Blood Stored In EDTA Tubes Provides Accurate Peanut Basophil Activation Test Results For 48 hours.

BACKGROUND: The peanut basophil activation test (BAT) has demonstrated excellent diagnostic accuracy with heparinized blood, but its clinical utility is limited by the short stability of samples stored in this anticoagulant. OBJECTIVE: Using EDTA anticoagulated blood, these investigations determined if Peanut BAT sample stability can be extended to 2 days, the minimum stability requirement for diagnostic tests currently offered through American reference laboratories. METHODS: Peanut non-allergic control (NAC), peanut IgE sensitized (PS), and peanut allergic (PA) children aged 6 months through 17 years were recruited from members of Kaiser Permanente Southern California. EDTA anti-coagulated blood samples were collected from participants, shipped to a centralized laboratory, and stored at 4oC for peanut BAT testing 1 and 2 days later. RESULTS: Peanut BAT results for 23 unblinded participants were used to establish sample rejection and interpretation criteria that were subsequently validated in a prospective double-blind study involving 112 additional children (39-NAC, 36-PS, 37-PA). Of 105 blinded blood samples tested on each study day, 88 (84%) day-1 and 90 (86%) day-2 peanut BAT results were considered interpretable, with diagnostic accuracies of 95.5% and 94.4%, respectively. Moreover, all interpretable PA results were considered positive (100% sensitivity). CONCLUSION: Using EDTA anti-coagulated blood samples collected remotely, 1 and 2 days before testing, study results highlight the favorable diagnostic performance characteristics of the peanut BAT and provide further evidence that the test could be readily operationalized for clinical use by interested commercial reference laboratories.

PI and PIII Ions Supported by BZIMPY Ligands.

We report a class of compounds in which both PIII -X and PI forms featuring the same ligand are stable and readily cycled with each other. A series of PIII -X (X=Cl, Br, I) dicationic triflate salts supported by benzyl- and allyl-substituted 2,6-bis(benzimidazole-2-yl)pyridine (BZIMPY) ligands is synthesized. Surprisingly, treatment of these with R3 PO (R=Et, Oct) results in reduction to BZIMPY-ligated PI monocationic triflate salts while treatment with Ph3 P reduces but also substitutes the compound to produce Ph3 P-BZIMPY-ligated PI dicationic triflate salts. The mechanisms of these surprising reductions are probed experimentally and rationalized computationally. The PIII -X dications are shown to be strong Lewis acids both experimentally and computationally and to readily behave as X+ , PX, and P+ transfer agents in reactions with phosphines, NHCs, and diazabutadienes. The PI mono- and dications are shown to be very effective P+ transfer agents when treated similarly. Oxidation from a monocationic PI salt back to the dicationic PIII -X (X=Cl, Br) salt was achieved by treatment with N-chlorosuccinimide (NCS) or N-bromosuccinimide (NBS). Full characterization is reported using multinuclear nuclear magnetic resonance spectroscopy, elemental analysis, and single-crystal X-ray diffractometry where suitable crystals were isolated.

Synthesis, Characterization, and Single-Crystal X-ray Structures of Refractory Metal Compounds as Precursors for the Single-Source Chemical Vapor Deposition of Metal Nitrides.

The chemical vapor deposition of refractory metal nitrides requires volatile precursors and has previously been achieved by using metal complexes containing a variety of imide ligands. Recently, the 1,4-di-tert-butyl-1,3-diazabutadiene (DAD) adduct of bis(tert-butylimide)dichloridemolybdenum(VI) was shown to be an excellent precursor for the single-source CVD of Mo2N thin films. Leveraging the success of this work, we prepared chromium and tungsten compounds with the same framework. Additionally, the framework has been modified slightly to allow the isolation of mono(tert-butylimide)trichloride complexes of vanadium, niobium, tantalum, and molybdenum(V) to extend the search for new vapor-phase precursors. These compounds were all fully characterized using the standard methods of multinuclear magnetic resonance spectroscopy, combustion analysis, and single-crystal X-ray diffraction. Their thermal properties were determined by using thermogravimetric analysis and differential scanning colorimetry to assess their utility as vapor-phase precursors. Finally, preliminary deposition studies were carried out to investigate their potential as single-source CVD precursors.

