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Therapeutic applications involving mesenchymal stem cells (MSCs) encounter challenges of attaining therapeutically potent and scaled up number during in-vitro batch culture. Recently, photobiomodulation (PBM) has emerged as a non-pharmacological method for enhancing MSC number, potency, and secretome production. However, the absence of a versatile, non-invasive technique to accurately identify PBM-induced biochemical alterations hinders the clinical translation of the approach. Raman spectroscopy (RS) can be a potential solution to this challenge. In this study, we demonstrate the utility of micro-RS to determine red light (∼660 nm) induced molecular alterations in human adipose tissue derived MSCs (hADMSCs) exposed to three different red light (∼660 nm) fluence; ∼3, 6 and 9 J/cm 2 . While the immediate changes in response to ∼660 nm exposure are subtle, at 6 and 24 h, there is increase in peak intensity of reducedCytochromes c, c1 and b, phenylalanine,CN stretching, CC lipids, OPO stretchingin cells. Maximum increase in intensity of these peaks was observed at ∼6 J/cm 2 . Raman peak at 1585 cm -1 , assigned to stretching vibration (CαCm) asymmetry of reduced Cyt c and sensitive to cellular redox status, shows notable change. Further, the intensity ratio of 1585 cm -1 and 1452 cm -1 , a suggestive Raman biomarker for cell proliferation, is increased in cells exposed to ∼3 &  ∼6 J/cm 2 followed by a decrease in cells exposed to ∼9 J/cm 2 . Furthermore, both micro-RS intensity ratio (1585 cm -1 /1452 cm -1 ) and MTT data on cell viability are in qualitative agreement with each other and show biphasic response to ∼660 nm exposure. While these results suggest the utility of micro-RS for label free assessment of PBM induced changes in hADMSCs, detailed studies on other cell types are necessary to validate the utility of micro-RS in this field., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: The dramatic increase of drug-resistant bacteria necessitates urgent development of platforms to simultaneously detect and inactivate bacteria causing wound infections, but are confronted with various challenges. Delta amino levulinic acid (ALA) induced protoporphyrin IX (PpIX) can be a promising modality for simultaneous bioburden diagnostics and therapeutics. Herein, we report utility of ALA induced protoporphyrin (PpIX) based simultaneous bioburden detection, photoinactivation and therapeutic outcome assessment in methicillin resistant Staphylococcus aureus (MRSA) infected wounds of mice., Methods: MRSA infected wounds treated with 10% ALA were imaged with help of a blue LED (∼405 nm) based, USB powered, hand held device integrated with a modular graphic user interface (GUI). Effect of ALA application time, bacteria load, post bacteria application time points on wound fluorescence studied. PpIX fluorescence observed after excitation with blue LEDs was used to detect bioburden, start red light mediated antimicrobial photodynamic therapy (aPDT), determine aPDT effectiveness and assess selectivity of the approach., Results: ALA-PpIX fluorescence of wound bed discriminates infected from uninfected wounds and detects clinically relevant load. While wound fluorescence pattern changes as a function of ALA incubation and post infection time, intra-wound inhomogeneity in fluorescence correlates with the Gram staining data on presence of biofilms foci. Lack of red fluorescence from wound granulation tissue treated with ALA suggests selectivity of the approach. Further, significant reduction (∼50%) in red fluorescence, quantified using the GUI, relates well with bacteria load reduction observed post topical aPDT., Conclusion: The potential of ALA induced PpIX for simultaneous detection of bioburden, photodynamic inactivation and "florescence-guided aPDT assessment" is demonstrated in MRSA infected wounds of mice., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2023. Published by Elsevier B.V.)

Antimicrobial photodynamic therapy (aPDT) can be a viable option for management of intranasal infections. However, there are light delivery, fluence, and photosensitizer-related challenges. We report in vitro effectiveness of an easily fabricated, low-cost, portable, LED device and a formulation comprising methylene blue (MB) and potassium iodide (KI) for photoinactivation of pathogens of the nasal cavity, namely, methicillin-resistant Staphylococcus aureus, antibiotic-resistant Klebsiella pneumoniae, multi-antibiotic-resistant Pseudomonas aeruginosa, Candida spp., and SARS-CoV-2.In a 96-well plate, microbial suspensions incubated with 0.005% MB alone or MB and KI formulation were exposed to different red light (~ 660 ± 25 nm) fluence using the LED device fitted to each well. Survival loss in bacteria and fungi was quantified using colony-forming unit assay, and SARS-CoV-2 photodamage was assessed by RT-PCR.The results suggest that KI addition to MB leads to KI concentration-dependent potentiation (up to ~ 5 log 10 ) of photoinactivation in bacteria and fungi. aPDT in the presence of 25 or 50 mM KI shows the following photoinactivation trend; Gm + ve bacteria  > Gm - ve bacteria > fungi  > virus. aPDT in the presence of 100 mM KI, using 3- or 5-min red light exposure, results in complete eradication of bacteria or fungi, respectively. For SARS-CoV-2, aPDT using MB-KI leads to a ~ 6.5 increase in cycle threshold value.The results demonstrate the photoinactivation effectiveness of the device and MB-KI formulation, which may be helpful in designing of an optimized protocol for future intranasal photoinactivation studies in clinical settings., (© 2024. The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.)

With the rise in microbial resistance to traditional antibiotics and disinfectants, there is a pressing need for the development of novel and effective antibacterial agents. Two major approaches being adopted worldwide to overcome antimicrobial resistance are the use of plant leaf extracts and metallic nanoparticles (NPs). However, there are no reports on the antibacterial potential of NPs coated with plant extracts, which may lead to novel ways of treating infections. This study presents an innovative approach to engineer antibacterial NPs by leveraging the inherent antibacterial properties of zinc oxide NPs (ZnO NPs) in combination with Azadirachta indica ( AI ) leaf extract, resulting in enhanced antibacterial efficacy. ZnO NPs were synthesised by the precipitation method and subsequently coated with AI leaf extract to produce ZnO- AI nanocore-shell structures. The structural and morphological characteristics of the bare and leaf extract coated ZnO NPs were analysed by x-ray diffraction and field emission scanning electron microscopy, respectively. The presence of an AI leaf extract coating on ZnO NPs and subsequent formation of ZnO- AI nanocore-shell structures was verified through Fourier transform infrared spectroscopy and photoluminescence techniques. The antibacterial efficacy of both ZnO NPs and ZnO- AI nanocore-shell particles was evaluated against methicillin-resistant Staphylococcus aureus using a zone of inhibition assay. The results showed an NP concentration-dependent increase in the diameter of the inhibition zone, with ZnO- AI nanocore-shell particles exhibiting superior antibacterial properties, owing to the combined effect of ZnO NPs and the poly phenols present in AI leaf extract. These findings suggest that ZnO- AI nanocore-shell structures hold promise for the development of novel antibacterial creams and hydrogels for various biomedical applications., (© 2024 IOP Publishing Ltd.)

