A novel micro-reactor for hydrogen production from solid NaBH4 hydrolysis in a dual-cycle methodology

Hydrogen-based Fuel Cells (FCs) hold significant potential as energy conversion technologies. In a previous study, we presented a pump-based hydrogen generator (PHG) that utilizes a catalytic reaction between sodium borohydride (NaBH4) powder and water. The pump circulates the water solution through the powder chamber in a closed-loop reaction. The PHG demonstrated clear advantages over alternative hydrogen sources in terms of both safety and energy density. However, as operating time increases, the solution in the closed-loop PHG becomes saturated, causing the reaction rate to decline. This limitation can be overcome in cases where an external water source is available, such as marine vehicles, drones equipped with water recovery systems from their fuel cells, or systems located near pipelines. In such scenarios, introducing freshwater feeding and product emission offers intriguing possibilities for significantly enhancing the fuel's energy density and extending its effective operation time. Our current research introduces an innovative concept: a dual-cycle generator (DCG) that effectively overcomes the issue of solution saturation over time. It achieves this by combining solution circulation with freshwater feeding and product emission. Our study employed a DCG prototype to examine various operating modes and to demonstrate the effectiveness of this approach. The DCG achieved a calculated energy density for the fuel of 3868 Wh/kg, with 93% H2 extraction yield from the powder. Our findings reveal substantial improvements in terms of extended operation duration (81%), increased hydrogen flow rate (36%), enhanced energy density (33%), and improved H2 yield extraction from the powder (39%). This methodology holds promise for mobile applications or off-grid systems situated in proximity to a water source.

Dynamics Management of Intermediate Water Storage in an Air-Breathing Single-Cell Membrane Electrode Assembly

In air-breathing proton exchange membrane fuel cells (Air PEM FCs), a high rate of water evaporation from the cathode might influence the resistance of the membrane electrode assembly (MEA), which is highly dependent on the water content of the Nafion membrane. We propose a dead-end hydrogen anode as a means of intermediate storage of water/humidity for self-humidification of the membrane. Such an inflatable bag integrated with a single lightweight MEA FC has the potential in blimp applications for anode self-humidification. A dynamic numerical water balance model, validated by experimental measurements, is derived to predict the effect of MEA configuration, and the membrane's hydration state and water transfer rate at the anode on MEA resistance and performance. The experimental setup included humidity measurements, and polarization and electrochemical impedance spectroscopy tests to quantify the effect of membrane hydration on its resistance in a lightweight MEA (12 g) integrated with an inflatable dead-end hydrogen storage bag. Varying current densities (5, 10, and 15 mA/cm2) and cathode humidity levels (20, 50, and 80%) were examined and compared with the numerical results. The validated model predicts that the hydration state of the membrane and water transfer rate at the anode can be increased by using a thin membrane and thicker gas diffusion layer.

Chemical-Dealloying-Derived PtPdPb-Based Multimetallic Nanoparticles: Dimethyl Ether Electrocatalysis and Fuel Cell Application

In this work, we report a novel multimetallic nanoparticle catalyst composed of Pt, Pd, and Pb and its electrochemical activity toward dimethyl ether (DME) oxidation in liquid electrolyte and polymer electrolyte fuel cells. Chemical dealloying of the catalyst with the lowest platinum-group metal (PGM) content, Pt2PdPb2/C, was conducted using HNO3 to tune the catalyst activity. Comprehensive characterization of the chemical-dealloying-derived catalyst nanoparticles unambiguously showed that the acid treatment removed 50% Pb from the nanoparticles with an insignificant effect on the PGM metals and led to the formation of smaller-sized nanoparticles. Electrochemical studies showed that Pb dissolution led to structural changes in the original catalysts. Chemical-dealloying-derived catalyst nanoparticles made of multiple phases (Pt, Pt3Pb, PtPb) provided one of the highest PGM-normalized power densities of 118 mW mgPGM-1 in a single direct DME fuel cell operated at low anode catalyst loading (1 mgPGM cm-2) at 70 °C. A possible DME oxidation pathway for these multimetallic catalysts was proposed based on an online mass spectrometry study and the analysis of the reaction products.

