Fluorescent Light Tubes Research Articles

Quality of Sour Cream Packaged in Cups with Different Light Barrier Properties Measured by Fluorescence Spectroscopy and Sensory Analysis

In this study, photooxidation of sour cream packaged in cups with different light barrier properties was investigated. The sour cream was light exposed for 36 h with a standard fluorescent light tube, simulating storage conditions in many Norwegian grocery stores. Three different cups were evaluated: a white cup, a cup with medium light barrier (LB), and a cup with high LB. The quality of the sour cream was evaluated by sensory analysis and front face fluorescence spectroscopy. The sour cream stored in white cups became very rancid during the light exposure, with a rancid flavor score of 7.8 on a scale from 1 to 9, where 9 is the highest intensity. Cups with high LB gave best protection against the light. The sensory assessors could not distinguish between sour cream stored in cups with high LB and sour cream stored in the dark. The rancid flavor intensity for the cups with medium LB was significantly different (P < 0.05) from both the white cup and the cup with high LB. The sensory flavor intensities indicated that with 36 h of light exposure, only a cup with high LB will protect the sour cream sufficiently. The fluorescence measurements corresponded well with the sensory analysis as the photosensitizers were somewhat degraded for sour cream stored in cups with medium LB and most degraded in the white cups. For the cups with high LB, the fluorescence peaks that originated from the photosensitizers were all intact. Dairy products such as sour cream will develop off-odor and taste faults ("sunlight taste") in a few hours if exposed to sufficient fluorescent lightning in the grocery stores. A light barrier can be incorporated in the packaging material to protect the dairy products from the light. Our experiment showed that the incorporation of a black pigment into 1 of the 3 plastic layers in the cup for packaging of sour cream protected the sour cream from degradation when exposed to light.

Light Emitting Diodes as an alternative ambient illumination source in photolithography environment

We explored an alternative light emitting diode (LED) - based solution to replace the existing yellow fluorescent light tubes (YFT) used in photolithography rooms. A no-blue LED lamp was designed and a prototype was fabricated. For both solutions, the spectral power distribution (SPD) was measured, the colorimetric values were calculated, and a visual comparison using Gretagmacbeth colorcharts was performed. The visual comparison showed that the LED bulb was better to render colors despite a low color rendering index (CRI). Furthermore, the LED bulb was tested in a photolithography room and there was no exposure to the photoresist even after 168 hours illumination.

Proyecto Marfa: Marfa, EE.UU.

In the desert landscape of Marfa, Texas sit 6 buildings that contain an installation of fluorescent light tubes by Dan Flavin. Part of his work is described ...

Comparison of illuminations to identify wheat classes using monochrome images

Wheat class identification using machine vision is an objective method which can be used for online testing to automate handling, binning and shipping operations in grain industry. The efficiencies of a monochrome camera-based vision system with three different illuminations (incandescent light (IL), fluorescent ring light (FRL), fluorescent tube light (FTL)) were determined to identify eight western Canadian wheat classes at four moisture levels (11%, 14%, 17% and 20%). The monochrome images of the bulk wheat samples were acquired at each moisture level (3 illuminations × 8 classes × 4 moisture contents × 100 replications = 9600 images). A linear discriminant function was used for the classification of wheat samples using 32 gray level textural features extracted from the monochrome images. The mean gray values of the wheat classes were in the ranges of 75–103, 73–115, and 107–143 for IL, FRL and FTL, respectively. The mean gray values of wheat classes were significantly different within each illumination and between different illuminations ( α = 0.05). Mean gray value was the highest for FTL and the lowest for IL illumination. The moisture content of the wheat samples had significant effect on the mean gray values. The overall classification accuracies were 90%, 81% and 96% for IL, FRL and FTL, respectively, when all the wheat classes were at the same moisture levels. It was 66%, 53% and 85% for IL, FRL and FTL, respectively, when the wheat classes were at different moisture levels. The classification accuracies of a 2-stage classification system for the classes with different moisture levels were 68%, 56% and 90% for IL, FRL and FTL, respectively.