Antimicrobial wound dressings play a crucial role in treatment of wound infections. However, existing commercial options fall short due to antibiotic resistance and the limited spectrum of activity of newly emerging antimicrobials against bacteria that are frequently encountered in wound infections. Antimicrobial photodynamic therapy (aPDT) is very promising alternative therapeutic approach against antibiotic resistant microbes such as methicillin resistant Staphylococcus aureus (MRSA) . However, delivery of the photosensitizer (PS) homogeneously to the wound site is a challenge. Though polymeric wound dressings based on synthetic and biopolymers are being explored for aPDT, there is paucity of data regarding their in vivo efficacy. Moreover, there are no studies on use of PS loaded, pluoronic (PL) and pectin (PC) based films for aPDT. We report development of a polymeric film for potential use in aPDT. The film was prepared using PL and PC via solvent casting approach and impregnated with methylene blue (MB) for photodynamic inactivation of MRSA in vitro and in vivo . Atomic force microscopic imaging of the films yielded vivid pictures of surface topography, with rough surfaces, pores, and furrows. The PL:PC ratio (2:3) was optimized that would result in an intact film but exhibit rapid release of MB in time scale suitable for aPDT. The film showed good antibacterial activity against planktonic suspension, biofilm of MRSA upon exposure to red light. Investigations on MRSA infected excisional wounds of mice reveal that topical application of MB loaded film for 30 min followed by red light exposure for 5 min (fluence; ∼30 J cm -2 ) or 10 min (fluence; ∼60 J cm -2 ) reduces ∼80% or ∼92% of bioburden, respectively. Importantly, the film elicits no significant cytotoxicity against keratinocytes and human adipose derived mesenchymal stem cells. Taken together, our data demonstrate that PS-loaded PL-PC based films are a promising new tool for treatment of MRSA infected wounds., (© 2024 IOP Publishing Ltd.)

Strontium sulphate (SrSO 4 ) is a defect-based photoluminescence material, generally used in thermoluminescence applications, and has been studied for infrared (IR) stimulated visible emission. The SrSO 4 particles were synthesized using a precipitation method. The orthorhombic phase of SrSO 4 was confirmed from the X-ray diffraction pattern and the formation of micron-sized particles was authenticated from field emission scanning electron micrographs. The elemental composition of oxygen and strontium was determined using energy-dispersive X-ray analysis measurement that confirmed the presence of V O • • and V Sr ' ' intrinsic defects in the material. Photoluminescence investigations showed the presence of various defect bands in the band gap giving rise to intrinsic luminescence in SrSO 4 . The emission in the visible region was attributed to the defect band arising due to V O • • . Photoluminescence lifetime measurement confirmed the presence of stable defect states with a lifetime in microseconds. The SrSO 4 sample was tested using IR lasers and a red-orange emission spot was observed from the powder sample when excited with IR lasers. The underlying principle for IR-to-visible conversion in the material is a defect-mediated phenomenon that has been described through the energy level diagram of the material., (© 2023 John Wiley & Sons Ltd.)

Lithium has been the treatment of choice for patients with bipolar disorder. However, lithium overdose happens more frequently since it has a very narrow therapeutic range in blood, necessitating investigation of its adverse effects on blood cells. The possible changes that lithium exposure may have on functional and morphological characteristics of human red blood cells (RBCs) have been studied ex vivo using single-cell Raman spectroscopy, optical trapping, and membrane fluorescent probe. The Raman spectroscopy was performed with excitation at 532 nm light, which also results in simultaneous photoreduction of intracellular hemoglobin (Hb). The level of photoreduction of lithium-exposed RBCs was observed to decline with lithium concentration, indicating irreversible oxygenation of intracellular Hb from lithium exposure. The lithium exposure may also have an effect on RBC membrane, which was investigated via optical stretching in a laser trap and the results suggest lower membrane fluidity for the lithium-exposed RBCs. The membrane fluidity of RBCs was further studied using the Prodan generalized polarization method and the results verify the reduction of membrane fluidity upon lithium exposure., (© 2023. European Biophysical Societies' Association.)

Titanium dioxide (TiO 2 ) photocatalyst has gained constant interest in the treatment of wastewater because of its greater stability, lower cost, low-toxicity, high efficiency, and more reactivity under UV radiation. On the other hand, Graphene oxide (GO) possesses high electron mobility, and therefore when GO is combined with TiO 2, the photocatalytic activity of TiO 2 is increased. In this study, nano-composite was synthesized in a hydrothermal reactor using two types of TiO 2 nanoparticles (TiO 2 consisting of a mixture of rutile and anatase phase (Type 1) and bioreduced TiO 2 (Type 2)) and the efficiency of both the TiO 2 -GO nanocomposite to remove the drug Carbamazepine (CBZ) was investigated. The TiO 2 -GO nanocomposite with the Type 1 TiO 2 exhibited greater efficiency hence further studies were conducted with that composite. The efficiency of TiO 2 -GO nanocomposite for the purpose of removing CBZ were investigated in presence of different types of incident radiation like Solar radiation, white light and three type of Ultraviolet radiation (A, B, C). The removal of the drug by TiO 2 -GO composite has been optimized using response surface methodology and artificial neural network. From this study, the maximum reduction was observed was 91.2% and whereas in case of the RSM optimization study the maximum removal that was observed was 91.7%. The validation of the RSM model was done using the mathematical analysis of the model equation of RSM. Different kinetics models was also analyzed using the experimental data and it was observed that it followed pseudo-second-order kinetics. The optimization using ANN also showed a close interaction with the experimental results., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Management of postprandial hyperglycemia is important for preventing severe complications like cardiovascular disease in diabetes patients. The associated glycemic instability in postprandial hyperglycemia may also cause disorders in circulating red blood cells (RBCs). Therefore, effects of short-term hyperglycemic stress on RBCs such as occur in the postprandial condition, have been studied here ex vivo using single-cell Raman spectroscopy and optical trapping. RBCs incubated in high glucose containing media relevant to postprandial hyperglycemia were studied for changes with respect to controls by analyzing the single-cell Raman spectra acquired with Raman optical tweezers with 532 nm excitation light. Use of 532 nm light for exciting Raman spectra also results in simultaneous photoreduction of intracellular hemoglobin (Hb). The level of photoreduction was noticed to be limited in hyperglycemia-exposed cells in comparison to the control. Since this suggests formation of permanently oxidized Hb in hyperglycemia-exposed RBCs, a fluorescence study was performed which showed elevated levels of oxidative stress in these cells. The changes in the RBC membrane, which may result due to higher levels of oxidative stress, were investigated using optical stretching experiments under the laser trap. The results indicated a loss of elasticity for the RBC membrane due to hyperglycemic exposure., (© 2021. European Biophysical Societies' Association.)

