll-Ann W

2012-01-01

To assess whether New Hampshire (NH) eighth graders were self-medicating with over-the-counter (OTC) medications, had literacy skills necessary to safely and accurately interpret OTC medication labels, and showed improvement in OTC medication safe use and literacy skills after student pharmacist-led education. Cross-sectional repeated-measures study. NH, five separate sessions, in 2010 and 2011. 101 NH eighth grade students. Participants answered questions derived from OTC drug facts labels that assessed OTC medication safe use and literacy before and after a student pharmacist-led presentation describing each section of the labels. Participant use of OTC medications, whether participants interpreted OTC drug facts labels correctly, and whether participants were able to identify safe use of OTC medications before and after instruction about OTC drug facts labels. 57% of participants reported taking OTC medications in the previous month, 22% reported taking OTC medications autonomously, and 43% reported checking with a trusted adult before self-administration. After student pharmacist-led education, significant improvements were seen in identifying product indications, calculating adult doses, interpreting adverse effects, knowing when to call a medical provider, understanding proper medication storage, identifying expiration dates, and identifying duplicate medications in products. NH eighth graders were self-medicating with OTC medications. Significant improvements in OTC medication label literacy were seen after student pharmacist-led education. These results provide evidence of the need for, and positive effects of, OTC medication education among U.S. adolescents.

Conflicting calculations of pelvic incidence and pelvic tilt secondary to transitional lumbosacral anatomy (lumbarization of S-1): case report.

PubMed

Crawford, Charles H; Glassman, Steven D; Gum, Jeffrey L; Carreon, Leah Y

2017-01-01

Advancements in the understanding of adult spinal deformity have led to a greater awareness of the role of the pelvis in maintaining sagittal balance and alignment. Pelvic incidence has emerged as a key radiographic measure and should closely match lumbar lordosis. As proper measurement of the pelvic incidence requires accurate identification of the S-1 endplate, lumbosacral transitional anatomy may lead to errors. The purpose of this study is to demonstrate how lumbosacral transitional anatomy may lead to errors in the measurement of pelvic parameters. The current case highlights one of the potential complications that can be avoided with awareness. The authors report the case of a 61-year-old man who had undergone prior lumbar surgeries and then presented with symptomatic lumbar stenosis and sagittal malalignment. Radiographs showed a lumbarized S-1. Prior numbering of the segments in previous surgical and radiology reports led to a pelvic incidence calculation of 61°. Corrected numbering of the segments using the lumbarized S-1 endplate led to a pelvic incidence calculation of 48°. Without recognition of the lumbosacral anatomy, overcorrection of the lumbar lordosis might have led to negative sagittal balance and the propensity to develop proximal junction failure. This case illustrates that improper identification of lumbosacral transitional anatomy may lead to errors that could affect clinical outcome. Awareness of this potential error may help improve patient outcomes.

Development of the Simbol-X science verification model and its contribution for the IXO Mission

NASA Astrophysics Data System (ADS)

Maier, Daniel; Aschauer, Florian; Dick, Jürgen; Distratis, Giuseppe; Gebhardt, Henry; Herrmann, Sven; Kendziorra, Eckhard; Lauf, Thomas; Lechner, Peter; Santangelo, Andrea; Schanz, Thomas; Strüder, Lothar; Tenzer, Chris; Treis, Johannes

2010-07-01

Like the International X-ray Observatory (IXO) mission, the Simbol-X mission is a projected X-ray space telescope with spectral and imaging capabilities covering the energy range from 500 eV up to 80 keV. To detect photons within this wide range of energies, a silicon based "Depleted P-channel Field Effect Transistor" (DePFET)- matrix is used as the Low Energy Detector (LED) on top of an array of CdTe-Caliste modules, which act as the High Energy Detector (HED). A Science Verification Model (SVM) consisting of one LED quadrant in front of one Caliste module will be set up at our institute (IAAT) and operated under laboratory conditions that approximate the expected environment in space. As a first step we use the SVM to test and optimize the performance of the LED operation and data acquisition chain, consisting of an ADC, an event-preprocessor, a sequencer, and an interface controller. All these components have been developed at our institute with the objective to handle the high readout rate of approximately 8000 frames per second. The second step is to study the behaviour and the interactions of LED and HED operating as a combined detector system. We report on the development status of the SVM and its associated electronics and present first results of the currently achieved spectral performance.