Vitamin D insufficiency reduces the protective effect of bisphosphonate on ovariectomy-induced bone loss in rats

The present study was carried out to obtain an experimental model of vitamin D (vit D) insufficiency and established osteopenia (experiment 1) to then investigate whether vit D status, i.e. normal or insufficient, interferes with bone mass recovery resulting from bisphosphonate therapy (experiment 2). Rats ( n = 40) underwent OVX ( n = 32) or a sham operation ( n = 8). The first 15 days post-surgery, all groups were kept under fluorescent tube lighting and fed a diet containing 200 IU% vit D (+ D). They were then assigned during an additional 45 days to receive either + D or a diet lacking vit D (− D) and kept under 12 h light/dark cycles using fluorescent or red lighting. Serum 25HOD was significantly lower in − D rats ( P < 0.0001). The type of lighting did not induce differences in 25OHD, calcium (sCa), phosphorus (sP), bone alkaline phosphatase (b-AL), CTX, bone density or histology. No osteoid was observed in undecalcified bone sections. Experiment 2 (105 days): rats were fed either + D or − D according to experiment 1 and were treated with either placebo or 16 μg olpadronate (OPD)/100 g rat/week during the last 45 days. Whereas 25HOD was significantly lower ( P < 0.0001) in − D/OPD than in + D/OPD rats, no significant differences in sCa, sP, b-AL or CTX were observed. OPD prevented the loss of lumbar spine (LS) and proximal tibia (PT) BMD and the decrease in bone volume (BV/TV) ( P < 0.05) and in the number of trabeculae observed in untreated rats. However, + D/OPD animals presented significantly higher values of LS BMD, PT BMD and BV/TV than − D/OPD rats ( P < 0.05). No osteoid was observed in undecalcified sections of bone. In summary, this is the first experimental study to provide evidence that differences in vit D status may affect the anticatabolic response to bisphosphonate treatment. However, the molecular mechanism through which vit D insufficiency reduces the effect of the aminobisphosphonate remains to be defined.

A Comparison of Manual and Automatic Moth Sampling Methods (Lepidoptera: Arctiidae, Geometridae) in a Rain Forest in Costa Rica

Abstract Sampling with UV fluorescent light tubes is a commonly used technique both in applied and basic insect studies. Our study compares the performance of two such methods: manual sampling (light towers) and automatic sampling (funnel light traps). The abundance, diversity, and body size of moths representing two species-rich families (Lepidoptera: Arctiidae, Geometridae) were analyzed in a lowland rain forest in Costa Rica (La Selva Biological Station, 10.4° N, 84.0° W) during 2003 and 2004. Light towers were equipped with two 15-W UV fluorescent tubes and were operated for 3 h in 16 nights. Traps equipped with single 8-W fluorescent tubes were run throughout 20 nights in the understory of the forest. In addition, parallel trap sampling was carried out in the canopy. A total of 1,238 arctiid moths representing 162 species and 1,769 geometrid moths representing 196 species were collected. In Geometridae, tower samples were significantly larger than trap samples. Towers also attracted a higher overall ...