Raman spectroscopy was performed on GSM 900 and 1800 MHz mobile phone signal exposed red blood cells (RBCs). The observed changes in the Raman spectra of mobile signal exposed RBCs compared to unexposed control suggest reduced hemoglobin-oxygen affinity for the exposed cells. The possible mechanism may involve activation of the voltage gated membrane Ca 2+ channels by the mobile phone emissions resulting in an increase in the levels of adenosine triphosphate (ATP) and 2,3-diphosphoglycerate (2,3-DPG) in cells via altered metabolic activities. Further studies carried out with fluorescent Ca 2+ indicator confirmed increased intracellular Ca 2+ level in the exposed cells. Since intracellular ATP level influences the shape and mechanics of RBCs, exposed cells were studied using diffraction phase microscopy and optical tweezers. Detectable changes in shape and mechanical properties were observed due to mobile signal exposure., (© 2021 Wiley-VCH GmbH.)

Antimicrobial photodynamic therapy (APDT) is a promising approach for treatment of wounds infected with antibiotic-resistant bacteria. In this approach, delivery of appropriate concentration of photosensitizer (PS) at the infected site is a critical step; it is therefore essential that PS need to be administered at the infected site in a suitable formulation. Here, we report preparation of PS-embedded composite biopolymer films and their photobactericidal properties against methicillin-resistant Staphylococcus aureus (MRSA) and biocompatibility. Sodium alginate (SA), pectin (PC), and carboxymethyl cellulose (CMC) were used for preparing films containing chlorin p 6 (Cp 6 , anionic PS) or methylene blue (MB, cationic PS). Films containing 1% CMC (15 mm diameter; 110 ± 09 μm thickness) showed ~ 55% light transmission in 500 to 750 nm region and high swelling rate as indicated by ~ 38% increase in diameter within 1 h. Absorption spectroscopic studies of PS-embedded films revealed that while Cp 6 existed mainly in monomeric state, MB existed in both dimeric and monomeric forms. MRSA incubated with the film for 1 h displayed substantial uptake of Cp 6 and MB as indicated by the presence of Cp 6 fluorescence and MB staining in cells under the microscope. Furthermore, photodynamic treatment (660 nm, 10 J/cm 2 ) of MRSA with Cp 6 embedded in film or free Cp 6 resulted in ~ 3 log reduction in colony-forming units (cfu), whereas decrease in cfu was less (~ 1 log) for MB-embedded film than for free MB (~ 6 logs). Studies on human keratinocyte (HaCaT) cells showed that there was no significant change in the viability of cells when they were incubated with solubilized films (plain) for 24 h or subjected to treatment with PS-containing films followed by PDT. These results suggest that films are biocompatible and have potential application in photodynamic treatment of MRSA-infected wounds.

Urine analysis is an important clinical test routinely performed in pathology labs for disease diagnosis and prognosis. In recent years, near-infrared Raman spectroscopy has drawn considerable attention for urine analysis as it can provide rapid, reliable, and reagent-free analysis of urine samples. However, one important practical problem encountered in such Raman measurements is the orders of magnitude stronger spectral background preventing one to utilize the full dynamic range of the detector which is required for the measurement of Raman signal with good signal-to-noise ratio (SNR). We report here the results of an exploratory study carried out on human urine samples to show that the photobleaching, which is a major disadvantage during the fluorescence measurement, could be utilized for suppressing the measured background to improve the SNR of the Raman peaks. It was found that once the photobleaching reached its plateau, there were improvements by ~67% and ~47% in the SNR and the signal to background ratio (SBR), respectively, of the Raman signals as compared to the spectra measured at the start of acquisition. Further, the reduced background also allowed us to utilize the full dynamic range of the detector at increased integration time without saturating the detector indicating the possibility of obtaining an improved detection limit., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In the present study, a combined approach of ozone-based advanced oxidation and adsorption by activated char was employed for the treatment of a pharmaceutical industrial effluent. Ozone is a selective oxidant, but the addition of H 2 O 2 generated in situ hydroxyl radicals, which is a non-selective stronger oxidant than ozone. The effluent obtained from the pharmaceutical industry mainly contained anti-cancer drugs, anti-psychotic drugs, and some pain killers. The peroxone process had 75-88.5% chemical oxygen demand (COD) reduction efficiency at pH 5-11 in 3 h. Adsorption by activated char further reduced the COD to 85.4-92.7% for pH 5-11 in 2.5 h. All other water quality parameters were significantly decreased (>73% removal) during ozonation. The primary operational parameters (system pH and H 2 O 2 concentration) were also varied, and their effects were analyzed. The pseudo-first-order rate constants for ozonation were calculated, and they were found to be in the range of 1.42 × 10 -4 to 3.35 × 10 -4 s -1 for pH 5-11. The kinetic parameters for adsorption were calculated for the pseudo-first-order, pseudo-second-order, and Elovich models. The fit of the pseudo-first-order kinetic model to the experimental data was the best., Competing Interests: The authors declare no competing financial interest., (© 2020 American Chemical Society.)

Nanomaterials exhibit different interesting physical, chemical, electronic and magnetic properties that can be used in a variety of biomedical applications such as molecular imaging, cancer therapy, biosensing, and targeted drug delivery. Among various types of nanoparticles, super paramagnetic iron oxide nanoparticles (SPIONs) have emerged as exogenous contrast agents for in vitro and in vivo deep tissue imaging. Here, we propose a facile, rapid, non-toxic, and cost-effective single step green synthesis method to fabricate eugenate (4-allyl-2-methoxyphenolate) capped iron oxide nanoparticles (E-capped IONPs). The magnetic E-capped IONPs are first time synthesized using a medicinal aromatic plant, Pimenta dioica. The Pimenta dioica leaf extract was used as a natural reducing agent for E-capped IONPs synthesis. The crystalline structure and size of the synthesized spherical nanoparticles were confirmed using the x-ray diffraction and electron microscopic images respectively. In addition, the presence of the functional groups, responsible for capping and stabilizing the synthesized nanoparticles, were identified by the Fourier transform infra-red spectrum. These nanoparticles were found to be safe for human cervical cancer (HeLa) and human embryonic kidney 293 (HEK 293) cell lines and their safety was established using MTT[3-(4, 5-Dimethylthiazol-2-yl)-2, 5-Diphenyltetrazolium Bromide] assay. These green synthesized E-capped IONPs display a distinct absorbance in the tissue transparent near-infrared (NIR) wavelength region. This property was used for the NIR photothermal application of E-capped IONPs. The results suggest that these E-capped IONPs could be used for deep tissue photothermal therapy along with its application as an exogenous contrast agent in biomedical imaging.

