Gas-Phase Anion Photoelectron Spectroscopy of Alkanethiolate-Protected PtAu12 Superatoms: Charging Energy in Vacuum vs Solution.

Charging behavior of molecular Au clusters protected by alkanethiolate (SCnH2n+1 = SCn) is, under electrochemical conditions, significantly affected by the penetration of solvent and electrolyte into the SCn layer. In this study, we estimated the charging energy EC(n) associated with [PtAu24(SCn)18]- + e → [PtAu24(SCn)18]2- (n = 4, 8, 12, and 16) in vacuum using mass-selected, gas-phase anion photoelectron spectroscopy of [PtAu24(SCn)18]z (z = -1 and -2). The EC(n) values of PtAu24(SCn)18 in vacuum are significantly larger than those in solution and decrease with n in contrast to the behavior reported for Au25(SCn)18 in solution. The effective relative permittivity (εm*) of the SCn layer in vacuum is estimated to be 2.3-2.0 based on the double-concentric-capacitor model. Much smaller εm* values in vacuum than those in solution are explained by the absence of solvent/electrolyte penetration into the monolayer. The gradual decrease of εm* with n is ascribed to the appearance of an exposed surface region due to the bundle formation of long alkyl chains.

Spontaneous Intercluster Electron Transfer X2- + X0 → 2 X- (X = PtAu24(SCnH2n+1)18) in Solution: Promotion by Long Alkyl Chains.

In this work, we systematically investigated the ligand effects on spontaneous electron transfer (ET) between alkanethiolate-protected metal clusters in solution. The donor and acceptor clusters used were [PtAu24(SCnH2n+1)18]2- (8e(Cn)) and [PtAu24(SCmH2m+1)18]0 (6e(Cm)) (n, m = 2-16), which have icosahedral Pt@Au12 cores with eight and six valence electrons, respectively. The ET rate constant (kET) from 8e(Cn) to 6e(Cm) in benzene exhibited a novel turnover behavior as a function of the total chain length n + m: the kET decreased with n + m in the range of 4-12, whereas it monotonically increased with n + m in the range of 12-32. Electrospray ionization mass spectrometry of the mixture of 8e(Cn) and 6e(Cm) detected the dimer complex 8e(Cn)·6e(Cm), the relative population of which increased with n + m. The activation energy (Ea), determined based on the Arrhenius plots for n = m, monotonically decreased with n (≥ 6). Based on these results, we proposed that the promotion of ET by longer alkanethiolates was ascribed to two effects on the key intermediate 8e(Cn)·6e(Cm): (1) elongation of the lifetime and (2) the contraction of the distance between 8e(Cn) and 6e(Cm) due to the stronger van der Waals interaction between the longer alkyl chains. Such alkyl-chain-promoted ET is specific to ultrasmall clusters in solution because a nonuniform ligand layer could be formed due to the large curvature of the cluster core.

Neonatal pain response to automatic lancet versus needle heel-prick blood sampling: A prospective randomized controlled clinical trial.

BACKGROUND: Automatic lancets have been reported to be superior to manual lancets in terms of pain and treatment time. However, no studies have yet been published comparing automatic lancet and needle puncture heel-prick blood sampling. The objective of this study was to compare the pain response and efficiency between the automatic lancet and needle at the time of heel blood sampling. The design was a randomized controlled trial. The inclusion criteria for the participants were a birthweight of ≧1,500 g and a gestational age of ≧30 weeks. METHODS: The study examined a total of 105 neonates who were randomized into an automatic lancet group (n = 53) and a needle group (n = 52). The parameters measured included blood collection time, number of calf squeezes, duration of audible crying, and the Neonatal Infant Pain Scale (NIPS) score. The main outcome measure was audible crying duration. RESULTS: The duration of audible crying was significantly shorter in the automatic lancet group when compared to the needle group (median 3 s, interquartile range (IQR) 0-33 s vs median 39 s, IQR 5-91.5 s, P = 0.0023). The NIPS score at the time of puncture was significantly lower in the automatic lancet group than in the needle group (median 1, IQR 0-5 vs median 5, IQR 3-6, P = 0.0060). There was no significant difference in the blood collection time and the number of calf squeezes between the two groups. The automatic lancet was found to be less painful than the needle puncture in neonatal heel-prick blood sampling with no significant difference in blood sampling time. CONCLUSION: The automatic lancet was found to be less painful than the needle puncture in neonatal heel-prick blood sampling with no significant difference in blood sampling time.

Stoichiometric Formation of Open-Shell [PtAu24(SC2H4Ph)18]- via Spontaneous Electron Proportionation between [PtAu24(SC2H4Ph)18]2- and [PtAu24(SC2H4Ph)18]0.

