Absorption Spectra Of Hemoglobin Research Articles

The ultra-wideband near-infrared luminescence properties and applications of K2SrGe8O18:Cr3+ phosphor

The near-infrared (NIR) light sources are fascinating in real-time nondestructive examination applications. Given that chemical bonds in organic substances (such as C–H, O–H and N–H) have extensive absorption and reflection of light in the NIR region, the emission spectrum of the NIR light sources should be as broad as possible. In this work, ultra-wideband K2SrGe8O18 (KSGO):Cr3+ NIR-emitting phosphors with a 650–1200 nm emission span are developed. Structural analysis combined with electron paramagnetic resonance (EPR), photoluminescence (PL) spectra, time-resolved spectrum (TRES) and temperature-dependent PL spectra confirm that the super broadband emission with full width at half-maximum (FWHM) of 214 nm originates from the double Cr3+ luminescence centers occupying different [GeO6] octahedra. Li+ ion as charge compensator is introduced to balance the negative charge induced by the un-equivalent replacement of Cr3+ for Ge4+, and the PL intensity and thermal stability are greatly enhanced. The NIR phosphor-converted luminescent diodes (pc-LEDs) prepared by combining optimized KSGO:0.10Cr3+, 0.07Li+ samples with 460 nm LED chips demonstrate their application in night vision. The measured absorption spectra of hemoglobin, water, ethyl alcohol and peanut oil illuminated by the as-prepared KSGO:0.10Cr3+, 0.07Li+ phosphors indicate nondestructive analysis in the areas of food safety.

Goniometric Examination of Diffuse Reflectance of a Skin Phantom in the Wavelength Range from 400 to 1600 nm

Since all of noninvasive optical monitors such as near-infrared spectroscopy are transcutaneous, it is important to consider the optical properties of the skin. The purpose of the present study was to clarify the effects of incident angle and source-detector separation (SDS) on the detection of components in the dermal layer. Here, we developed a novel skin phantom consisting of epidermal and dermal layers with optical properties ranging from 400 to 1600 nm. The phantom was simulated by only water, scatters and absorbers, without agarose, silicone or other materials. The phantom showed reflectance spectra very similar to those of actual human skin by the integrating sphere measurements. Furthermore, an optical system was assembled in which the incident angle could be changed from 20º to 80º and the SDS from 0 to 6 mm independently. For the wavelength range of 400 to 900 nm, the absorption spectrum of hemoglobin in the dermal layer was investigated to assess detectability. For the wavelength range of 900 to 1600 nm, the absorption spectrum was confirmed by including glucose in the dermal layer. The absorbance was calculated from the measured diffuse reflected light intensity. The optimal incident angle and SDS for optical measurements focused on the dermal layer were estimated by the signal-to-noise ratio (SNR). In the wavelength range of 400 to 900 nm, the absorption spectrum of hemoglobin with the highest SNR was obtained at an incident angle of 70° and SDS of 4 mm. In the wavelength range of 900 to 1600 nm, the absorption spectrum of glucose with the highest SNR was obtained at an incident angle of 20° and SDS of 0 mm. These conditions are expected to be optimal for transcutaneous measurement of biomolecules within the dermis using diffuse reflected light of wavelength range from 400 to 1600 nm.