Photo-stability of urine is of crucial importance for the applicability of fluorescence spectroscopy of urine samples for diagnosis of cancer. We report the results of a detailed study on fluorescence photo-bleaching of human urine samples. We also present the results of a preliminary investigation on evaluation of the applicability of photo-bleaching characteristics of urine for discriminating patients with oral cancer from healthy volunteers. The time-lapse fluorescence induced by continuous shining of 405 nm radiation from a diode laser was recorded from the urine samples obtained from 18 patients with oral cancer as well as from 22 healthy volunteers with history of no known major illness in the past two months. The integrated fluorescence intensity (ΣI), calculated for each spectrum, was found to decrease with time till a point after which no further decrease was observed. Further, while significant differences were observed in the spectra of cancerous patients and healthy volunteers, these differences were found to be varying with time till the intensities of the observed fluorescence spectra corresponding to the two categories of urine samples became stable. The curve, generated by plotting ΣI vs. time, was found to be best fitted (R 2  > 0.95) with a double-exponential decay function. The photo-bleaching constants, obtained from curve-fitting, were found to have statistically significant differences corresponding to the urine samples of cancerous patients and healthy volunteers. A classification algorithm developed based on nearest-mean classifier (NMC) and applied on the photo-bleaching constants in leave-one-subject-out cross-validation mode was found to provide a sensitivity and specificity of up to ∼ 86% in discriminating the two categories of urine samples., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Inverse spatially offset Raman spectroscopy (I-SORS) seeks to interrogate deep inside a Raman-active, layered, diffusely scattering sample. It makes a collimated laser beam incident onto the sample surface in the form of concentric illumination rings (of varying radii) from whose center the back-scattered Raman signal is collected for detection. Since formation of illumination rings of different sizes requires an axicon to be moved along the axis of the collimated laser beam and axicons below a certain minimum size (~1 inch) are not readily available, this classical configuration incorporating an axicon cannot be used for designing a compact I-SORS probe of narrower diameter. We report a novel scheme of implementing I-SORS which overcomes this limitation by implementing ring illumination and point collection using two multi-mode optical fibers. An important advantage of the proposed scheme is that unlike the previously reported inverse SORS configurations, it does not require physical movement of any of the optical components for generating spatial offsets needed for probing sub-surface depths. Another advantage is its fiber-optic configuration which is ideally suited for designing a compact and pencil-sized I-SORS probe, often desired in many practical situations for carrying out depth-sensitive Raman measurements in situ from a layered turbid sample., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Simultaneous photoreduction and Raman spectroscopy with 532 nm laser has been used to study the effects of organophosphate (chlorpyrifos [CPF]) exposure on human red blood cells (RBCs). Since in RBCs, auto-oxidation causes oxidative stress, which, in turn, is balanced by the cellular detoxicants, any possible negative effect of CPF on this balance should results in an increased level of damaged (permanently oxygenated) hemoglobin. Therefore, when 532 nm laser, at a suitable power, was applied to photoreduce the cells, only common oxygenated form of hemoglobin got photoreduced leaving the permanently oxygenated hemoglobin detectable in the Raman spectra simultaneously excited by the same laser. Using the technique effects of CPF to build up oxidative stress on RBCs could be detected at concentrations as low as 10 ppb from a comparison of relative strengths of different Raman bands. Experiments performed using simultaneously exposing the cells, along with CPF, to H 2 O 2 (oxidative agent) and/or 3-Aminotriazole (inhibitor of anti-oxidant catalase), suggested role of CPF to suppress the cellular anti-oxidant mechanism. Since the high level of damaged hemoglobin produced by the action of CPF (at concentrations >100 ppm) is expected to cause membrane damage, atomic force microscopy (AFM) was used to identify such damages.Upper panel: Raman spectra of normal, photoreduced CPF exposed and unexposed RBCs. Lower panel: The weak Fe-O 2 Raman band for CPF exposed cells shown on the left. The AFM images of unexposed and exposed cells are shown on the right. Scale bar, 2.5 μm., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Reliable diagnosis of disease using body fluids requires sensitive and accurate detection of disease-specific analytes present in the fluid. In recent years, there has been increasing interest in using surface-enhanced Raman spectroscopy (SERS) for this purpose. The demonstrable signal enhancement and sensitivity of SERS makes it ideally suited for detection of a trace quantity of any analyte. However, lack of reproducibility along with large spatial variability in the measured Raman intensities due to differential (and often random) distribution of surface "hot spots" limits its routine clinical use. We propose here a technique, nanotrap-enhanced Raman spectroscopy (NTERS), for overcoming these long-standing limitations and challenges of SERS. In this technique, hot spots are formed by drying up a microvolume drop of the liquid, containing the mixture of nanoparticles and analytes in the focal volume of the Raman excitation laser, and the Raman signal is detected from these spots containing the analytes localized within the nanoparticle aggregates. The performance of the technique was evaluated in detecting trace quantities of two Raman-active analytes, Rhodamine 6G (R6G) and urea. It was found that R6G and urea could be detected down to a concentration of 50 nM with signal-to-noise ratio (SNR) value of ∼75 and 4 mM with SNR value of ∼500, respectively. A comparison with SERS revealed that NTERS not only had significantly superior (around 2 orders of magnitude) signal enhancement but also had high reproducibility because of its intrinsic ability to form nanoparticle aggregates with high repetitiveness. Another advantage of NTERS is its simplicity and cost effectiveness as it does not require any specialized substrate.

Rapid membrane damage of optically trapped red blood cells (RBCs) was observed at trapping powers ≥280 mW. An excellent agreement between the estimated laser-induced thermal gradient across trapped cell's membrane and that typically required for membrane electropermeabilization suggests a mechanism involving temperature gradient-induced electropermeabilization of membrane. Also the rapid collapse of the trapped cell due to membrane rupture was seen to cause shock waves in the surroundings permeabilizing nearby untrapped cells. When the experiments were carried out with RBCs collected from type II diabetic patients, a noticeable change in the damage rate compared to normal RBCs was seen suggesting a novel optical diagnosis method for the disease., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Superoleophobic surfaces exhibiting tunable wettability are prepared by the combination of simple spray coating of Ultra Violet (UV) responsive titania nanoparticles and a low surface energy coating of a self-assembled monolayer (SAM) of 1 H ,1 H ,2 H ,2 H -perflurodecyltrichlorosilane (PFDTS). Spray coating creates random micron-sized roughness with reentrant geometry, a necessary requirement for the superoleophobic surface, and a porous network at the nanometer size level, confirmed by the field emission scanning electron microscope (FE-SEM) images. By employing the rough surface and a low surface energy monolayer, the substrates possess superhydrophobicity with a water ( γ = 72 mN m -1 ) contact angle of 163° and superoleophobicity with a decane ( γ = 23 mN m -1 ) contact angle of 144°. Wettability of these surfaces is completely reversed to the superoleophilic state upon 6 h of UV irradiation. A quantitative X-ray photoelectron spectroscopy (XPS) analysis has confirmed the mechanism of decomposition of PFDTS molecules on the superoleophilic surfaces via interaction with the defect Ti 3+ states of titania upon UV exposure. Furthermore, the superoleophobicity is restored to complete the transition cycle by changing the surface chemistry of the UV exposed surface via annealing and regrafting of the PFDTS monolayer., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Shape variations of red blood cells (RBCs) are known to occur upon exposure to various drugs or under diseased conditions. The commonly observed discocytic RBCs can be transformed to echinocytic or stomatocytic shape under such conditions. Raman spectra of the three major shape variations, namely discocyte, echinocyte, and stomatocyte, of RBCs were studied while subjecting the cells to oxygenated and deoxygenated conditions. Analysis of the recorded spectra suggests an increased level of hemoglobin (Hb)-oxygen affinity for the echinocytes. Also, some level of Hb degradation could be noticed for the deoxygenated echinocytes. The effects may arise from a reduced level of intracellular adenosine triphosphate in echinocytic cells and an increased fraction of submembrane Hb., ((2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).)

