An Atomistic Molecular Dynamics Study of Titanium Dioxide Adhesion to Lipid Bilayers.

Titanium dioxide (TiO2) nanoparticles are found in an array of consumer and industrial products, and human exposure to these nanoparticles involves interaction with biological membranes. To understand the effect of the membrane lipid composition on bilayer perturbation by TiO2, we performed all-atom molecular dynamics simulations of nanosized TiO2 interacting with three single component bilayers differing only in their headgroup composition: the zwitterionic DOPC, which is overall neutral containing negatively charged phosphate and positively charged choline in its head, DOPG, which is overall anionic containing negatively charged phosphate and neutral glycerol, and the anionic DOPS, containing negatively charged phosphate attached to the hydroxyl side-chain of the amino acid, serine containing negatively charged carboxyl and positively charged ammonium. The nanoparticle adheres to all three bilayers causing a negative curvature on their top leaflet. However, the local deformation of DOPG was more pronounced than DOPC and DOPS. The anionic DOPG, which is the thinnest of the three bilayers, interacted most strongly with the TiO2. DOPS has the next strongest interaction; however, its high bending modulus enables it to resist deformation by the nanoparticle. DOPC has the weakest interaction with the nanoparticle of the three as it has the highest bending modulus and its zwitterionic head groups have strong cohesive interactions. We also observed a nonuniform response of the bilayers: the orientational order of the lipids near the nanoparticle decreases, while that of the lipids away from the nanoparticle increases. The overall thickness and bending modulus of DOPG increased upon contact with the nanoparticle owing to overall stiffening of the bilayer despite local softening, while the average structural and mechanical properties of DOPC and DOPS remain unchanged, which can be explained in part by the greater bilayer bending elasticicty of DOPC and DOPS. The above findings suggest that regions of biological membranes populated by anionic lipids with weaker bending elasticity will be more susceptible to perturbation by TiO2 nanoparticles than zwitterionic-rich regions.

Lipid-Detergent Phase Transitions During Detergent-Mediated Liposome Solubilization.

We investigate the phase transition stages for detergent-mediated liposome solubilization of bio-mimetic membranes with the motivation of integrating membrane-bound Photosystem I into bio-hybrid opto-electronic devices. To this end, the interaction of two non-ionic detergents n-dodecyl-ß-D-maltoside (DDM) and Triton X-100 (TX-100) with two types of phospholipids, namely DPhPC (1,2-diphytanoyl-sn-glycero-3-phosphocholine) and DPPG (1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol)), are examined. Specifically, solubilization processes for large unilamellar liposomes are studied with the aid of turbidity measurements, dynamic light scattering, and cryo-transmission electron microscopy imaging. Our results indicate that the solubilization process is well depicted by a three-stage model, wherein the lamellar-to-micellar transitions for DPhPC liposomes are dictated by the critical detergent/phospholipid ratios. The solubilization of DPhPC by DDM is devoid of formation of a "gel-like" phase. Furthermore, our results indicate that DDM is a stable candidate for DPhPC solubilization and proteoliposome formation. Finally, although the solubilization of DPPG with DDM indicated the familiar three-stage process, the same process with TX-100 indicate structural deformation of vesicles into complex network of kinetically trapped micro- and nanostructured arrangements of lipid bilayers.

Elucidating the role of methyl viologen as a scavenger of photoactivated electrons from photosystem I under aerobic and anaerobic conditions.

We present detailed electrochemical investigations into the role of dissolved O2 in electrolyte solutions in scavenging photoactivated electrons from a uniform photosystem I (PS I) monolayer assembled on alkanethiolate SAM (self-assembled monolayer)/Au surfaces while using methyl viologen (MV(2+)) as the redox mediator. To this end, we report results for direct measurements of light induced photocurrent from uniform monolayer assemblies of PS I on C9 alkanethiolate SAM/Au surfaces. These measurements, apart from demonstrating the ability of dissolved O2 in the electrolyte medium to act as an electron scavenger, also reveal its essential role in driving the solution-phase methyl viologen to initiate light-induced directional electron transfer from an electron donor surface (Au) via surface assembled PS I trimers. Specifically, our systematic electrochemical measurements have revealed that the dissolved O2 in aqueous electrolyte solutions form a complex intermediate species with MV that plays the essential role in mediating redox pathways for unidirectional electron transfer processes. This critical insight into the redox-mediated electron transfer pathways allows for rational design of electron scavengers through systematic tuning of mediator combinations that promote such intermediate formation. Our current findings facilitate the incorporation of PS I-based bio-hybrid constructs as photo-anodes in future photoelectrochemical cells and bio-electronic devices.