Disturbance of intermolecular forces: eutectics as a new tool for the preparation of vapor-phase deposition precursors.

The volatile bis(tert-butylimido)dichloromolybdenum(VI) compounds, (tBuN)2MoCl2·dad (dad = 1,4-di-tert-butyl-1,3-diazabutadiene) (1) and [(tBuN)2MoCl(µ-Cl)·(tBuNH2)]2 (2), form a eutectic, with a two to one composition (χ2 = 0.33). A decrease of 40 °C in the melting temperature has been observed between the eutectic mixture and the pure compounds. We have isolated a co-crystal of (tBuN)2MoCl2·dme (dme = 1,2-dimethoxyethane) (3) and 2, also in a two to one ratio, which serves as a structural model for such mixtures. The lower melting point of carefully chosen eutectic mixtures can offer more consistent precursor delivery in deposition processes.

Thermal Stability and Decomposition Pathways in Volatile Molybdenum(VI) Bis-imides.

The vapor deposition of many molybdenum-containing films relies on the delivery of volatile compounds with the general bis(tert-butylimido)molybdenum(VI) framework, both in atomic layer deposition and chemical vapor deposition. We have prepared a series of (tBuN)2MoCl2 adducts using neutral N,N'-chelates and investigated their volatility, thermal stability, and decomposition pathways. Volatility has been determined by thermogravimetric analysis, with the 1,4-di-tert-butyl-1,3-diazabutadiene adduct (5) found to be the most volatile (1 Torr of vapor pressure at 135 °C). Thermal stability was measured primarily using differential scanning calorimetry, and the 1,10-phenanthroline adduct (4) was found to be the most stable with an onset of decomposition of 303 °C. We have also investigated molybdenum compounds with other alkyl-substituted imido groups: these compounds all follow a similar decomposition pathway, γ-H activation, with varying reaction barriers. The tert-pentyl, 1-adamantyl, and a cyclic imido (from 2,5-dimethylhexane-2,5-diamine) were systematically studied to probe the kinetics of this pathway. All of these compounds have been fully characterized, including via single-crystal X-ray diffraction, and a total of 19 new structures are reported.

Origin of Decomposition in a Family of Molybdenum Precursor Compounds.

The bis(tert-butylimido)-molybdenum(VI) framework has been used successfully in the design of vapor-phase precursors for molybdenum-containing thin films, so understanding its thermal behavior is important for such applications. Here, we report the thermal decomposition mechanism for a series of volatile bis(alkylimido)-dichloromolybdenum(VI) adducts with neutral N,N'-chelating ligands, to probe the stability and decomposition pathways for these molecules. The alkyl groups explored were tert-butyl, tert-pentyl, 1-adamantyl, and a cyclic imido (from 2,5-dimethylhexane-2,5-diamine). We also report the synthesis of the new tert-octyl imido adducts, (tOctN)2MoCl2·L (L = N,N,N',N'-tetramethylethylenediamine or 2,2'-bipyridine), which have been fully characterized by spectroscopic techniques as well as single-crystal X-ray diffraction and thermal analysis. We found that the decomposition of all compounds follows the same general pathway, proceeding first by the dissociation of the chelating ligand to give the coordinatively unsaturated species (RN)2MoCl2. Subsequent dimerization results in either an imido bridged adduct, [(RN)Mo(µ-NR)Cl2]2, or a chloride bridged adduct, [(RN)2Mo(µ-Cl)Cl]2, depending on the size of the R group. The dimeric species then likely undergoes an intramolecular γ-hydrogen transfer to yield a nitrido-amido adduct, (RHN)MoNCl2, and an alkene. Ultimately, the resulting molybdenum species appears to decompose into free tert-alkylamine and Mo2N or Mo2C. The thermolysis reactions have been monitored using 1H NMR spectroscopy, and the volatile decomposition products were analyzed using gas chromatography-mass spectrometry. A key intermediate has also been detected using electron ionization high-resolution mass spectrometry. Finally, a detailed computational investigation supports the mechanism outlined above and helps explain the relative stabilities of different N,N'-chelated bis(alkylimido)-dichloromolybdenum(VI) adducts.