Anode amendment with kaolin and activated carbon increases electricity generation in a microbial fuel cell

The bacterial anode is a key factor for microbial fuel cell (MFC) performance. This study examined the potential of kaolin (fine clay) to enhance bacteria and conductive particle attachment to the anode. The bio-electroactivity of MFCs based on a carbon-cloth anode modified by immobilization with kaolin, activated carbon, and Geobacter sulfurreducens (kaolin-AC), with only kaolin (kaolin), and a bare carbon-cloth (control) anodes were examined. When the MFCs were fed with wastewater, the MFCs based on the kaolin-AC, kaolin, and bare anodes produced a maximum voltage of 0.6 V, 0.4 V, and 0.25 V, respectively. The maximum power density obtained by the MFC based on the kaolin-AC anode was 1112 mW‧m^-2 at a current density of 3.33 A‧m^-2, 12% and 56% higher than the kaolin and the bare anodes, respectively. The highest Coulombic efficiency was obtained by the kaolin-AC anode (16%). The relative microbial diversity showed that Geobacter displayed the highest relative distribution of 64% in the biofilm of the kaolin-AC anode. This result proved the advantage of preserving the bacterial anode exoelectrogens using kaolin. To our knowledge, this is the first study evaluating kaolin as a natural adhesive for immobilizing exoelectrogenic bacteria to anode material in MFCs.

A trifunctional N-doped activated carbon-ceria-shell, derived from covalent porphyrin polymers for promoting Pt-activity in fuel cell's cathode performance

Developing an active, durable and cost-effective air cathode catalyst is critical for commercializing proton exchange membrane fuel cells (PEMFCs). CeO2 was reported as a scavenger of harmful peroxide by-products, yet...

Metal-Organic Polymer-Derived Interconnected Fe-Ni Alloy by Carbon Nanotubes as an Advanced Design of Urea Oxidation Catalysts

The electrochemical urea oxidation reaction (UOR) is considered as a promising renewable source for harvesting energy from waste. We report a new synthetic design approach to produce an iron-nickel alloy nanocatalyst from a metal-organic polymer (MOP) by a single-step carbonization process at 500 °C, thus forming a core-shell of iron-nickel-coated carbon (C@FeNi) nanostructures wired by embedded carbon nanotubes (CNTs) (CNT/C@FeNi). Powder X-ray diffraction confirmed the formation of metallic FeNi₃ alloy nanoparticles (∼20 to 28 nm). Our experimental results showed that MOP containing CNTs acquired an interconnected hierarchical topology, which prevented the collapse of its microstructure during pyrolysis. Hence, CNT/C@FeNi shows higher porosity (10 times) than C@FeNi. The electrochemical UOR in alkaline electrolytes on these catalysts was studied using cyclic voltammetry (CV). The result showed a higher anodic current (3.5 mA cm^-2) for CNT/C@FeNi than for C@FeNi (1.1 mA cm^-2) at 1.5 V/RHE. CNT/C@FeNi displayed good stability in chronoamperometry experiments and a lower Tafel slope (33 mV dec^-1) than C@FeNi (41.1 mV dec^-1). In this study, CNT/C@FeNi exhibits higher exchange current density (3.2 μA cm^-2) than does C@FeNi (2 μA cm^-2). The reaction rate orders of CNT/C@FeNi and C@FeNi at a kinetically controlled potential of 1.4 V/RHE were 0.5 and 0.9, respectively, higher than the 0.26 of β-Ni(OH)₂, Ni/Ni(OH)₂ electrodes. The electrochemical impedance result showed a lower charge-transfer resistance for CNT/C@FeNi (61 Ω·cm^-2) than for C@FeNi (162 Ω·cm^-2), due to faster oxidation kinetics associated with the CNT linkage. Moreover, CNT/C@FeNi exhibited a lower Tafel slope and resistance and higher heterogeneity (25.2 × 10^-5 cm s^-1), as well as relatively high faradic efficiency (68.4%) compared to C@FeNi (56%). Thus, the carbon-coated FeNi₃ core connected by CNT facilitates lower charge-transfer resistance and reduces the UOR overpotential.