A facile route for the synthesis of nanostructured oxides and hydroxides of cobalt using laser ablation synthesis in solution (LASIS).

We used a pulsed laser ablation synthesis in solution (LASIS) to produce cobalt oxide/hydroxide nanoparticles (NPs) with tailored size, morphology and structure at different laser fluences, wavelengths (532 and 1064 nm) and solvent conditions. Specifically, LASIS on bulk Co in the presence and absence of O2 in an aqueous solution initially produces cobalt monoxide (CoO) and single crystal ß-cobalt hydroxide (ß-Co(OH)2) nanoparticles (NPs) respectively that finally transform into cobaltosic oxide (Co3O4) through oxidation and/or thermal decomposition. Transmission electron microscopy (TEM) and scanning mobility particle sizer (SMPS) measurements on the final products reveal a bimodal size distribution of agglomerated NPs (for the 1064 and 532 nm laser) at low laser fluences, where the ablation mechanism is dominated by vaporization and normal boiling. In contrast, more efficient and predominant explosive boiling at higher laser fluences produces a mono-modal size distribution of spherically shaped primary NPs in agglomerates. Furthermore, higher absorbance of the 532 nm laser by solution-phase colloidal NPs re-ablates them into spherical shapes of larger size (∼13-22 nm) as compared to the ones from using 1064 nm LASIS (∼10-14 nm), while rendering 532 nm LASIS less productive than 1064 nm LASIS over an extended period of time. Finally, Co3O4 nanorods with enhanced localized surface plasmon resonance (LSPR) are synthesized at high pH (pH ≥ 13) and low laser fluence (<5 mJ cm(-2)) conditions. Such nanostructured materials are promising candidates as photocatalysts or additives in nanocomposite materials with enhanced light absorption properties.

Deep Learning Models for Data-Driven Laser Induced Breakdown Spectroscopy (LIBS) Analysis of Interstitial Oxygen Impurities in Czochralski-Si Crystals.

Analytical advantages of facile and expeditious spectral data collections from laser-induced breakdown spectroscopy (LIBS) are often offset by the low-accuracy quantitative analyses offered by the technique due to non-equilibrium plasma-matrix interactions. Herein, we developed a one-dimensional (1D) convolutional neural network (CNN) and a least absolute shrinkage and selection operator (LASSO) models for LIBS data analyses to predict trace amounts of interstitial oxygen impurities in commercial Czochralski-silicon (Cz-Si) crystals with known interstitial oxygen concentrations at 0-16 parts per million (ppm). While traditional spectral analyses from O(I) (777.2 nm) atomic lines offer poor accuracy, CNN and LASSO analyses generate excellent predictions for the interstitial oxygen concentrations. Specifically, CNN-based spectral analyses uniquely identified systematic alterations in LIBS fingerprints manifested by laser-matter interactions. Our results pave the path for combining facile and voluminous LIBS data collection with deep learning driven high-fidelity data analytics.

3D printed interdigitated supercapacitor using reduced graphene oxide-MnO x /Mn3O4 based electrodes.

