In vivo time-domain diffuse correlation spectroscopy above the water absorption peak.

Time-domain diffuse correlation spectroscopy (TD-DCS) is a newly emerging optical technique that exploits pulsed, yet coherent light to non-invasively resolve the blood flow in depth. In this work, we have explored TD-DCS at longer wavelengths compared to those previously used in literature (i.e., 750-850 nm). The measurements were performed using a custom-made titanium-sapphire mode-locked laser, operating at 1000 nm, and an InGaAs photomultiplier as a detector. Tissue-mimicking phantoms and in vivo measurements during arterial arm cuff occlusion in n=4 adult volunteers were performed to demonstrate the proof of concept. We obtained a good signal-to-noise ratio, following the hemodynamics continuously with a relatively fast (1 Hz) sampling rate. In all the experiments, the auto-correlation functions show a decay rate approximately five-fold slower compared to shorter wavelengths. This work demonstrates the feasibility of in vivo TD-DCS in this spectral region and its potentiality for biomedical applications.

In vivo time-gated diffuse correlation spectroscopy at quasi-null source-detector separation.

We demonstrate time domain diffuse correlation spectroscopy at quasi-null source-detector separation by using a fast time-gated single-photon avalanche diode without the need of time-tagging electronics. This approach allows for increased photon collection, simplified real-time instrumentation, and reduced probe dimensions. Depth discriminating, quasi-null distance measurement of blood flow in a human subject is presented. We envision the miniaturization and integration of matrices of optical sensors of increased spatial resolution and the enhancement of the contrast of local blood flow changes.

Time domain diffuse Raman spectrometer based on a TCSPC camera for the depth analysis of diffusive media.

We present a time domain diffuse Raman spectrometer for depth probing of highly scattering media. The system is based on, to the best of our knowledge, a novel time-correlated single-photon counting (TCSPC) camera that simultaneously acquires both spectral and temporal information of Raman photons. A dedicated non-contact probe was built, and time domain Raman measurements were performed on a tissue mimicking bilayer phantom. The fluorescence contamination of the Raman signal was eliminated by early time gating (0-212 ps) the Raman photons. Depth sensitivity is achieved by time gating Raman photons at different delays with a gate width of 106 ps. Importantly, the time domain can provide time-dependent depth sensitivity leading to a high contrast between two layers of Raman signal. As a result, an enhancement factor of 2170 was found for our bilayer phantom which is much higher than the values obtained by spatial offset Raman spectroscopy (SORS), frequency offset Raman spectroscopy (FORS), or hybrid FORS-SORS on a similar phantom.

Unveiling the multifunctional roles of hitherto known capping ligand oleic acid as blue emitter and sensitizer in tuning the emission colour to white in red-emitting phosphors.

Capping ligands are vital in stabilizing various nanostructures and semiconductor quantum dots in which unusual optical properties, especially white light emission, have been realized. Oleic acid (OA) is a widely used capping ligand. Here, we report blue emission from OA in its free molecular form and further demonstrate this by anchoring OA over the surfaces of Al2O3, ZnAl2O4(ZA), ZnAl2O4:Eu3+ (ZA:Eu3+), and Y2O3:Eu3+. White light emission was observed from OA-modified ZA:Eu3+ nanophosphor due to mixing of broad blue emission of OA and red emission of Eu3+ through energy transfer from OA to Eu3+. A detailed study revealed the characteristic binding modes of OA and their dependence on Eu3+ concentration, structural inversion in ZA, and the optical properties and surface states in the pristine and OA-modified ZA:Eu3+. First principles density functional theory calculations were employed to provide an insight into the HOMO-LUMO levels of OA molecule and, electronic structure of pristine and OA-modified ZA surface. The binding of OA with the ZA:xEu3+ surface changes from bridging bidentate to chelating bidentate with increasing Eu3+ concentration in the lattice. The surface binding nature of the carboxylate group with the optimized surface of ZA and the creation of mid-gap states were deduced theoretically by using butanoic acid instead of OA. The blue emission from OA and its mixing with Eu3+ emission was further confirmed experimentally by anchoring it over Y2O3:Eu3+ red phosphor. These results show the multifunctional roles of OA as capping ligand, blue emitter and sensitizer in tuning the emission colour of red phosphors into white.