Photodynamic therapy of dermatoses other than non‐melanotic skin cancer

Even though photodynamic therapy (PDT) is a firmly established niche treatment for non-melanoma skin cancer (NMSC), its potential as a treatment for other dermatoses has been somewhat neglected. It is disappointing that little clinical research has been conducted in this area, as it may prove to be even more useful for treating dermatoses than it is for NMSC. 1 Dr Gerald Weinstein and colleagues at the University of California have performed much of the work investigating PDT in dermatoses other than NMSC. 2 In one of their studies, they assessed various concentrations of aminolaevulinic acid (ALA) for their capacity to induce fluorescence, using a Wood’s light in a darkened room. Solar keratoses (SK) and inflammatory dermatoses (psoriasis and acne vulgaris) developed visibly significant fluorescence. Fluorescence tended to be brighter in sun-exposed skin (both lesional and non-lesional skin), and brighter in inflammatory dermatoses than in SK. 2 Another study involved treating psoriasis with ALA PDT three times weekly using blue fluorescent tube light. 3 Modest improvement was noted after a few weeks of treatment, but the trial was limited by its design; the ALA concentrations used were too strong and the treatments too frequent. Most subjects could not tolerate more than approximately one minute of blue light exposure because of pain. Regular intermittent treatments (e.g. monthly) may be the best approach to treating dermatoses other than NMSC. The evidence for this relates to the experience of one of the trial subjects, who applied 10 and 20% ALA to psoriasis on the left and right sides of his abdomen on rising. After driving to his 08.30 am appointment for light treatment, the areas were already sore and red; presumably light through the windscreen, and his white shirt and possibly within his home had triggered the PDT reaction. Accordingly, his treatment that day was cancelled, and the reaction was followed for the next few weeks. At four weeks, 90% of the psoriasis had resolved, leaving completely flat, brown areas. The psoriasis gradually recurred over the following weeks; some 50% of the plaques were in remission 4 months later. However, the long-term outcome for repeated treatment in this manner is unknown. It has been difficult to obtain sponsorship to conduct trials in this area, but now that suitable creams and PDT devices are commercially available, studies may be more readily organized, and the longterm implications assessed. Erythropoietic porphyria (EPP) patients who have survived to adulthood may also provide some indication of the long-term effects of topical PDT. Erythropoietic porphyria is not strictly equivalent to PDT, since EPP patients tend to avoid sun exposure, but it would be interesting to assess the incidences of SK, basal cell and squamous cell carcinoma and also inflammatory dermatoses in these patients. In the future it may be possible to treat solar damaged skin by using a tiny amount of an appropriate erythroprotoporphyrin precursor in a suitable sunscreen base, to use regularly on photo-damaged skin. This may lead to photorejuvenation but also prevention of development of skin cancers and solar keratoses.

Prevalence of annoyance attributed to electrical equipment and smells in a Swedish population, and relationship with subjective health and daily functioning

Self-reported annoyance from electrical equipment has been in evidence since the mid-1980s, and the first reports of illness from everyday chemicals arose in the 1960s. However, the extent of the problem has not yet been fully established. The aim of this study was to estimate the prevalence of annoyance related to electrical and chemical factors in a Swedish general population, and to assess possible relationships with subjective health and daily functioning. In total, 13,604 subjects, representative of the population of Scania, Sweden, answered a survey containing five questions regarding annoyance from five environmental factors: fluorescent tube lighting, visual display units, other electrical equipment, air that smells of chemicals, and other smells. The survey also obtained data on self-reported health (SRH-7), mental well-being [General Health Questionnaire (GHQ)-12], work situation and daily functioning. Almost one-third of the respondents reported annoyance from at least one environmental factor. Annoyance was more frequent among women, subjects of working age and immigrants. Subjects who reported environmental annoyance scored higher on GHQ-12 and lower on SRH-7, indicating impaired subjective physical and mental well-being. They were also more likely to report deteriorated daily functioning. Annoyance related to electrical and/or chemical factors was common in a Swedish population. Subjects reporting environmental annoyance rated their overall health significantly poorer than the general population. The association with subjective health and functional capacity increased with severity of annoyance, which suggests that there is some connection between environmental annoyance, well-being and functional capacity.

Coping and self-image in patients with visual display terminal-related skin symptoms and perceived hypersensitivity to electricity

The aim of the present study was to measure coping resources and self-image in patients with visual display terminal (VDT)-related skin symptoms and hypersensitivity to electricity (HE). From 1980 to 1998, 350 patients with electrical sensitivity were registered. The patients were subdivided into two groups: patients with skin symptoms evoked by VDTs, television screens, and fluorescent-light tubes and patients with so-called hypersensitivity to electricity with multiple symptoms evoked by exposure to different electrical environments. A questionnaire was sent to all patients and contained the coping resources inventory (CRI) and the structural analysis of social behaviour (SASB) in order for us to measure coping resources and self-image, respectively. The CRI and SASB scores were compared with those of control groups. Two hundred and fifty respondents (73%) returned the questionnaire, 200 (78.5% women) in the VDT group and 50 (62% women) in the HE group. The patient group rated high on the CRI spiritual/philosophical scale and high on the SASB spontaneous, positive and negative clusters but low on the controlled cluster. The female patients scored high on the CRI emotional scale. The VDT group rated lower than the controls on the SASB controlled cluster and higher on both the positive and negative cluster. The HE group scored higher than the control group on the SASB spontaneous and positive clusters. The women in the HE group scored higher on the CRI cognitive and CRI total scale than the VDT group and control group and higher on the CRI emotional scale than the controls. The women in the HE group rated higher than both the women in the VDT and control groups on the SASB spontaneous and positive clusters. The deviant self-image found in these patients, especially the female HE patients, support the view that VDT and HE symptoms can be stress related. In the clinic, a trustful alliance should be established with the patient in order for a more realistic view to be achieved of the capacity.

