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Background Human milk feeding is associated with decreased risk of necrotizing enterocolitis (NEC). Purpose To determine whether a quality improvement project in New Jersey neonatal intensive care units (NICUs) to promote human milk (HM) feedings would be associated with a decrease in NEC. Methods Fourteen New Jersey NICUs engaged in efforts to reduce infection and promote HM feeding in very low birth-weight (VLBW) infants. Donor human milk (DHM) availability and NEC rates were assessed. Results From 2009 to 2016, NICUs with DHM increased from 0 to 7. VLBW infants discharged on any HM increased from 35% in 2007 before the formation of the New Jersey NICU Collaborative to more than 55% in 2016. Time to first oropharyngeal colostrum decreased from 37 to 30 hours from 2014 to 2016. HM at first feeding increased from 71% in 2013 to 82% in 2016. There was an increase in the percentage of feeds that were HM over the first 7 days of feeding. Analyses of data from 9400 VLBW infants born between 2009 and 2016 showed that the incidence of NEC when DHM was not available was 5.1% (367/7182) whereas the incidence when DHM was available (64/2218) was significantly lower (2.9%; P Implications for practice These findings show advantages of feeding HM and effectiveness of forming an NICU collaborative for improving care for preterm infants. Implications for research New research projects should measure the quantity of HM consumed daily during the entire NICU stay and assess the timing and amount of HM consumption in relationship to incidence of NEC and infection in neonates.

Ground-based VLF transmitters located around the world generate signals that leak through the bottom side of the ionosphere in the form of whistler mode waves. Wave and particle measurements on satellites have observed that these man-made VLF waves can be strong enough to scatter trapped energetic electrons into low pitch angle orbits, causing loss by absorption in the lower atmosphere. This precipitation loss process is greatly enhanced by intentional amplification of the whistler waves in the ionosphere using a newly discovered process called Rocket Exhaust Driven Amplification (REDA). Satellite measurements of REDA have shown between 30 and 50 dB intensification of VLF waves in space using a 60-second burn of the 150 g/s thruster on the Cygnus satellite that services the International Space Station (ISS) [Bernhardt et al. 2021; Bernhardt 2021]. This controlled amplification process is adequate to deplete the energetic particle population in the radiation belts in a few minutes rather than the multi-day period it would take naturally. Numerical simulations of the pitch angle diffusion for radiation belt particles use the UCLA quasi-linear Fokker Planck model (QLFP) to assess the impact of REDA on radiation belt remediation (RBR) of newly injected energetic electrons [Bernhardt et al., 2022]. The simulated precipitation fluxes of energetic electrons are applied to models of D-region electron density and bremsstrahlung x-rays for predictions of the modified environment that can be observed with satellite and ground-based sensors. References:Bernhardt, P.A., et al., Strong Amplification of ELF/VLF Signals in Space Using Neutral Gas Injections from a Satellite Rocket Engine (2021), Radio Science, 56(2), e2020RS007207, https://doi.org/10.1029/ 2020RS007207.Bernhardt, P.A., The Whistler Traveling Wave Parametric Amplifier (WTWPA) Driven by an Ion Ring-Beam Distribution from a Neutral Gas Injection in Space Plasmas (2021), IEEE Transactions on Plasma Science. 49, 6, 1983-1996, DOI: 10.1109/TPS.2021.3079130.Bernhardt, P.A., et al., Active Precipitation of Radiation Belt Electrons using Rocket Exhaust Driven Amplification (REDA) of Man-Made Whistlers, Submitted to the Journal of Geophysical Research, 2022.

In December 2012, a multidisciplinary task force was implemented to address the elevated number of central line associated boodstream infections (CLABSIs) at Newark Beth Israel Medical Center from January 2012 to December 2012. Sixty-eight CLABSIs were documented within the adult inpatient population, resulting in a rate of 14.7 CLABSIs/1,000 central line days in the adult inpatient population. This was well above the national average of 1.87 infections per 1,000 central line days. Most of these infections were noted to be within the critical care units where the rate was at 2.86 CLABSIs/1,000 central line days. However, in 2013, the annual rate was decreased to 0.709 CLABSIs/1000 line days (P<0.001) with similar trends observed across the critical care units. Analysis of CLASBI data indicates that the implementation of a multidisciplinary task force dedicated to appropriate central line insertion, maintenance, and the removal of unnecessary central venous catheters can have an impact on reducing rates of CLASBIs throughout the adult inpatient population, including those within critical care units.