Surface modifications of carbon nanodots reveal the chemical source of their bright fluorescence

Fluorescent carbon nanodots (CNDs) have drawn increasing attention in recent years. These cost-effective and eco-friendly nanomaterials with bright fluorescence have been investigated as promising materials for electrooptic and bioimaging applications. However, the chemical source stimulating their strong fluorescence has not been completely identified to date. Depending on the chemical composition, two absorption peaks are observed in the visible range. In this study, we applied selected chemical modifications to CNDs in order to elucidate the correlation between the chemical structure and optical behavior of CNDs. Varying the amount of acetic acid in the synthesis process resulted in different effects on the absorbance and fluorescence photo-spectra. Specifically, at a low concentration (10%), the fluorescence is dramatically red shifted from 340 to 405 nm. Comprehensive characterization of the chemical modification by FTIR and XPS allows identification of the role of acetic acid in the reaction mechanism leading to the modified photoactivity. The functional group responsible for the 405 nm peak was identified as HPPT. We describe a chemical mechanism involving acetic acid that leads to an increased concentration of HPPT groups on the surface of the CNDs. Applying two additional independent chemical and consequently optical modifications namely solution pH and annealing on the nanodots further supports our proposed explanation. Understanding the molecular origin of CND fluorescence may promote the design and control of effective CND fluorescence in optical applications.

NH3-Plasma pre-treated carbon supported active iron–nitrogen catalyst for oxygen reduction in acid and alkaline electrolytes

A new strategy in the synthesis of M–N–C type catalysts was introduced through the combination of plasma pre-treatment followed by conventional pyrolysis, which demonstrated higher ORR activity and stability than pristine M–N–C catalysts.

P3607Temporal trends in the characteristics, management, and clinical outcomes of patients with prior myocardial infarction who are admitted with an acute coronary syndrome

Background

Patients with prior myocardial infarction (MI) are at increased risk for recurrent cardiovascular events. Advances in treatment in the last decade has improved prognosis of patients with acute coronary syndrome (ACS), yet it is not known whether similar trends exist in patients with prior MI who are admitted with an ACS, a particularly high-risk group.

Methods

Patients admitted with ACS who were enrolled in the ACS Israeli Surveys (ACSIS). Patients were stratified by early (2000–2008) and late (2010–2016) time-periods and by prior MI status. Clinical outcomes included 30-d MACE (death, MI, stroke, unstable angina, stent thrombosis, urgent revascularization) and 1-year mortality.

Results

A total of 15,211 ACS patients were included, of whom 4627 (30%) had a prior MI. These patients were older (67y vs. 63y), more commonly male, had more prior comorbidities, and a higher proportion had a GRACE score>140 (38.4% vs 12.2%). Patients with prior MI received more prior medications such as aspirin, statins, antihypertensives and hypoglycemics. During time, utilization of guideline-recommended therapies such as P2Y12 inhibitors, statins, and PCI had significantly improved in patients with prior MI. However, compared with patients without prior MI, they were still treated less commonly by PCI (61% vs. 74%). Overall, patients with prior MI had a higher 30-d MACE (13.7% vs 17.2%, p<0.001) and 1-year mortality (8.2% vs. 13.1%, p<0.001). In patients with prior MI, during time, 30d MACE nearly halved (22.7% to 11.8%) and 1-year mortality also decreased (15.5% to 10.7%). Upon adjustment, prior MI was independently associated with 1-year mortality (HR 1.13, 95% CI 1.01–1.26, p=0.04) and the late time-period was associated with reduced 1-year mortality (HR 0.75, 95% CI 0.65–0.84, p<0.001).

Conclusion

Patients with prior MI have a worse prognosis after ACS despite being treated with prior medications and improvement in guideline-based therapies. Although still undertreated, their clinical outcome has significantly improved throughout the years.

