Normal Light Conditions Research Articles

Effect of light specters (red and blue) on two-potato varieties tissue (spunta and Agria)

This study was carried out in plant tissue culture laboratory which belong to bio technology research center in order to test the effect of raid and blue spectral light colors and white lighting as a control and white fluorescent lamps as a second control on plant growth stages while two potato variety ( Spunta , Agria) were used in this experiment . potato plant samples were collected and cultured in special jars contain MS media after being sterilized by Clorox solution in order to avoid the any contamination risk , while the culture stage of the explant started in sterilized condition in sited the hood cabinet, wherever the culture stage completed the cultured plants were placed in the growth room under controlled condition with raid , blue and normal light condition. The obtained results showed that the wait normal color treatment was significantly higher than the other two treatments in plant length factor for the tow used potato variety, while for the number of leaves factor the results showed that the normal light color treatment was significantly higher than the other two treatments in plant number of leaves factor followed by raid color treatment in the two used variety Spunta and Agria while the Raid color treatment scored average of leaves (23.9, 23.3 ) leaf respectively.

Perception of risk of tripping under lighting and obstacle conditions

AbstractA gait experiment was performed to test the effects of obstacle presence on the perception of the risk of tripping. The experimental conditions included lighting condition, obstacle type, color contrast, and obstacle height. Both male and female participants attended this study. The participants reported a perceived risk of tripping (PRT), on a five‐point scale, both before and after a walk. A rating of gait disturbance, also on a five‐point scale, was recorded. The results indicated that lighting condition, obstacle type, color contrast, and obstacle height were all significant on the PRT ratings, both before and after the walk, and on the rating of gait disturbance. The PRTs were positively correlated with the rating of gait disturbance. The possibility of obstacle‐contact, or tripping without falling, in the dimmed condition was 15.5 times of that in the normal lighting condition. A high rating of perceived risk of tripping before a walk was associated with a high gait disturbance score. It, however, did not necessarily lead to the low occurrence of tripping.

Melatonin and its ubiquitous anticancer effects.

Melatonin (N-acetyl-5-methoxy-tryptamine), which is generally considered as pleiotropic and multitasking molecule, secretes from pineal gland at night under normal light or dark conditions. Apart from circadian regulations, Melatonin also has antioxidant, anti-ageing, immunomodulation and anticancer properties. From the epidemiological research, it was postulated that Melatonin has significant apoptotic, angiogenic, oncostatic and anti-proliferative effects on various oncological cells. In this review, the underlying anticancer mechanisms of Melatonin such as stimulation of apoptosis, Melatonin receptors (MT1 and MT2) stimulation, paro-survival signal regulation, the hindering of angiogenesis, epigenetic alteration and metastasis have been discussed with recent findings. The Melatonin utilization as an adjuvant with chemotherapeutic drugs for the reinforcement of therapeutic effects was also discussed. This review precisely emphasizes the anticancer effect of Melatonin on various cancer cells. This review exemplifies the epidemiology and anticancer efficiency of Melatonin with prior attention to the mechanisms of actions.

A pragmatic effectiveness randomized controlled trial of the duration of psychiatric hospitalization in a trans-diagnostic sample of patients with acute mental illness admitted to a ward with either blue-depleted evening lighting or normal lighting conditions

BackgroundThere is increasing recognition of the need to stabilize sleep-wake cycles in individuals with major mental disorders. As such, clinicians and researchers advocate the use of interventions targeted at sleep and circadian dysrhythmias as an adjunct to the standard treatments offered for acute illness episodes of a broad range of diagnoses. To determine the trans-diagnostic generalizability of chronotherapy, we explore the benefits of admitting individuals with an acute illness episode to a psychiatric inpatient unit where changes in light exposure are integrated into the therapeutic environment.Methods/designA two-arm, pragmatic effectiveness, randomized controlled treatment trial, where individuals admitted for acute inpatient psychiatric care will be allocated to a ward with blue-depleted evening light or to a ward with the same layout and facilities but lacking the new lighting technology. The trial will test whether the experimental lighting conditions offer any additional benefits beyond those associated with usual treatment in an acute psychiatric inpatient unit. The main objectives are to examine any differences between groups in the mean duration of hospitalization in days. Additional analyses will compare group differences in symptoms, functioning, medication usage, and side effects and whether length of stay is associated with stability of sleep-wake cycles and circadian rhythms. Ancillary investigations should determine any benefits according to diagnostic subgroups and potential drawbacks such as any adverse effects on the well-being of professionals working across both wards.DiscussionThis unit offers a unique opportunity to explore how exposure to different lighting conditions may modify sleep-wake cycles and how any changes in sleep-wake cycle may impact on the clinical and functional outcomes of individuals experiencing an acute episode of a severe mental disorder that requires inpatient care. The findings could influence the future design of hospital units offering care to patients with mental or physical disorders.Trial registrationClinicalTrials.gov, ID: NCT03788993. Retrospectively registered on 28 December 2018.