The mechanobiological aetiopathogenesis of tendinopathy: is it the over-stimulation or the under-stimulation of tendon cells?

PubMed Central

Arnoczky, Steven P; Lavagnino, Michael; Egerbacher, Monika

2007-01-01

While there is a significant amount of information available on the clinical presentation(s) and pathological changes associated with tendinopathy, the precise aetiopathogenesis of this condition remains a topic of debate. Classically, the aetiology of tendinopathy has been linked to the performance of repetitive activities (so-called overuse injuries). This has led many investigators to suggest that it is the mechanobiologic over-stimulation of tendon cells that is the initial stimulus for the degradative processes which have been shown to accompany tendinopathy. Although several studies have been able to demonstrate that the in vitro over-stimulation of tendon cells in monolayer can result in a pattern(s) of gene expression seen in clinical cases of tendinopathy, the strain magnitudes and durations used in these in vitro studies, as well as the model systems, may not be clinically relevant. Using a rat tail tendon model, we have studied the in vitro mechanobiologic response of tendon cells in situ to various tensile loading regimes. These studies have led to the hypothesis that the aetiopathogenic stimulus for the degenerative cascade which precedes the overt pathologic development of tendinopathy is the catabolic response of tendon cells to mechanobiologic under-stimulation as a result of microscopic damage to the collagen fibres of the tendon. In this review, we examine the rationale for this hypothesis and provide evidence in support of this theory. PMID:17696902

Carrier transport and emission efficiency in InGaN quantum-dot based light-emitting diodes

NASA Astrophysics Data System (ADS)

Barettin, Daniele; Auf der Maur, Matthias; di Carlo, Aldo; Pecchia, Alessandro; Tsatsulnikov, Andrei F.; Lundin, Wsevolod V.; Sakharov, Alexei V.; Nikolaev, Andrei E.; Korytov, Maxim; Cherkashin, Nikolay; Hÿtch, Martin J.; Karpov, Sergey Yu

2017-07-01

We present a study of blue III-nitride light-emitting diodes (LEDs) with multiple quantum well (MQW) and quantum dot (QD) active regions (ARs), comparing experimental and theoretical results. The LED samples were grown by metalorganic vapor phase epitaxy, utilizing growth interruption in the hydrogen/nitrogen atmosphere and variable reactor pressure to control the AR microstructure. Realistic configuration of the QD AR implied in simulations was directly extracted from HRTEM characterization of the grown QD-based structures. Multi-scale 2D simulations of the carrier transport inside the multiple QD AR have revealed a non-trivial pathway for carrier injection into the dots. Electrons and holes are found to penetrate deep into the multi-layer AR through the gaps between individual QDs and get into the dots via their side edges rather than via top and bottom interfaces. This enables a more homogeneous carrier distribution among the dots situated in different layers than among the laterally uniform quantum well (QWs) in the MQW AR. As a result, a lower turn-on voltage is predicted for QD-based LEDs, as compared to MQW ones. Simulations did not show any remarkable difference in the efficiencies of the MQW and QD-based LEDs, if the same recombination coefficients are utilized, i.e. a similar crystal quality of both types of LED structures is assumed. Measurements of the current-voltage characteristics of LEDs with both kinds of the AR have shown their close similarity, in contrast to theoretical predictions. This implies the conventional assumption of laterally uniform QWs not to be likely an adequate approximation for the carrier transport in MQW LED structures. Optical characterization of MQW and QD-based LEDs has demonstrated that the later ones exhibit a higher efficiency, which could be attributed to better crystal quality of the grown QD-based structures. The difference in the crystal quality explains the recently observed correlation between the growth pressure of LED structures and their efficiency and should be taken into account while further comparing performances of MQW and QD-based LEDs. In contrast to experimental results, our simulations did not reveal any advantages of using QD-based ARs over the MQW ones, if the same recombination constants are assumed for both cases. This fact demonstrates importance of accounting for growth-dependent factors, like crystal quality, which may limit the device performance. Nevertheless, a more uniform carrier injection into multi-layer QD ARs predicted by modeling may serve as the basis for further improvement of LED efficiency by lowering carrier density in individual QDs and, hence, suppressing the Auger recombination losses.

