Blood lead and cadmium levels are negatively associated with bone mineral density in young female adults.

Background: The organ toxicities of lead and cadmium have been extensively studied; however, studies of their toxic effects on bone remain limited, especially in young adults. The objective of this study was to examine the associations of blood lead levels (BLL) and blood cadmium levels (BCL) with bone mineral density (BMD) among young adults.

Methods: We performed a cross-sectional study using the National Health and Nutrition Examination Survey 2011-2018 database.

Association between plasma total homocysteine level within normal range and bone mineral density in adults.

Background: Growing evidence indicates that homocysteine is a noteworthy marker for general health status. However, research regarding plasma total homocysteine (tHcy) levels and bone mineral density (BMD) is sparse and controversial. Hence, we aimed to investigate the association between plasma tHcy level within normal range and lumbar BMD in adults.

Association Between Pulmonary Vessel-Related Structures and Cryptogenic Fibrosing Alveolitis Using Derived Computed Tomography Among Chinese Patients.

BACKGROUND The aim of this study was to assess the association between pulmonary vessel-related structures and cryptogenic fibrosing alveolitis (CFA) in a drug trial in a Chinese population using derived computed tomography (dCT) to evaluate functional reduction and survival. MATERIAL AND METHODS Discovery and validation cohorts were chosen separately by fulfilment of drug trial entry criteria, and we enrolled 269 and 292 consecutive patients, respectively. CFA patients who had undergone imaging based on volumetric non-contrast CT at our hospital were subjected to pulmonary vessel-related structure (PVS) measures and dCT to forecast mortality and reduction in reduced forced vital capacity of CFA.

Discovery of novel pyruvate dehydrogenase kinases inhibitors by screening of an in-house small molecule library for anti-lung cancer therapeutics.

Pyruvate dehydrogenase kinases (PDKs) are widely over-expressed in various human solid cancers, making them attractive therapeutic targets for cancer treatment. Herein, we report the identification of structurally novel PDKs inhibitors by screening of an in-house small molecule library. Biochemical assay indicated that the identified compounds 1-4 inhibited PDK1 activity with EC values of 0.

Rational design of a neutral pH functional and stable organic photocathode.

In this work we lay out design guidelines for catalytically more efficient organic photocathodes achieving stable hydrogen production in neutral pH. We propose an organic photocathode architecture employing a NiO hole selective layer, a PCDTBT:PCBM bulk heterojunction, a compact TiO2 electron selective contact and a RuO2 nanoparticle catalyst. The role of each layer is discussed in terms of durability and function.

Frequency and reactivity of antigen-specific T cells were concurrently measured through the combination of artificial antigen-presenting cell, MACS and ELISPOT.

Conventional peptide-major histocompatibility complex (pMHC) multimer staining, intracellular cytokine staining, and enzyme-linked immunospot (ELISPOT) assay cannot concurrently determine the frequency and reactivity of antigen-specific T cells (AST) in a single assay. In this report, pMHC multimer, magnetic-activated cell sorting (MACS), and ELISPOT techniques have been integrated into a micro well by coupling pMHC multimers onto cell-sized magnetic beads to characterize AST cell populations in a 96-well microplate which pre-coated with cytokine-capture antibodies. This method, termed AAPC-microplate, allows the enumeration and local cytokine production of AST cells in a single assay without using flow cytometry or fluorescence intensity scanning, thus will be widely applicable.

Evidence for ion migration in hybrid perovskite solar cells with minimal hysteresis.

Ion migration has been proposed as a possible cause of photovoltaic current-voltage hysteresis in hybrid perovskite solar cells. A major objection to this hypothesis is that hysteresis can be reduced by changing the interfacial contact materials; however, this is unlikely to significantly influence the behaviour of mobile ionic charge within the perovskite phase. Here, we show that the primary effects of ion migration can be observed regardless of whether the contacts were changed to give devices with or without significant hysteresis.

How mobile are dye adsorbates and acetonitrile molecules on the surface of TiO nanoparticles? A quasi-elastic neutron scattering study.

Motions of molecules adsorbed to surfaces may control the rate of charge transport within monolayers in systems such as dye sensitized solar cells. We used quasi-elastic neutron scattering (QENS) to evaluate the possible dynamics of two small dye moieties, isonicotinic acid (INA) and bis-isonicotinic acid (BINA), attached to TiO nanoparticles via carboxylate groups. The scattering data indicate that moieties are immobile and do not rotate around the anchoring groups on timescales between around 10 ps and a few ns (corresponding to the instrumental range).