Optoacoustic imaging of the glymphatic system

Background: The glymphatic system is a brain waste clearance system mediated via cerebrospinal fluid (CSF) flow,1 with implications for influence on neurodegenerative diseases.2 Most preclinical glymphatic studies employ fluorescence imaging, which provides higher specificity, but a smaller field-of-view (FOV), or magnetic resonance imaging (MRI), which provides brain-wide FOV, but lower specificity. Functional optoacoustic neuro-tomography3 (FONT) offers a larger FOV compared to classical optical methods, and higher specificity compared to MRI. However, FONT has not yet been applied to probe the glymphatic system. In this study, we used fluorescence and optoacoustic imaging of a near-infrared dye, Janelia Fluor 669 (JF669), to track CSF and multimodal CSF-hemodynamic flows in mice.
 Methods: After observing strong fluorescence and optoacoustic signatures of JF669 in phantom experiments, we performed a series of in vivo experiments in isoflurane-anesthetized C57BL/6 mice (n=3 fluorescence and n=4 FONT experiments, respectively) (Figure 1A). The lumbar injection was applied to deliver JF669 at a rate of 2 µL/min for 30 minutes. A polyethylene tube was placed intrathecally at the lumbar region (L4-L5). The scalp was removed. Fluorescence or FONT images were obtained every 5 minutes after injection.
 Results: Fluorescence imaging and FONT probe CSF flow Images (Figure 1B) and time traces (Figure 1C) revealed time-dependent anatomical routes of paravascular influx, including the transport along the olfactory artery (OFA), superior cerebellar artery (SCA), and bilateral middle cerebral artery (MCA). For FONT imaging, since the OFA showed strong fluorescence (Figure 1B), we positioned the ultrasound transducer array at the anterior of the mouse brain with a FOV of 5x5 mm2 (Figure 1A). Standard filtered back-projection reconstruction was applied. Besides the OFA route of the paravascular influx, the dynamic images (Figure 1D) and time-traces (Figure 1E) also revealed time-dependent anatomical routes of CSF-interstitial fluid (ISF) exchange in the olfactory bulb (OFB) and paravascular efflux in the superior sagittal sinus (SSS) and the bilateral inferior cerebral vein (ICV). Next, we studied the aquaporin-4 (AQP4) dependence of glymphatic flow by subcutaneously injecting AQP4 inhibitor TGN020, in addition to the prior procedures. Under fluorescence imaging and FONT, we observed that TGN020 significantly decreased and spatially restricted the spread of JF669 in the brain. FONT spectral unmixing separates CSF and blood We swept the OPO through 680 nm to 750 nm, with 10 nm steps at 10 Hz in the phantom and in each animal. The multispectral reconstructions were unmixed using the known absorption spectra of hemoglobin and the JF669 OA spectrum obtained from the phantom.4 This enabled the separation of blood and JF669 signal (Figure 1D).
 Conclusions: We characterized anatomical routes of paravascular influx (OFA), CSF-ISF exchange (OFB) and paravascular efflux using FONT, while fluorescence imaging only enabled visualization of the paravascular influx. We thus demonstrated the feasibility and advantages of FONT for probing the glymphatic system. These findings present great opportunities for monitoring and understanding the glymphatic system during development, aging, disease, pharmacological interventions and genetic modifications.

Intraocular reflectance of the ocular fundus and its impact on increased retinal hazard

PurposeInside the eye light can be reflected multiple times due to light-tissue interactions and the spherical geometry of the eye. Due to these optical properties, a defined retinal area is not only illuminated by direct light but also by indirect, reflected light from the inner side of the eyewall. During illumination for ophthalmic surgery, this could lead to an unintended increase in intraocular retinal irradiance, which was already discussed in previous studies but without a detailed consideration of spectral differences and a potential influence of pigmentation. In this study this effect is investigated wavelength-dependent to see if different wavelengths lead to different increase in irradiance, with a special focus on the raise in photochemical and thermal hazard to the retina. It is also examined whether this effect is dependent on the pigmentation of the eye. MethodsThe reflectance properties of either less or highly pigmented porcine eyes are measured in the wavelength range between 350 and 1100nm with an integrating sphere and a spectrometer. With these reflectance spectra the wavelength-dependent Sphere Multiplier M of porcine eyes can be calculated, which represents the increase of radiance due to multiple reflections inside a sphere compared to a planar diffuser of the same size. Based on measurements of the emitted irradiance of ophthalmic illumination fibers the increase in photochemical and thermal retinal hazard due to these multiple reflections is calculated for eyes with small and high amounts of pigmentation. ResultsThe reflectance of the inner eyewall in the range between 350 and 1100nm is significantly higher for eyes with low pigmentation (between 4.90% and 37.44% reflectance) in comparison to eyes with a high amount of pigmentation (between 4.30% and 28.88% reflectance). The Sphere Multiplier for the inner side of the eyewall (sclera, choroid and retina) ranges between 1.13 and 1.59 and between 1.13 and 1.48 for eyes with low and high pigmentation, respectively, in the range between 350 and 1100nm. The reflectance, as well as the Sphere Multiplier, is strongly wavelength-dependent due to the absorption spectra of melanin and hemoglobin, which are located in the eye. With increasing wavelength, the reflection properties and the Sphere Multiplier also increases. With this, the photochemical retinal hazard of highly pigmented eyes increases by (14.11± 0.09)% and of lightly pigmented eyes by (16.75±0.35)% compared to if the reflection properties are not considered. The thermal retinal hazard increases by (14.30±0.07)% for highly pigmented eyes and by (19.65±0.17)% for low pigmented eyes. ConclusionThis study demonstrates that the anatomy and pigmentation of the eye plays an important role for the reflectance properties of the eye and for the photochemical and thermal hazard to the retina.