Carrier transport and emission efficiency in InGaN quantum-dot based light-emitting diodes.

PubMed

Barettin, Daniele; Auf der Maur, Matthias; di Carlo, Aldo; Pecchia, Alessandro; Tsatsulnikov, Andrei F; Lundin, Wsevolod V; Sakharov, Alexei V; Nikolaev, Andrei E; Korytov, Maxim; Cherkashin, Nikolay; Hÿtch, Martin J; Karpov, Sergey Yu

2017-07-07

We present a study of blue III-nitride light-emitting diodes (LEDs) with multiple quantum well (MQW) and quantum dot (QD) active regions (ARs), comparing experimental and theoretical results. The LED samples were grown by metalorganic vapor phase epitaxy, utilizing growth interruption in the hydrogen/nitrogen atmosphere and variable reactor pressure to control the AR microstructure. Realistic configuration of the QD AR implied in simulations was directly extracted from HRTEM characterization of the grown QD-based structures. Multi-scale 2D simulations of the carrier transport inside the multiple QD AR have revealed a non-trivial pathway for carrier injection into the dots. Electrons and holes are found to penetrate deep into the multi-layer AR through the gaps between individual QDs and get into the dots via their side edges rather than via top and bottom interfaces. This enables a more homogeneous carrier distribution among the dots situated in different layers than among the laterally uniform quantum well (QWs) in the MQW AR. As a result, a lower turn-on voltage is predicted for QD-based LEDs, as compared to MQW ones. Simulations did not show any remarkable difference in the efficiencies of the MQW and QD-based LEDs, if the same recombination coefficients are utilized, i.e. a similar crystal quality of both types of LED structures is assumed. Measurements of the current-voltage characteristics of LEDs with both kinds of the AR have shown their close similarity, in contrast to theoretical predictions. This implies the conventional assumption of laterally uniform QWs not to be likely an adequate approximation for the carrier transport in MQW LED structures. Optical characterization of MQW and QD-based LEDs has demonstrated that the later ones exhibit a higher efficiency, which could be attributed to better crystal quality of the grown QD-based structures. The difference in the crystal quality explains the recently observed correlation between the growth pressure of LED structures and their efficiency and should be taken into account while further comparing performances of MQW and QD-based LEDs. In contrast to experimental results, our simulations did not reveal any advantages of using QD-based ARs over the MQW ones, if the same recombination constants are assumed for both cases. This fact demonstrates importance of accounting for growth-dependent factors, like crystal quality, which may limit the device performance. Nevertheless, a more uniform carrier injection into multi-layer QD ARs predicted by modeling may serve as the basis for further improvement of LED efficiency by lowering carrier density in individual QDs and, hence, suppressing the Auger recombination losses.

High modulation bandwidth of a light-emitting diode with surface plasmon coupling (Conference Presentation)

NASA Astrophysics Data System (ADS)

Lin, Chun-Han; Tu, Charng-Gan; Yao, Yu-Feng; Chen, Sheng-Hung; Su, Chia-Ying; Chen, Hao-Tsung; Kiang, Yean-Woei; Yang, Chih-Chung

2017-02-01

Besides lighting, LEDs can be used for indoor data transmission. Therefore, a large modulation bandwidth becomes an important target in the development of visible LED. In this regard, enhancing the radiative recombination rate of carriers in the quantum wells of an LED is a useful method since the modulation bandwidth of an LED is related to the carrier decay rate besides the device RC time constant To increase the carrier decay rate in an LED without sacrificing its output power, the technique of surface plasmon (SP) coupling in an LED is useful. In this paper, the increases of modulation bandwidth by reducing mesa size, decreasing active layer thickness, and inducing SP coupling in blue- and green-emitting LEDs are illustrated. The results are demonstrated by comparing three different LED surface structures, including bare p-type surface, GaZnO current spreading layer, and Ag nanoparticles (NPs) for inducing SP coupling. In a single-quantum-well, blue-emitting LED with a circular mesa of 10 microns in radius, SP coupling results in a modulation bandwidth of 528.8 MHz, which is believed to be the record-high level. A smaller RC time constant can lead to a higher modulation bandwidth. However, when the RC time constant is smaller than 0.2 ns, its effect on modulation bandwidth saturates. The dependencies of modulation bandwidth on injected current density and carrier decay time confirm that the modulation bandwidth is essentially inversely proportional to a time constant, which is inversely proportional to the square-root of carrier decay rate and injected current density.