Heavy Metals Make a Chain: A Catenated Bismuth Compound.

Catenation is common for the light main-group elements whereas it is rare for the heavy elements. Herein, we report the first example of a neutral molecule containing a Bi4 chain. It is prepared in a one-step reaction between bismuth trichloride and bis(diisopropylphosphino)amine in methanol suspension. The same reaction carried out in dichloromethane gives quite different products. All products have been characterized spectroscopically and using single-crystal X-ray analysis.

Eye movements of vertebrates and their relation to eye form and function.

The types of eye movements shown by all vertebrates originated in the earliest fishes. These consisted of compensatory movements, both vestibular and visual, to prevent image motion, and saccades to relocate gaze. All vertebrates fixate food items with their heads to enable ingestion, but from teleosts onwards some species also use eye movements to target particular objects, especially food. Eye movement use is related to the resolution distribution in the retina, with eyes that contain foveas, or areas of high ganglion cell density, being more likely to make targeting eye movements, not seen in animals with more uniform retinas. Birds, in particular, tend mainly to use head movements when shifting gaze. Many birds also make translatory head saccades (head bobbing) when walking. It is common for animals to use both eyes when locating food items ahead, but the use of binocular disparity for distance judgment is rare, and has only been demonstrated in toads, owls, cats and primates. Smooth tracking with eyes alone is probably confined to primates. The extent of synchrony and directional symmetry in the movements of the two eyes varies greatly, from complete independence in the sandlance and chameleon, to perfect coordination in primates.

Eye and head movements shape gaze shifts in Indian peafowl.

Animals selectively direct their visual attention toward relevant aspects of their environments. They can shift their attention using a combination of eye, head and body movements. While we have a growing understanding of eye and head movements in mammals, we know little about these processes in birds. We therefore measured the eye and head movements of freely behaving Indian peafowl (Pavo cristatus) using a telemetric eye-tracker. Both eye and head movements contributed to gaze changes in peafowl. When gaze shifts were smaller, eye movements played a larger role than when gaze shifts were larger. The duration and velocity of eye and head movements were positively related to the size of the eye and head movements, respectively. In addition, the coordination of eye and head movements in peafowl differed from that in mammals; peafowl exhibited a near-absence of the vestibulo-ocular reflex, which may partly result from the peafowl's ability to move their heads as quickly as their eyes.

Rapid, Reversible, Solid-Gas and Solution-Phase Insertion of CO2 into In-P Bonds.

The P,P-chelated heteroleptic complex bis[bis(diisopropylphosphino)amido]indium chloride [(i-Pr2P)2N]2InCl was prepared in high yield by treating InCl3 with 2 equiv of (i-Pr2P)2NLi in Et2O/tetrahydrofuran solution. Samples of [(i-Pr2P)2N]2InCl in a pentane slurry, a CH2Cl2 solution, or in the solid state were exposed to CO2, resulting in the insertion of CO2 into two of the four M-P bonds to produce [O2CP(i-Pr2)NP(i-Pr2)]2InCl in each case. Compounds were characterized by multinuclear NMR and IR spectroscopy, as well as single-crystal X-ray diffraction. ReactIR solution studies show that the reaction is complete in less than 1 min at room temperature in solution and in less than 2 h in the solid-gas reaction. The CO2 complex is stable up to at least 60 °C under vacuum, but the starting material is regenerated with concomitant loss of carbon dioxide upon heating above 75 °C. The compound [(i-Pr2P)2N]2InCl also reacts with CS2 to give a complicated mixture of products, one of which was identified as the CS2 cleavage product [S═P(i-Pr2)NP(i-Pr2)]2InCl]2(µ-Cl)[µ-(i-Pr2P)2N)].

