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Background: Breast cancer is the most commonly diagnosed and leading cause of cancer-related morbidity and mortality in females worldwide. Significant disparities exist in breast cancer incidence and mortalities between low- to middle- and high-income countries. The purpose of this study was to analyze the distribution of prognostic and predictive clinicopathological features of invasive breast cancer at a single institution in Jamaica across three age groups. Methods: Data from patients diagnosed with invasive breast cancer who underwent definitive surgery between August 2017 and September 2018 were identified. The patients were divided into three age groups ( 59 years) and the distribution of tumor size, grade, molecular subtype, nodal status and anatomic stage were determined and compared with the US population registry. Comparisons of the various characteristics were performed using the Fisher's exact test. Results: Ninety-nine definitive operations were performed and met the criteria for analysis. Average age at the time of diagnosis was 54 years compared to 62 years reported in the US databases. Thirty-six percent of the patients presented below age 50 years, which was twice the corresponding rate reported for Caucasian females (18%) in the USA. Fifty percent of patients in our registry had axillary lymph node metastases at presentation and they were younger than patients with negative axillary nodes (95% confidence interval (CI) -12.06 to -1.93, P = 0.007). Patients in the age group less than age 50 years were more likely to have advanced stage, high histological grade cancers compared to the older age blocks (95% CI 0.039 - 0.902, P = 0.033). Conclusion: Invasive breast cancer presents at an earlier age in Jamaican women and is associated with poor prognostic features such as high rates of axillary lymph node metastases, high histological grade, advanced stage, triple-negative subtypes and low luminal A subtypes. World J Oncol. 2021;12(4):93-103 doi: https://doi.org/10.14740/wjon1389

The energetic performance of aluminum(Al)-based nanothermite composites is hindered by the native alumina shell on the surface of Al nanoparticles. To maximize the energetic release and lower the reaction temperature between Al and metal oxide nanoparticles, a novel fluorine and oxygen co-functionalized graphene (FGO) is reported. The material was synthesized by gas–solid reaction between graphene oxide paper and XeF2 gas. The stability of FGO in atmospheric humidity, heating, and exfoliation by sonication in different solvents were obtained by FTIR and SEM-EDS. The FGO contained both unstable acyl fluoride groups and stable carbon-fluorine covalent/semi-ionic bonds in its structure. The FGO was introduced as a functional additive in an Al/Bi2O3 nanothermite composite, leading to a heat of reaction heat of 1123 J/g, 58% greater than that from loose Al/Bi2O3 powder. The reaction completed before reaching the melting temperature of Al, indicating a novel all-solid-state reaction between Al and Bi2O3. The decreased reaction temperature is attributed to fluorine etching of the native alumina shell surrounding the Al nanoparticle fuel.

Lead halide perovskites provide a test bed for exploring nonlinear optical properties. Although the underlying centrosymmetric crystal structure of 3D lead halide perovskites precludes the phenomenon of second harmonic generation, the third and higher-order harmonic generation are allowed. In this work, we probe the third harmonic generation (THG) from CsPbBr3 nanocrystals (NCs) and compare it to the THG from CsPbBr3 NCs with Ruddlesden-Popper planar faults (RP-CsPbBr3), formed via postsynthetic fusion-growth. The THG from CsPbBr3 NCs is negligible compared with that of RP-CsPbBr3 NCs within a wide range of femtosecond excitation wavelengths. We further compare the THG from a thin film of RP-CsPbBr3 with that of a single crystal of methylammonium lead bromide (MAPbBr3). The THG efficiency of RP-CsPbBr3 is found to be three times greater than that of MAPbBr3. An effective third-order susceptibility of the order of 10-18 m2 V-2 is obtained for a RP-CsPbBr3 film, opening up the prospect of inorganic halide perovskite NCs with planar defects for a range of nonlinear optical applications.

The ability to image single molecules (SM) has been the dream of scientists for centuries, and because of the substantial recent advances in microscopy, individual fluorescent molecules can now be observed on a regular basis. However, the development of such imaging systems was not without dilemmas, such as the detection and separation of individual fluorescence emissions. One method to solve this problem utilized surface plasmon resonance (SPR) to enhance the emission intensity of SMs. Although enhancing the SM emission intensity has yielded promising results, this method does not fully utilize the unique plasmonic properties that could vastly improve the SM imaging capabilities. Here, we use SPR excitation as well as surface plasmon-coupled emission from a high-definition digital versatile disc grating structure to image and identify different fluorophores using the angular emission of individual molecules. Our results have important implications for research in multiplexed SM spectroscopy and SM fluorescence imaging.