LED deep UV source for charge management of gravitational reference sensors

NASA Astrophysics Data System (ADS)

Sun, Ke-Xun; Allard, Brett; Buchman, Saps; Williams, Scott; Byer, Robert L.

2006-04-01

Proof mass electrical charge management is an important functionality for the ST-7-LTP technology demonstration flight and for LISA. Photoemission for charge control is accomplished by using deep ultraviolet (UV) light to excite photoelectron emission from an Au alloy. The conventional UV source is a mercury vapour lamp. We propose and demonstrate charge management using a deep UV light emitting diode (LED) source. We have acquired selected AlGaN UV LEDs, characterized their performance and successfully used them to realize charge management. The UV LEDs emit at a 257 nm central wavelength with a bandwidth of ~12 nm. The UV power for a free-space LED is ~120 µW, and after fibre coupling is ~16 µW, more than sufficient for LISA applications. We have directly observed the LED UV light-induced photocurrent response from an Au photocathode and an Au-coated GRS/ST-7 proof mass. We demonstrated fast switching of UV LEDs and associated fast changes in photocurrent. This allows modulation and continuous discharge to meet stringent LISA disturbance reduction requirements. We propose and demonstrate AC charge management outside the gravitational wave signal band. Further, the megahertz bandwidth for UV LED switching allows for up to six orders of magnitude dynamic power range and a number of novel modes of operations. The UV LED based charge management system offers the advantages of small-size, lightweight, fibre-coupled operation with very low power consumption. Presented at 'Amaldi6', Poster 73, Space Detector, 6th Edoardo Almadi Conference on Gravitational Waves, 20-24 June 2005.

Medical Students' Learning from Patient-Led Teaching: Experiential versus Biomedical Knowledge

ERIC Educational Resources Information Center

Henriksen, Ann-Helen; Ringsted, Charlotte

2014-01-01

The aim of this study was to explore how medical students perceive the experience of learning from patient instructors (patients with rheumatism who teach health professionals and students) in the context of coupled faculty-led and patient-led teaching session. This was an explorative study with a qualitative approach based on focus group…

Argumentation as a Lens to Examine Student Discourse in Peer-Led Guided Inquiry for College General Chemistry

ERIC Educational Resources Information Center

Kulatunga, Ushiri Kumarihamy

2013-01-01

This dissertation work entails three related studies on the investigation of Peer-Led Guided Inquiry student discourse in a General Chemistry I course through argumentation. The first study, "Argumentation and participation patterns in general chemistry peer-led sessions," is focused on examining arguments and participation patterns in…

Evaluation of LED vehicular and pedestrian modules.

DOT National Transportation Integrated Search

2009-04-01

This study was conducted to verify the compliance of vehicular and pedestrian LED traffic signal modules with the Institute : of Transportation Engineers specifications; and to assess drivers preferences of the LED modules. Four vehicular modules ...

Validation of thermal effects of LED package by using Elmer finite element simulation method

NASA Astrophysics Data System (ADS)

Leng, Lai Siang; Retnasamy, Vithyacharan; Mohamad Shahimin, Mukhzeer; Sauli, Zaliman; Taniselass, Steven; Bin Ab Aziz, Muhamad Hafiz; Vairavan, Rajendaran; Kirtsaeng, Supap

2017-02-01

The overall performance of the Light-emitting diode, LED package is critically affected by the heat attribution. In this study, open source software - Elmer FEM has been utilized to study the thermal analysis of the LED package. In order to perform a complete simulation study, both Salome software and ParaView software were introduced as Pre and Postprocessor. The thermal effect of the LED package was evaluated by this software. The result has been validated with commercially licensed software based on previous work. The percentage difference from both simulation results is less than 5% which is tolerable and comparable.

Bright Visible-Infrared Light Emitting Diodes Based on Hybrid Halide Perovskite with Spiro-OMeTAD as a Hole-Injecting Layer.