Upconversion Nanoparticles Encapsulated with Molecularly Imprinted Amphiphilic Copolymer as a Fluorescent Probe for Specific Biorecognition.

A fluorescent probe for specific biorecognition was prepared by a facile method in which amphiphilic random copolymers were encapsulated with hydrophobic upconversion nanoparticles (UCNPs). This method quickly converted the hydrophobic UCNPs to hydrophilic UNCPs. Moreover, the self-folding ability of the amphiphilic copolymers allowed the formation of molecular imprinting polymers with template-shaped cavities. LiYF4:Yb3+/Tm3+@LiYF4:Yb3+ UCNP with up-conversion emission in the visible light region was prepared; this step was followed by the synthesis of an amphiphilic random copolymer, poly(methacrylate acid-co-octadecene) (poly(MAA-co-OD)). Combining the UCNPs and poly(MAA-co-OD) with the templates afforded a micelle-like structure. After removing the templates, UCNPs encapsulated with the molecularly imprinted polymer (MIP) (UCNPs@MIP) were obtained. The adsorption capacities of UCNPs@MIP bound with albumin and hemoglobin, respectively, were compared. The results showed that albumin was more easily bound to UCNPs@MIP than to hemoglobin because of the effect of protein conformation. The feasibility of using UCNPs@MIP as a fluorescent probe was also studied. The results showed that the fluorescence was quenched when hemoglobin was adsorbed on UCNPs@MIP; however, this was not observed for albumin. This fluorescence quenching is attributed to Förster resonance energy transfer (FRET) and overlap of the absorption spectrum of hemoglobin with the fluorescence spectrum of UCNPs@MIP. To our knowledge, the encapsulation approach for fabricating the UCNPs@MIP nanocomposite, which was further used as a fluorescent probe, might be the first report on specific biorecognition.

NEAR-INFRARED SPECTROSCOPY IN HEALTHY SUBJECTS: POSSIBLE APPLICATION IN AVIATION AND AVIATION MEDICINE

Abstract: Functional near-infrared spectroscopy (fNIRS) is a non-invasive optical brain monitoring technology for mapping the functioning of the human cortex in response to sensory or motor activation. There is a growing interest in implementing fNIRS to monitor the cognitive performance of military pilots. The method relies on differences in hemoglobin absorption spectra depending on blood oxygenation. However, this method was relatively rarely utilized in aviation and aviation medicine. Therefore, we will provide a broad review of applying this method in various avenues of medicine and cognitive psychology, as well as cover its documented use in aviation and aviation medicine. In this review, we cover the following topics: 1) fNIRS in comparison to most commonly used neuroimaging methods, 2) fNIRS in the evaluation of human performance, 3) fNIRS application in aviation and aviation medicine, and 4) fNIRS-based Brain-Computer-Interface (BCI) to overcome cognitive restrictions and for optimizing pilot training. In conclusion, over the years, fNIRS has become a neuroimaging technique that contributes to making advances toward understanding the functioning of the human brain.