Medical and social prognosis for patients with perceived hypersensitivity to electricity and skin symptoms related to the use of visual display terminals.

This study attempted to give a medical and social prognosis for patients with perceived "electrical sensitivity". In 1980-1998, 350 patients with electrical sensitivity were registered at the University Hospital of Northern Sweden in Umeå, Sweden. Those with hypersensitivity to electricity had multiple symptoms evoked by exposure to different electric environments. Those with skin symptoms related to the use of visual display terminals (VDT) predominantly had facial skin symptoms evoked by a VDT, television screens, or fluorescent light tubes. A questionnaire on civil status, current health status, care, treatment and other measures taken, consequences of the problem, eliciting factors, and current employment was sent to all the patients. The response rate was 73%. Of the 50 respondents with hypersensitivity to electricity, 38% were men and 62% were women. Of the 200 patients with skin symptoms related to VDT use, 21.5% were men and 78.5% women. More women than men had turned to caregivers, including complementary therapies. A larger proportion of patients with hypersensitivity to electricity (38%) than those with skin symptoms related to VDT use (17%) was no longer gainfully employed. Both groups reported a higher symptom frequency than that reported by the the general population. Over time, the medical prognosis improved in the latter group but not in the former. Patients with hypersensitivity to electricity, particularly women, have extensive medical problems and a considerable number of them stop working. Many patients with skin symptoms related to VDT use have a favorable prognosis. Both groups need early and consistent management.

Influence of Wavelength and Packaging Material on Lipid Oxidation and Colour Changes in Low-fat Mayonnaise

The influence of light of different wavelengths on lipid oxidation and colour changes in unpacked low-fat mayonnaise was studied using fluorescent light tubes emitting ultraviolet radiation and blue, yellow and red light. The protective effect of the polyester materials PET (polyethylene terephtalate), PEN (polyethylene naphtalate) and PET/PEN copolymer was evaluated by exposing mayonnaise packed in these materials to cool white fluorescent light. The change in colour of samples representing all storage conditions was almost entirely due to a decrease in yellowness, presumably as a result of photobleaching of β -carotene. The colour was affected by wavelengths shorter than 470 nm with the greatest effect produced by wavelengths in the 410–450 nm range. The concentration of hexanal in the headspace was used as an indicator of lipid oxidation. The effect on lipid oxidation was most pronounced with ultraviolet radiation, although short wavelength visible light also had a significant effect. The polyester materials offered some protection against lipid oxidation by filtering out the ultraviolet radiation to varying degrees. PEN and PET/PEN copolymer offered better protection than PET. None of the materials offered sufficient protection against colour changes.

Education

Both papers in this issue's Education Section use mathematical modeling to help explain very commonplace and interesting phenomena: the design of light reflectors such as fluorescent lights, and the operation of water rockets. In doing so they show the power of bringing calculus and differential equations to bear upon interesting, accessible phenomena. And one of them may allow students to go play with water rockets as part of their homework assignment! The reflective properties of given curves, such as conic sections, are often studied in elementary calculus as a means of understanding the geometric properties of the curves. More interesting and challenging is the inverse problem: given a desired level of illumination over a given region from a point light source, find a reflector curve that achieves this. The paper "Exploring Reflection: Designing Light Reflectors for Uniform Illumination," by Gary De Young, applies a combination of concepts and techniques from calculus, geometry, and differential equations to the design of reflectors that achieve desired illumination properties. The approach taken results in a system of differential equations whose solution describes the desired curve. A specific example derived in detail is a reflector curve that provides uniform illumination over a straight line segment at some given distance from the source, which is applicable, for example, to the design of a suitable reflector for a flat diffusion panel for a fluorescent light tube. The material should be suitable either for third-semester calculus courses or in differential equations. As the author says, the paper should help to "lead students away from finding solutions to equations, toward finding equations that describe solutions." "Hydrodynamics of a Water Rocket," by Joseph Prusa, presents the application of mass, momentum, and energy balance laws to the determination of the trajectory of a simple water rocket. Faculty will appreciate that the context permits the use of a variety of aspects of applied mathematics, including scale analysis, model development and approximation, and numerical methods for initial-value problems. Additionally, physical experiments may be conducted and comparisons made of model predictions with real experimental data. Students should find this aspect particularly appealing. The material is intended to be suitable for courses or topics in fluid dynamics at either the advanced undergraduate or the graduate level. The modeling exercise will provide a great opportunity for students to bring together skills in physical reasoning, analysis, and numerical methods. Besides, how many exercises in applied mathematics carry the caution "be careful not to get too wet"?

