Towards Near-Infrared Chiroptically Switching Materials: Theoretical and Experimental Studies on Viologen-Containing 1,1′-Binaphthyls

ChemPhysChem ◽  
2008 ◽  
Vol 9 (9) ◽  
pp. 1265-1269 ◽  
Author(s):  
Jian Deng ◽  
Naiheng Song ◽  
Wenjian Liu ◽  
Qifeng Zhou ◽  
Zhi Yuan Wang
Keyword(s):  
Near Infrared ◽  
Experimental Studies

Tuning Optical Absorption and Emission of Sub-Nanometer Gold-Caged Metal Systems M@Au14 by Substitutional Doping

2006 ◽  
Vol 3 (2) ◽  
pp. 312-314 ◽  
Author(s):  
John R. H. Xie ◽  
Chiu Fung Cheung ◽  
Jijun Zhao
Keyword(s):  
Optical Absorption ◽  
Spectral Properties ◽  
Near Infrared ◽  
Experimental Studies ◽  
Optoelectronic Devices ◽  
Wavelength Region ◽  
Optical Excitation ◽  
Substitutional Doping ◽  
Energy Gaps ◽  
Tuning Scheme

Gao, Bulusu and Zeng have recently reported a new series of isoelectronic, sub-nanometer gold-caged metal systems M@Au14 which have large energy gaps than icosahedral W@Au12 and Au32 and tetrahedral Au20. In this communication, we propose a "tuning" scheme, substitutional-doping, to achieve the tunable optical excitation and emission of M@Au14 over a broad wavelength region. For example, the optical absorption gaps of isoelectronic M@Au14 could be tuned from the near infrared to green by substituting the metal M with group IIIB, IVB, and VB constituents in the periodic table. Our results provide basic guidelines for further experimental studies on the spectral properties of M@Au14 as well as for the development of M@Au14-based tunable optoelectronic devices.

Safety Considerations for Sample Analysis Using a Near-Infrared (785 nm) Raman Laser Source

2003 ◽  
Vol 57 (5) ◽  
pp. 580-587 ◽  
Author(s):  
S. D. Harvey ◽  
T. J. Peters ◽  
B. W. Wright
Keyword(s):  
Near Infrared ◽  
Energetic Material ◽  
Experimental Studies ◽  
Thermal Response ◽  
Raman Laser ◽  
Medical Diagnostics ◽  
Laser Source ◽  
Analytical Technique ◽  
Nir Laser

Raman spectroscopy is often considered a nondestructive analytical technique; however, this is not always the case. The 300-mW 785-nm near-infrared (NIR) laser source used with many commercially available instruments has sufficient power to burn samples. This destructive potential is of special concern if the sample is irreplaceable (e.g., fine art, forensic evidence, or for in vivo medical diagnostics) or a hazardous energetic material (explosive or pyrophoric samples). This study quantifies the heat resulting from illuminating an extensive color array with a 785-nm NIR laser and relates these values to the hazards associated with Raman analysis. In general, darker colors were found to be more problematic. Since visible colors are not ideally correlated with absorptive characteristics at 785 nm, predictions based on thermography are not perfect; however, this approximation gives a useful method for predicting the thermal response of unknown samples to NIR exposure. Additionally, experimental studies evaluated the analysis of flammable organic solvents, propellants, military explosives, mixtures containing military explosives, shock-sensitive explosives, and gunpowders (i.e., smokeless, black, and Pyrodex powders). Safety guidelines for analysis are presented.

Photobiomodulation inside the brain: a novel method of applying near-infrared light intracranially and its impact on dopaminergic cell survival in MPTP-treated mice

2014 ◽  
Vol 120 (3) ◽  
pp. 670-683 ◽  
Author(s):  
Cécile Moro ◽  
Nabil El Massri ◽  
Napoleon Torres ◽  
David Ratel ◽  
Xavier De Jaeger ◽  
...  
Keyword(s):  
Near Infrared ◽  
Neuroprotective Effect ◽  
Experimental Studies ◽  
Substantia Nigra Pars Compacta ◽  
Infrared Light ◽  
Target Cells ◽  
Sprague Dawley ◽  
Near Infrared Light ◽  
Dopaminergic Cells ◽  
The Brain