The emergence of multilayer metamaterials in the research field of enhancing spontaneous emission rates has recently received extensive attention. Previous research efforts mostly focus on periodic metal-dielectric multilayers in hyperbolic dispersion region; however, the influence of lattice order in subwavelength multilayers on spontaneous emission is rarely studied. Here, we observe the stronger Purcell enhancement of quantum dots coupled to the aperiodic metal-dielectric multilayer with Thue-Morse lattice order from elliptical to hyperbolic dispersion regions, compared to the periodic multilayer with the same metal filling ratio. This work demonstrates the potential of utilizing quasiperiodic metamaterial nanostructures to engineer the local density of states for various nanophotonic applications.

Author(s): Wood, Aaron; Barizuddin, Syed; Darr, Charles M; Mathai, Cherian J; Ball, Alexey; Minch, Kyle; Somoskovi, Akos; Hamasur, Beston; Connelly, John T; Weigl, Bernhard; Andama, Alfred; Cattamanchi, Adithya; Gangopadhyay, Keshab; Bok, Sangho; Gangopadhyay, Shubhra | Abstract: BACKGROUND:Timely diagnosis of tuberculosis disease is critical for positive patient outcomes, yet potentially millions go undiagnosed or unreported each year. Sputum is widely used as the testing input, but limited by its complexity, heterogeneity, and sourcing problems. Finding methods to interrogate noninvasive, non-sputum clinical specimens is indispensable to improving access to tuberculosis diagnosis and care. In this work, economical plasmonic gratings were used to analyze tuberculosis biomarker lipoarabinomannan (LAM) from clinical urine samples by single molecule fluorescence assay (FLISA) and compared with gold standard sputum GeneXpert MTB/ RIF, culture, and reference ELISA testing results. METHODS AND FINDINGS:In this study, twenty sputum and urine sample sets were selected retrospectively from a repository of HIV-negative patient samples collected before initiation of anti-tuberculosis therapy. GeneXpert MTB/RIF and culture testing of patient sputum confirmed the presence or absence of pulmonary tuberculosis while all patient urines were reference ELISA LAM-negative. Plasmonic gratings produced by low-cost soft lithography were bound with anti-LAM capture antibody, incubated with patient urine samples, and biotinylated detection antibody. Fluorescently labeled streptavidin revealed single molecule emission by epifluorescence microscope. Using a 1 fg/mL baseline for limit of detection, single molecule FLISA demonstrated good qualitative agreement with gold standard tests on 19 of 20 patients, including accurately predicting the gold-standard-negative patients, while one gold-standard-positive patient produced no observable LAM in urine. CONCLUSIONS:Single molecule FLISA by plasmonic grating demonstrated the ability to quantify tuberculosis LAM from complex urine samples of patients from a high endemic setting with negligible interference from the complex media itself. Moreover, agreement with patient diagnoses by gold standard testing suggests that single molecule FLISA could be used as a highly sensitive test to diagnose tuberculosis noninvasively.

Partially aggregated Rhodamine 6G (R6G) dye is used as a lights-on temperature sensor to analyze the spatiotemporal heating of aluminum nanoparticles (Al NPs) embedded within a tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride (THV) fluoropolymer matrix. The embedded Al NPs were photothermally heated using an IR laser, and the fluorescent intensity of the embedded dye was monitored in real time using an optical microscope. A plasmonic grating substrate enhanced the florescence intensity of the dye while increasing the optical resolution and heating rate of Al NPs. The fluorescence intensity was converted to temperature maps via controlled calibration. The experimental temperature profiles were used to determine the Al NP heat generation rate. Partially aggregated R6G dyes, combined with the optical benefits of a plasmonic grating, offered robust temperature sensing with sub-micron spatial resolution and temperature resolution on the order of 0.2 °C.