Spin orbit interaction and the resulting Spin Hall effect of light are under recent intensive investigations because of their fundamental nature and potential applications. Here, we report an interesting manifestation of spin Hall effect of light and demonstrate its tunability in an inhomogeneous anisotropic medium exhibiting spatially varying retardance level. In our system, the beam shift occurs only for one circular polarization mode keeping the other orthogonal mode unaffected, which is shown to arise due to the combined spatial gradients of the geometric phase and the dynamical phase of light. The constituent two orthogonal circular polarization modes of an input linearly polarized light evolve in different trajectories, eventually manifesting as a large and tunable spin separation. The spin dependent beam shift and the demonstrated principle of simultaneously tailoring space-varying geometric and dynamical phase of light for achieving its tunability (of both magnitude and direction), may provide an attractive route towards development of spin-optical devices.

Cyclone Aila hit the South-West coast of Bangladesh in May 2009, when in Dacope Upazilla over 50,000 people were left homeless as climate refugees (CRs) for over two years. We determined neurodevelopmental status of children born as CRs compared to their non-Climate Refugee (NCR) counterparts. Pregnant mothers were enrolled from May 2009 to April 2010 in entire Dacope in a study which profiled their health conditions. From among these mothers, 12 months post-Aila 267 CR mother-child dyads, and 552 NCR mother-child dyads were enrolled to assess their children's neurodevelopmental outcomes. There were significantly more landless families among CRs compared to NCRs (p value = 0.0001; OR = 1.86, 95% CI: 1.37 - 2.51). The mean±SD age at assessment of CR children was 8.52±4.57 months compared to a mean age 9.09±4.13 months of the NCR children (p=0.610). Neurodevelopmental Impairments (NDIs) were three times higher in the former (21.3%), compared to the latter (7.4%) group (p=0.0001; OR 3.83, 95% CI: 2.16 - 5.21). Specifically, expressive language (p value 0.002; OR 2.86, 95% CI: 1.46 - 5.57) and gross motor functions (p=0.007; OR 2.27, 95% CI 1.22 - 4.20) were the most significantly affected areas of impairment. Children born to CR mothers had a three times higher proportion of NDIs. The findings are of concern as in Bangladesh large populations are forced to leave their homes and become CRs annually. Optimum antenatal care of pregnant women as well as their offsprings within refugee situations needs to be ensured to prevent NDIs and poor quality of survival.

The broad range of applications of spatially-offset Raman spectroscopy (SORS) were found to involve samples having only marginal differences in Raman cross-sections between the surface and subsurface targets. We report the results of a feasibility study to evaluate the potential of the approach to identify the presence of a very low Raman-active turbid sample placed inside a highly Raman-active diffusely scattering matrix. Paraffin sandwiched tissue blocks prepared by embedding slices of chicken muscle tissue into solid paraffin blocks were employed as representative samples for the study. It was found that in contrast to the several millimetres of probing depth reported in the earlier applications, the Raman signatures of tissue were best recovered when it was located beneath the surface of the paraffin block at a depth of around a millimetre, beyond which the quality of recovery was increasingly poorer. However, the probing depth could be further increased by increasing the thickness of the embedded tissue sections. The results clearly suggest that though the probing depth achievable under the current condition is less than that found in previous applications, nevertheless it is sufficient for various other applications that would not require probing as deep as was required earlier., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We report the development of a depth-sensitive Raman spectroscopy system using the configuration of cone-shell excitation and cone detection. The system uses a 785 nm diode laser and three identical axicons for Raman excitation of the target sample in the form of a hollow conic section. The Raman scattered light from the sample, passed through the same (but solid) conic section, is collected for detection. Apart from its ability of probing larger depths (~ few mm), an important attraction of the system is that the probing depths can be varied by simply varying the separation between axicons in the excitation arm. Furthermore, no adjustment is required in the sample arm, which is a significant advantage for noncontact, depth-sensitive measurement. Evaluation of the performance of the developed setup on nonbiological phantom and biological tissue sample demonstrated its ability to recover Raman spectra of layers located at depths of ~2-3 mm beneath the surface., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Oxidation of Brilliant Green dye was performed using ozone microbubbles in a pilot plant scale. Decolourisation was very effective at both acidic and alkaline pH. The colour of the aqueous solution was below detectable limit after 30 min at 1.7 mg/s ozone generation rate. The reaction between the dye and ozone was first-order in nature with respect to both ozone and the dye. The enhancement factor increased with increasing dye concentration. The samples were analysed by the ultra-violet-visible (UV-Vis) spectrophotometry, gas chromatography-mass spectrometry (GC-MS) and Fourier transform infra-red (FTIR) spectroscopy. From the GC-MS analysis, 13 intermediates were detected as oxidation products of this dye at various stages of oxidation. The changes in the FTIR spectra showed the destruction of the dye and the formation of new compounds. The oxidation mechanism was divided into two reaction pathways. The mineralisation of Brilliant Green was up to 80% in 60 min, as determined by total organic carbon analysis.

We report a pilot study carried out to evaluate the applicability of in vivo Raman spectroscopy for differential diagnosis of malignant and potentially malignant lesions of human oral cavity in a clinical setting. The study involved 28 healthy volunteers and 171 patients having various lesions of oral cavity. The Raman spectra, measured from multiple sites of normal oral mucosa and of lesions belonging to three histopathological categories, viz. oral squamous cell carcinoma (OSCC), oral submucous fibrosis (OSMF) and leukoplakia (OLK), were subjected to a probability based multivariate statistical algorithm capable of direct multi-class classification. With respect to histology as the gold standard, the diagnostic algorithm was found to provide an accuracy of 85%, 89%, 85% and 82% in classifying the oral tissue spectra into the four tissue categories based on leave-one-subject-out cross validation. When employed for binary classification, the algorithm resulted in a sensitivity and specificity of 94% in discriminating normal from the rest of the abnormal spectra of OSCC, OSMF and OLK tissue sites pooled together., (Copyright © 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.)

Uterine prolapse is commonly seen in the geriatric age group. Congenital vaginouterine prolapse is a rare condition occurring in neonates and is usually associated with spinal cord malformations in about 85% of cases. Several modalities of treatment have been described for neonatal uterine prolapse. Conservative treatment in the form of simple digital reposition, use of pessary or other self-retaining device is usually sufficient to treat this condition, which is self-limiting and regressive. Here we report our first case of neonatal uterine prolapse, managed successfully with simple digital reposition.