Object Previous experimental studies have documented the neuroprotection of damaged or diseased cells after applying, from outside the brain, near-infrared light (NIr) to the brain by using external light-emitting diodes (LEDs) or laser devices. In the present study, the authors describe an effective and reliable surgical method of applying to the brain, from inside the brain, NIr to the brain. They developed a novel internal surgical device that delivers the NIr to brain regions very close to target damaged or diseased cells. They suggest that this device will be useful in applying NIr within the large human brain, particularly if the target cells have a very deep location. Methods An optical fiber linked to an LED or laser device was surgically implanted into the lateral ventricle of BALB/c mice or Sprague-Dawley rats. The authors explored the feasibility of the internal device, measured the NIr signal through living tissue, looked for evidence of toxicity at doses higher than those required for neuroprotection, and confirmed the neuroprotective effect of NIr on dopaminergic cells in the substantia nigra pars compacta (SNc) in an acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of Parkinson disease in mice. Results The device was stable in freely moving animals, and the NIr filled the cranial cavity. Measurements showed that the NIr intensity declined as distance from the source increased across the brain (65% per mm) but was detectable up to 10 mm away. At neuroprotective (0.16 mW) and much higher (67 mW) intensities, the NIr caused no observable behavioral deficits, nor was there evidence of tissue necrosis at the fiber tip, where radiation was most intense. Finally, the intracranially delivered NIr protected SNc cells against MPTP insult; there were consistently more dopaminergic cells in MPTP-treated mice irradiated with NIr than in those that were not irradiated. Conclusions In summary, the authors showed that NIr can be applied intracranially, does not have toxic side effects, and is neuroprotective.

scholarly journals Micropulse transscleral cyclophotocoagulation for the treatment of glaucoma

2020 ◽  
Vol 13 (2) ◽  
pp. 105-111
Author(s):  
N. S. Khodzhaev ◽  
A. V. Sidorova ◽  
A. V. Starostina ◽  
M. A. Eliseeva
Keyword(s):  
Ciliary Body ◽  
Near Infrared ◽  
Continuous Wave ◽  
Laser Energy ◽  
Experimental Studies ◽  
Laser Pulses ◽  
Hypotensive Effect ◽  
Infrared Wavelength ◽  
A New Technique ◽  
The Moment

Because of the unpredictable hypotensive effect and serious complications during continuous-wave cyclophotocoagulation (CW-CPC), the use of this method in the treatment of glaucoma is limited. Therefore, a new technique was developed, known as micropulse trans-scleral cyclophotocoagulation (MP-CPC). During MP-CPC, a series of short bursts of laser pulses deliver energy to the ciliary body at the near-infrared wavelength of 810 nm, which is strongly absorbed by melanin. As shown by experimental studies, there are several acting mechanisms which reduce IOP decrease during MP-CPC. In clinical studies, patients with different forms and stages of glaucoma received laser energy of similar parameters during MP-CPC. It may be concluded that MP-CPC is a safe and effective alternative to traditional CW-CPC. However if laser irradiation directed to the ciliary body during MP-CPC gets longer, the incidence of complications increases. The variation of glaucoma forms in patients who underwent MP-CPC and a relatively small number of cases involved in the studies prevent us from making an unambiguous recommendation of this technique at the moment. An extensive research of the technique is required.

Control of deposition processes and structures of fibroin nanofilms by IR pulsed laser ablation

2008 ◽  
Vol 80 (11) ◽  
pp. 2499-2512
Author(s):  
Mamoru Senna ◽  
Sayuri Nakayama
Keyword(s):  
Deposition Rate ◽  
Near Infrared ◽  
Unique Feature ◽  
Experimental Studies ◽  
Pulsed Laser ◽  
Structure And Properties ◽  
Pull Out ◽  
Powder Particles ◽  
Deposition Processes ◽  
Made In

Control of structural and morphological features of silk fibroin (SF), one of the most popular and stable structural proteins, prepared by near infrared (1064 nm) pulsed laser deposition (PLD) are discussed, based mainly on the recent experimental studies made in the authors' laboratory. The small deposition rate and mingling of much larger units, called chunks or debris, are the main problems. The structure and properties of irradiation targets are highlighted, in an attempt to make the protein PLD technique affordable for practical purposes. Firm adhesion among fibroin powder particles is a straightforward way to avoid pull-out of the particles from the powder-consolidated target, being one of the main sources of debris. This alone cannot, however, satisfactorily increase the homogeneity of the nanostructures and increase the deposition rate. Finer control of the properties of grain-boundary in the target was therefore devised by using binders, including an autogenous one. A unique feature of the ablation mechanisms of fibroin was also discussed by taking account of the optical properties of fibroin, being transparent to a 1064 nm laser beam.

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