Ultrafast transient absorption measurements reveal that the rate constant for photoinduced electron transfer (PET) from colloidal CdS quantum dots (QDs) to alkylcarboxylate-functionalized viologens is independent of the number of methylene groups in the alkyl chain (n). The rate constant for PET is (1.2 ± 0.3) × 1010 s–1 for n = 1, 2, and 3, and for n = 0 (methylviologen). The insensitivity of the electron transfer rate constant to the length of the functional groups on the viologen suggests that a “through-space” pathway, where the electron bypasses the alkylcarboxylate and tunnels instead through only the orbitals of the QD and of the bipyridinium core, is the dominant PET pathway.

This review outlines the set of technical approaches to answering three major questions about the surface chemistry of colloidal semiconductor quantum dots (QDs): (i) What is the chemical structure of the ligands on the surface of the QD? (ii) How many of each type of ligand are on the surface of the QD? (iii) What is the intermolecular structure (geometry) of the ligands on the surface of the QD? Each section addresses the accessability of the relevant techniques—which include 1D and 2D NMR, vibrational and electronic absorption and transient absorption spectroscopies, and various elemental analyses—and their sensitivity and applicability to the specified observable of interest.

This Perspective discusses recent work on mechanisms by which organic ligands affect the electronic structure and exciton dynamics of colloidal quantum dots (QDs). Much of the work described here uses some combination of steady-state absorption, transient absorption, steady-state photoluminescence, and transient photoluminescence spectroscopies to characterize QD–ligand complexes. Ligands affect the ground-state electronic structure of QDs via mixing of the frontier orbitals at the QD–ligand interface and influence the dynamics of excitonic decay by mediating charge trapping or by participating in charge transfer. This Perspective highlights strategies to address the various forms of structural and chemical heterogeneity of QD ensembles in identifying the mechanisms of these ligand-mediated processes. Finally, four-wave mixing techniques are discussed as promising methods for direct measurement of ligand-mediated nonradiative dissipation of the QD exciton.

A study of the adsorption equilibrium of solution-phase CdS quantum dots (QDs) and acid-derivatized viologen ligands (N-[1-heptyl],N'-[3-carboxypropyl]-4,4'-bipyridinium dihexafluorophosphate, V(2+)) reveals that the structure of the surfaces of the QDs depends on their concentration. This adsorption equilibrium is monitored through quenching of the photoluminescence of the QDs by V(2+) upon photoinduced electron transfer. When modeled with a simple Langmuir isotherm, the equilibrium constant for QD-V(2+) adsorption, K(a), increases from 6.7 × 10(5) to 8.6 × 10(6) M(-1) upon decreasing the absolute concentration of the QDs from 1.4 × 10(-6) to 5.1 × 10(-8) M. The apparent increase in K(a) upon dilution results from an increase in the mean number of available adsorption sites per QD from 1.1 (for [QD] = 1.4 × 10(-6) M) to 37 (for [QD] = 5.1 × 10(-8) M) through desorption of native ligands from the surfaces of the QDs and through disaggregation of soluble QD clusters. A new model based on the Langmuir isotherm that treats both the number of adsorbed ligands per QD and the number of available binding sites per QD as binomially distributed quantities is described. This model yields a concentration-independent value for K(a) of 8.7 × 10(5) M(-1) for the QD-V(2+) system and provides a convenient means for quantitative analysis of QD-ligand adsorption in the presence of competing surface processes.