In this study hybrid nanocomposites (HNCs) based on manganese oxides (MnO x /Mn3O4) and reduced graphene oxide (rGO) are synthesized as active electrodes for energy storage devices. Comprehensive structural characterizations demonstrate that the active material is composed of MnO x /Mn3O4 nanorods and nanoparticles embedded in rGO nanosheets. The development of such novel structures is facilitated by the extreme synthesis conditions (high temperatures and pressures) of the liquid-confined plasma plume present in the Laser Ablation Synthesis in Solution (LASiS) technique. Specifically, functional characterizations demonstrate that the performance of the active layer is highly correlated with the MnO x /Mn3O4 to rGO ratio and the morphology of MnO x /Mn3O4 nanostructures in HNCs. To that end, active layer inks comprising HNC samples prepared under optimal laser ablation time windows, when interfaced with a percolated conductive network of electronic grade graphene and carbon nanofibers (CNFs) mixture, indicate superior supercapacitance for functional electrodes fabricated via sequential inkjet printing of the substrate, current collector layer, active material layer, and gel polymer electrolyte layer. Electrochemical characterizations unequivocally reveal that the electrode with the LASiS synthesized MnO x /Mn3O4-rGO composite exhibits significantly higher specific capacitance compared to the ones produced with commercially available Mn3O4-graphene NCs. Moreover, the galvanostatic charge-discharge (GCD) experiments with the LASiS synthesized HNCs show a significantly larger charge storage capacity (325 F g-1) in comparison to NCs synthesized with commercially available Mn3O4-graphene (189 F g-1). Overall, this study has paved the way for use of LASiS-based synthesized functional material in combination with additive manufacturing techniques for all-printed electronics with superior performance.

Observation of anomalous carotenoid and blind chlorophyll activations in photosystem I under synthetic membrane confinements.

The role of natural thylakoid membrane confinements in architecting the robust structural and electrochemical properties of PSI is not fully understood. Most PSI studies till date extract the proteins from their natural confinements that can lead to non-native conformations. Recently our group had successfully reconstituted PSI in synthetic lipid membranes using detergent-mediated liposome solubilizations. In this study, we investigate the alterations in chlorophylls and carotenoids interactions and reorganization in PSI based on spectral property changes induced by its confinement in anionic DPhPG and zwitterionic DPhPC phospholipid membranes. To this end, we employ a combination of absorption, fluorescence, and circular dichroism (CD) spectroscopic measurements. Our results indicate unique activation and alteration of photoresponses from the PSI carotenoid (Car) bands in PSI-DPhPG proteoliposomes that can tune the Excitation Energy Transfer (EET), otherwise absent in PSI at non-native environments. Specifically, we observe broadband light harvesting via enhanced absorption in the otherwise non-absorptive green region (500-580 nm) of the Chlorophylls (Chl) along with ~64% increase in the full-width half maximum of the Qy band (650-720 nm). The CD results indicate enhanced Chl-Chl and Chl-Car interactions along with conformational changes in protein secondary structures. Such distinct changes in the Car and Chl bands are not observed in PSI confined in DPhPC. The fundamental insights into membrane microenvironments tailoring PSI subunits reorganization and interactions provide novel strategies for tuning photoexcitation processes and rational designing of biotic-abiotic interfaces in PSI-based photoelectrochemical energy conversion systems.

Baseline Microperimetry and OCT in the RUSH2A Study: Structure-Function Association and Correlation With Disease Severity.

PURPOSE: To investigate baseline mesopic microperimetry (MP) and spectral domain optical coherence tomography (OCT) in the Rate of Progression in USH2A-related Retinal Degeneration (RUSH2A) study. DESIGN: Natural history study METHODS: Setting: 16 clinical sites in Europe and North AmericaStudy Population: Participants with Usher syndrome type 2 (USH2) (N = 80) or autosomal recessive nonsyndromic RP (ARRP) (N = 47) associated with biallelic disease-causing sequence variants in USH2AObservation Procedures: General linear models were used to assess characteristics including disease duration, MP mean sensitivity and OCT intact ellipsoid zone (EZ) area. The associations between mean sensitivity and EZ area with other measures, including best corrected visual acuity (BCVA) and central subfield thickness (CST) within the central 1 mm, were assessed using Spearman correlation coefficients. MAIN OUTCOME MEASURES: Mean sensitivity on MP; EZ area and CST on OCT. RESULTS: All participants (N = 127) had OCT, while MP was obtained at selected sites (N = 93). Participants with Usher syndrome type 2 (USH2, N = 80) and nonsyndromic autosomal recessive Retinitis Pigmentosa (ARRP, N = 47) had the following similar measurements: EZ area (median (interquartile range [IQR]): 1.4 (0.4, 3.1) mm2 vs 2.3 (0.7, 5.7) mm2) and CST (median (IQR): 247 (223, 280) µm vs 261 (246, 288), and mean sensitivity (median (IQR): 3.5 (2.1, 8.4) dB vs 5.1 (2.9, 9.0) dB). Longer disease duration was associated with smaller EZ area (P < 0.001) and lower mean sensitivity (P = 0.01). Better BCVA, larger EZ area, and larger CST were correlated with greater mean sensitivity (r > 0.3 and P < 0.01). Better BCVA and larger CST were associated with larger EZ area (r > 0.6 and P < 0.001). CONCLUSIONS: Longer disease duration correlated with more severe retinal structure and function abnormalities, and there were associations between MP and OCT metrics. Monitoring changes in retinal structure-function relationships during disease progression will provide important insights into disease mechanism in USH2A-related retinal degeneration.