Factors affecting high-density lipoprotein cholesterol in HIV-infected patients on nevirapine-based antiretroviral therapy.

BACKGROUND & OBJECTIVES: Cardiovascular disease (CVD) risk with low high-density lipoprotein cholesterol (HDL-C) and high triglycerides is common in the general population in India. As nevirapine (NVP)-based antiretroviral therapy (ART) tends to increase HDL-C, gene polymorphisms associated with HDL-C metabolism in HIV-infected adults on stable NVP-based ART were studied. METHODS: A cross-sectional study was conducted between January 2013 and July 2014 among adults receiving NVP-based ART for 12-15 months. Blood lipids were estimated and gene polymorphisms in apolipoprotein C3 (APOC3), cholesteryl ester transfer protein (CETP) and lipoprotein lipase (LPL) genes were analyzed by real-time polymerase chain reaction. Framingham's 10-yr CVD risk score was estimated. Logistic regression was done to show factors related to low HDL-C levels. RESULTS: Of the 300 patients included (mean age: 38.6±8.7 yr; mean CD4 count 449±210 cell/µl), total cholesterol (TC) >200 mg/dl was observed in 116 (39%) patients. Thirty nine per cent males and 47 per cent females had HDL-C levels below normal while 32 per cent males and 37 per cent females had TC/HDL ratio of 4.5 and 4.0, respectively. Body mass index [adjusted odds ratio (aOR)=1.70, 95% confidence interval (CI) 1.01-2.84, P=0.04] and viral load (aOR=3.39, 95% CI: 1.52-7.52, P=0.003) were negatively associated with serum HDL-C levels. The 10-yr risk score of developing CVD was 11-20 per cent in 3 per cent patients. Allelic variants of APOC3 showed a trend towards low HDL-C. INTERPRETATION & CONCLUSIONS: High-risk lipid profiles for atherosclerosis and cardiovascular disease were common among HIV-infected individuals, even after 12 months of NVP-based ART. Targeted interventions to address these factors should be recommended in the national ART programmes.

Strengthening the laboratory diagnosis of pathogenic Corynebacterium species in the Vaccine era.

Over the last three decades, successful implementation of the diphtheria vaccination in the developed and developing countries has reduced the infections caused by the toxigenic strains of Corynebacterium diphtheriae, but a concomitant increase in the invasive infections due to the nontoxigenic strains was seen. In addition, the recent reports on the emergence of nontoxigenic toxin gene-bearing strains, having the potential to revert back to toxigenic form poses a significant threat to human beings. Besides infections caused by C. diphtheriae, the emergence of the respiratory, cutaneous and invasive infections by related pathogenic Corynebacterium species like C. ulcerans and C. pseudotuberculosis, complicate the diagnosis and management of infection. These observations together with the widespread prevalence of diphtheria in the vaccine era, necessitates the strengthening of the epidemiological surveillance and laboratory diagnosis of the pathogen. This review provides the overview of the advantages and limitations of different molecular methods and the role of MALDI-TOF in the laboratory diagnosis of Diphtheria. The contribution of next generation sequencing technology and different genotyping techniques in understanding the pathogenicity, transmission dynamics and epidemiology of the C. diphtheriae is discussed.

Anisotropic optical and conductive properties of oriented 1D-nanoparticle thin films made by spray-assisted self-assembly.

We report on the fabrication of oriented anisotropic metal nanoparticle thin films made by Grazing Incidence Spraying (GIS) and on the anisotropic plasmonic properties of the resulting thin films. Gold nanorods of two different aspect ratios and silver nanowires were self-assembled as a uniaxially aligned monolayer with the GIS approach. In particular, we examine the influence of the nanowire/nanorod length and diameter on the degree of ordering determined by electron microscopy pictures. Furthermore, we show that the anisotropy of the optical properties (probed by polarized UV-visible-near infrared spectroscopy) strongly depend on the quality of alignment. The prepared monolayer thin films have an orientation order parameter of up to 0.83 for silver nanowires, which is reflected in an optical anisotropy of 0.57 in the UV-visible and 0.76 in the near infrared through the selective excitation of transverse and longitudinal surface plasmon resonance modes. The electronic transport in oriented silver nanowire monolayers is also shown to be highly directional, with the sheet resistance varying over almost an order of magnitude depending on the transport direction. Such anisotropic conductive plasmonic thin films may find applications in various fields like biochemical sensing, energy transport and harvesting or optoelectronic devices.