Tracking a Golf Ball With High-Speed Stereo Vision System

Professional long drivers can hit golf balls to a speed of up to 350 km/h. Extremely short exposure time is required to capture the objects moving that fast without blur. The very high frame rate is also required to capture the sufficient sequence of object movements within the field of view in order to predict trajectory, which means a sacrifice in frame image resolution at fixed data throughput. This paper presents a high-speed stereo vision system that is able to track the golf ball motion at the speed of up to 360 km/h under normal indoor lighting conditions. Binocular camera operated at 810 frames/s with 35- $\mu \text{s}$ exposure time, requiring no additional strobe lights in order not to compromise user experiences. Ball markers were designed for spin measurement. To detect balls and identify markers from highly underexposed low resolution images, new algorithms were developed and implemented on field-programmable gate array board with an advanced RISC machines CPU. The experimental results showed high detection rate and high accuracy with overall processing time less than 300 ms.

Investigation of visible light emission from hydrogen-air research flames

Due to the urgency of reducing greenhouse gases in the combustion process, low-carbon renewable gaseous fuels are needed to replace the pipeline natural gas. Hydrogen is a competitive sustainable energy source, and also a promising energy carrier because of its zero-carbon property and low molecular weight. This study analyzed the flame characteristics of a cooktop burner operating on different natural gas/hydrogen mixtures. As hydrogen percentage increasing from 0% to 75% in the fuel mixture, more reddish color was observed in the flame, which is against the scientific fact that hydrogen flame color is usually pale blue color or even invisible under normal light condition. Therefore, combustion experiments and electron microscopy analysis are conducted to track the source of the abnormal color in the flame. The results suggest that the abnormal reddish flame color is from hydrogen embrittlement on the storage and transport facilities.

Real-Time Visible-Infrared Image Fusion using Multi-Guided Filter

Visible-infrared image fusion is a process of synthesizing an infrared image and a visible image into a fused image. This process synthesizes the complementary advantages of both images. The infrared image is able to capture a target object in dark or foggy environments. However, the utility of the infrared image is hindered by the blurry appearance of objects. On the other hand, the visible image clearly shows an object under normal lighting conditions, but it is not ideal in dark or foggy environments. In this paper, we propose a multi-guided filter and a real-time image fusion method. The proposed multi-guided filter is a modification of the guided filter for multiple guidance images. Using this filter, we propose a real-time image fusion method. The speed of the proposed fusion method is much faster than that of conventional image fusion methods. In an experiment, we compare the proposed method and the conventional methods in terms of quantity, quality, fusing speed, and flickering artifacts. The proposed method synthesizes 57.93 frames per second for an image size of 320 × 270. Based on our experiments, we confirmed that the proposed method is able to perform real-time processing. In addition, the proposed method synthesizes flicker-free video.

Copper(II) oxide nanoparticles coated cellulose sponge-an effective heterogeneous catalyst for the reduction of toxic organic dyes.

Discharge of unprocessed coloured waste water from industries gives rise to water contamination. In the current work, we propose the application of CuO nanoparticles supported on cellulose kitchen wipe sponge as a heterogeneous catalyst for the reductive decolourization of various toxic cationic and anionic dye molecules. The catalytic activity of the CuO nanoparticles under normal light for reduction has been examined in which sunlight irradiation is not necessitated. The CuO nanoparticles were synthesized by a simple wet chemical method and characterized using High Resolution Transmission Electron Microscope (HRTEM), SEM, EDX, XRD, XPS and TGA analyses. In the presence of CuO@CS catalyst and sodium borohydride, decolourization reaction of dyes such as acid red, acid green, methylene blue, rhodamine B and solochrome black-T was carried out. The catalytic reduction behaves as a pseudo-first-order reaction and is found to be superior in comparison with other reported catalysts in terms of reaction velocity. The reduction reaction can be further accelerated by increasing the reaction temperature. The developed catalyst drives the reduction faster on exposing the reaction mixture to sunlight confirming the usage of the catalyst at normal light and sunlight conditions. The catalyst retains 100% efficiency even after 5cycles and remains suitable even for further use. Thus, a low-cost heterogeneous catalyst has been successfully developed and employed to decolourize various dye molecules in short duration with good recyclability and therefore can be used as the potential candidate in environmental remediation.