Controlling the morphology of Photosystem I assembly on thiol-activated Au substrates.

Morphological variations of Photosystem I (PS I) assembly on hydroxyl-terminated alkanethiolate self-assembled monolayer (SAM)/Au substrates with various deposition techniques is presented. Our studies indicate that deposition conditions such as PS I concentration and driving force play a central role in determining organization of immobilized PS I on thiol-activated Au surfaces. Specifically, atomic force microscopy (AFM) and ellipsometry analyses indicate that gravity-driven deposition from concentrated PS I solutions results in a large number of columnar PS I aggregates, which assemble perpendicular to the Au surface. PS I deposition yields much more uniform layers when deposited at lower concentrations, suggesting preassembly of the aggregate formation in the solution phase. Moreover, in electric field assisted deposition at high field strengths, columnar self-assembly is largely prevented, thereby allowing a uniform, monolayer-like deposition even at very high PS I concentrations. In situ dynamic light scattering (DLS) studies of solution-phase aggregation dynamics of PS I suspensions in both the presence and absence of an applied electric field support these observations and clearly demonstrate that the externally imposed electric field effectively fragments large PS I aggregates in the solution phase, thereby permitting a uniform deposition of PS I trimers on SAM/Au substrates.

A new platform for development of photosystem I based thin films with superior photocurrent: TCNQ charge transfer salts derived from ZIF-8.

The transmembrane photosynthetic protein complex Photosystem I (PSI) is highly sought after for incorporation into biohybrid photovoltaic devices due to its remarkable photoactive electrochemical properties, chiefly driving charge separation with ∼1 V potential and ∼100% quantum efficiency. In pursuit of these integrated technologies, three factors must be simultaneously tuned, namely, direct redox transfer steps, three-dimensional coordination and stabilization of PSI aggregates, and interfacial connectivity with conductive pathways. Building on our recent successful encapsulation of PSI in the metal-organic framework ZIF-8, herein we use the zinc and imidazole cations from this precursor to form charge transfer complexes with an extremely strong organic electron acceptor, TCNQ. Specifically, the PSI-Zn-H2mim-TCNQ charge transfer salt complex was drop cast on ITO to form dense films. Subsequent voltammetric cycling induced cation exchange and electrochemical annealing of the film was used to enhance electron conductivity giving rise to a photocurrent in the order of 15 µA cm-2. This study paves the way for a myriad of future opportunities for successful integration of this unique class of charge transfer salt complexes with biological catalysts and light harvesters.

Management of asymptomatic hyperuricemia: Integrated Diabetes & Endocrine Academy (IDEA) consensus statement.

AIM: The definition and management of asymptomatic hyperuricemia has been an area of controversy for many decades. Debate persists regarding the benefit of treating all cases of asymptomatic hyperuricemia and hence, unsurprisingly there are no clear clinical practice guidelines from our country. PARTICIPANTS: Ten members consisting of eminent physicians, endocrinologists, nephrologist and a rheumatologist were selected by the Integrated Diabetes & Endocrine Academy (IDEA) for a closed meeting with the aim to come to a consensus. EVIDENCE: A literature search was performed using PubMed and Cochrane library following which published articles in indexed peer review journals were selected. CONSENSUS PROCESS: Each participant voiced their opinion after reviewing the available data and a consensus was reached after three meetings by voting. CONCLUSION: Recommendations were made on important areas such as definition, investigation and management of asymptomatic hyperuricemia.

Effect of 1,25 dihydroxy vitamin D3 supplementation on pain relief in early rheumatoid arthritis.