The ratio of Cd to Se (Cd/Se) within colloidal CdSe quantum dots (QDs) synthesized with 90% trioctylphosphine oxide (TOPO) as the coordinating solvent increases from 1.2:1 for QDs with radius R ≥ 3.3 nm to 6.5:1 for R = 1.9 nm, as measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The highest value of Cd/Se reported previously for CdSe QDs was 1.8:1. The dependence of Cd/Se on R fits a geometric model that describes the QDs as CdSe cores with Cd/Se = 1:1 encapsulated by a shell of Cd−organic complexes. Use of 99% TOPO as the coordinating solvent produces QDs with Cd/Se ≈ 1:1 for all values of R, and use of 99% TOPO “doped” with n-octylphosphonic acid (OPA), an impurity in 90% TOPO, produces QDs with values of Cd/Se up to 1.5:1. These results imply that Cd enrichment of the QDs is driven by tight-binding Cd2+−alkylphosphonate complexes that stabilize the interface between the polar CdSe core and the organic medium.

This paper describes a quantitative analysis of the chemical composition of organic/inorganic interfaces of colloidal 3.1-nm CdSe quantum dots (QDs) synthesized with trioctylphosphine oxide (TOPO) as the coordinating solvent and purified by successive precipitations from a chloroform/methanol solvent/nonsolvent system. A combination of X-ray photoelectron spectroscopy, inductively coupled plasma-atomic emission spectroscopy, and NMR (both 1H and 31P) reveals that the only ligands that form a stable population on the surface of the QDs are X-type alkylphosphonate and carboxylate ligands. n-Octylphosphonate (OPA), a known impurity in technical-grade (90%) TOPO, and P′-P′-(di-n-octyl) pyrophosphonate (PPA), the self-condensation product of OPA, cover ∼84% of the atoms on the surface of the QDs, whereas few of the L-type (datively bound) ligands hexadecylamine (HDA), TOPO, and trioctylphosphine selenide (TOPSe) are present as bound ligands once the excess free surfactant is removed from the reaction mixture. ...

This study examined the effects of sucking on a pacifier immediately before feeding on cardiovascular responses to feeding. Twenty-eight bottle-feeding infants were studied at 12 to 40 hr of age. Blood pressure and heart rate measurements were made during three periods: Period 1—while infants rested in their cribs before a regularly scheduled feeding, Period 2—while being held by the feeder immediately before feeding, and Period 3—during the first 3 to 5 min of feeding. Half of the infants were given a pacifier during Period 2. Blood pressures and heart rates increased across the periods; however, increases in systolic blood pressure during feeding were reduced for the group of infants given a pacifier prior to feeding. We suggest that cardiovascular responses to feeding in infants are comprised of multiple elements. Most of the systolic blood pressure responses to feeding are elicited by sucking whereas the heart rate response is dependent on both sucking and nutrient intake. © 2001 John Wiley & Sons, Inc. Dev Psychobiol 39: 34–39, 2001

Two-dimensional diffusion ordered spectroscopy (2D DOSY) NMR was used to probe the micellar structure of sodium dodecyl sulfate (SDS) and sodium cholate (SC) in aqueous solutions with and without semiconducting and metallic single-walled carbon nanotubes (SWCNTs). The solutions contain SDS and SC at weight ratios of 1:4 and 3:2, the ratios commonly used to isolate semiconducting and metallic SWCNTs through density gradient ultracentrifugation (DGU). These results show that the coverage of surfactant on the semiconducting and metallic SWCNTs is nearly identical in the 1:4 surfactant mixture, and a lower degree of bundling is responsible for the greater buoyancy of semiconducting SWCNTs. In the 3:2 surfactant mixture, the metallic SWCNTs are only encapsulated in SC while the semiconducting SWCNTs remain encapsulated in a poorly packed two-surfactant micelle, leading to a large buoyant density difference between the electronic species. This work provides insight into future directions to increase the purity of semiconducting and metallic SWCNTs sorted through DGU and demonstrates the utility of 2D DOSY NMR in probing SWCNT-surfactant complexes.