Effect of Moringa oleifera leaves extract against electromagnetic field impairments on hemoglobin and testes of rat

The present study has revealed the effect of Moringa oleifera leaves extract against electromagnetic field induced impairments. Forty-two adult white Albino male rats, weighting 150-180 g were involved in this study and divided into six equal groups. The first group was the control while the second group was daily supplemented with 200 mg/kg Moringa oleifera leaves extract orally for six days. The third group was exposed to an electromagnetic field of 1.5 mT, 50 Hz for 9 hours. The other three groups were exposed to an electromagnetic field of 1.5 mT, 50 Hz for 9 hours, and received the Moringa oleifera leaves extract in different supplemented ways. Blood samples were collected for the absorption spectrum of hemoglobin molecules analysis and serum total testosterone was studied. Samples of testes were taken for histopathological observations. The results showed that exposure of the animals to the electromagnetic field resulted in changing the absorption spectrum of hemoglobin, a highly significant reduction in testosterone level, and degenerative changes in testes. All these induced changes were decreased in groups treated by Moringa oleifera leaves extract in all ways. So through this study, one can conclude that damages induced by exposure to the electromagnetic field can be decreased by Moringa oleifera leaves extract.

Off-Peak 594-nm Light Surpasses On-Peak 532-nm Light in Silencing Distant ArchT-Expressing Neurons InVivo.

SummaryFor large brain volume manipulations using optogenetics, both effective opsin excitation and efficient light delivery with minimal light absorption are required to minimize the illuminating light intensity and concomitant off-target effects. ArchT, a widely used potent inhibitory opsin, is commonly activated by 532-nm light, which lies on its in vitro excitation peak. However, 532-nm light also lies on a peak range of the hemoglobin absorption spectrum. Therefore, we predicted that 594-nm light is superior in suppressing distant ArchT-expressing neurons, which is slightly off the ArchT-excitation-plateau and largely off the peak of the hemoglobin absorption spectrum. We quantitatively tested this prediction by the electrophysiological recording of the rat cortex in vivo. At illumination distances greater than 500 μm, 594-nm light was more effective than 532-nm light. Its superiority increased with distance. These results validate our prediction and highlight the significance of excitation-absorption trade-off in selecting illumination wavelength for optogenetics in vivo.

Protective properties of Myrtus communis extract against oxidative effects of extremely low-frequency magnetic fields on rat plasma and hemoglobin

Purpose: This study investigates the protective properties of Myrtus communis extract against the oxidative effects of extremely low-frequency magnetic fields (ELFMF). Also, this study is aimed to analyze the conformational changes of hemoglobin, oxidative damages to plasma proteins and antioxidant power of plasma following exposure to ELFMF.Materials and methods: Adult male rats were divided into 3 groups: (1) control, (2) ELFMF exposure, and (3) ELFMF exposure after M. communis extract administration. The magnetic field (0.7 mT, 50 Hz) was produced by a Helmholtz coil for one month, 2 hours a day. The M. communis extract was injected intraperitoneally at a dose of 0.5 mg/kg before exposure to ELFMF. The oxidative effects of ELFMF were studied by evaluating the hemoglobin, methemoglobin (metHb) and hemichrome levels, absorption spectrum of hemoglobin (200–700 nm), oxidative damage to plasma proteins by measuring protein carbonyl (PCO) levels and plasma antioxidant power according to the ferric reducing ability of plasma (FRAP). The mean and standard errors of the mean were determined for each group. One-way ANOVA analysis was used to compare the means of groups. The significance level was considered to be p < .05. Moreover, artificial neural network (ANN) analysis was used to identify the predictive parameters for estimating the oxyhemoglobin (oxyHb) concentration.Results: Exposure to ELFMF decreased the FRAP which was in concomitant with a significant increase in plasma PCO, metHb and hemichrome concentrations (p < .001). Oxidative modifications of Hb were shown by reduction in optical density at 340 nm (globin-heme interaction) and 420 nm (heme-heme interaction). Administration of M. communis extract increased FRAP values and decreased plasma POC, metHb, and hemichrome concentrations. Also, a significant increase in Hb absorbance at 340, 420, 542, and 577 nm showed the protective properties of M. communis extract against ELFMF-induced oxidative stress in erythrocytes. ANN analysis showed that optical absorption of hemoglobin at 520, 577, 542, and 630 nm and concentration of metHb and hemichrome were the most important parameters in predicting the oxyHb concentration.Conclusions: Myrtus communis extract enhances the ability of erythrocytes and plasma to deal with oxidative conditions during exposure to ELFMF. Also, ANN analysis can predict the most important parameters in relation to Hb structure during oxidative stress.