The direct reduction of graphene oxide (GO) by hydroiodic acid is an established method to produce iodine functionalized reduced GO (I-rGO). However, the stability of the iodine species within I-rGO upon heating and dispersing into different solvents, as required for many applications, has not been examined. Herein we examined the stability of I-rGO and utilized it to promote self-assembled nanoenergetic composites. I-rGO intercalated with polyiodide was found to be unstable at elevated temperature and when dispersed in organic solvents. The I-rGO exhibited excellent dispersion in dimethylformamide but resulted in a loss of iodine content as exfoliation released weakly-bound intercalated iodine species. The dispersed I-rGO was utilized as a scaffold to self-assemble I-rGO/Al and I-rGO/Al/Bi2O3 nanoenergetic composites. The I-rGO both prevented the phase separation of Al and Bi2O3 particles and provided a source for reactive iodine to etch the alumina shell surrounding Al fuel nanoparticles. Differential scanning calorimetry showed that the use of the I-rGO assembly template reduced the temperature of initiation and peak reaction and produced 70% greater energy release than randomly mixed Al/Bi2O3 nanoenergetic powder. In fact, 95% of the exothermal energy released by the reaction occurred while Al was in the solid state, suggesting that the reaction between free iodine and alumina was significant enough to greatly reduce the diffusion barrier between solid Al fuel and surrounding oxidizer. Further, the underlying conductive I-rGO scaffold reduces electrostatic discharge sensitivity of the nanoenergetic composite by almost four orders of magnitude.

Since the development of fluoroimmunoassays, researchers have sought a method of substantially enhancing fluorescence intensity to extend the limits of detection to new levels of sensitivity. Surface plasmon resonance (SPR) and metal enhanced fluorescence has long been a topic of research and has led to the development of prism- and grating-based SPR systems. However, with the wide coupling range and ease of exciting SPR on plasmonic gratings with a simple microscope objective, they have tremendous potential for revolutionizing the fields of plasmonics, fluorescence, and sensors. In an effort to better understand the influence of grating profile and metal film properties on the extraordinary fluorescence enhancement capabilities of plasmonic gratings, a novel microcontact printing process and different metal deposition techniques were used to fabricate silver gratings with varying grain diameters, roughnesses, heights, and duty cycles using thermal evaporation and RF sputtering. The resulting plasmonic gratings exhibited fluorescence enhancements up to 116× that of dye-coated glass slides using an epifluorescence microscope, much higher than more expensive prism-based SPR systems. This silver grating represents an extraordinary opportunity to quickly and easily enhance fluorescence and widen the detection limits of common fluorescence based assays with little to no equipment modification.

Plasmonic gratings with incorporated nanoprotrusions can replace traditional imaging substrates to extend the current detection limitations of fluoroimmunoassays and enable sub-diffraction limit image resolution.

We present an indium tin oxide/polymethylsilsesquioxane (ITO/PMSSQ) photonic crystal (PC) with grating structure. This topography exhibits multiple coupling resonances in specific regions of the solar spectrum, which can be controlled by tuning the angle and polarization of incident light as demonstrated through simulation and experimental results. The ITO/PMSSQ grating structures are prepared by simple soft lithography procedures using commercial HD-DVD and Blu-ray as template molds. The surface topography also includes geometrical singularities such as nanogaps and nanocones, which lead to further enhanced light trapping characteristics. Together, these singularity-embedded photonic crystal gratings result in concentrated electromagnetic fields at the aforementioned singularities, which could be especially helpful in separating the tightly bonded excitons in organic solar cells. Simulation shows an absorption enhancement over the full spectral range of ITO PCs-based solar cells with substantial increases closer to the band edge under s-polarized light.