Distribution and effects of ionic titanium application on energy partitioning and quantum yield of soybean under different light conditions

Soybean growth and development response to ionic titanium application have never been investigated. Therefore, such study is needed to better explain the titanium (Ti) application for soybean crop. For the first time, we studied the effects of application of two Ti concentrations (12.5 and 25 mg L-1) on photosynthetic and chlorophyll (Chl) fluorescence parameters of soybean under normal light (NL) and shade conditions (SC). Compared to NL, SC significantly decreased Chl contents, leaf area (LA), leaf thickness (LT), plant dry mater (PDM), photosynthetic and Chl fluorescence parameters, total soluble sugar, and Ti uptake. Overall, Ti application (12.5 mg L-1) had more distinct effects on LA, LT, PDM, Chl content and Chl fluorescence parameters. In conclusion, these results implied that an appropriate Ti content can improve plant morphological and anatomical features by enhancing the photosynthetic characteristics, especially under shade conditions.

Transcriptome analysis reveals regulation of gene expression during photoacclimation to high irradiance levels in Dunaliella salina (Chlorophyceae)

SUMMARYThe unicellular green alga Dunaliella salina is an attractive organism for studying photoacclimation responses. Changes in irradiance level during cell growth affect the organization and structure of the photosystem and the composition of pigments. In this study, D. salina was exposed to different irradiance levels, and cell growth, photosynthetic activity, pigments, and neutral lipids were analyzed. Photosystem II activity and chlorophyll content were reduced, carotenoids content and neutral lipids increased as light intensity increased, suggesting that photosynthetic apparatus was reduced and photoprotection mechanisms were activated. The RNA of D. salina was sequenced to investigate the transcriptomic response of the organism after transitioning from normal light conditions to higher light intensity. Genes encoding for enzymes involved in photosynthesis were downregulated, whereas genes involved in the metabolism of carotenoid and triacylglycerol were upregulated. Genes encoding for photoprotective enzymes related to reactive oxygen species scavenging and to the xanthophyll cycle were also upregulated at higher irradiance levels. The present transcriptomic study would assist in the comprehensive understanding of photoacclimation mechanisms of D. salina.

Blood biochemical changes in common carp (Cyprinus carpio) upon co-exposure to titanium dioxide nanoparticles and paraquat

Research on eliminating organic pollutants in water by using heterogeneous photocatalysts such as nano-TiO2 abound. However, the question is whether metabolites, resulting from optical dispersion of environmental pollutants, are still toxic to aquatic organisms. Therefore, this study was designed to evaluate the effect of a co-exposure to paraquat and TiO2-NPs on blood biochemical indices of common carp. Fish were exposed to 0.2 and 0.4 mg L-1 paraquat with 0.125 mg L-1 TiO2-NPs for 21 days under different light conditions, including natural photoperiod (16 L 8h-1 D) and complete darkness. No significant alterations in the Aspartate aminotransferase (AST), Alanine aminotransferase (ALT), Lactate dehydrogenase (LDH), Alkaline phosphatase (ALP) and Creatine phosphokinase (CPK), activities and total protein, albumin, globulin, glucose, cholesterol and triglyceride levels were observed in fish exposed to TiO2-NPs and 0.2 mg L-1 paraquat under normal lighting conditions. However, a significant change in blood biochemical indices in fish exposed to TiO2-NPs with 0.4 mg L-1 paraquat (16 L 8h-1 D) and in fish exposed to TiO2-NPs and paraquat (under darkness). A significant decrease in the activity of Gamma-glutamyltransferase (GGT) and a significant increase in creatinine level were observed in all groups which were exposed to TiO2-NPs and paraquat. The results of this study indicate that using 0.125 mg L-1 nano-TiO2 in order to remove paraquat (0.2 mg L-1) under lighting conditions can minimize the adverse effects of paraquat and its metabolites on blood biochemical indices of fish. So, using nano-TiO2 (0.125 mg L-1) to remove paraquat under lighting conditions can significantly reduce its toxic effects.

Improved CoChR Variants Restore Visual Acuity and Contrast Sensitivity in a Mouse Model of Blindness under Ambient Light Conditions.