Simultaneous Mapping of Oxygen Reduction Activity and Hydrogen Peroxide Generation on Electrocatalytic Surfaces

Electrochemical scanning probe microscopies have become valuable experimental tools, owing to their capability of capturing topographic features in addition to mapping the electrochemical activity of nanoscale oxygen reduction catalysts. However, most scanning probe techniques lack the ability to correlate topographic features with the electrochemical oxygen reduction and peroxide formation in real time. In this report, we show that it is indeed possible to construct high-resolution catalytic current maps at an electrified solid-liquid interface by placing a specially made Au-coated SiO₂ Pt atomic force microscopy and scanning electrochemical microscopy (AFM-SECM) dual electrode tip approximately 4-8 nm above the reaction center. The catalytic current measured every 16 nm and high collection efficiency (≈90 %) of the reverse current of peroxide byproducts was also demonstrated with the help of the dual electrode tip. Simultaneous oxygen reduction and intermediate peroxide oxidation current mapping was demonstrated using this Au-coated SiO₂ Pt probe on two model surfaces, namely highly oriented pyrolytic graphite and Pt nanoparticles (NPs) supported on a glassy carbon surface.

Electrochemical Ammonia Generation Directly from Nitrogen and Air Using an Iron-Oxide/Titania-Based Catalyst at Ambient Conditions

Ammonia was produced electrochemically from nitrogen/air in aqueous alkaline electrolytes by using a Fe₂O₃/TiO₂ composite catalyst under room temperature and atmospheric pressure. At an applied potential of 0.023 V versus reversible hydrogen electrode, the rate of ammonia formation was 1.25 × 10^-8 mmol mg^-1 s^-1 at an overpotential of just 34 mV. This rate increased to 2.7 × 10^-7 mmol mg^-1 s^-1 at -0.577 V. The chronoamperometric experiments on Fe₂O₃/TiO₂/C clearly confirmed that Fe₂O₃ along with TiO₂ shows superior nitrogen reduction reaction activity compared to Fe₂O₃ alone. Experimental parameters such as temperature and applied potential have a significant influence on the rate of ammonia formation. The activation energy of nitrogen reduction on the employed catalyst was found to be 25.8 kJ mol^-1. Real-time direct electrochemical mass spectrometry analysis was used to monitor the composition of the evolved gases at different electrode potentials.

Nanoscale mapping of catalytic hotspots on Fe, N-modified HOPG by scanning electrochemical microscopy-atomic force microscopy

The scanning electrochemical microscopy-atomic force microscopy (SECM-AFM) technique is used to map catalytic currents post Fe and N surface modification of graphitic carbon with an ultra-high resolution of 50 nm. The oxidation current of the partial reduction product, hydrogen peroxide, was also mapped in the same location in the graphitic carbon. The current mapping and ex situ spectroscopic evidence revealed that Fe-coordinated nitrogen sites formed both in the edge and basal planes of highly ordered pyrolytic graphite (HOPG) constitute the primary oxygen reduction catalytic sites in acid solutions of this important yet insufficiently understood class of catalysts.

Exceptionally Active and Stable Spinel Nickel Manganese Oxide Electrocatalysts for Urea Oxidation Reaction

Spinel nickel manganese oxides, widely used materials in the lithium ion battery high voltage cathode, were studied in urea oxidation catalysis. NiMn2O4, Ni1.5Mn1.5O4, and MnNi2O4 were synthesized by a simple template-free hydrothermal route followed by a thermal treatment in air at 800 °C. Rietveld analysis performed on nonstoichiometric nickel manganese oxide-Ni1.5Mn1.5O4 revealed the presence of three mixed phases: two spinel phases with different lattice parameters and NiO unlike the other two spinels NiMn2O4 and MnNi2O4. The electroactivity of nickel manganese oxide materials toward the oxidation of urea in alkaline solution is evaluated using cyclic voltammetric measurements. Ni1.5Mn1.5O4 exhibits excellent redox characteristics and lower charge transfer resistances in comparison with other compositions of nickel manganese oxides and nickel oxide prepared under similar conditions.The Ni1.5Mn1.5O4modified electrode oxidizes urea at 0.29 V versus Ag/AgCl with a corresponding current density of 6.9 mA cm(-2). At a low catalyst loading of 50 μg cm(-2), the urea oxidation current density of Ni1.5Mn1.5O4 in alkaline solution is 7 times higher than that of nickel oxide and 4 times higher than that of NiMn2O4 and MnNi2O4, respectively.