Effect of light source and regimen on growing broilers

1. The aim of this study was to determine the effect of different light sources and light schedules on the growth and quality of commercial broilers. 2. In each experiment 810 broiler chicks were divided into 3 groups, 3 replicates per group. All were reared at 20 lux. Body weight and food consumption were recorded weekly . 3. Experiment 1. Birds were reared under 3 light sources: incandescent light bulb, warm-white fluorescent light tube or warm-white mini-fluorescent light bulb. Experiment 2. Birds were reared on 3 light schedules. 23 h light and 1 h dark (23L:1D) throughout; an increasing light schedule with initial 23L:1D then 8L:16D increasing daylight gradually to 16L:8D or an intermittently increasing daylight schedule (16:8P) where light and dark periods were shorter but portioned to achieve the same total hours per day up to 16L:8D. 4. Broilers reared under mini-fluorescent light bulb were heavier than those under fluorescent tubes or incandescent bulbs by 49 d. 5. Until 42 d of age, photoperiod had no effect on growth. However, at 49 d broilers reared under 16:8P and 16L:8D regimens were heavier than those or 23L:1D. 6. At 42 d, female broilers on 23L:1D, were heavier than those on 16L:8D and 16:8P . 7. Mortality was higher in groups on 23L:1D than on 16L:8D on 16:8P . 8. At 49 d incidence of leg condemnation was higher in the 16:8P group. However, skin damage was lower in this group than in those on 23L:1D and 16L:8D.

Outbreak of Leaf Spot of Saponaria Caused by Alternaria saponariae in California.

Saponaria (Saponaria vaccaria [= Vaccaria hispanica]) is a Caryophyllaceae plant that is grown commercially in California as a cut flower. In 1998, a leaf spot disease devastated the commercially grown saponaria in coastal California. The entire saponaria crop was completely unmarketable because of extensive leaf spotting. Symptoms consisted of circular, brown, necrotic leaf spots with diameters up to 8 mm and concentric zones of lighter and darker tissue. Chlorotic borders developed around the spots. Conidia from leaves were obclavate, usually had 7 transverse and 1 to 4 longitudinal septa, and narrowed gradually toward the apex into a blunt-tipped, unbranched beak cell. The spore body measured 69 to 90 (to 119) × 17 to 21 (to 25) μm, with the distinctive beak cell 17 to 53 μm long. Conidia formed short chains on host tissue. The fungus was identified as Alternaria saponariae (Peck) Neergaard (2). For pathogenicity tests, six representative isolates were grown on V8 juice agar under fluorescent tube lighting. Potted saponaria were sprayed with either conidial concentrations (1 × 10e5 conidia per ml) or water. Plants were incubated in a chamber with a humidifier for 48 h and then maintained in a greenhouse (23 to 25°C). After 14 days, leaf spots similar to the original symptoms developed on all inoculated plants, and the pathogen was reisolated. Plants sprayed with water were symptomless. The experiment was repeated and the results were similar. Using the same isolates and method, we inoculated carnation (Dianthus caryophyllus), sweet William (Dianthus barbatus), and saponaria. However, disease developed only on saponaria. While A. saponariae on saponaria was reported previously in California (1), this is the first report to characterize the pathogen and document that isolates are pathogenic on saponaria but not on other commercial Caryophyllaceae hosts.