PubMed

Jaramillo-Quintero, Oscar A; Sanchez, Rafael S; Rincon, Marina; Mora-Sero, Ivan

2015-05-21

Hybrid halide perovskites that are currently intensively studied for photovoltaic applications, also present outstanding properties for light emission. Here, we report on the preparation of bright solid state light emitting diodes (LEDs) based on a solution-processed hybrid lead halide perovskite (Pe). In particular, we have utilized the perovskite generally described with the formula CH3NH3PbI(3-x)Cl(x) and exploited a configuration without electron or hole blocking layer in addition to the injecting layers. Compact TiO2 and Spiro-OMeTAD were used as electron and hole injecting layers, respectively. We have demonstrated a bright combined visible-infrared radiance of 7.1 W·sr(-1)·m(-2) at a current density of 232 mA·cm(-2), and a maximum external quantum efficiency (EQE) of 0.48%. The devices prepared surpass the EQE values achieved in previous reports, considering devices with just an injecting layer without any additional blocking layer. Significantly, the maximum EQE value of our devices is obtained at applied voltages as low as 2 V, with a turn-on voltage as low as the Pe band gap (V(turn-on) = 1.45 ± 0.06 V). This outstanding performance, despite the simplicity of the approach, highlights the enormous potentiality of Pe-LEDs. In addition, we present a stability study of unsealed Pe-LEDs, which demonstrates a dramatic influence of the measurement atmosphere on the performance of the devices. The decrease of the electroluminescence (EL) under continuous operation can be attributed to an increase of the non-radiative recombination pathways, rather than a degradation of the perovskite material itself.

Modular design of the LED vehicle projector headlamp system.

PubMed

Hsieh, Chi-Chang; Li, Yan-Huei; Hung, Chih-Ching

2013-07-20

A well designed headlamp for a vehicle lighting system is very important as it provides drivers with safe and comfortable driving conditions at night or in dark places. With the advances of the semiconductor technology, the LED has become the fourth generation lighting source in the auto industry. In this study, we will propose a LED vehicle projector headlamp system. This headlamp system contains several LED headlamp modules, and every module of it includes four components: focused LEDs, asymmetric metal-based plates, freeform surfaces, and condenser lenses. By optimizing the number of LED headlamp modules, the proposed LED vehicle projector headlamp system has only five LED headlamp modules. It not only provides the low-beam cutoff without a shield, but also meets the requirements of the ECE R112 regulation. Finally, a prototype of the LED vehicle projector headlamp system was assembled and fabricated to create the correct light pattern.

Impact of a web-based intervention on the awareness of medication adherence.

PubMed

Gupta, Vasudha; Hincapie, Ana L; Frausto, Sonya; Bhutada, Nilesh S

Medication nonadherence is a widely recognized problem that leads to adverse outcomes and increased health care costs. Reasons for medication nonadherence are multifactorial, and patient awareness of the salience of medication adherence is critical. The purpose of this research was to assess the impact of a pharmacist-led, web-based video presentation in increasing patients' awareness of the importance of medication adherence. Patients aged 35 years and above, taking at least 1 chronic prescription medication were included in the study (n = 166). Patients completed a pre-survey, watched a pharmacist-led web-based video presentation educating them on the importance of medication adherence, then completed a 1-month follow-up survey. The primary outcome was measurement of change in patients' awareness of the importance of medication adherence. Results indicated a statistically significant increase in the primary outcome of increasing awareness of the importance of medication adherence. More patients in the follow-up survey indicated that it was important for their health to take their medications around the same time daily (P = 0.002), and more patients identified that their family will be impacted as a result of their medication nonadherence (P = 0.001) as compared to the pre-survey. More patients in the follow-up survey reported that they expected to experience fewer emergency room visits (P = 0.0001) and anticipated that they would get more time to spend with friends and family (P = 0.0039) as benefits of taking medications as prescribed. A pharmacist-led web-based video presentation may be a low-cost intervention to increase patients' awareness of the importance of medication adherence. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of LED or laser phototherapy on bone defects grafted with MTA and irradiated with laser or LED light: a comparative Raman spectroscopic study

NASA Astrophysics Data System (ADS)

Pinheiro, Antonio L. B.; Soares, Luiz G. P.; Barbosa, Artur Felipe S.; Silveira, Landulfo, Jr.