Subionospheric VLF recordings are investigated in relation with intense cloud-to-ground (CG) lightning data. Lightning impacts the lower ionosphere via heating and ionization changes which produce VLF signal perturbations known as early VLF events. Typically, early events recover in about 100 s, but a small subclass does not recover for many minutes, known as long-recovery early events (LORE). In this study, we identify LORE as a distinct category of early VLF events, whose signature may occur either on its own or alongside the short-lived typical early VLF event. Since LORE onsets coincide with powerful lightning strokes of either polarity (±), we infer that they are due to long-lasting ionization changes in the uppermost D region ionosphere caused by electromagnetic pulses emitted by strong ±CG lightning peak currents of typically>250 kA, which are also known to generate elves. The LORE perturbations are detected when the discharge is located within ~250 kmfromthe great circle path of a VLF transmitter-receiver link. The probability of occurrence increases with stroke intensity and approaches unity for discharges with peak currents >= ~300 kA. LOREs are nighttime phenomena that occur preferentially, at least in the present regional data set, during winter when strong ±CG discharges are more frequent and intense. The evidence suggests LORE as a distinct signature representing the VLF fingerprint of elves, a fact which, although was predicted by theory, it escaped identification in the long-going VLF research of lightning effects in the lower ionosphere.

Transformation toughening has been widely applied in metastable austenitic steels. Recently this toughening mechanism has been extended to ultrahigh strength secondary-hardening martensitic steels, bearing suitable austenitic dispersions. The resulting dispersed-phase transformation toughening depends on the stability of the austenitic dispersions. The stability of dispersed austenite depends on various factors including the chemical composition and size of austenite particles, the stress state and the yield strength of the matrix. A single-parameter characterization of the stability of the austenitic dispersion is provided by the M s σ temperature and a functional form relating that temperature with the above-mentioned factors is developed. The microstructural requirements for dispersed-phase transformation toughening are then derived in terms of the austenite particle size and chemical enrichment in stabilizing solutes. Compositional effects on austenite stability have been studied by performing thermodynamic calculations using the Thermo-Calc software. The free-energy change ΔG ch = G b.c.c. − G f.c.c. for martensitic transformation (a measure of austenite stability) has been evaluated as a function of composition in the ternary FeNiCo system. This information, when superimposed on isothermal sections at the tempering temperatures of interest, provides a way for selecting alloy compositions that maximize the thermodynamic stability of dispersed austenite.

Layoutgetreues Digitalisat der Ausg.: München : Langen, 1903 Standort: Fachgebiet für Geschichte der Medizin (192) Signatur: 300/II Provenienz: Behring, Emil von

This paper describes a study of the rates of photoinduced electron transfer (PET) from CdSe quantum dots (QDs) to poly(viologen) within thin films, as a function of the length of the ligands passivating the QDs. Ultrafast (10 ps), quantitative PET occurs from CdSe QDs coated with HS-(CH(2))(n)-COOH for n = 1, 2, 5, and 7 to viologen units. The observed decrease in the magnitude of the PET rate constant with n is weaker than that expected from the decay of the electron tunneling probability across extended all-trans mercaptocarboxylic acids but well-described by electron tunneling across a collapsed ligand shell. The PET rate constants for films with n = 10 and 15 are much slower than those expected based on the trend for n = 1-7; this deviation is ascribed to the formation of bundles of ligands on the surface of the QD that make the tunneling process prohibitively slow by limiting access of the viologen units to the surfaces of the QDs. This study highlights the importance of molecular-level morphology of donor and acceptor materials in determining the rate and yield of interfacial photoinduced electron transfer in thin films.

Transient absorption (TA) spectroscopy of solution-phase mixtures of colloidal CdS quantum dots (QDs) with acid-derivatized viologen molecules, N-[1-heptyl],N'-[3-carboxypropyl]-4,4'-bipyridinium dihexafluorophosphate (V(2+)), indicates electron transfer occurs from the conduction band of the QD to the LUMO of V(2+) after photoexcitation of a band-edge exciton in the QD. Analysis of the magnitude of the ground state bleach of the QD as a function of the molar ratio QD:V(2+) yields the QD-ligand adsorption constant, K(a) (4.4 × 10(4) M(-1)) for V(2+) ligands adsorbed in geometries conducive to electron transfer. The value of K(a), together with the measured rates of (i) formation of the V(+•) electron transfer product and (ii) recovery of the ground state bleach of the QD, enables determination of the intrinsic rate constant for charge separation, k(CS,int) ~ 1.7 × 10(10) s(-1), the rate for a single QD-V(2+) donor-acceptor pair. This analysis confirms previous reports that the number of ligands adsorbed to each QD is well-described by a Poisson distribution. This is the first report where the QD-ligand charge transfer and binding equilibria are quantitatively investigated simultaneously with a single technique.