Classical methods for enhancing the electromagnetic field from substrates for spectroscopic applications, such as surface-enhanced Raman spectroscopy (SERS), have involved the generation of hotspots through directed self-assembly of nanoparticles or by patterning nanoscale features using expensive nanolithography techniques. A novel large-area, cost-effective soft lithographic technique involving glancing angle deposition (GLAD) of silver on polymer gratings is reported here. This method produces hierarchical nanostructures with high enhancement factors capable of analyzing single-molecule SERS. The uniform ordered and patterned nanostructures provide extraordinary field enhancements that serve as excitatory hotspots and are herein interrogated by SERS. The high spatial homogeneity of the Raman signal and signal enhancement over a large area from a self-assembled monolayer (SAM) of 2-naphthalenethiol demonstrated the uniformity of the hotspots. The enhancement was shown to have a critical dependence on the underlying nanostructure via the surface energy landscape and GLAD angles for a fixed deposition thickness, as evidenced by atomic force microscopy and scanning electron microscopy surface analysis of the substrate. The nanostructured surface leads to an extremely concentrated electromagnetic field at sharp nanoscale peaks, here referred to as 'nano-protrusions', due to the coupling of surface plasmon resonance (SPR) with localized SPR. These nano-protrusions act as hotspots which provide Raman enhancement factors as high as 108 over a comparable SAM on silver. Comparison of our substrate with the commercial substrate Klarite™ shows higher signal enhancement and minimal signal variation with hotspot spatial distribution. By using the proper plasmon resonance angle corresponding to the laser source wavelength, further enhancement in signal intensity can be achieved. Single-molecule Raman spectra for rhodamine 6G are obtained from the best SERS substrate (a GLAD angle of 60°). The single-molecule spectrum is invariant over the substrate, due to the patterned ordered nanostructures (nano-protrusions).

We developed a novel plasmonic grating platform as a fluorescence-based temperature sensor for in-situ imaging of localized temperature and dynamic mapping of temperature in nanoscale due to photothermal heating of aluminum nanoparticles. Al/polymer nanoenergetics films with temperature sensitive dyes (Rhodamine 6G) were prepared and calibrated to obtain temperature-dependent dye fluorescence intensity. A tunable laser heating setup was developed for microscope imaging. We monitored the in-situ laser heating on Al/polymer/R6G systems by microscope and then constructed the spatial thermal mapping over time. Based on the fluorescence microscopic imaging, we can monitor Al nanoparticles movement and morphology changes for Al/polymer/Rhodamine 6G systems induced by laser heating. Al nanoparticles play an important role in laser heating due to the plasmonic, interband and intraband absorption characteristics of Al nanoparticles. Plasmonic grating platforms can not only significantly enhance the photothermal heating of Al compared with glass platforms, but also act as superlensing for sub-diffraction limited imaging of nanoparticles.

Surface reactions between heated aluminum nanoparticles (Al NPs) and thin α-MoO3 sheets are investigated. Localized photothermal heating on Al NP clusters is provided by a Raman spectrometer laser, while enhanced heating rates and imaging resolution are enabled by the use of a plasmonic grating substrate. Prominent linear reaction zones extending from Al NPs in the 〈001〉 crystal direction are observed on the surface of the host MoO3 sheets after heating. Raman spectroscopy and x-ray diffraction indicate that α-Al2O3 is generated within these extended reacted regions, while AFM and SEM indicate that the topology of the reaction regions are indistinguishable from the MoO3 host. We hypothesize that these Al2O3 zones are formed by surface diffusion and subsequent sub-surface adsorption of heated Al adatoms along the low-energy 〈001〉 MoO3 direction. Understanding and controlling these reaction mechanisms could lead to enhanced combustion of Al/MoO3 nanothermite systems.

Ultra-broadband strong absorption over 92% covering the infrared wavelength range of 1~6μm is demonstrated by using the tapered hyperbolic Au-SiO2 multilayer waveguides on glass substrates. Such broadband absorption is formed by the stop-light modes at various wavelengths located at different waveguide widths. A planar hyperbolic waveguide model is built to determine the stop-light modes by considering both forward and backward guided modes. The stop-light modes located inside the Au-SiO2 multilayer waveguide are simulated at the absorption peaks by reducing the Au loss. Tapered multilayer waveguides with varying top widths are further simulated, fabricated and measured, indicating the almost linear relation between the waveguide width and the stop-light wavelength. Moreover, the broadband absorption of tapered waveguide is proved to be angle-insensitive and polarization-independent, and the heat generation and temperature increase are also discussed.