2012-03-01

We studied peaks of calcium hydroxyapatite - CHA on defects grafted with MTA, treated or not with Light Emitting Diode - LED or IR Laser. 54 rats were divided in 6 groups each subdivided into 3 subgroups (15,21,30d). LED (λ850 +/- 10nm) or IR Laser (λ850 nm) was applied over (LED) or in 4 points around the defect at 48 h intervals for 15 days. Raman readings were taken at the surface of the defect. The smaller overall intensity of the peak was found in Group MTA + Laser (1510.2 +/- 274.1) and the highest on Group LED (2322 +/- 715). There were no statistically significant differences between non-irradiated subjects on regards the CHA peaks. On the other hand, there were statistically significant differences between the Group Clot and LED, Clot and Laser, and Clot and MTA + Laser (p =0.01, p = 0.02, p = 0.003). There were no significant differences between Group MTA and MTA + LED (p=0.2) but significant differences were seen between Groups MTA and MTA + Laser (p=0.01). Significant differences were also observed between Groups LED and Laser (p <0.001) and between Groups MTA + LED and MTA + Laser (p=0.009). MTA, due to its characteristics, seemed to be directly affected by the light. However, the use of either phototherapy positively affected bone healing similarly as observed on different studies using other biomaterials. The overall analysis of our results indicated that the use of either light source resulted in a better, more advanced, and of quality bone repair.

Light-Emitting Diode (LED) Traps Improve the Light-Trapping of Anopheline Mosquitoes.

PubMed

Costa-Neta, B M; da Silva, A A; Brito, J M; Moraes, J L P; Rebêlo, J M M; Silva, F S

2017-11-07

Numerous advantages over the standard incandescent lamp favor the use of light-emitting diodes (LEDs) as an alternative and inexpensive light source for sampling medically important insects in surveillance studies. Previously published studies examined the response of mosquitoes to different wavelengths, but data on anopheline mosquito LED attraction are limited. Center for Disease Control and Prevention-type light traps were modified by replacing the standard incandescent lamp with 5-mm LEDs, one emitting at 520 nm (green) and the other at 470 nm (blue). To test the influence of moon luminosity on LED catches, the experiments were conducted during the four lunar phases during each month of the study period. A total of 1,845 specimens representing eight anopheline species were collected. Anopheles (Nyssorhynchus) evansae (35.2%) was the most frequently collected, followed by An. (Nys.) triannulatus (21.9%), An. (Nys.) goeldii (12.9%), and An. (Nys.) argyritarsis (11.5%). The green LED was the most attractive light source, accounting for 43.3% of the individuals collected, followed by the blue (31.8%) and control (24.9%) lights. The LED traps were significantly more attractive than the control, independent of the lunar phase. Light trapping of anopheline mosquitoes was more efficient when the standard incandescent lamp was replaced with LEDs, regardless of the moon phase. The efficiency of LEDs improves light trapping results, and it is suggested that the use of LEDs as an attractant for anopheline mosquitoes should be taken into consideration when sampling anopheline mosquitoes. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Sacral Stress Fracture Mimicking Lumbar Radiculopathy in a Mounted Police Officer: Case Report and Literature Review.

PubMed

Bednar, Drew A; Almansoori, Khaled

2015-10-01

Study Design Case report and review of the literature. Objective To present a unique case of L5 radiculopathy caused by a sacral stress fracture without neurologic compression. Methods We present our case and its clinical evolution and review the available literature on similar pathologies. Results Relief of the unusual mechanical loading causing sacral stress fracture led to rapid resolution of radiculopathy. Conclusion L5 radiculopathy can be caused by a sacral stress fracture and can be relieved by simple mechanical treatment of the fracture.

Use of space-filling curves to select sample locations in natural resource monitoring studies

Treesearch

Andrew Lister; Charles T. Scott

2009-01-01

The establishment of several large area monitoring networks over the past few decades has led to increased research into ways to spatially balance sample locations across the landscape. Many of these methods are well documented and have been used in the past with great success. In this paper, we present a method using geographic information systems (GIS) and fractals...