Simultaneous Arteriole and Venule Segmentation of Dual-Modal Fundus Images Using a Multi-Task Cascade Network

Differentiating arterioles and venules in the fundus image is important for not only various eye diseases but also systemic diseases such as hypertension and ischemic stroke. In this paper, we use dual-modal fundus images and develop a cascade refined U-net (CRU-net) to improve the arteriovenous segmentation. In this paper, dual-modal fundus images include not only a regular color fundus image (RGB image) but also another two monochromic images acquired using two different wavelengths, 570 and 610 nm. The choice of these two wavelengths is based on the absorption spectra of hemoglobin. The two monochromic images provide much richer information on the arteriole and venule. Our proposed CRU-net can fully utilize the information and achieves the state-of-the-art performance on our dual-modal dataset (DualModal2019). The arteriovenous classification accuracy evaluated on the automatically detected vessels is 97.27%, significantly surpassed previous methods. The F1-scores are 77.69% and 79.53% for the arteriole and venule segmentation, respectively. We also test our CRU-net on the public DRIVE dataset with only the color fundus images. We achieve the accuracy of 93.97%, F1-scores of 73.50%, and 75.54% for the arteriole and venule, all of which significantly surpassed previously published methods. Our DualModal2019 dataset with manually annotated arterioles and venules is publicly available.

Age Determination of Blood-Stained Fingerprints Using Visible Wavelength Reflectance Hyperspectral Imaging

The ability to establish the exact time a crime was committed is one of the fundamental aims of forensic science. The analysis of recovered evidence can provide information to assist in age determination, such as blood, which is one of the most commonly encountered types of biological evidence and the most common fingerprint contaminant. There are currently no accepted methods to establish the age of a blood-stained fingerprint, so progress in this area would be of considerable benefit for forensic investigations. A novel application of visible wavelength reflectance, hyperspectral imaging (HSI), is used for the detection and age determination of blood-stained fingerprints on white ceramic tiles. Both identification and age determination are based on the unique visible absorption spectrum of haemoglobin between 400 and 680 nm and the presence of the Soret peak at 415 nm. In this study, blood-stained fingerprints were aged over 30 days and analysed using HSI. False colour aging scales were produced from a 30-day scale and a 24 h scale, allowing for a clear visual method for age estimations for deposited blood-stained fingerprints. Nine blood-stained fingerprints of varying ages deposited on one white ceramic tile were easily distinguishable using the 30-day false colour scale.

Study on mechanism of release oxygen by photo-excited hemoglobin in low-level laser therapy

According to the calculated results on the charge distribution of oxygenated heme and deoxygenated heme, and based on the theory of electron excitations in photo-acceptor molecules and the absorption spectra of hemoglobin, it is found that low-level laser within the waveband of about 800-1060nm can promote the release of oxygen from oxyhemoglobin and improve the oxygen supply of capillaries to surrounding tissues. Furthermore, the reasons have been explained that why the low-level laser at a wavelength of 830nm is better in the treatment on burn injury and stimulation of hair growth. We also explained why the near-infrared laser of 1064nm is applied to the forehead to improve cerebral oxygenation in healthy humans. Finally, according to comparison of atomic charge distribution in heme before and after bound to small molecule of carbon monoxide or nitric oxide, it could be inferred that the low-level laser with an appropriate wavelength can promote the carbon monoxide hemoglobin and nitric oxide hemoglobin to dissociate the carbon monoxide molecules and the nitric oxide molecules. This may be used for adjuvant therapy of carbon monoxide poisoning or nitric oxide poisoning.

Reaction of Dimethyl Trisulfide with Hemoglobin.

Dimethyl trisulfide (DMTS) is a promising antidotal candidate for cyanide intoxication. DMTS acts as a sulfur donor in the conversion of cyanide to the less-toxic thiocyanate. The alternate reaction pathways of DMTS in the blood are not well understood. We report changes in the hemoglobin absorption spectrum upon reaction with DMTS. These changes closely match those induced by the known methemoglobin former, sodium nitrite. The kinetics of methemoglobin formation with DMTS is slower than with sodium nitrite. These results support the hypothesis that a potentially significant side-reaction of the therapeutically administered DMTS is the oxidization of hemoglobin to methemoglobin.