Objectives: To estimate the usefulness of the Indian diabetes risk score for detecting undiagnosed diabetes in the rural area of Tamil Nadu. Materials and Methods: The present study was conducted in the field practice area of rural health centers (Chunampett and Annechikuppam, Tamil Nadu), covering a population of 35000 from February to March 2008 by using a predesigned and pretested protocol to find out the prevalence and the risk of diabetes mellitus in general population by using Indian diabetes risk score. Results: 1936 respondents comprising 1167 (60.27%) females and 769 (39.73%) males were studied. Majority 1203 (62.50%) were Hindus. 1220 (63.%) had studied up to higher secondary. 1200 (62%) belonged to lower and lower-middle socio-economic class. A large number of the subjects 948 (50%) were below 35 years of age. Most of the respondents 1411 (73%) indulged in mild to moderate physical activity. 1715 (87.91%) had no family history of diabetes mellitus. 750 (39.64%) individuals were in the overweight category (>25 BMI). Out of these overweight persons, 64% had high diabetic risk score. It is observed that chances of high diabetic score increase with the increase in BMI. Prevalence of diabetes in studied population was 5.99%; out of these, 56% known cases of diabetes mellitus had high (>60) IDRS. Co-relation between BMI and IDRS shows that, if BMI increases from less than 18.50 to more than 30, chances of high risk for developing diabetes mellitus also significantly increase. Conclusion: This study estimates the usefulness of simplified Indian diabetes risk score for identifying undiagnosed high risk diabetic subjects in India. This simplified diabetes risk score has categorized the risk factors based on their severity. Use of the IDRS can make mass screening for undiagnosed diabetes in India more cost effective.

We report the cost-effective fabrication of a plasmonic grating for improved light coupling in a fluorescence-based sensor platform by a simple micro-contact printing technique. The fluorescence of Rhodamine 6G (R6G) film on gratings was enhanced by up to 239-fold with respect to glass using a fluorescence microplate reader. The silver gratings are made suitable for use in biological buffers by a protective alumina layer. The platform has been optimized to detect Interferon-gamma (IFN δ ), a commonly used biomarker for M. tuberculosis infection and other autoimmune diseases, with an immunofluorescence assay. The platform demonstrates 500 fg/ml limit of detection (LOD) while commercial enzyme-linked immunosorbent assays (ELISA) report 2 pg/mL LOD. The extraordinary fluorescence enhancement was compared with simulation result to predict and support the experimental analysis. These results can be used to expand the platform for numerous fast, robust, sensitive biosensors.

The optical nonlocality in metal-dielectric multilayer metamaterials is characterized experimentally as a function of the angle of incidence with respect to the TE-polarized incident light. The physical mechanism of the difference between the nonlocal effective permittivity and the effective-medium-theory-based effective permittivity depending on the incident angle is theoretically revealed through the analysis of the band structure, the dispersion relation, and the iso-frequency contours according to the transfer-matrix method. Such effective permittivity difference is also retrieved in the metal-dielectric multilayers based on the measured transmission and reflection spectra.

The optical nonlocalities in metal-dielectric multilayer metamaterials are characterized as functions of incident angles for different polarizations. The measured epsilon-near-zero frequency shifts due to nonlocal effects agree with the theoretical analysis developed from transfer-matrix method.

This paper describes a tilted-target RF magnetron sputter deposition system to grow nanoparticles in a controlled way. With detailed characterization of ultra-high density (up to 1.1 × 10¹³ cm⁻²) and ultra-small size Pt nanoparticles (0.5-2 nm), it explains their growth and crystalline properties on amorphous Al₂O₃ thin films. It is shown that Pt nanoparticle size and number density can be precisely engineered by varying selected experimental parameters such as target angle, sputtering power and time of deposition to control the energy of the metal atoms in the deposition flux. Based on rate equation modelling of nanoparticle growth, three distinct growth regimes, namely nucleation dependent, coalescence dependent and agglomeration dependent regimes, were observed. The correlation between different nanoparticle growth regimes and the consequent crystal structure transformation, non-crystalline clusters → single crystalline nanoparticles → polycrystalline islands, is also discussed.