Collagen based magnetic nanobiocomposite as MRI contrast agent and for targeted delivery in cancer therapy.

BACKGROUND: In this study, an attempt has been made with the advent of technology to prepare a multifunctional nanobiocomposite (NBC) for targeted drug delivery in cancer therapy. METHODS: Collagen (C) was fabricated as nanofibers with multifunctional moieties viz. CFeAb*D by incorporating iron oxide nanoparticles (Fe), coupling with fluorescein isothiocyanate (FITC) labeled antibody (Ab*) and loading an anticancer gemcitabine drug (D). This NBC was characterized by conventional methods and evaluated for its biological activities. RESULTS: The UV-vis and FTIR spectroscopic studies revealed the fluorescein to protein ratio and revealed the presence of iron oxide nanoparticles and their interaction with the collagen molecules, respectively. While SDS-PAGE showed the proteinaceous nature of collagen, VSM and TEM studies revealed magnetic saturation as 54.97emu/g and a magnetic nanoparticle with a diameter in the range of 10-30nm and the dimension of nanofiber ranging from 97 to 270nm. A MRI scan has shown a super paramagnetic effect, which reveals that the prepared NBC can be used as a MRI contrast agent. The MTT assay has shown biocompatibility and an apoptotic effect while phase contrast microscopy exhibited receptor mediated uptake of endocytosis. CONCLUSION: The novelty in the prepared NBC lies in the collagen nanofibers, which have a higher penetrating property without causing much cell damage, biocompatibility and multifunctional properties and is able to carry multifunctional agents. GENERAL SIGNIFICANCE: The study has demonstrated the possible use of CFeAb*D as a multifunctional NBC for biomedical applications.

Evidence of a two-step process and pathway dependency in the thermodynamics of poly(diallyldimethylammonium chloride)/poly(sodium acrylate) complexation.

Recent studies have pointed out the importance of polyelectrolyte assembly in the elaboration of innovative nanomaterials. Beyond their structures, many important questions on the thermodynamics of association remain unanswered. Here, we investigate the complexation between poly(diallyldimethylammonium chloride) (PDADMAC) and poly(sodium acrylate) (PANa) chains using a combination of three techniques: isothermal titration calorimetry (ITC), static and dynamic light scattering and electrophoresis. Upon addition of PDADMAC to PANa or vice-versa, the results obtained by the different techniques agree well with each other, and reveal a two-step process. The primary process is the formation of highly charged polyelectrolyte complexes of size 100 nm. The secondary process is the transition towards a coacervate phase made of rich and poor polymer droplets. The binding isotherms measured are accounted for using a phenomenological model that provides the thermodynamic parameters for each reaction. Small positive enthalpies and large positive entropies consistent with a counterion release scenario are found throughout this study. Furthermore, this work stresses the importance of the underestimated formulation pathway or mixing order in polyelectrolyte complexation.

Beam-profile compensation for quantum yield characterisation of Yb-Tm codoped upconverting nanoparticles emitting at 474 nm, 650 nm and 804 nm.

Upconverting nanoparticles (UCNPs) have found widespread applications in biophotonics and energy harvesting due to their unique non-linear optical properties arising from energy transfer upconversion (ETU) mechanisms. However, accurately characterising the power density-dependent efficiency of UCNPs using the internal quantum yield (iQY) is challenging due to the lack of methods that account for excitation beam-profile distortions. This limitation hinders the engineering of optimal UCNPs for diverse applications. To address this, this work present a novel beam profile compensation strategy based on a general analytical rate-equations model, enabling the evaluation of iQY for ETU processes of arbitrary order, such as ETU2, ETU3, and beyond. The method was applied to characterise the ETU2 and ETU3 processes corresponding to the main emission peaks (474 nm, 650 nm, and 804 nm) of a Yb-Tm codoped core-shell ß-UCNP. Through this approach, the transition power density points (which delimit the distinct non-linear regimes of the upconversion luminescence (UCL)), and the saturation iQY values (which are reached at high excitation power densities above the transition points) were determined. The ETU2 process exhibits a single transition power density point, denoted as ρ2, while the ETU3 processes involve two transition points, ρ2 and ρ3. By compensating for the beam profile, we evaluate the iQY of individual lines across a wide dynamic range of excitation power densities (up to 105 W cm-2), encompassing both non-linear and linear regimes of UCL. This study introduces a valuable approach for accurately characterising the iQY of UCNPs, facilitating a deeper understanding of the upconversion and its performance. By addressing excitation beam-profile distortions, this method provides a comprehensive and reliable assessment of the power density-dependent iQY. The results highlight the applicability and effectiveness of this beam profile compensation strategy, which can be employed for a wide range of UCNPs. This advancement opens new avenues for the tailored design and application of UCNPs in various fields, especially for biophotonics.