BACKGROUND: To assess effect of 1,25 dihydroxy vitamin D3 supplementation on pain relief in early rheumatoid arthritis (RA). MATERIALS AND METHODS: An open-labeled randomized trial was conducted comparing 60,000 IU 1,25 dihydroxy vitamin D3 + calcium (1000 mg/day) combination [Group A] versus calcium (1000 mg/day) only [Group B], as supplement to existing treatment regimen in early RA. Primary outcome included (i) minimum time required for onset of pain relief (Tm) assessed through patients' visual analog scale (VAS); (ii) % change in VAS score from onset of pain relief to end of 8 weeks. Secondary outcome included change in disease activity score (DAS-28). RESULTS: At the end of 8-weeks, Group A reported 50% higher median pain relief scores (80% vs. 30%; P < 0.001) and DAS-28 scores (2.9 ± 0.6 vs. 3.1 ± 0.4; P = 0.012) compared to Group B; however, Tm remained comparable (19 ± 2 vs. 20 ± 2 days; P = 0.419). Occurrence of hypovitaminosis-D was lower (23.3%) compared to Indian prevalence rates and was a risk factor for developing active disease (Odds Ratio (OR) = 7.52 [95% Confidence Interval (CI) 2.67-21.16], P < 0.0001). Vitamin D deficiency was significantly (P < 0.001) more common in female gender, active disease, and shorter mean disease duration. Vitamin D levels were inversely correlated to disease activity as assessed by DAS-28 (r = -0.604; P < 0.001). CONCLUSIONS: Vitamin-D deficiency is a risk factor for developing active disease in RA. Weekly supplementation of 60,000 IU of 1,25 dihydroxy vitamin D3 in early RA results in greater pain relief. The number needed to treat for this additional pain relief was 2. IDENTIFIER: CTRI/2018/01/011532 (www.ctri.nic.in).

Detection of interstitial oxygen contents in Czochralski grown silicon crystals using internal calibration in laser-induced breakdown spectroscopy (LIBS).

We use an internal calibration approach in laser-induced breakdown spectroscopy (LIBS) for quantitative detection of dead load interstitial oxygen contents (Oi) in industrial-grade silicon (Si) crystal ingots. Si crystal samples were grown via Czochralski technique and supplied by SunEdison Semiconductor Ltd. with known Oi contents measured via gas fusion analysis (GFA) and Fourier transform infrared (FTIR) spectroscopy. The LIBS analyses reported here use and compare a direct approach based on the known oxygen atomic emission line at 777. 19 nm and an indirect approach based on an internal calibration technique using an emission line at 781 nm associated to Si I. Unlike the first direct approach, the latter exhibited much higher sensitivity, reliability and less error. In this approach, an internal calibration uses systematic variations in the 781 nm emission line in conjunction with observed changes in plasma excitation temperatures as a quantitative measure of changes in plasma conditions and laser-matter interactions due to varying Oi contents in the analyte matrix. Using this technique, we establish the detection limit of LIBS in measuring Oi in Si crystal ingots down to 8 ±â€¯1 ppma level. The approach assists to overcome the limitations of common industrial techniques such as FTIR that cannot provide accurate quantitative measurements for heavily doped Si crystals and GFA that is significantly cumbersome to be an online technique. Our results establish LIBS at the forefront of alternative industrial analytical tools heretofore not considered for rapid, potential on-line monitoring of dead loads in commercial grade Si wafers during their growth processes.

Estimation of Gestational Age via Image Analysis of Anterior Lens Capsule Vascularity in Preterm Infants: A Pilot Study.