Application of Near-Infrared Spectroscopy in Neurological Disorders: Especially in Orthostatic Intolerance

Near-infrared spectroscopy (NIRS), a noninvasive optical method, utilizes the characteristic absorption spectra of hemoglobin in the near-infrared range to provide information on cerebral hemodynamic changes in various clinical situations. NIRS monitoring have been used mainly to detect reduced perfusion of the brain during orthostatic stress for three common forms of orthostatic intolerance (OI); orthostatic hypotension, neurally mediated syncope, and postural orthostatic tachycardia syndrome. Autonomic function testing is an important diagnostic test to assess their autonomic nervous systems for patients with symptom of OI. However, these techniques cannot measure dynamic changes in cerebral blood flow. There are many experimentations about study of NIRS to reveal the pathophysiology of patients with OI. Research using NIRS in other neurologic diseases (stroke, epilepsy and migraine) are ongoing. NIRS have been experimentally used in all stages of stroke and may complement the established diagnostic and monitoring tools. NIRS also provide pathophysiological approach during rehabilitation and secondary prevention of stroke. The hemodynamic response to seizure has long been a topic for discussion in association with the neuronal damage resulting from convulsion. One critical issue when unpredictable events are to be detected is how continuous NIRS data are analyzed. Besides, NIRS studies targeting pathophysiological aspects of migraine may contribute to a deeper understanding of mechanisms relating to aura of migraine. NIRS monitoring may play an important role to trend regional hemodynamic distribution of flow in real time and also highlights the pathophysiology and management of not only patients with OI symptoms but also those with various neurologic diseases. Key Words: Orthostatic intolerance, Spectroscopy, Near-Infrared, Clinical neurology

High-Resolution Multispectral Optoacoustic Tomography of the Vascularization and Constitutive Hypoxemia of Cancerous Tumors

Diversity of the design and alignment of illumination and ultrasonic transducers empower the fine scalability and versatility of optoacoustic imaging. In this study, we implement an innovative high-resolution optoacoustic mesoscopy for imaging the vasculature and tissue oxygenation within subcutaneous and orthotopic cancerous implants of mice in vivo through acquisition of tomographic projections over 180° at a central frequency of 24 MHz. High-resolution volumetric imaging was combined with multispectral functional measurements to resolve the exquisite inner structure and vascularization of the entire tumor mass using endogenous and exogenous optoacoustic contrast. Evidence is presented for constitutive hypoxemia within the carcinogenic tissue through analysis of the hemoglobin absorption spectra and distribution. Morphometric readouts obtained with optoacoustic mesoscopy have been verified with high-resolution ultramicroscopic studies. The findings described herein greatly extend the applications of optoacoustic mesoscopy toward structural and multispectral functional measurements of the vascularization and hemodynamics within solid tumors in vivo and are of major relevance to basic and preclinical oncological studies in small animal models.

Visible Raman excitation laser induced power and exposure dependent effects in red blood cells

We present results of Raman spectroscopic studies carried out on optically trapped red blood cells with Raman excitation wavelength in Q-band region of the hemoglobin (Hb) absorption spectrum. The results obtained suggest that when exposed to the Raman excitation laser the RBCs get deoxygenated due to photo-dissociation of oxygen from hemoglobin. For smaller exposure durations (5s) the level of deoxygenation increases with an increase in power. However, for longer exposure durations the deoxygenated hemoglobin in the cells gets irreversibly oxidized to form a low spin ferric derivative of hemoglobin. The rate of oxidation depends upon the initial level of deoxygenation; higher the initial level of deoxygenation, higher is the rate of oxidation. However, the RBCs deoxygenated via oxygen deprivation (i.e. N2 purging) were found to be very stable against any laser induced effect. These observations suggests that in case of laser induced deoxygenation of RBCs the free oxygen generated by photo-dissociation acts as the oxidizing agent and leads to oxidative damage of the RBCs.