Severe photoreceptor cell death in retinal degenerative diseases leads to partial or complete blindness. Optogenetics is a promising strategy to treat blindness. The feasibility of this strategy has been demonstrated through the ectopic expression of microbial channelrhodopsins (ChRs) and other genetically encoded light sensors in surviving retinal neurons in animal models. A major drawback for ChR-based visual restoration is low light sensitivity. Here, we report the development of highly operational light-sensitive ChRs by optimizing the kinetics of a recently reported ChR variant, Chloromonas oogama (CoChR). In particular, we identified two CoChR mutants, CoChR-L112C and CoChR-H94E/L112C/K264T, with markedly enhanced light sensitivity. The improved light sensitivity of the CoChR mutants was confirmed by exvivo electrophysiological recordings in the retina. Furthermore, the CoChR mutants restored the vision of a blind mouse model under ambient light conditions with remarkably good contrast sensitivity and visual acuity, as evidenced by the results of behavioral assays. The ability to restore functional vision under normal light conditions with the improved CoChR variants removed a major obstacle for ChR-based optogenetic vision restoration.

Chromatin State-Based Analysis of Epigenetic H3K4me3 Marks of Arabidopsis in Response to Dark Stress.

Light is essential to plant growth and development. Extended darkness causes dramatic gene expression changes, leading to leaf senescence, hypocotyl growth, petiole elongation, reduced leaf area, and early flowering, etc. However, the underlying mechanism of response to darkness at epigenetic levels remains largely unknown. In this study, we conducted ChIP-seq to generate global epigenomic profiles of H3K4me3 under 3-day extended darkness and normal light conditions in Arabidopsis. We applied chromatin state analysis together with self-organization mapping (SOM) to study the combination of epigenetic regulation under dark stress. The SOM map clusters the segments on the genome according to multiple diverse epigenomic datasets, which breaks the limit of dispersed distribution of epigenetic marks on the genome. Through SOM analysis, we also found that the signals of H3K4me3 were mainly increased after darkness. Analysis of H3K4me3-changed genes together with differentially expressed genes indicated that the genes showing dark-increased H3K4me3 were most involved in senescence and autophagy, and cross-talk existed between dark-induced and natural senescence. In summary, we studied the regulation of the epigenetic H3K4me3 marks of Arabidopsis in response to dark stress using chromatin state and SOM analyses. Our study revealed the regulatory mechanisms of the epigenome in response to dark stress, and SOM analysis based on chromatin states used in our study will also be helpful for other studies on dynamic changes of multiple epigenetic marks.

Shade effect on carbohydrates dynamics and stem strength of soybean genotypes

We selected four genotypes from the recombinant inbred lines based on their agronomic traits in terms of lodging resistance. Then, we investigated the morphological characteristics and stem carbohydrate accumulation of different soybean (Glycine max L.) genotypes under different light environments (normal light, low light and shading stress). Based upon metabolic accumulation of carbohydrates in the stem, we explored the reasons for the differences in stem strength of different soybean genotypes and expounded the relationship between accumulation and distribution of carbohydrates. Results of the present study showed that with the advancement of soybean growth period, the cellulose and lignin contents in soybean stem increased while the hemicellulose, sucrose and soluble sugars contents decreased. Compared with normal light conditions, the lignin, cellulose, soluble sugar and sucrose contents in the soybean plants under shading stress were reduced to different levels. Moreover, low light significantly reduced non-structural carbohydrate content in soybean stem while the lignin and cellulose contents were not significantly changed. The correlation analysis showed that there was a significant positive correlation among the stem snapping resistance, cellulose and lignin contents. The results showed that the stem strength was mainly determined by lignin and cellulose contents. The lignin content in the stem had a greater effect on the stem strength compared to cellulose. The xylose in soybean stem was also significantly reduced under the shading stress, which reduced lignin synthesis substrates. Under low light and shading stress, the minimum decrease in sucrose and structural carbohydrates content of a genotype (B23) was noticed indicating that B23 had high stem strength and increased decomposition of sucrose into cellulose synthesis. This trait of increased decomposition reduces the plant’s inefficient decomposition of sucrose thus most of the sucrose is used to synthesize cellulose. Conclusively, these results suggested that deposition of a relatively large amount of structural carbohydrates (e.g. lignin, cellulose, hemicellulose and monosaccharides) leads to thicker stem tissues which could be helpful to reduce lodging due to shading stress under multiple cropping systems.