The use of ozone in the treatment of water and wastewater is rapidly increasing due to its high oxidizing power. Arsenic is one the most toxic elements found in water. As(III) and As(V) are the major sources of arsenic poisoning. It is known that As(V) can be more easily removed from water by adsorptive methods than As(III). In this work, oxidation of more toxic As(III) to less toxic As(V) was studied in a pilot-plant by using ozone microbubbles. The microbubbles were effective in dissolving ozone in water. The oxidation was fast over a wide range of pH (e.g., 4-9). The role of hydroxyl radical in the oxidation of As(III) under acidic conditions was investigated by using 2-propanol as the hydroxyl radical scavenger. Under acidic conditions, the addition of 2-propanol slowed down the oxidation, which proves that hydroxyl radicals were involved in the oxidation process. The effect of carbonate ions on the rate of oxidation was investigated. It was found that the generation of carbonate ion radical from the carbonate ion accelerated the oxidation of As(III). The kinetics of oxidation of As(III) by ozone was studied., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Complete characterization of a layered tissue requires probing both the biochemical and the morphological information from its different layers at various depths. We report the development of a combined Raman spectroscopy (RS) and optical coherence tomography (OCT) system that is capable of measuring depth-sensitive Raman signal from the tissue layers imaged by the OCT. The sample arm of a real-time time-domain OCT system was modified to allow for co-alignment of the OCT with the Raman probe beam. The depth sensitivity of Raman was obtained by incorporating confocal Raman configuration that minimized out-of-focus Raman scattered light. The system was first validated using a layered phantom prepared by depositing a thin layer of paraffin over acetaminophen. A good correlation was observed between the OCT images and the Raman signal. The system was also used to record OCT and Raman images of a resected mucosal tissue sample. While OCT image showed the presence of epithelial and stromal layers, Raman spectra measured from these layers confirmed the biochemical difference between the two., (Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In this paper, we examine how variations in normal tissue can influence disease classification of Raman spectra. Raman spectra from normal areas may be affected by previous disease or proximity to areas of dysplasia. Spectra were acquired in vivo from 172 patients and classified into five tissue categories: true normal (no history of disease), previous disease normal (history of disease, current normal diagnosis), adjacent normal (disease on cervix, spectra acquired from visually normal area), low grade, and high grade. Taking into account the various "normal" states of the tissue before statistical analysis led to a disease classification accuracy of 97%. These results indicate that abnormal changes significantly affect Raman spectra, even when areas are histopathologically normal. The sensitivity of Raman spectroscopy to subtle biochemical differences must be considered in order to successfully implement it in a clinical setting for diagnosing cervical dysplasia and cancer.

Background and Objective: Most women with early stage breast cancer have the option of breast conserving therapy, which involves a partial mastectomy for removal of the primary tumor, usually followed by radiotherapy. The presence of tumor at or near the margin is strongly correlated with the risk of local tumor recurrence, so there is a need for a non-invasive, real-time tool to evaluate margin status. This study examined the use of autofluorescence and diffuse reflectance spectroscopy and spectral imaging to evaluate margin status intraoperatively., Materials and Methods: Spectral measurements were taken from the surface of the tissue mass immediately following removal during partial mastectomies and/or from tissues immediately after sectioning by surgical pathology. A total of 145 normal spectra were obtained from 28 patients, and 34 tumor spectra were obtained from 12 patients., Results: After correlation with histopathology, a multivariate statistical algorithm classified the spectra as normal (negative margins) or tumor (positive margins) with 85% sensitivity and 96% specificity. A separate algorithm achieved 100% classification between neo-adjuvant chemotherapy-treated tissues and non-treated tissues. Fluorescence and reflectance-based spectral images were able to demarcate a calcified lesion on the surface of a resected specimen as well., Conclusion: Fluorescence and reflectance spectroscopy could be a valuable tool for examining the superficial margin status of excised breast tumor specimens, particularly in the form of spectral imaging to examine entire margins in a single acquisition.

Raman spectroscopy has been widely used for cancer diagnosis, but conventional forms provide limited depth information. Spatially offset Raman spectroscopy (SORS) can solve the depth issue, but it has only been used to detect hard tissues such as bone. We explore the feasibility of using SORS to discriminate two layers of soft tissue. Measurements were taken with individual source and detector fibers at a number of spatial offsets from samples consisting of various thicknesses of normal human breast tissues overlying breast tumors. Results show that SORS can detect tumors beneath normal tissue, marking, to the best of our knowledge, the first application of SORS for discriminating two layers of soft tissue.

Background and Objectives: Nonmelanoma skin cancers, including basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), are the most common skin cancers, presenting nearly as many cases as all other cancers combined. The current gold-standard for clinical diagnosis of these lesions is histopathologic examination, an invasive, time-consuming procedure. There is thus considerable interest in developing a real-time, automated, noninvasive tool for nonmelanoma skin cancer diagnosis. In this study, we explored the capability of Raman microspectroscopy to provide differential diagnosis of BCC, SCC, inflamed scar tissue, and normal tissue in vivo., Study Design: Based on the results of previous in vitro studies, we developed a portable confocal Raman system with a handheld probe for clinical study. Using this portable system, we measured Raman spectra of 21 suspected nonmelanoma skin cancers in 19 patients with matched normal skin spectra. These spectra were input into nonlinear diagnostic algorithms to predict pathological designation., Results: All of the BCC (9/9), SCC (4/4), and inflamed scar tissues (8/8) were correctly predicted by the diagnostic algorithm, and 19 out of 21 normal tissues were correctly classified. This translates into a 100% (21/21) sensitivity and 91% (19/21) specificity for abnormality, with a 95% (40/42) overall classification accuracy., Conclusions: These findings reveal Raman microspectroscopy to be a viable tool for real-time diagnosis and guidance of nonmelanoma skin cancer resection.

For a given diagnostic problem, important considerations are the relative performances of the various optical biopsy techniques. A comparative evaluation of fluorescence, diffuse reflectance, combined fluorescence and diffuse reflectance, and Raman spectroscopy in discriminating different histopathologic categories of human breast tissues is reported. Optical spectra were acquired ex vivo from a total of 74 breast tissue samples belonging to 4 distinct histopathologic categories: invasive ductal carcinoma (IDC), ductal carcinoma in situ (DCIS), fibroadenoma (FA), and normal breast tissue. A probability-based multivariate statistical algorithm capable of direct multiclass classification was developed to analyze the diagnostic content of the spectra measured from the same set of breast tissue sites with these different techniques. The algorithm uses the theory of nonlinear maximum representation and discrimination feature for feature extraction, and the theory of sparse multinomial logistic regression for classification. The results reveal that the performance of Raman spectroscopy is superior to that of all others in classifying the breast tissues into respective histopathologic categories. The best classification accuracy was observed to be approximately 99%, 94%, 98%, and 100% for IDC, DCIS, FA, and normal breast tissues, respectively, on the basis of leave-one-sample-out cross-validation, with an overall accuracy of approximately 99%.