Improvement of efficiency of ITO/Se thin film solar cells using tellurium stimulator

AbstractIndium Tin Oxide ITO/Se thin film solar cells have been fabricated by vacuum deposition. Prior to deposition of selenium film, ultrathin tellurium film has been deposited on ITO thin film. Tellurium film acts as a stimulator for bringing improvement in crystallite size, adhesion to ITO and electrical behaviour of selenium thin films. The maximum efficiency of the ITO/Se thin film solar cells without tellurium stimulator and with tellurium stimulator under illumination AM1 (100 mW cm−2) are found to be 1.68% and 2.27% while under fluorescent tubelight (0.15 mW cm−2) are found to be 5.85% and 7.05% respectively. The ITO/Se thin film solar cells exhibits high spectral response at short wavelength. The barrier height of the ITO/Se thin film solar cells was determined.

Variação da composição química do meio de cultura e da bioquímica celular de Phaeodactylum tricomutum (Bohlin), em cultivos estanques

P. tricornutum was grown batch cultures under 21oC temperature and continuous irradiance of 183 µE.m-2 . s-1, provided by fluorescent light tubes. Cultures growth were followed by cell countings, in vivo fluorescence and cellular protein, carbohydrate and chlorophyll-α content. The maximum value of protein/carbohydrate ratio was found at the exponential phase and the minimum value at the stationary phase. This ratio characterizes the physiological stage of the culture. Cell uptake rates for nitrate, ammonium and phosphate from the media were higher during the lag-phase. Nitrite excretion by the cells were detected following nitrate uptake.

Extraction and Refining of High Purity Terbium Metal From Rare Earth Resources

Terbium metal finds applications in the phosphor industry such as in fluorescent lighting and television tubes, and in the electronic industry for the production of magneto-optical recording media for computer storage discs, and in the production of specialty alloys. There are no direct high grade ores of terbium, rather it occurs as a very minor constituent in ores of the rare-earth minerals. For example, terbium oxide constitutes only 0.01% of California's bastnaesite. 0.05-0.16% of Florida' s monazite. and in the order of 1.00% in the Malaysian xenotime. Currently, the chief rare-earth bearing minerals of commercial importance are bastnaesite (California), monazite (Florida, Australia. India and China) and xenotime( Malaysia). Extraction of high purity terbium metal involves several major steps. These are (1) Recovery of rare earth minerals from ores into (REO)concentrates (2)Leaching of rare earth metals (REM) into leach solutions. This step is often preceded by a roasting step and a mild leaching to ...

Fluorescent Light Tube Compaction: Evaluation of Employee Exposure to Airborne Mercury

Abstract Air monitoring using direct reading instrumentation revealed that potentially high levels of inorganic mercury were present during and shortly after completion of a fluorescent tube compaction operation. The compaction process was standardized, and background and process air samples were collected. Resultant analyses of the air samples by atomic absorption spectrophotometry, using the procedure developed by Rathje and Marcero, indicated that levels of elemental mercury above the ACGIH TLV-TWA of 0.05 mg/m3 could be evolved during this common industrial operation. A successful method of lowering workers exposure to airborne mercury during the compaction process was implemented: a separate enclosure to house the tube grinder was built, the grinder/collector interface was modified with gasketing, and the disposal process simplified to eliminate one transfer of the final waste material. While the continued use of fluorescent tube compactors is desirable in order to reduce handling and waste volume problems, compactors of the type studied here should be considered as mercury emitters unless adequate ventilation or controls are added.

Fluorescent tube light evokes flicker responses in visual neurons

Single neurons in the cat visual system respond distinctly to the temporal information present in light from fluorescent tubes driven by 50 or 60 Hz alternating current. Despite the resulting flicker frequencies of 100 or 120 Hz all retinal and most thalamic neurons show strong phase locking of the neuronal responses to the modulation of fluorescent tube light. Some retinal ganglion cells have not yet reached their critical flicker fusion frequency under such conditions. Though usually beyond perception, the frequency and depth of modulation of artificial light thus might well play a role in biological light effects.

Light Induced Fading in CaSO4:Dy Teflon Thermoluminescence Discs

The light induced fading in CaSO4:Dy Teflon discs exposed to intense sunlight and fluorescent tube light is reported.