Superoleophobic Surfaces Obtained via Hierarchical Metallic Meshes

Hierarchical metallic surfaces demonstrating pronounced water and oil repellence are reported. The surfaces were manufactured with stainless-steel microporous meshes, which were etched with perfluorononanoic acid. As a result, a hierarchical relief was created, characterized by roughness at micro- and sub-microscales. Pronounced superoleophobicity was registered with regard to canola, castor, sesame, flax, crude (petroleum), and engine oils. Relatively high sliding angles were recorded for 5 μL turpentine, olive, and silicone oil droplets. The stability of the Cassie-like air trapping wetting state, established with water/ethanol solutions, is reported. The omniphobicity of the surfaces is due to the interplay of their hierarchical relief and surface fluorination.

Vertically Aligned Nitrogen-Doped Carbon Nanotube Carpet Electrodes: Highly Sensitive Interfaces for the Analysis of Serum from Patients with Inflammatory Bowel Disease

The number of patients suffering from inflammatory bowel disease (IBD) is increasing worldwide. The development of noninvasive tests that are rapid, sensitive, specific, and simple would allow preventing patient discomfort, delay in diagnosis, and the follow-up of the status of the disease. Herein, we show the interest of vertically aligned nitrogen-doped carbon nanotube (VA-NCNT) electrodes for the required sensitive electrochemical detection of lysozyme in serum, a protein that is up-regulated in IBD. To achieve selective lysozyme detection, biotinylated lysozyme aptamers were covalently immobilized onto the VA-NCNTs. Detection of lysozyme in serum was achieved by measuring the decrease in the peak current of the Fe(CN)6(3-/4-) redox couple by differential pulse voltammetry upon addition of the analyte. We achieved a detection limit as low as 100 fM with a linear range up to 7 pM, in line with the required demands for the determination of lysozyme level in patients suffering from IBD. We attained the sensitive detection of biomarkers in clinical samples of healthy patients and individuals suffering from IBD and compared the results to a classical turbidimetric assay. The results clearly indicate that the newly developed sensor allows for a reliable and efficient analysis of lysozyme in serum.

Current production in a microbial fuel cell using a pure culture of Cupriavidus basilensis growing in acetate or phenol as a carbon source

A microbial fuel cell (MFC) was operated with a pure culture of Cupriavidus basilensis bacterial cells growing in the anode compartment in a defined medium containing acetate or phenol. Operating this mediator-less MFC under a constant external resistor of 1 kΩ with acetate or phenol led to current generation of 902 and 310 mA m⁻² respectively. In the MFC which was operated using acetate or phenol, the current density measured from the plankton bacterial cells with a fresh electrode was 125 and 109 mA m⁻², respectively, whereas the current obtained with biofilm-covered electrodes in sterile medium was 541 and 228 mA m⁻² respectively. After 72 h in the MFC, 86% of the initial phenol concentration was removed, while only 64% was removed after the same time in the control MFC which was held at an open circuit potential (OCP). Furthermore, SEM and confocal microscopy analyses demonstrated a developed biofilm with a live C. basilensis population. In conclusion, in this study we demonstrated, for the first time, use of C. basilensis facultative aerobe bacterial cells in a MFC using acetate or phenol as the sole carbon source which led to electricity generation.

Effect of external voltage on Pseudomonas putida F1 in a bio electrochemical cell using toluene as sole carbon and energy source

A bio electrochemical cell (BEC) was constructed as a typical two-chamber microbial fuel cell (MFC), except that it was operated under external voltage instead of constant resistance as in an MFC. The anode chamber contained a pure culture of Pseudomonas putida F1 grown in a minimal medium containing toluene as the sole carbon and energy source. Operating the BEC under external voltages of 75, 125, 175, 250 and 500 mV (versus an Ag/AgCl reference electrode) led to increased bacterial cell growth to an OD(600) of 0.62-0.75, while the control BEC, which was not connected to external voltage, reached an OD(600) of only 0.3. Examination of the current generated under external voltages of 75, 125, 175, 250 and 500 mV showed that the maximal currents were 11, 23, 28, 54 and 94 mA m(-2), respectively. Cyclic voltammetry experiments demonstrated an anodic peak at 270 mV, which may imply oxidation of a vital molecule. The average residual toluene concentration after 147 h in the BEC operated under external voltage was 22 %, whereas in the control BEC it was 81 %. Proteome analysis of bacterial cells grown in the BEC (125 mV) revealed two groups of proteins, which are ascribed to charge transfer in the bacterial cells and from the cell to the electrode. In conclusion, operating the BEC at 75-500 mV enabled growth of a pure culture of P. putida F1 and toluene degradation even in an oxygen-limited environment.