We investigate the potential of near-infrared Raman microspectroscopy to differentiate between normal and malignant skin lesions. Thirty-nine skin tissue samples consisting of normal, basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma from 39 patients were investigated. Raman spectra were recorded at the surface and at 20-microm intervals below the surface for each sample, down to a depth of at least 100 microm. Data reduction algorithms based on the nonlinear maximum representation and discrimination feature (MRDF) and discriminant algorithms using sparse multinomial logistic regression (SMLR) were developed for classification of the Raman spectra relative to histopathology. The tissue Raman spectra were classified into pathological states with a maximal overall sensitivity and specificity for disease of 100%. These results indicate the potential of using Raman microspectroscopy for skin cancer detection and provide a clear rationale for future clinical studies.

Epithelial cancers, including those of the skin and cervix, are the most common type of cancers in humans. Many recent studies have attempted to use Raman spectroscopy to diagnose these cancers. In this paper, Raman spectral markers related to the temporal and spatial effects of cervical and skin cancers are examined through four separate but related studies. Results from a clinical cervix study show that previous disease has a significant effect on the Raman signatures of the cervix, which allow for near 100% classification for discriminating previous disease versus a true normal. A Raman microspectroscopy study showed that Raman can detect changes due to adjacent regions of dysplasia or HPV that cannot be detected histologically, while a clinical skin study showed that Raman spectra may be detecting malignancy associated changes in tissues surrounding nonmelanoma skin cancers. Finally, results of an organotypic raft culture study provided support for both the skin and the in vitro cervix results. These studies add to the growing body of evidence that optical spectroscopy, in this case Raman spectral markers, can be used to detect subtle temporal and spatial effects in tissue near cancerous sites that go otherwise undetected by conventional histology.

This paper reports the development of a probability-based spectroscopic diagnostic algorithm capable of simultaneously discriminating tumor core and tumor margins from normal human brain tissues. The algorithm uses a nonlinear method for feature extraction based on maximum representation and discrimination feature (MRDF) and a Bayesian method for classification based on sparse multinomial logistic regression (SMLR). Both the autofluorescence and the diffuse-reflectance spectra acquired in vivo from patients undergoing craniotomy or temporal lobectomy at the Vanderbilt University Medical Center were used to train and validate the algorithm. The classification accuracy was observed to be approximately 96%, 80%, and 97% for the tumor, tumor margin, and normal brain tissues, respectively, for the training data set and approximately 96%, 94%, and 100%, respectively, for the corresponding tissue types in an independent validation data set. The inherently multi-class nature of the algorithm facilitates a rapid and simultaneous classification of tissue spectra into various tissue categories without the need for a hierarchical multi-step binary classification scheme. Further, the probabilistic nature of the algorithm makes it possible to quantitatively assess the certainty of the classification and recheck the samples that are classified with higher relative uncertainty.

Optical biopsy has been shown to discriminate between normal and diseased tissue with high sensitivity and specificity. Fiber-optic probe-based spectroscopy systems do not provide the necessary spatial information to guide therapy effectively, ultimately requiring a transition from probe-based spectroscopy to spectral imaging. The effect of such a transition on fluorescence and diffuse reflectance line shape is investigated. Inherent differences in spectral line shape between spectroscopy and imaging are characterized and many of these differences may be attributed to a shift in illumination-collection geometry between the two systems. Sensitivity of the line-shape disparity is characterized with respect to changes in sample absorption and scattering as well as to changes in various parameters of the fiber-optic probe design (e.g., fiber diameter, beam steering). Differences in spectral line shape are described in terms of the relative relationship between the light diffusion within the tissue and the distribution of source-detector separation distances for the probe-based and imaging illumination-collection geometries. Monte Carlo simulation is used to determine fiber configurations that minimize the line-shape disparity between the two systems. In conclusion, we predict that fiber-optic probe designs that mimic a spectral imaging geometry and spectral imaging systems designed to emulate a probe-based geometry will be difficult to implement, pointing toward a posteriori correction for illumination-collection geometry to reconcile imaging and probe-based spectral line shapes or independent evaluation of tissue discrimination accuracy for probe-based and spectral imaging systems.

We report development of a direct multi-class spectroscopic diagnostic algorithm for discrimination of high-grade cancerous tissue sites from low-grade as well as precancerous and normal squamous tissue sites of human oral cavity. The algorithm was developed making use of the recently formulated theory of total principal component regression (TPCR). The in vivo autofluorescence spectral data acquired from patients screened for neoplasm of oral cavity at the Government Cancer Hospital, Indore, was used to train and validate the algorithm. The diagnostic algorithm based on TPCR was found to provide satisfactory performance in classifying the tissue sites in four different classes - high-grade squamous cell carcinoma, low-grade squamous cell carcinoma, leukoplakia, and normal squamous tissue. The classification accuracy for these four classes was observed to be approximately 94%, 100%, 100% and 91% for the training data set (based on leave-one-out cross-validation), and was approximately 90%, 90%, 85% and 88%, respectively for the corresponding classes for the independent validation data set.

Prospective study was carried out on 100 patients since May 2005 in my private practice and in the department of pediatric surgery of MMCH. Under caudal anesthesia along with or without ketaminie induction and gas inhalation all the patients underwent different surgical procedure namely anorectal surgery (eg. anoplasty, rectal polyp), urogenital surgery (Circumcision, hypospadias, meatotomy), groin surgery (hernia, hydrocele) and foot & leg surgery. Calculated dose schedule of drugs used in anesthesia and volume were maintained. Time of giving anesthesia and time of starting analgesia were recorded. Per-operative and postoperative analgesia were evaluated. Every parent was explained regarding the merit of caudal anesthesia calculated and compared with that of general anesthesia. Application of caudal anesthesia with or without ketamine & diazepam induction can be used safely and cost effectively and may be put into protocol in many of the pediatric surgical practice both in institute and also in private practice.

The paper reports results of an in vitro study on autofluorescence spectroscopy of fresh and formalin-fixed human breast tissue samples to investigate the effect of formalin fixation on the measured autofluorescence spectra. It also explores the applicability of the approach in discriminating cancerous from the uninvolved sites of the formalin-fixed breast tissues based on their autofluorescence spectra. A probability-based diagnostic algorithm, making use of the theory of relevance vector machine (RVM), a powerful recent approach for statistical pattern recognition, was developed for that purpose. The algorithm provided sensitivity values of up to 97% and specificity values of up to 100% towards cancer for both the independent validation data set as well as for the training data set based on leave-one-out cross-validation. These results suggest that autofluorescence spectroscopy may prove to be a valuable additional in vitro diagnostic modality in clinical pathology setting for discriminating cancerous tissue sites from normal sites.