A Combination Strategy for Construction of Peptide-β2m-H-2K Single Chain with Overlap Extension PCR and One-Step Cloning.

The time-consuming and high-cost preparation of soluble peptide-major histocompatibility complexes (pMHC) currently limits their wide uses in monitoring antigen-specific T cells. The single-chain trimer (SCT) of peptide-β2m-MHC class I heavy chain was developed as an alternative strategy, but its gene fusion is hindered in many cases owing to the incompatibility between the multiple restriction enzymes and the restriction endonuclease sites of plasmid vectors. In this study, overlap extension PCR and one-step cloning were adopted to overcome this restriction.

Photocurrents from photosystem II in a metal oxide hybrid system: Electron transfer pathways.

We have investigated the nature of the photocurrent generated by Photosystem II (PSII), the water oxidizing enzyme, isolated from Thermosynechococcus elongatus, when immobilized on nanostructured titanium dioxide on an indium tin oxide electrode (TiO2/ITO). We investigated the properties of the photocurrent from PSII when immobilized as a monolayer versus multilayers, in the presence and absence of an inhibitor that binds to the site of the exchangeable quinone (QB) and in the presence and absence of exogenous mobile electron carriers (mediators). The findings indicate that electron transfer occurs from the first quinone (QA) directly to the electrode surface but that the electron transfer through the nanostructured metal oxide is the rate-limiting step.

The dynamics of methylammonium ions in hybrid organic-inorganic perovskite solar cells.

Methylammonium lead iodide perovskite can make high-efficiency solar cells, which also show an unexplained photocurrent hysteresis dependent on the device-poling history. Here we report quasielastic neutron scattering measurements showing that dipolar CH3NH3(+) ions reorientate between the faces, corners or edges of the pseudo-cubic lattice cages in CH3NH3PbI3 crystals with a room temperature residence time of ∼14 ps. Free rotation, π-flips and ionic diffusion are ruled out within a 1-200-ps time window.

Optoelectronic Studies of Methylammonium Lead Iodide Perovskite Solar Cells with Mesoporous TiO₂: Separation of Electronic and Chemical Charge Storage, Understanding Two Recombination Lifetimes, and the Evolution of Band Offsets during J-V Hysteresis.

Methylammonium lead iodide (MAPI) cells of the design FTO/sTiO2/mpTiO2/MAPI/Spiro-OMeTAD/Au, where FTO is fluorine-doped tin oxide, sTiO2 indicates solid-TiO2, and mpTiO2 is mesoporous TiO2, are studied using transient photovoltage (TPV), differential capacitance, charge extraction, current interrupt, and chronophotoamperometry. We show that in mpTiO2/MAPI cells there are two kinds of extractable charge stored under operation: a capacitive electronic charge (∼0.2 μC/cm(2)) and another, larger charge (40 μC/cm(2)), possibly related to mobile ions.

A functionalised nickel cyclam catalyst for CO₂ reduction: electrocatalysis, semiconductor surface immobilisation and light-driven electron transfer.

The immobilisation of electrocatalysts for CO2 reduction onto light harvesting semiconductors is proposed to be an important step towards developing more efficient CO2 reduction photoelectrodes. Here, we report a low cost nickel cyclam complex covalently anchored to a metal oxide surface. Using transient spectroscopy we validate the role of surface immobilisation on enhancing the rate of photoelectron transfer.

Performance and stability of lead perovskite/TiO2, polymer/PCBM, and dye sensitized solar cells at light intensities up to 70 suns.

Three organic or hybrid photovoltaic technologies are compared with respect to performance and stability under the harsh regime of concentrated light. Although all three technologies show surprisingly high (and linear) photocurrents, and better than expected stability, no golden apples are awarded.

Rediscovering a key interface in dye-sensitized solar cells: guanidinium and iodine competition for binding sites at the dye/electrolyte surface.

We propose a new mechanism by which the common electrolyte additive guanidinium thiocyanate (GdmSCN) improves efficiency in dye-sensitized solar cells (DSSCs). We demonstrate that binding of Gdm(+) to TiO2 is weak and does not passivate recombination sites on the TiO2 surface as has been previously claimed. Instead, we show that Gdm(+) binds strongly to the N719 and D131 dyes and probably to many similar compounds.