Epsilon-near-zero (ENZ) metamaterial slabs at visible frequencies based on metal-dielectric multilayers are experimentally realized. Transmission, reflection and absorption spectra are measured and used to determine the complex refractive indices and the effective permittivities of the ENZ slabs, which agree with the results obtained from both the numerical simulations and the optical nonlocalities analysis. Furthermore, light propagation in ENZ slabs and directional emission from ENZ prisms are also analyzed. The accurate determination of the ENZ wavelength for metal-dielectric multilayer metamaterial slabs is important for realizing many unique applications, such as phase front manipulation and enhancement of photonic density of states., Comment: 9 pages, 5 figures

We have developed and tested transparent microelectrode arrays capable of simultaneous amperometric measurement of oxidizable molecules and fluorescence imaging through the electrodes. Surface patterned microelectrodes were fabricated from three different conducting materials: Indium-tin-oxide (ITO), nitrogen-doped diamond-like carbon (DLC) deposited on top of ITO, or very thin (12 - 17 nm) gold films on glass substrates. Chromaffin cells loaded with lysotracker green or acridine orange dye were placed atop the electrodes and vesicle fluorescence imaged with total internal reflection fluorescence (TIRF) microscopy while catecholamine release from single vesicles was measured as amperometric spikes with the surface patterned electrodes. Electrodes fabricated from all three materials were capable of detecting amperometric signals with high resolution. Unexpectedly, amperometric spikes recorded with ITO electrodes had only about half the amplitude and about half as much charge as those detected with DLC or gold electrodes, indicating that the ITO electrodes are not as sensitive as gold or DLC electrodes for measurement of quantal catecholamine release. The lower sensitivity of ITO electrodes was confirmed by chronoamperometry measurements comparing the currents in the presence of different analytes with the different electrode materials.

Electrochemical microelectrodes are commonly used to detect spikes of amperometric current that correspond to exocytosis of oxidizable transmitter from individual vesicles, i.e., quantal exocytosis. We are developing transparent multi- electrochemical electrode arrays on microchips in order to automate measurement of quantal exocytosis. Here we report development of an improved device to target individual cells to each microelectrode in an array. Efficient targeting (~75%) is achieved using cell-sized micro-well traps fabricated in SU-8 photoresist together with patterning of poly (L-lysine) in register with electrodes to promote cell adhesion. The surface between electrodes is made resistant to cell adhesion using poly (ethylene glycol) in order to facilitate movement of cells to electrode “docking sites”. We demonstrate the activity of the electrodes using the test analyte ferricyanide and perform recordings of quantal exocytosis from bovine adrenal chromaffin cells on the device. Multiple cell recordings on a single device demonstrate the consistency of spike measurements and multiple recordings from the same electrodes demonstrate that the device can be cleaned and reused without degradation of performance. The new device will enable high-throughput studies of quantal exocytosis and may also find application in rapidly screening drugs or toxins for effects on exocytosis.

Electrochemical microelectrodes are commonly used to detect spikes of amperometric current that correspond to exocytosis of oxidizable transmitter from individual vesicles, i.e., quantal exocytosis. We are developing transparent multi- electrochemical electrode arrays on microchips in order to automate measurement of quantal exocytosis. Here we report the development of an improved device to target individual cells to each microelectrode in an array. Efficient targeting (∼75%) was achieved using cell-sized micro-well traps fabricated in SU-8 photoresist together with patterning of poly (L-lysine) in register with electrodes to promote cell adhesion. The surface between electrodes was made resistant to cell adhesion using poly (ethylene glycol) grafted to a poly (dopamine) adhesive in order to facilitate movement of cells to electrode microwells. We demonstrated the activity of the electrochemical microelectrodes using the test analyte ferricyanide and perform recordings of quantal exocytosis from bovine adrenal chromaffin cells on the devices. Dozens of cell recordings on a single device illustrated the consistency of recordings and multiple recordings from the same electrode demonstrated that the device could be cleaned and re-used without degradation of performance. The novel device will enable high-throughput studies of quantal exocytosis and may also have applications in rapidly screening drugs or toxins for effects on exocytosis. (Supported by NIH R01 NS048826.)