Delayed clinical and ex vivo response to mammalian meat in patients with IgE to galactose-alpha-1,3-galactose.

BACKGROUND: In 2009, we reported a novel form of delayed anaphylaxis to red meat related to serum IgE antibodies to the oligosaccharide galactose-alpha-1,3-galactose (alpha-gal). Although patients were remarkably consistent in their description of a 3- to 6-hour delay between eating mammalian meat and the appearance of symptoms, this delay has not been demonstrated under observed studies. OBJECTIVES: We sought to formally document the time course of clinical symptoms after the ingestion of mammalian meat in subjects with IgE to alpha-gal and to monitor ex vivo for the appearance of markers of an allergic reaction. METHODS: Open food challenges were performed with mammalian meat in 12 subjects with a history of severe urticarial reactions 3 to 6 hours after eating beef, pork, or lamb, as well as in 13 control subjects. Blood samples were taken hourly during each challenge. RESULTS: Ten of 12 subjects with IgE to alpha-gal had clinical evidence of a reaction during the food challenge (vs none of the control subjects, P < .001). The reactions occurred 3 to 7 hours after the initial ingestion of mammalian meat and ranged from urticaria to anaphylaxis. Tryptase levels were positive in 3 challenges. Basophil activation, as measured by increased expression of CD63, correlated with the appearance of clinical symptoms. CONCLUSION: The results presented provide clear evidence of an IgE-mediated food allergy that occurs several hours after ingestion of the inciting allergen. Moreover, here we report that in vivo basophil activation during a food challenge occurs in the same time frame as clinical symptoms and likely reflects the appearance of the antigen in the bloodstream.

Comment on "crystallographic snapshot of an arrested intermediate in the biomimetic activation of CO2 ".

Out of focus: A recent Communication published in this journal describes the synthesis of [nBu4 N]HCO3 . The authors performed a single-crystal X-ray study that revealed a putative species described as an incipient hydroxide ion engaging in a long, and presumably weak, interaction with CO2 . Our recent exploration of the coordination chemistry of CO2 with small ions leads us to believe that such an exceptional bonding situation is unlikely. Instead, we argue that the crystal structure is that of [nBu4 N]O2 CCH3 and therefore not representative of the bulk powder from the synthesis.

An Improved Synthesis of PN-adamantanoid Cages P4 (NR)6 and a Mechanistic Study of their Fourfold Oxidation.

Phosphorus-nitrogen (PN) adamantanoid cages are valuable precursors for materials chemistry, but their syntheses are based on harsh methods that sometimes require access to restricted reagents. We report a new and scalable synthesis of PN adamantanoid compounds by chlorosilane elimination between bis-silylated amines and phosphorus trichloride. We further study the mechanism of the recently-reported four-fold oxidation of such cages with Me3 SiN3 to yield tetravalent tetrahedral connectors for materials chemistry. Reaction monitoring and kinetic modelling revealed the key rate-limiting step, but attempts to accelerate this using Lewis acid additives were unsuccessful. Nevertheless, a new four-fold oxidized PN-adamantanoid cage has been prepared and structurally characterized.

The evolution of lenses.

Structures which bend light and so form images are present in all the major phyla. Lenses with a graded refractive index, and hence reduced spherical aberration, evolved in the vertebrates, arthropods, annelid worms, and several times in the molluscs. Even cubozoan jellyfish have lens eyes. In some vertebrate eyes, multiple focal lengths allow some correction for chromatic aberration. In land vertebrates the cornea took over the main ray-bending task, leaving accommodation as the main function of the lens. The spiders are the only other group to make use of a single cornea as the optical system in their main eyes, and some of these - the salticids - have evolved a remarkable system based on image scanning. Similar scanning arrangements are found in some crustaceans, sea-snails and insect larvae.

A pathergic response to fractional CO2.

Pathergy is a nonspecific response to stimuli seen in a multitude of disease states. We present what we feel is a unique variant of this phenomenon, a case of multiple keratoacanthomas developing following treatment with Fractional CO2. This state of acute tumor emergence, which is similar to an isomorphic response, is believed to be related to changes in both the inflammatory and immune response. It is imperative that one keeps this process in their differential when evaluating a patient that has not only a potential predisposing disease, but also a history of traumatic exposure.