This manuscript describes a global regression analysis of near-infrared (NIR, 900-1300 nm) transient absorptions (TA) of colloidal CdSe quantum dots (QDs) photoexcited to their first (1S(e)1S(3/2)) excitonic state. Near-IR TA spectroscopy facilitates charge carrier-resolved analysis of excitonic decay of QDs because signals in the NIR are due exclusively to absorptions of photoexcited electrons and holes, as probe energies in this region are not high enough to induce absorptions across the optical bandgap that crowd the visible TA spectra. The response of each observed component of the excitonic decay to the presence of a hole-trapping ligand (1-octanethiol) and an electron-accepting ligand (1,4-benzoquinone), and comparison of time constants to those for recovery of the ground state bleaching feature in the visible TA spectrum, allow for the assignment of the components to (i) a 1.6 ps hole trapping process, (ii) 19 ps and 274 ps surface-mediated electron trapping processes, and (iii) a ∼5 ns recombination of untrapped electrons.

This talk describes a global regression analysis of near-infrared (NIR, 900 nm - 1300 nm) transient absorptions (TA) of colloidal CdSe quantum dots (QDs) photoexcited to their first (1Se1S3/2) excitonic state.

Martensitic nucleation under normal circumstances is a heterogeneous process, and the heterogeneity can be explained by the potency distribution of defects that provide the nucleation sites, including both preexisting and autocatalytically generated defects. The potency distribu- tion of the preexisting defects has been shown earlier by small-particle studies to follow an exponential function, whereas that of the autocatalytic defects is found in the present work to obey a Gaussian function. A major distinction between these two distributions is that the number density of thepreexisting defects increases monotonically with decreasing defect potency, while the number density of theautocatalytic defects is distributed about a mode, giving a saturation level of its cumulative distribution. As a result of these potency distributions, the nucleating sites of both origins exhibit distributions in their activation energies for nucleation, and a distributed- activation kinetic model is now proposed to take these variations into account for martensitic transformations. The features of this model are tested with considerable success in experiments on an Fe-32.3Ni alloy, leading to calculations of the entire course of martensitic transformation curves (including the athermal, anisothermal, and isothermal contributions), the changing shapes of time-temperature-transformation (TTT) diagrams for a range of Fe-Ni compositions, and the grain-size dependence of “bursting” behavior.

Some recent findings concerning heterogeneous martensitic nucleation are highlighted in this memorial tribute to Professor Zenji Nishiyama. It is now possible, with appropriate experimental observations, to express the distributions of nucleation-defect potencies (or equivalently, the activation energies) of both preexisting and autocatalytically-generated defects. Based on this treatment, the full course of a martensitic transformation on cooling or on isothermal holding can be derived

Aim: This study tested the hypothesis that, within a few hours of delivery, cardiorespiratory measure taken during feeding provides markers of group differences related to birth weight. A secondary hypothesis was that high-frequency heart period variability would be related to underlying differences in autonomic control associated with birth weight. Methods and Subjects: One hundred four term infants in the lowest, middle, and highest birth weight quintiles were enrolled. Exclusion criteria were evidence of drug abuse, congenital anomalies, Apgar scores less than 7 or admission to the neonatal intensive care unit. Within 96 h of delivery, heart and respiratory rates, blood pressures and heart period variability were measured before, during and after feeding. Results: Term babies in the lowest quintile of birth weights have lower heart rates prior to feeding but greater increases in heart rate during the early postprandial period. Assessments of high-frequency heart period variability suggest that small term infants have greater parasympathetic tone before feeding and more sustained parasympathetic withdrawal following feeding. Conclusion: Measurements of cardiorespiratory functions before and after feeding are related to birth weight and may provide markers that can help identify the most vulnerable of infants with small size at birth.