A novel cross-linked human amniotic membrane for corneal implantations.

The aim of this study was to evaluate the efficacy of Al2(SO4)3 cross-linked human amniotic membrane for ocular surface reconstruction using tissue culture techniques. The human amniotic membrane was cross-linked with Al2(SO4)3, and the cross-linked human amniotic membrane was characterized for its mechanical properties, percentage of swelling in water, sterility, infrared spectroscopy and scanning electron microscopy. The potential of cross-linked human amniotic membrane to support the attachment and proliferation of corneal limbal epithelial cells was assessed in vitro, using static culture system. About 125% increase in the tensile strength was observed in the cross-linked human amniotic membrane compared to human amniotic membrane. Infrared spectroscopy studies have confirmed the cross-linking of human amniotic membrane with Al2(SO4)3. The cross-linked human amniotic membrane was found to be sterile up to 1 year. In culture studies, confluent sheets of epithelial cells were seen at the end of 14th day resembling the morphological features of limbal epithelia. The cross-linked human amniotic membrane has exhibited improved mechanical properties, and the tissue culture studies have shown its feasibility to be used as a limbal transplant. It was concluded that the crosslinked human amniotic membrane with its improved mechanical properties could be used on par with human amniotic membrane.

In vitro anti-prostate adenocarcinoma and lung cancer studies of phenoxyaniline-block-poly(methyl methacrylate) based nanocomposites via controlled radical polymerization.

A phenoxyaniline-based macroinitiator is utilized for the first time in order to produce phenoxyaniline-block-poly(methyl methacrylate) composites through single electron transfer-living radical polymerization (SET-LRP) under mild conditions. A different weight percentage of Cloisite 93A is added into the polymer mixtures in order to increase their biochemical properties. The prepared block copolymer nanocomposites are characterized using ATR-IR, UV-vis-spectroscopy, XRD, Raman, TGA, DSC, a particle size analyzer, contact angle measurements and SEM in order to characterize their structural, thermal, surface and morphological properties. Further, the developed polymeric nanocomposites are successfully applied in two different cancer cell lines (prostate adenocarcinoma and lung cancer), which show excellent anticancer properties. Also, acridine orange/ethidium bromide (AO/EtBr) dual staining is performed, which causes drastic cell death by apoptosis in both A549 and PC-3 cell lines, which indicated that the prepared polymeric nanocomposites effectively inhibit the cell proliferation and induce the apoptosis in both the cancer cells. Here nanoclay is used for cancer treatment because of its complete water solubility, which essentially causes the formation of a cationic complex between the clay and drug through electrostatic interactions. Hence, the exchange of ions between the clay and other ions in the biological environment leads to inhibition of the proliferation of prostate adenocarcinoma and lung cancer cells in the system.

Generalised analytical model of the transition power densities of the upconversion luminescence and quantum yield.

The quantum yield (QY) evaluation of upconverting nanoparticles (UCNPs) is an essential step in the characterisation of such materials. The QY of UCNPs is governed by competing mechanisms of populating and depopulating the electronic energy levels involved in the upconversion (UC), namely linear decay rates and energy transfer rates. As a consequence, at low excitation, the QY excitation power density (ρ) dependence obeys the power law ρn-1, where n represents the number of absorbed photons required for the emission of a single upconverted photon and determines the order of the energy transfer upconversion (ETU) process. At high power densities, the QY transits to a saturation level independent of the ETU process and the number of excitation photons, as a result of an anomalous power density dependence present in UCNPs. Despite the importance of this non-linear process for several applications (e.g., living tissue imaging and super-resolution-microscopy), little has been reported in the literature regarding theoretical studies to describe the UC QY, especially for ETUs with order higher than two. Therefore, this work presents a simple general analytical model, which introduces the concept of the transition power density points and QY saturation to characterise the QY of an arbitrary ETU process. The transition power density points determine where the power density dependence of the QY and the UC luminescence changes. The results provided in this paper from fitting the model to experimental QY data of a Yb-Tm codoped ß-UCNP for 804 nm and 474 nm emissions (ETU2 and ETU3 processes, respectively) exemplify the application of the model. The common transition points found for both processes were compared to each other showing strong agreement with theory, as well as, compared to previous reports when possible.