Interpretation of optoelectronic transient and charge extraction measurements in dye-sensitized solar cells.

Tools that assess the limitations of dye sensitized solar cells (DSSCs) made with new materials are critical for progress. Measuring the transient electrical signals (voltage or current) after optically perturbing a DSSC is an approach which can give information about electron concentration, transport and recombination. Here we describe the theory and practice of this class of optoelectronic measurements, illustrated with numerous examples.

Measured binding coefficients for iodine and ruthenium dyes; implications for recombination in dye sensitised solar cells.

We have measured the binding coefficients of iodine to three dyes used in Dye Sensitised Solar Cells (DSSCs). Binding coefficients are quantified via the effect of iodine binding on the UV-vis spectrum of the dye. From iodine titration curves of dye sensitised TiO(2) films we find that the binding coefficients of iodine to the dyes C101, N719 and AR24 (vide infra) are in the range of 2000-4000 M(-1).

Non-emissive colour filters for fluorescence detection.

We describe a simple technique for fabricating non-emissive colour filters based on the sensitisation of a highly porous nanostructured metal-oxide film with a monolayer of dye molecules. Ultrafast electron transfer at the oxide/dye interface induces efficient quenching of photogenerated excitons in the dye, reducing the photoluminescence quantum yield by many orders of magnitude. The resultant filters exhibit much less autofluorescence than conventional colour filters (where the chromophore is dispersed in a glass or polymer host), and are a viable low cost alternative to interference filters for microfluidic devices and other applications requiring non-emissive filtering.

Factors controlling charge recombination under dark and light conditions in dye sensitised solar cells.

A simple and powerful approach for assessing the recombination losses in dye sensitised solar cells (DSSCs) across the current voltage curve (j-V) as a function of TiO(2) electron concentration (n) is demonstrated. The total flux of electrons recombining with iodine species in the electrolyte and oxidised dye molecules can be thought of as a recombination current density, defined as j(rec) = j(inj)-j where j(inj) is the current of electrons injected from optically excited dye states and j is the current density collected at cell voltage (V). The electron concentration at any given operating conditions is determined by charge extraction.

Spectroelectrochemical studies of hole percolation on functionalised nanocrystalline TiO2 films: a comparison of two different ruthenium complexes.

We report the application of spectroelectrochemical techniques to compare the hole percolation dynamics of molecular networks of two ruthenium bipyridyl complexes adsorbed onto mesoporous, nanocrystalline TiO(2) films. The percolation dynamics of the ruthenium complex cis-di(thiocyanato)(2,2'-bipyridyl-4,4'-dicarboxylic acid)-(2,2'-bipyridyl-4,4'-tridecyl) ruthenium(II), N621, is compared with those observed for an analogous dye with an additional tri-phenyl amine (TPA) donor moiety, cis-di(thiocyanato)(2,2'-bipyridyl-4,4'-dicarboxylic acid)-(2,2'-bipyridyl-4,4'-bis(vinyltriphenylamine)) ruthenium(II), HW456. The in situ oxidation of these ruthenium complexes adsorbed to the TiO(2) films is monitored by cyclic voltammetry and voltabsorptometry, whilst the dynamics of hole (cation) percolation between adsorbed ruthenium complexes is monitored by potentiometric spectroelectrochemistry and chronoabsorptometry.

Re-evaluation of recombination losses in dye-sensitized cells: the failure of dynamic relaxation methods to correctly predict diffusion length in nanoporous photoelectrodes.

Photocurrents generated by thick, strongly absorbing, dye-sensitized cells were reduced when the electrolyte iodine concentration was increased. Electron diffusion lengths measured using common transient techniques (L(n)) were at least two times higher than diffusion lengths measured at steady state (L(IPCE)). Charge collection efficiency calculated using L(n) seriously overpredicted photocurrent, while L(IPCE) correctly predicted photocurrent.

Opportunities for mesoporous nanocrystalline SnO2 electrodes in kinetic and catalytic analyses of redox proteins.

PFV (protein film voltammetry) allows kinetic analysis of redox and coupled-chemical events. However, the voltammograms report on the electron transfer through a flow of electrical current such that simultaneous spectroscopy is required for chemical insights into the species involved. Mesoporous nanocrystalline SnO(2) electrodes provide opportunities for such 'spectroelectrochemical' analyses through their high surface area and optical transparency at visible wavelengths.