Background and Objectives: A probability-based, robust diagnostic algorithm is an essential requirement for successful clinical use of optical spectroscopy for cancer diagnosis. This study reports the use of the theory of relevance vector machine (RVM), a recent Bayesian machine-learning framework of statistical pattern recognition, for development of a fully probabilistic algorithm for autofluorescence diagnosis of early stage cancer of human oral cavity. It also presents a comparative evaluation of the diagnostic efficacy of the RVM algorithm with that based on support vector machine (SVM) that has recently received considerable attention for this purpose., Study Design/materials and Methods: The diagnostic algorithms were developed using in vivo autofluorescence spectral data acquired from human oral cavity with a N(2) laser-based portable fluorimeter. The spectral data of both patients as well as normal volunteers, enrolled at Out Patient department of the Govt. Cancer Hospital, Indore for screening of oral cavity, were used for this purpose. The patients selected had no prior confirmed malignancy and were diagnosed of squamous cell carcinoma (SCC), Grade-I on the basis of histopathology of biopsy taken from abnormal site subsequent to acquisition of spectra. Autofluorescence spectra were recorded from a total of 171 tissue sites from 16 patients and 154 healthy squamous tissue sites from 13 normal volunteers. Of 171 tissues sites from patients, 83 were SCC and the rest were contralateral uninvolved squamous tissue. Each site was treated separately and classified via the diagnostic algorithm developed. Instead of the spectral data from uninvolved sites of patients, the data from normal volunteers were used as the normal database for the development of diagnostic algorithms., Results: The diagnostic algorithms based on RVM were found to provide classification performance comparable to the state-of-the-art SVMs, while at the same time explicitly predicting the probability of class membership. The sensitivity and specificity towards cancer were up to 88% and 95% for the training set data based on leave- one-out cross validation and up to 91% and 96% for the validation set data. When implemented on the spectral data of the uninvolved oral cavity sites from the patients, it yielded a specificity of up to 91%., Conclusions: The Bayesian framework of RVM formulation makes it possible to predict the posterior probability of class membership in discriminating early SCC from the normal squamous tissue sites of the oral cavity in contrast to dichotomous classification provided by the non-Bayesian SVM. Such classification is very helpful in handling asymmetric misclassification costs like assigning different weights for having a false negative result for identifying cancer compared to false positive. The results further demonstrate that for comparable diagnostic performances, the RVM-based algorithms use significantly fewer kernel functions and do not need to estimate any hoc parameters associated with the learning or the optimization technique to be used. This implies a considerable saving in memory and computation in a practical implementation., (Copyright 2005 Wiley-Liss, Inc.)

We report the application of a support vector machine (SVM) for the development of diagnostic algorithms for optical diagnosis of cancer. Both linear and nonlinear SVMs have been investigated for this purpose. We develop a methodology that makes use of SVM for both feature extraction and classification jointly by integrating the newly developed recursive feature elimination (RFE) in the framework of SVM. This leads to significantly improved classification results compared to those obtained when an independent feature extractor such as principal component analysis (PCA) is used. The integrated SVM-RFE approach is also found to outperform the classification results yielded by traditional Fisher's linear discriminant (FLD)-based algorithms. All the algorithms are developed using spectral data acquired in a clinical in vivo laser-induced fluorescence (LIF) spectroscopic study conducted on patients being screened for cancer of the oral cavity and normal volunteers. The best sensitivity and specificity values provided by the nonlinear SVM-RFE algorithm over the data sets investigated are 95 and 96% toward cancer for the training set data based on leave-one-out cross validation and 93 and 97% toward cancer for the independent validation set data. When tested on the spectral data of the uninvolved oral cavity sites from the patients it yielded a specificity of 85%., (Copyright 2005 Society of Photo-Optical Instrumentation Engineers.)

We show that, when a turbid medium with a layered fluorophore distribution is excited by linearly polarized light, measurement of angle-resolved polarized fluorescence can provide depth-resolved fluorescence measurements.

Background and Objectives: Use of laser induced fluorescence (LIF) spectroscopy for the diagnosis of cancer requires an appropriate diagnostic algorithm for spectral pattern recognition. While most of the diagnostic algorithms reported in the literature use standard linear feature extraction techniques like principal component analysis (PCA), partial least square (PLS) analysis etc., use of nonlinear techniques is expected to provide improved discrimination. We report here the performance of an algorithm based on nonlinear Maximum Representation and Discrimination Feature (MRDF) method for diagnosis of early stage cancer of human oral cavity. The diagnostic efficacy of the algorithm has been compared with a linear PCA based algorithm., Study Design/materials and Methods: The diagnostic algorithms were developed based on spectral data acquired in an in-vivo LIF study, at the outpatient department (OPD) of the Government Cancer Hospital, Indore, involving 16 patients with cancer of oral cavity and 13 normal volunteers with healthy oral cavity. In-vivo autofluorescence spectra were recorded using a N(2) laser based portable fluorimeter. The patients had no prior confirmed malignancy, were suspected on visual examination of having early cancer of the oral cavity and were diagnosed of squamous cell carcinoma (SCC) on the basis of histopathology of biopsy taken from abnormal site subsequent to acquisition of spectra. The spectra were acquired from a total of 171 tissue sites from patients, of which 83 were from SCC and 88 were from uninvolved squamous tissue, and 154 sites from healthy squamous tissue from normal volunteers. In each patient, the normal tissue sites interrogated were from the adjacent apparently uninvolved region of the oral cavity. Each site was treated separately and classified via the diagnostic algorithm developed. Instead of the spectral data from uninvolved sites of patients, the data from normal volunteers were used as the normal database for the development of diagnostic algorithms., Results: The nonlinear diagnostic algorithm based on MRDF provided a sensitivity of 93% and a specificity of 96% towards cancer for the training set data and a sensitivity of 95% and a specificity of 96% towards cancer for the validation set data. When implemented on the spectral data of the uninvolved oral cavity sites from the patients it yielded a specificity of 96%. On the other hand, the linear PCA based algorithm provided a sensitivity of 83% and a specificity of 66% towards cancer for the training set data and a sensitivity of 80% and a specificity of 58% towards cancer for the validation set data. When spectral data of the uninvolved oral cavity sites from the patients were considered as the unknown data set, it resulted in a specificity value of 56%., Conclusions: The nonlinear MRDF algorithm provided significantly improved diagnostic performance as compared to the linear PCA based algorithm in discriminating the cancerous tissue sites of the oral cancer patients from the healthy squamous tissue sites of normal volunteers as well as the uninvolved tissue sites of the oral cavity of the patients with cancer., (Copyright 2003 Wiley-Liss, Inc.)

We report the results of a study carried out to investigate the effect of blood absorption on polarized and unpolarized fluorescence from resected tissue samples and tissue phantoms. The signatures of blood absorption were found to be significantly smaller in polarized fluorescence than in unpolarized fluorescence spectra. The reduced effect of blood absorption on polarized fluorescence also leads to reduced site-to-site variability in polarized fluorescence intensity and line shape compared with unpolarized fluorescence.

For a monodisperse scattering medium, we investigate the dependence on scatterer size parameter for the change in anisotropy of fluorescence due to single scattering at excitation or emission wavelength. The value for the ratio of the anisotropy of fluorescence after one scattering at excitation or emission wavelength to the initial value was observed to increase with increasing value of scatterer size parameter. The effect of multiple scattering on anisotropy of fluorescence from fluorophores embedded in a scattering medium was incorporated using a photon migration model. The model was validated by experiments carried out on samples with known concentration of polystyrene microspheres as scatterers and riboflavins or reduced form of nicotinamide adenine dinucleotide as fluorophores.