Self-contained, passive, non-contact, photoplethysmography: Real-time extraction of heart rates from live view within a Canon Powershot

Photoplethysmography (PPG) is the detection of blood flow or pressure by optical means. The most common method involves direct skin-contact measurement of light from an LED. However, the small color changes in skin under normal lighting conditions, as recorded by conventional video, potentially allow passive, non-contact, PPG. A variety of methods have been applied to extract heartrate from such a video. In another paper submitted to this conference by the same authors, a new processing algorithm based on autocorrelation is shown to be effective without needing extensive video preprocessing to enhance the signal. That method was implemented using floating-point arithmetic in MatLab to analyze complete videos. However, the algorithm’s structure suggested that it might be possible to create a simplified, integer-only, approximation that is entirely incremental: updating a heart rate estimate as each frame is captured. This new, simplified, incremental algorithm allows a reprogrammed Canon PowerShot camera to function as a stand-alone, passive, non-contact, PPG device. The incremental integer algorithm and implementation are explained and evaluated in this paper.

Autocorrelation-based, passive, non-contact, photoplethysmography: Computationally-efficient, noise-tolerant, extraction of heart rates from video

Photoplethysmography (PPG) is the detection of blood flow or pressure by optical means. The most common method involves direct skin-contact measurement of light from an LED. However, the small color changes in skin under normal lighting conditions, as recorded by conventional video, potentially allow passive, noncontact, PPG. Eulerian Video Magnification (EVM) was used to demonstrate that small color changes in a subject’s face can be amplified to make them visible to a human observer. A variety of methods have been applied to extract heart rate from video. The signal obtained by PPG is not a simple sinusoid, but has a relatively complex structure, which in video is degraded by ambient lighting variations, motion, noise, and a low sampling rate. Although EVM and many other analysis methods in the literature essentially operate in the frequency domain, fitting the video data to their model requires extensive preprocessing. In this paper a time-based autocorrelation method is applied directly to the video signal that exhibits superior noise rejection and resolution for detecting quasi-periodic waveforms. The method described in the current work avoids both the preprocessing computational cost and the potential signal distortions.

Lifesaving interventions in blackout conditions using night vision technology: Come to the dark side.

During military combat operations and civilian night-time aeromedical transport, medical providers are frequently required to perform lifesaving interventions (LSIs) in low-light environments. Because definitive surgical care is often delayed until a white light environment is permissible, we sought to determine if night optical device (NOD) technology could enable surgical capabilities in blackout conditions. Using a crossover design, six surgeons performed 11 different procedures on six swine, three in normal light conditions (LC) and 3 in blackout conditions (BC) using two-chamber NODs after familiarization with the procedures in both conditions on manikins. Successful completion and procedural times were compared between groups. Blackout conditions were confirmed with ambient light reading of 0.2 lux during BC versus 3962.9 lux for LC (p < 0.001). There were no significant differences in success rates for any procedure. There were no differences in operative times between BC and LC for extremity tourniquet placement, femoral artery cut-down and clamping, resuscitative thoracotomy, or percutaneous resuscitative endovascular balloon occlusion of the aorta placement. The following procedures took significantly longer in BC vs. LC: Focused Assessment with Sonography for Trauma examination (98 seconds vs. 62 seconds), peripheral IV placement (140 seconds vs. 35 seconds), intraosseous access (51 seconds vs. 26 seconds), jugular vein cut-down and access (237 seconds vs. 104 seconds), laparotomy and packing (71 seconds vs. 51 seconds), stapled splenectomy (137 seconds vs. 74 seconds), resuscitative endovascular balloon occlusion of the aorta placement via cutdown (1,008 seconds vs. 338 seconds), and cricothyroidotomy (177 seconds vs. 109 seconds) (all p < 0.05). Lifesaving interventions can be safely and effectively performed in blackout conditions using NODs, although increased difficulty with select procedure types was identified. Focused training and technological improvements to currently available devices are needed. Basic science.