The non-contact detection and identification of blood stained fingerprints using visible wavelength reflectance hyperspectral imaging: Part 1

Blood is one of the most commonly encountered types of biological evidence found at scenes of violent crime and one of the most commonly observed fingerprint contaminants. Current visualisation methods rely on presumptive tests or chemical enhancement methods. Although these can successfully visualise ridge detail, they are destructive, do not confirm the presence of blood and can have a negative impact on DNA sampling.A novel application of visible wavelength reflectance hyperspectral imaging (HSI) has been used for the detection and positive identification of blood stained fingerprints in a non-contact and non-destructive manner on white ceramic tiles. The identification of blood was based on the unique visible absorption spectrum of haemoglobin between 400 and 500nm.HSI has been used to successfully visualise ridge detail in blood stained fingerprints to the ninth depletion. Ridge detail was still detectable with diluted blood to 20-fold dilutions. Latent blood stains were detectable to 15,000-fold dilutions. Ridge detail was detectable for fingerprints up to 6months old. HSI was also able to conclusively distinguish blood stained fingerprints from fingerprints in six paints and eleven other red/brown media with zero false positives.

Narrow band imaging: clinical applications in oral and oropharyngeal cancer.

Narrow Band Imaging (NBI) is an endoscopic optical imaging enhancement technology that improves the contrast of mucosal surface texture, and enhances visualisation of mucosal and submucosal vasculature. White light is filtered to emit two 30-nm narrow bands of blue (415 nm) and green light (540 nm) light simultaneously, the former corresponding to the main peak absorption spectrum of haemoglobin, and the latter allowing visualisation of blood vessels in the deeper mucosal and submucosal layers. NBI has been used to better assess oral potentially malignant disorders (OPMD), identify oral and oropharyngeal squamous cell carcinoma (SCC), and to define surgical margins of head and neck malignancies. NBI shows great potential in improving detection rates of OPMD, facilitating better assessment of oral and oropharyngeal SCC, and reducing the risk of recurrence for oral SCC. Although further research is required to better understand and define intrapapillary capillary loop (IPCL) patterns and to relate these with clinical, histopathological and molecular parameters especially for early mucosal changes, there is building evidence to recommend its use as the new gold standard for endoscopic assessment in head and neck oncology.

A comparison of visible wavelength reflectance hyperspectral imaging and Acid Black 1 for the detection and identification of blood stained fingerprints

Bloodstains are often encountered at scenes of violent crime and have significant forensic value for criminal investigations.Blood is one of the most commonly encountered types of biological evidence and is the most commonly observed fingerprint contaminant. Presumptive tests are used to test blood stain and blood stained fingerprints are targeted with chemical enhancement methods, such as acid stains, including Acid Black 1, Acid Violet 17 or Acid Yellow 7. Although these techniques successfully visualise ridge detail, they are destructive, do not confirm the presence of blood and can have a negative impact on DNA sampling.A novel application of visible wavelength hyperspectral imaging (HSI) is used for the non-contact, non-destructive detection and identification of blood stained fingerprints on white tiles both before and after wet chemical enhancement using Acid Black 1. The identification was obtained in a non-contact and non-destructive manner, based on the unique visible absorption spectrum of haemoglobin between 400 and 500nm. Results from the exploration of the selectivity of the setup to detect blood against ten other non-blood protein contaminants are also presented. A direct comparison of the effectiveness of HSI with chemical enhancement using Acid Black 1 on white tiles is also shown.

In Vivo Capillary Loop Hemoglobin Spectroscopy in Labial, Sublingual, and Periodontal Tissues.

Reproducible estimates of hemoglobin absorption spectra from human capillaroscopy images of arterioles, capillaries, and venules in sublingual and labial mucosa in vivo and venules in the tissues lining the periodontal pocket. By reducing the size of both the imaging lens and the light guide to a maximum 1 mm diameter and opposing them with a gap of 600 μm we have been able to transmit light through the loop of tissues which moves into the gap between the lens and light guide when these are placed in contact with the labial and sublingual oral mucosa. This allows in vivo transillumination of the microvessels supplying the mucosa. Images from five volunteers showed similar patterns and the ratio of optical densities at 410 nm and 430 nm had a range from 2.5 at 90-100% saturation to 0.5 at zero % saturation. Measured optical density ratios ranged from 0.5 to 1.6 ± 0.1 in the afferent arm of the capillary loops and 0.5 to 1.1 ± 0.1 in the efferent arm of the capillary loops. In vivo spectroscopic hemoglobin optical density ratios in oral mucosal microvessels show a qualitatively consistent result within the expected in vitro parameters.