Introduction: Anterior lens capsule vascularity (ALCV) is resorbed in the developing fetus from 27 to 35 weeks gestation. In this pilot study, we evaluated the feasibility and validity of combining smartphone ophthalmoscope videos of ALCV and image analysis for gestational age estimation. Methods: ALCV videos were captured longitudinally in preterm neonates from delivery using a PanOptic® Ophthalmoscope with an iExaminer® adapter (Welch-Allyn). ALCV video frames were manually selected and quantified using semi-automatic image analysis. A predictive model based on ALCV features was compared to gold-standard ultrasound gestational age estimates. Results: A total of 64 image-capture sessions were carried out in 24 neonates. Ultrasound-estimated gestational age and ALCV-predicted gestational age estimates indicate that the two methods are similar (r = 0.78, p < 0.0001). ALCV estimates of gestational age were within 0.11 ± 1.3 weeks of ultrasound estimates. In the final model, gestational age was predicted within ± 1 week for 54% and within ± 2 weeks for 86% of the measures. Conclusions: This novel application of smartphone ophthalmoscopy and ALCV image analysis may provide a safe, accurate and non-invasive technology to estimate postnatal gestational age, especially in low income countries where gestational age may not be known at birth.

Jolly green MOF: confinement and photoactivation of photosystem I in a metal-organic framework.

Photosystem I (PSI) is a ∼1000 kDa transmembrane protein that enables photoactivated charge separation with ∼1 V driving potential and ∼100% quantum efficiency during the photosynthetic process. Although such properties make PSI a potential candidate for integration into bio-hybrid solar energy harvesting devices, the grand challenge in orchestrating such integration rests on rationally designed 3D architectures that can organize and stabilize PSI in the myriad of harsh conditions in which it needs to function. The current study investigates the optical response and photoactive properties of PSI encapsulated in a highly stable nanoporous metal-organic framework (ZIF-8), denoted here as PSI@ZIF-8. The ZIF-8 framework provides a unique scaffold with a robust confining environment for PSI while protecting its precisely coordinated chlorophyll networks from denaturing agents. Significant blue shifts in the fluorescence emissions from UV-vis measurements reveal the successful confinement of PSI in ZIF-8. Pump-probe spectroscopy confirms the photoactivity of the PSI@ZIF-8 composites by revealing the successful internal charge separation and external charge transfer of P700 + and FB - even after exposure to denaturing agents and organic solvents. This work provides greater fundamental understanding of confinement effects on pigment networks, while significantly broadening the potential working environments for PSI-integrated bio-hybrid materials.

Characterization of carbon-containing aerosolized drugs using laser-induced breakdown spectroscopy.

Aerosolized drug delivery methods have increasingly become popular for pharmaceutical applications. This is mainly due to their ease of application and the more recent advancements incorporating nano-sized generation of particles that find deeper penetration routes and more efficient administration of the drug to specific target organs. Their effectiveness heavily relies on the uniformity of the chemical composition of these aerosolized drugs. Thus, it calls for a real-time on-line analytical tool that can accurately characterize the chemical constituents of the drug powder particles generated to ensure a stringent quality control. We present laser-induced breakdown spectroscopy (LIBS) for the first time as an efficient analytical tool to carry out on-line quantitative chemical characterization of aerosolized drugs. We used three different carbon based aerosolized drugs, namely L-ascorbic acid 2-phosphate sesquimagnesium salt hydrate (C(6)H(9)Mg(1.5)O(9)P.xH(2)O), Iron(II) L-ascorbate (C(12)H(14)FeO(12)), and DL-pantothenic acid hemicalcium salt (C(9)H(16)NO(5)0.5Ca) for our quantitative LIBS studies here. Our results show that LIBS can effectively estimate the quantitative ratios of carbon to various trace elements for each of these drugs, thereby enabling on-line unique characterization of individual aerosolized drugs. The quantitative LIBS technique predicted the [C]/[Mg], [C]/[Fe], and [C]/[Ca] ratios as 4.02+/-0.76, 12.42+/-2.36, and 18.47+/-4.39 for each of the above aerosolized drugs, respectively. Within error limits, we find these ratios in good agreement with the respective stoichiometric values of 4, 12, and 18 corresponding to the drugs above. Thus, the work demonstrated the utility and validity of LIBS in accurate on-line identification of drug powders during real-time manufacturing processes.

In-vitro analysis of early calcification in aortic valvular interstitial cells using Laser-Induced Breakdown Spectroscopy (LIBS).