BACKGROUND Fetal exposure of animals to antiepileptic drugs at doses lower than those required to produce congenital malformations can produce cognitive and behavioral abnormalities, but cognitive effects of fetal exposure of humans to antiepileptic drugs are uncertain. METHODS Between 1999 and 2004, we enrolled pregnant women with epilepsy who were taking a single antiepileptic agent (carbamazepine, lamotrigine, phenytoin, or valproate) in a prospective, observational, multicenter study in the United States and the United Kingdom. The primary analysis is a comparison of neurodevelopmental outcomes at the age of 6 years after exposure to different antiepileptic drugs in utero. This report focuses on a planned interim analysis of cognitive outcomes in 309 children at 3 years of age. RESULTS At 3 years of age, children who had been exposed to valproate in utero had significantly lower IQ scores than those who had been exposed to other antiepileptic drugs. After adjustment for maternal IQ, maternal age, antiepileptic-drug dose, gestational age at birth, and maternal preconception use of folate, the mean IQ was 101 for children exposed to lamotrigine, 99 for those exposed to phenytoin, 98 for those exposed to carbamazepine, and 92 for those exposed to valproate. On average, children exposed to valproate had an IQ score 9 points lower than the score of those exposed to lamotrigine (95% confidence interval [CI], 3.1 to 14.6; P=0.009), 7 points lower than the score of those exposed to phenytoin (95% CI, 0.2 to 14.0; P=0.04), and 6 points lower than the score of those exposed to carbamazepine (95% CI, 0.6 to 12.0; P=0.04). The association between valproate use and IQ was dose dependent. Children's IQs were significantly related to maternal IQs among children exposed to carbamazepine, lamotrigine, or phenytoin but not among those exposed to valproate. CONCLUSIONS In utero exposure to valproate, as compared with other commonly used antiepileptic drugs, is associated with an increased risk of impaired cognitive function at 3 years of age. This finding supports a recommendation that valproate not be used as a first-choice drug in women of childbearing potential.

High-strength low-alloy (HSLA) steels constitute a classic metallurgical development in which alloying additions and thermomechanical processing have been brought together effectively to attain desired combinations of engineering properties through microstructural control. Moreover, the microstructural control is relatively inexpensive because the alloying elements are used only in small concentrations as carbide-formers, and the associated thermomechanical processing is introduced merely as a modification of the final hot-rolling operation. A key feature of the resulting microstructure is the small ferritic grain size that provides a favorable balance of strength and toughness in the as-rolled steel. Here, we examine the interactions in columbium-treated HSLA steels among austenite chemistry, plastic deformation, strain-induced carbonitride precipitation, recrystallization characteristics, and the subsequent transformation of the thermomechanically-processed or conditioned austenite to the final ferrite-based structures. The latter transformations are studied in order to relate the ferrite nucleation and growth as well as its ultimate morphology to the state of the prior austenite.

An earlier theory for the nonequilibrium transformation of austenite in Fe-C alloys to partially supersaturated plates of ferrite is extended to include a recent solute trapping model by Aziz. The previous model yielded a relationship between interface velocity and supersaturation for a specified transformation temperature. However, a unique growth velocity was determined from a velocity maximization criterion that could not be justified. By including the Aziz solute trapping function as a third interface response function (in addition to functions describing the diffusion field velocity and interface mobility), it has been possible to obtain a more physically based unique solution to the growth velocity for a specified temperature. The new calculations on an Fe-C alloy indicate a smoothly increasing supersaturation during both nucleation and growth, as the transformation temperature is reduced. Both the nucleation and growth processes tend to become completely diffusionless only below the martensite start temperature.

This article summarizes results from a program of research that has focused on understanding the characteristics of, and factors that shape, acute cardiovascular responses to feeding in infants. The work developed from behavioral observations in rats suggesting a linkage between variations in maternal behavior and adult blood pressure. However, the hypothesis that specific types of interactions, in particular those associated with feeding, might alter cardiovascular function was greatly influenced by a serendipitous observation made by Myron Hofer several years earlier. Myron discovered that nutrient availability is a key regulator of cardiovascular function in newborn rats. Our spin-off studies established that, in newborn rats and human infants, ingestion of nutrient is associated with robust increases in heart rate and blood pressure. © 2005 Wiley Periodicals, Inc. Dev Psychobiol 47: 268–277, 2005.