Recent Studies of Interfacial Phenomena which Determine the Electrochemical Behavior of Lithium and Lithiated Carbon Anodes with the Emphasis on In Situ Techniques

This paper reports on some new results on the application of surface sensitive techniques for the study of the correlation of surface chemistry, morphology and electrochemical behavior of lithium and lithiated graphite as anodes for rechargeable batteries. Surface sensitive FTIR spectroscopy, atomic force microscopy (AFM), electrochemical quartz crystal microbalance (EQCM) were applied to Li and Li-graphite electrodes in a variety of electrolyte solutions of interest, in conjunction with standard electrochemical techniques. The similarity in the surface chemistry developed on Li and lithiated graphite in solutions is demonstrated and discussed. We demonstrate the strong impact of the surface chemistry on the morphology of Li deposition-dissolution processes, and the use of in situ EQCM measurements for the choice of optimal electrolyte solutions for rechargeable batteries with Li metal anodes.

The reversible giant change in the contact angle on the polysulfone and polyethersulfone films exposed to UV irradiation

Water contact angles on polysulfone and polyethersulfone films exposed to UV irradiation have been found to decrease dramatically. We relate this phenomenon to the formation and release of disulfonic acid from the irradiated films, a well-known surfactant. The phenomenon appears to be reversible, namely, cleansed surfaces retained their initial contact angle. The revealed phenomenon may provide a means of controlling the spreading of liquids on polysulfone and polyethersulfone films and seems promising for use in microfluidics applications.

Prototype systems for rechargeable magnesium batteries

The thermodynamic properties of magnesium make it a natural choice for use as an anode material in rechargeable batteries, because it may provide a considerably higher energy density than the commonly used lead-acid and nickel-cadmium systems. Moreover, in contrast to lead and cadmium, magnesium is inexpensive, environmentally friendly and safe to handle. But the development of Mg batteries has been hindered by two problems. First, owing to the chemical activity of Mg, only solutions that neither donate nor accept protons are suitable as electrolytes; but most of these solutions allow the growth of passivating surface films, which inhibit any electrochemical reaction. Second, the choice of cathode materials has been limited by the difficulty of intercalating Mg ions in many hosts. Following previous studies of the electrochemistry of Mg electrodes in various non-aqueous solutions, and of a variety of intercalation electrodes, we have now developed rechargeable Mg battery systems that show promise for applications. The systems comprise electrolyte solutions based on Mg organohaloaluminate salts, and Mg(x)Mo3S4 cathodes, into which Mg ions can be intercalated reversibly, and with relatively fast kinetics. We expect that further improvements in the energy density will make these batteries a viable alternative to existing systems.

There is binding of collagen IV to beta 1 integrin during early skin basement membrane assembly

This study is concerned with the mechanism of basement membrane assembly in an in vitro 3-dimensional skin-culture system. Dermal fibroblasts alone can synthesize collagen IV, perlecan, and nidogen, but cannot assemble them into a basement membrane. When keratinocytes are added to the culture, however, linear assembly of collagen IV, perlecan, and nidogen is noted at the epidermo-dermal interface. Northern blots and in situ hybridization showed that perlecan and nidogen mRNAs derive exclusively from fibroblasts, while the alpha 2 (IV) collagen chain is expressed by both keratinocytes and fibroblasts, although the major source is in the mesenchyma (80%). Prior to the development of the lamina densa, collagen IV colocalizes with beta 1 integrins, most likely alpha 1 beta 1 and alpha 2 beta 1, which are known receptors for this collagen. Blocking experiments with the AIIB2 mAb (anti-beta 1 integrin subunit) and by peptide inhibition with the CB3(IV) collagen fragment disrupted the assembly of collagen IV. This study suggests that the initiation of basement-membrane formation involves binding of collagen IV molecules to keratinocyte cell-matrix integrins. These complexes act as nucleation sites for further polymerization of collagen IV molecules mostly derived from fibroblasts, by a process of self-assembly.