Calcific aortic valve disease (CAVD) is a major cardiovascular disorder caused by osteogenic differentiation of valvular interstitial cells (VICs) within aortic valves. Conventional methods like colorimetric assays and histology fail to detect small calcium depositions during in-vitro VIC cultures. Laser-induced breakdown spectroscopy (LIBS) is a robust analytical tool used for inorganic materials characterizations, but relatively new to biomedical applications. We employ LIBS, for the first time, for quantitative in-vitro detection of calcium depositions in VICs at various osteogenic differentiation stages. VICs isolated from porcine aortic valves were cultured in osteogenic media over various days. Colorimetric calcium assays based on arsenazo dye and Von Kossa staining measured the calcium depositions within VICs. Simultaneously, LIBS signatures for Ca I (422.67 nm) atomic emission lines were collected for estimating calcium depositions in lyophilized VIC samples. Our results indicate excellent linear correlation between the calcium assay and our LIBS measurements. Furthermore, unlike the assay results, the LIBS results could resolve calcium signals from cell samples with as early as 2 days of osteogenic culture. Quantitatively, the LIBS measurements establish the limit of detection for calcium content in VICs to be ∼0.17±0.04 µg which indicates a 5-fold improvement over calcium assay. Picture: Quantitative LIBS enables in-vitro analysis for early stage detection of calcium deposition within aortic valvular interstitial cells (VICs).

Plasmon-Enhanced Photocurrent from Photosystem I Assembled on Ag Nanopyramids.

Plasmonic metal nanostructures have been known to tune optoelectronic properties of fluorophores. Here, we report the first-ever experimental observation of plasmon-induced photocurrent enhancements from Photosystem I (PSI) immobilized on Fischer patterns of silver nanopyramids (Ag-NP). To this end, the plasmonic peaks of Ag-NP were tuned to match the PSI absorption peaks at ∼450 and ∼680 nm wavelengths. Specifically, the plasmon-enhanced photocurrents indicate enhancement factors of ∼6.5 and ∼5.8 as compared to PSI assembly on planar Ag substrates for nominal excitation wavelengths of 660 and 470 nm, respectively. The comparable enhancement factors from both 470 and 660 nm excitations, in spite of a significantly weaker plasmon absorption peak at ∼450 nm for the Ag-NP structures, can be rationalized by previously reported excessive plasmon-induced fluorescence emission losses from PSI in the red region as compared to the blue region of the excitation wavelengths.

Open-source, machine and deep learning-based automated algorithm for gestational age estimation through smartphone lens imaging.

Gestational age estimation at time of birth is critical for determining the degree of prematurity of the infant and for administering appropriate postnatal treatment. We present a fully automated algorithm for estimating gestational age of premature infants through smartphone lens imaging of the anterior lens capsule vasculature (ALCV). Our algorithm uses a fully convolutional network and blind image quality analyzers to segment usable anterior capsule regions. Then, it extracts ALCV features using a residual neural network architecture and trains on these features using a support vector machine-based classifier. The classification algorithm is validated using leave-one-out cross-validation on videos captured from 124 neonates. The algorithm is expected to be an influential tool for remote and point-of-care gestational age estimation of premature neonates in low-income countries. To this end, we have made the software open source.

Evaluation of inner retinal layers as biomarkers in mild cognitive impairment to moderate Alzheimer's disease.

Inner retina in Alzheimer's Disease (AD) may experience neuroinflammation resulting in atrophy. The objective of our study was to determine whether retinal GCIPL (ganglion cell-inner plexiform layer) or nerve fiber layer (NFL) thickness may serve as noninvasive biomarkers to diagnose AD. This cross-sectional case-control study enrolled 15 mild cognitive impairment (MCI) patients, 15 mild-moderate AD patients, and 18 cognitively normal adults. NFL and GCIPL thicknesses on optical coherence tomography (OCT) were measured using Duke Optical Coherence Tomography Retinal Analysis Program (DOCTRAP) and Spectralis software. We demonstrated that regional thicknesses of NFL or GCIPL on macular or nerve OCTs did not differ between groups. However, a multi-variate regression analysis identified macular areas with a significant thickening or thinning in NFL and GCIPL in MCI and AD patients. Our primary findings controvert previous reports of thinner NFL in moderate-to-severe AD. The areas of thickening of GCIPL and NFL in the macula adjacent to areas of thinning, as revealed by a more complex statistical model, suggest that NFL and GCIPL may undergo dynamic changes during AD progression.