We are developing transparent multi- electrochemical electrode arrays on microchips in order to automate measurement of quantal exocytosis. Design goals are that one and only one cell be positioned directly over each electrode and working electrodes have μm-scale dimensions in order to resolve pA-level currents. Patterning of cell-adhesion molecules in register with electrodes using conventional photolithographic approaches is problematic because organic solvents can disable sensitive biomolecule films. We report the parylene “dry liftoff” approach pioneered by Ilic and Craighead (Biomed Microdev 2: 317, 2000) can be used to pattern single cell-electrode pairs on the chip. A 1 μm-thick parylene C film is deposited on the multi-electrode array and S1813 photoresist is spin coated onto the device and patterned. The unprotected parylene over the electrodes is then removed using Reactive Ion Etch. Poly-l-lysine (PLL) is then added to promote cell attachment. Chromaffin cells are loaded on the chip in standard culture media and left in an incubator overnight. Finally, the parylene film is peeled off to remove excess cells and PLL, leaving tightly adhered chromaffin cells at the desired locations. Importantly, we find that promoting cell attachment with PLL films does not passivate the electrochemical electrodes. Experiments are in process to explore an alternative approach whereby PLL is patterned using the dry liftoff approach but cells are added after peel off of the parylene. With this approach, cell attachment to inactive areas of the chip is blocked by using “cytophobic” materials such as Teflon AF. This alternative approach may allow efficient targeting of cells at lower cell densities as cells migrate from cytophobic areas to the electrode binding sites (Supported by NIH BRP grant RO1 NS048826).

In a survey for beta-thalassemia carrier status among students in the State of Punjab in India, a surprisingly large number were found to have an elevated red cell volume over 99 fl. The finding was predominantly but not exclusively in females. Similar student surveys from other states showed less macrocytosis. Follow-up tests in a group of affected students were carried out. Volunteers were asked to modify their diet then after six months they were provided with oral vitamin B12. The resulting changes are reported and the implications of the probable vitamin B12 and or folic acid deficiency are considered.

Single-electron transistors incorporating single ∼1 nm gold nanocluster (AuNCs) and pentacene as a complex charge transport system have been used to study the quantum Coulomb blockade and its single electron tunnelling behaviour at room temperature (RT) (300 K). Monodisperse ultra-small (0.86 ± 0.30 nm) AuNCs were deposited by the tilted-target sputtering technique into 12 nm nanogaps fabricated by high-resolution e-beam lithography. Tunnelling resistance was modulated to ∼10(9) Ω by addition of a pentacene layer, allowing clear observation of quantum staircases and Coulomb oscillations with on/off current modulation ratio of ∼100 in RT current-voltage measurements. The electron addition energy and average quantized energy level spacing were found to be 282 and 80.4 meV, respectively, which are significantly larger than the thermal energy at 300 K (25.9 meV).

We present an indium tin oxide/polymethylsilsesquioxane (ITO/PMSSQ) photonic crystal with grating structure. This topography exhibits multiple coupling resonances in specific regions of the solar spectrum, which can be controlled by tuning the angle and polarization of incident light. The ITO/PMSSQ grating structures are prepared via simple soft lithography procedures using HD-DVDs as templates. The surface topology also includes geometrical singularities such as nanogaps and nanocones, which lead to further enhanced light trapping characteristics as demonstrated by theoretical and experimental results. Together, these singularity-embedded photonic crystal gratings result in extremely concentrated electromagnetic fields at the aforementioned singularities, which could be especially helpful in separating the tightly bonded excitons in organic solar cells and, hence, improve the efficiency significantly.

The paper analyzes foreign investment and asset prices in a context of uncertainty over future government policy. The model endogenizes the process of learning by foreign investors facing a potentially opportunistic government, which chooses strategically the timing of a policy reversal in order to attract more capital. We characterize the evolution of confidence, investment, and asset prices over time, as well as perceived policy risk. Quite generally, perceived risk abates as current policy is maintained, leading to a gradual appreciation of asset prices and a gradual decrease in their conditional variance. The approach thus provides a measure of the evolution over time of perceived political risk from market prices. We next compute option prices under the process generated by the model's hazard rate of policy reversal plus an additional market risk component. We show that both the time series and the term structure of conditional volatility in general is downward sloping and its overall level falls steadily over time, although it may exhibit initially a hump shape in the case of very low initial reputation. Another testable implication is that in price series without a policy reversal, implied volatility from option prices will exceed actual volatility. Over time, and in the absence of a reversal, this wedge progressively disappears. This may be viewed as the volatility analogue of the 'peso premium' for assets subject to large, infrequent price drops.

A high rate of association between supernumerary nipples (SNN) and genitourinary abnormalities has been reported previously. We examined all patients attend-ing one particular unit, in the age group between 12 and 20 years for the presence of SNN and urinary tract abnormalities. We could find only a weak association between these two conditions.