N6-Methyladenosine RNA Modification in Host Cells Regulates Peste des Petits Ruminants Virus Replication.

N6-methyladenosine (m6A) modification is a major RNA epigenetic regulatory mechanism. The dynamics of m6A levels in viral genomic RNA and their mRNAs have been shown to have either pro- or antiviral functions, and therefore, m6A modifications influence virus-host interactions. Currently, no reports are available on the effect of m6A modifications in the genome of Peste des petits ruminants virus (PPRV). In the present study, we took PPRV as a model for nonsegmented negative-sense single-stranded RNA viruses and elucidate the role of m6A modification on viral replication. We detected m6A-modified sites in the mRNA of the virus and host cells, as well as the PPRV RNA genome. Further, it was found that the level of m6A modification in host cells alters the viral gene expression. Knockdown of the METTL3 and FTO genes (encoding the m6A RNA modification writer and eraser proteins, respectively) results in alterations of the levels of m6A RNA modifications in the host cells. Experiments using these genetically modified clones of host cells infected with PPRV revealed that both higher and lower m6A RNA modification in the host cells negatively affect PPRV replication. We found that m6A-modified viral transcripts had better stability and translation efficiency compared to the unmodified mRNA. Altogether, from these data, we conclude that the m6A modification of RNA regulates PPRV replication. These findings contribute toward a way forward for developing novel antiviral strategies against PPRV by modulating the dynamics of host m6A RNA modification. IMPORTANCE Peste des petits ruminants virus (PPRV) causes a severe disease in sheep and goats. PPRV infection is a major problem, causing significant economic losses to small ruminant farmers in regions of endemicity. N6-methyladenosine (m6A) is an important RNA modification involved in various functions, including virus-host interactions. In the present study, we used stable clones of Vero cells, having knocked down the genes encoding proteins involved in dynamic changes of the levels of m6A modification. We also used small-molecule compounds that interfere with m6A methylation. This resulted in a platform of host cells with various degrees of m6A RNA modification. The host cells with these different microenvironments were useful for studying the effect of m6A RNA modification on the expression of viral genes and viral replication. The results pinpoint the level of m6A modifications that facilitate the maximum replication of PPRV. These findings will be useful in increasing the virus titers in cultured cells needed for the economical development of the vaccine. Furthermore, the findings have guiding significance for the development of novel antiviral strategies for limiting PPRV replication in infected animals.

Preparation and evaluation of biocomposites as wound dressing material.

Collagen was isolated from the chrome containing leather waste (CCLW) which is a major solid waste in leather industry. Composite films were made using sago starch (SG), soya protein (SY), and collagen (C) and were cross linked with glutaraldehyde (G).The films prepared were characterized for their physico chemical properties like tensile strength, infrared spectra, thermogravimetric analysis, surface morphology, and water absorption studies. Better mechanical properties and surface morphology were observed for SG-SY-G-C films compared to other films prepared using collagen. The composite films prepared were used as wound dressing material on the experimental wounds of rats and healing pattern was evaluated using planimetric, biochemical, and histopathological studies. These studies have revealed better wound healing capacity of SG-SY-G-C film and utilization of CCLW in the preparation of value added product like wound dressing material.

Assessment and Evaluation of Soft Tissue Measurements between Various Mandibular Divergences in the South Indian Population: A Cephalometric Study.