Changes in morphology, chlorophyll fluorescence performance and Rubisco activity of soybean in response to foliar application of ionic titanium under normal light and shade environment

Titanium (Ti) is considered an essential element for plant growth; however, its role in crop performance through stimulating the activities of certain enzymes, enhancing chlorophyll content and photosynthesis, and improving crop morphology and growth requires more study. We therefore conducted a laboratory experiments to study the effects of ionic Ti application on morphology, growth, biomass distribution, chlorophyll fluorescence performance and Rubisco activity of soybean (Glycine max L.) under normal light (NL) and shade conditions (SC). In this study, we sprayed soybean plants with five different levels of ionic Ti (T1 = 0, T2 = 1.25, T3 = 2.5, T4 = 5 and T5 = 10 mg Ti Plant−1) through foliar application method. Our results show that with increasing moderate (2.5 mg Ti Plant−1) Ti concentration, the chlorophyll pigments (chlorophyll [Chl] a, b, carotenoid [Car]), plant biomass, photochemical efficiency of photosystem II (Fv/Fm), and electron transport rate (ETR) of soybean increased, but higher levels (5–10 mg Ti Plant−1), resulted in leaf anatomical and chloroplast structural disruptions under both NL and SC. Soybean plants showed maximum biomass, leaf area, leaf thickness, Chl a, b, Car, Rubisco activity, Fv/Fm and ETR for T3 at 2.5 mg Ti Plant−1; however, declined significantly for T5 at high concentration of 10 mg Plant−1. In NL, the application of 2.5 mg Ti Plant−1 (T3) increased the Chl a, b, and total Chl contents 40, 20, and 27% as compared to control treatment (T1). In SC, the application of 1.25 mg Ti mg Plant−1 (T2) increased the Chl a, b, and total Chl contents 38, 19, and 14% as compared to control treatment. In NL, the Fv/Fm, qP, PSII, and ETR were higher in the T3 treatment over the T1 (control) by 7, 0.3, 16, and 16%, respectively. In SC, the Fv/Fm, qP, PSII, and ETR were higher in the T3 treatment over the T1 (control) by 5, 5, 19, and 19%, respectively. Moreover, Rubisco activity was at peak (55 and 6% increase under NL and SC) at 2.5 mg Ti Plant−1and decreased with increasing Ti concentration, reaching the lowest at 10 mg Ti Plant−1, which indicates that leaf cells were damaged as observed in the leaf anatomy. We concluded that ionic Ti expresses a hormesis effect: at lower concentrations, promoting soybean growth, however, at higher concentrations, suppressing soybean growth both under NL and SC. We therefore suggest that under different light stress conditions, Ti application could serve to mitigate abiotic stresses, especially in intercropping systems.

Underpotential co-deposition of ternary Cu-Te-Se semiconductor nanofilm on both flexible and rigid substrates

To achieve homogeneous ternary compounds, the growth rates of the component species in a solution must be equal and the processes must be simultaneous. The conditions necessary for the growth of one species should not prevent the growth of the others. Herein we present a synthesis of Cu3Te2Se2 semiconductor nanofilms on indium tin oxide (ITO)-coated polyethylene terephthalate (ITO-PET), ITO-coated glass, and Au plate substrates by an electrochemical underpotential co-deposition (UPCD) method from the same solution at a constant potential. The chemical, morphological, and optical properties of the synthesized nanofilms were determined by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, ultraviolet–visible absorption spectroscopy (UV/Vis), and current-voltage (I-V) studies. The chemical formula of the deposited nanofilms was confirmed as Cu3Te2Se2 by X-ray photoelectron spectroscopy. The SEM images exhibited uniform nano-scale (∼40 nm) distribution of the Cu3Te2Se2 nanofilms. The band gaps of the deposited films were determined according to the different deposition times and potentials. The XRD results showed crystalline and single-phase forms of Cu3Te2Se2 nanofilm. Finally, the I-V curves of the Cu3Te2Se2/ITO heterojunctions at room temperature (RT) under normal light conditions indicated matched those of a diode model.

Effect of light and dark on callus induction and regeneration in tobacco (Nicotiana tabacum L.)

To determine the effect of light and dark on callus induction and plant regeneration from five different explants of three tobacco varieties were studied. Normal white light (3000 lux) and dark conditions were considered for callus induction. Among the explants earliest callusing initiated at 5th day from nodal segment and the highest amount of callus (97.20%) was recorded from leaf blade of Motihari variety in light condition. The lowest callusing was recorded 24.40% in dark condition for root of Virginia variety and it was initiated after 13 days of culture initiation. The calli developed in dark showed watery, glossy silver color and less embryogenic features. The highest plant regeneration (95.56%) was recorded from nodal segment in light which was around five times higher than root in dark for Motihari variety. Nodal segments that received light (treatment) showed maximum relative growth rate (4.58) for Motihari variety while the lowest value was 0.91 scored from root of Virginia variety which received dark treatment.