Geostatistical Mapping of Salinity Conditioned on Borehole Logs, Montebello Oil Field, California.

We present a geostatistics-based stochastic salinity estimation framework for the Montebello Oil Field that capitalizes on available total dissolved solids (TDS) data from groundwater samples as well as electrical resistivity (ER) data from borehole logging. Data from TDS samples (n = 4924) was coded into an indicator framework based on falling below four selected thresholds (500, 1000, 3000, and 10,000 mg/L). Collocated TDS-ER data from the surrounding groundwater basin were then employed to produce a kernel density estimator to establish conditional probabilities for ER data (n = 8 boreholes) falling below the selected TDS thresholds within the Montebello Oil Field area. Directional variograms were estimated from these indicator coded data, and 500 TDS realizations from conditional indicator simulation were generated for the subsurface region above the Montebello Oil Field reservoir. Simulations were summarized as 3D maps of median TDS, most likely salinity class, and probability for exceeding each of the specified TDS thresholds. Results suggested TDS was below 500 mg/L in most of the study area, with a trend toward higher values (500 to 1000 mg/L) to the southwest; consistent with the average regional groundwater flow direction. Discrete localized zones of TDS greater than 1000 mg/L were observed, with one of these zones in the greater than 10,000 mg/L range; however, these areas were not prevalent. The probabilistic approach used here is adaptable and is readily modified to include additional data and types and can be employed in time-lapse salinity modeling through Bayesian updating.

Biological optics: circularly polarised crustaceans.

A novel visual capability, the detection of circularly polarised light, has been demonstrated in a mantis shrimp, a colourful crustacean from tropical reefs.

Eye guidance in natural vision: reinterpreting salience.

Models of gaze allocation in complex scenes are derived mainly from studies of static picture viewing. The dominant framework to emerge has been image salience, where properties of the stimulus play a crucial role in guiding the eyes. However, salience-based schemes are poor at accounting for many aspects of picture viewing and can fail dramatically in the context of natural task performance. These failures have led to the development of new models of gaze allocation in scene viewing that address a number of these issues. However, models based on the picture-viewing paradigm are unlikely to generalize to a broader range of experimental contexts, because the stimulus context is limited, and the dynamic, task-driven nature of vision is not represented. We argue that there is a need to move away from this class of model and find the principles that govern gaze allocation in a broader range of settings. We outline the major limitations of salience-based selection schemes and highlight what we have learned from studies of gaze allocation in natural vision. Clear principles of selection are found across many instances of natural vision and these are not the principles that might be expected from picture-viewing studies. We discuss the emerging theoretical framework for gaze allocation on the basis of reward maximization and uncertainty reduction.

Vision, eye movements, and natural behavior.

Historically, the principal function of vision has been to provide the information needed to support action. Visually mediated actions rely on three systems: the gaze system responsible for locating and fixating task-relevant objects, the motor system of the limbs to carry out the task, and the visual system to supply information to the other two. All three systems are under the control of a fourth system, the schema system, which specifies the current task and plans the overall sequence of actions. These four systems have separate but interconnected cortical representations. The way these systems interact in time and space is discussed here in relation to two studies of the gaze changes and manipulations made during two ordinary food preparation tasks. The main conclusions are that complex action sequences consist of a succession of individual object-related actions, each of which typically involve a turn toward the object (if needed), followed by fixation and finally manipulation monitored by vision. Gaze often moves on to the next object just before manipulation is complete. Task-irrelevant objects are hardly ever fixated, implying that the control of fixation comes principally from top-down instructions from the schema system, not bottom-up salience. Single fixations have identifiable functions (locating, directing, guiding, and checking) related to the action to be taken. Several variants of the basic object-related action scheme are discussed, including single-action events in ball sports involving only one anticipatory gaze shift, continuous production loops in text and music reading, and storage-action alternation in copying tasks such as portrait sketching.