Aim: The aim of this study is to evaluate the association between the mandibular divergent patterns and soft tissue chin (STC) thickness measured at different chin levels in nongrowing patients. Methodology: Pretreatment lateral cephalograms of 400 adult patients were segregated into four groups based on mandibular divergence pattern defined by the mandibular plane to cranial base angle (average 32° ± 5°), Group I with low angle (below 27°), Group II with medium low angle (28°-32°), Group III with medium high angle (33°-36°), and Group IV with high angle (above 37°). STC thickness was measured between Pog-Pog' (pogonion), Gn-Gn' (gnathion), and Me-Me' (menton), thickness and height of the upper and lower lips were also measured. Statistical analysis was done using one-way analysis of variance followed by post hoc Tukey analysis. Results: A significant difference in the STC thickness at Pog, Gn, and Me was observed among all four groups with hyperdivergent patterns, showing decreased STC thickness than the hypodivergent mandibular pattern. Thickness of the upper and lower lips was greater in hypodivergent mandible, whereas height of the lips was greater in hyperdivergent mandible.

Synthesis and Analysis of Impregnation on Activated Carbon in Multiwalled Carbon Nanotube for Cu Adsorption from Wastewater.

Industrial wastes contain more toxins that get dissolved in the rivers and lakes, which are means of freshwater reservoirs. The contamination of freshwater leads to various issues for microorganisms and humans. This paper proposes a novel method to remove excess copper from the water. The nanotubes are used as a powder in membrane form to remove the copper from the water. The multiwalled carbon nanotube is widely used as a membrane for filtration. It contains many graphene layers of nm size that easily adsorbs the copper when the water permeates through it. Activated carbon is the earliest and most economical method that also adsorbs copper to a certain extent. This paper proposes the methods of involving the activated carbon in the multiwalled carbon nanotube to improve the adsorption capability of the copper. Here, activated carbon is impregnated on the multiwalled carbon nanotube's defect and imperfect surface areas. It makes more adsorption sites on the surface, increasing the adsorption amount. The same method is applied to Hydroxyl functionalized multiwalled carbon nanotubes. Both the methods showed better results and increased the copper removal. The functionalized method removed 93.82% copper, whereas the nonfunctionalized method removed 80.62% copper from the water.

Development and Characterization of Carbon-Based Adsorbents Derived from Agricultural Wastes and Their Effectiveness in Adsorption of Heavy Metals in Waste Water.

The current work focuses on peanut shells and agricultural wastes richly in many nations subjected to pyrolysis treatment at various temperatures in the range of 500-800°C to determine the feasible physiochemical characteristics of the biochar. The biochars with the high surface area were employed to adsorb Pb2+ (lead) ions, the heaviest pollutants in the water bodies. The raw material, biochar, and pyrolyzed biochar were characterized by SEM, FTIR, partial and elemental analysis, and BET tests. The adsorption characteristics of the biochar, pre- and postpyrolysis treatment, were studied with the assistance of batch adsorption tests under varying test conditions. Adsorbing conditions were determined by evaluating the effects of adsorbing parameters like initial concentration of the lead in water, pH of the adsorbent, contact time, and mixing speed on the effective adsorption of Pb2+ ions from water. Langmuir, Freundlich, and Themkin isotherm expressions were employed to study the experimental results. The adsorption kinetics study showed that the synthesized biochars were chemically stable enough to adsorb the Pb ions onto the surface.

Evaluation of relative beam-profile-compensated quantum yield of upconverting nanoparticles over a wide dynamic range of power densities.

The presented work uses a discrete strategy of beam profile compensation to evaluate the local internal quantum yield (iQY) of upconverting nanoparticles (UCNPs) at the pixel level of the beam profile using a compact CMOS camera. The two-photon process of upconversion with a central emission peak at 804 nm was studied for a ß-phase core-shell Tm-codoped UCNP under 976 nm excitation. At the balancing power density point, ρb, found to be 44 ± 3 W cm-2, the iQY, ηb, was obtained as 2.3 ± 0.1%. Combining the power density dynamic range provided by the pixel depth of the camera with the dynamic range achieved using two distinct beam profiles to excite the UCNPs, the iQY was evaluated throughout a range of 104 in the iQY scale (from 0.0003% to 4.6%) and 106 in power densities of excitation (from 0.003 W cm-2 to 1050 W cm-2). To the best of our knowledge, these are the lowest values ever obtained as QY results have never been reported under 0.02% or at excitation power densities below 0.01 W cm-2.