Skin fibroblasts are the only source of nidogen during early basal lamina formation in vitro

The purpose of this study was to determine whether nidogen, the linkage protein of the basal lamina, is of epidermal or dermal origin. The development of the basal lamina was studied in an in vitro skin model. Preputial fibroblasts seeded onto a nylon mesh attached, proliferated, and developed a rich extracellular matrix (dermal model). Preputial keratinocytes were added to the dermal model to form a keratinocyte dermal model that ultrastructurally resembled in many respects human skin. Ultrastructural analysis revealed early stages of dermal development, including an incomplete basal lamina, aggregates of dermal filamentous material connecting to the lamina densa, bundles of 10-nm microfibrils, formation of premature hemidesmosomes, anchoring filaments, and anchoring fibrils. The cell origin of nidogen was determined in the dermal model and in the epidermal and dermal components of the keratinocyte dermal model. Specific antibodies and a cDNA probe for nidogen were used for immunofluorescence microscopy, Western and Northern blots, and for in situ hybridization studies. Our data show that fibroblasts are the only source of nidogen during early basal lamina formation. Although fibroblasts can synthesize nidogen and deposit it in the dermal matrix, no basal lamina will form unless they are recombined with keratinocytes. This suggests that the epidermis plays a major regulatory role in the production and assembly of nidogen into the basal lamina.

Severe periodic febrile myalgia in infancy due to carnitine palmitoyltransferase deficiency

A 7 1/2-yr-old girl suffered, since early infancy, severe recurrent myalgia during periodic attacks of fever, vomiting and pharyngitis. Neither myoglobinuria nor exercise-induced muscle pain was present. She was found to have carnitine palmitoyltransferase deficiency (CPTD) in leukocytes, fibroblasts and muscle. This case exemplifies the importance of looking for an associated metabolic etiology of recurrent febrile myalgia even in the absence of myoglobinuria.

Phototoxicity involving the ocular lens: in vivo and in vitro studies

Our laboratory has demonstrated the cataractogenic potential of UV radiation and several photosensitizing drugs in laboratory animals and in humans. We have utilized lens fluorescence measurements (which we have demonstrated to be a reliable marker for pre-cataractous and early cataractous changes), NMR pulse relaxation techniques, and our recently developed magnetic resonance imaging method to measure lens T2 values in the normal and UV exposed Degus lens (in vivo and in vitro) to detect pre-cataractous changes in the lens. These approaches will permit us to employ two parameters (increased non-tryptophan fluorescence and a decrease in T2 values) to monitor for such changes months before the lens opacities become manifest by conventional slit lamp examinations.

In vivo non-invasive studies on the human lens

Progress in biophysical technology now permits us to monitor aging and precataractous changes in the human ocular lens in vivo as well as in vitro. We are employing two noninvasive techniques to measure changes in lens fluorescence and in one lens water compartment (T2) utilizing Scheimpflug lens fluorescence densitography and magnetic resonance imaging. These studies demonstrate age-related changes in the normal lens as reflected by enhanced fluorescence and longer T2 values. Precataractous changes can also be detected with this approach.

Lanthony desaturated panel D15 test in sickle cell patients

The Lanthony D15 desaturated test was used to compare color vision in sickle cell patients with 20/20 visual acuity and peripheral lesions of sickle cell retinopathy with normal controls. Sickle cell patients had significantly higher Lanthony error scores and significantly more blue-yellow and mixed color vision defects than controls. Among patients with sickle cell anemia (SS), Lanthony and Farnsworth Munsell 100 Hue test scores were significantly correlated, and both tests showed good agreement in identifying the presence or absence of a color defect. These results suggest that the Lanthony D15 test may be a useful clinical tool to identify blue-yellow color defects, especially because of its brevity and simplicity of administration.