[PtAu24(SC2H4Ph)18]0 ([PtAu24]0) was fully and selectively converted to [PtAu24]-, having an open electronic structure with seven valence electrons, upon the addition of an equiamount of NaBH4. Stoichiometric production of [PtAu24]- by the reaction between an equal amount of [PtAu24]0 and [PtAu24]2- revealed that the above reaction proceeds via the spontaneous electron transfer (ET) from [PtAu24]2- nascently reduced by H--mediated reduction to [PtAu24]0 remaining in the solution. Theoretical calculation suggested that the driving force of this novel ET reaction was the larger adiabatic electron affinity of [PtAu24]0 compared to that of [PtAu24]-, partly associated with reduction-induced relief of the Jahn-Teller strain. We propose that ET proceeds via the dimer complex of [PtAu24]2- and [PtAu24]0 formed through the aurophilic interaction between Au(I) sites in the surface layer.

Hydride Doping of Chemically Modified Gold-Based Superatoms.

Atomically size-selected gold (Au) clusters protected by organic ligands or stabilized by polymers provide an ideal platform to test fundamental concepts and size-specific phenomena, such as the superatomic concept and metal-to-nonmetal transition. Recent studies revealed that these stabilized Au clusters take atomlike quantized electronic structures and can be viewed as chemically modified Au superatoms. An analogy between Au and hydrogen (H) atoms is an interesting proposal made for bare Au clusters: a Au atom at a low-coordination site of a Au cluster can be replaced with a H atom while retaining the structural motif and electronic structure. However, this proposal has not been experimentally proved in chemically modified Au superatoms while a recent theoretical study predicted the formation of [HAu25(SR)18]0 (RS = thiolate). This Account summarizes our recent studies on the interaction of hydride(s) with two types of chemically modified Au-based superatoms: (1) the Au cores of [Au9(PPh3)8]3+ and [PdAu8(PPh3)8]2+ formally described as (Au9)3+ and (PdAu8)2+, respectively, and (2) Au34 cluster stabilized by poly( N-vinyl-2-pyrrolidone) (PVP). The (Au9)3+ and (PdAu8)2+ cores correspond to oblate-shaped superatoms with six electrons and a coordinatively unsaturated site at the center, whereas the Au34 cluster in PVP is viewed as a nearly spherical superatom having a closed electronic structure with 34 electrons and multiple uncoordinated sites on the surface. Through this study, we aimed to deepen our understanding on the role of a hydride in the formation processes of Au superatoms, the effect of adsorbed hydride(s) on the electronic structure of Au superatoms, and the activity of adsorbed hydrogen species for hydrogenation catalysis. Mass spectrometry and nuclear magnetic resonance spectroscopy demonstrated that a single hydride (H-) was selectively doped to (Au9)3+ and (PdAu8)2+ upon reactions with BH4- to form (HAu9)2+ and (HPdAu8)+, respectively. Density functional theory (DFT) calculations showed that (HAu9)2+ and (HPdAu8)+ were more spherical than the original superatoms and had a closed electronic structure with eight electrons. The hydride-doped (HAu9)2+ was selectively converted to the well-known (Au11)3+ by electrophilic addition of two Au(I) units whereas (HPdAu8)+ was converted to a new hydride-doped (HPdAu10)3+. A two-step mechanism was proposed for hydride-mediated growth of Au-based superatoms: closure of the electronic structures by adsorption of a hydride, followed by the addition of two Au(I) units. The selective formation of Au34 superatoms in PVP is also explained by assuming that hydride-doped Au clusters with 34 electrons were involved as key intermediates. The Au34 superatom exhibited the localized surface plasmon resonance (LSPR) band by reacting with BH4- due to the electron donation by multiply adsorbed hydrides. The LSPR band disappeared by exposing hydride-doped Au34 to dissolved O2, but reappeared by reaction with BH4-. Catalysis for hydrogenation of C═C bonds was generated by doping a single Pd or Rh atom to Au34. The results reported here demonstrate that the hydride doped to chemically modified Au superatoms mimics Au- in terms of electron count. The hydride-mediated growth processes observed will contribute to the development of an atomically precise, bottom-up method of synthesizing new artificial elements in a periodic table for nanoscale materials. The interaction of hydride(s) with Au superatoms will find application in hydrogenation catalysis and hydrogen sensing.

Ultrasonography of the internal carotid artery during therapeutic hypothermia.

The purpose of this study was to determine the accuracy of mean blood flow velocity (mean V) in the internal carotid artery (ICA) for prediction of outcome in infants with hypoxic-ischemic encephalopathy (HIE) exposed to therapeutic hypothermia (TH). Five newborns with HIE who met the criteria for TH were enrolled. Ultrasonography of the right and left ICA was performed before, during, and after TH. Mean V of the sampling point in each ICA was measured. Mean V was suppressed during TH and increased after rewarming in four infants with normal neurological development. In one infant with neurological disability, however, mean V increased during TH and decreased after therapy. In conclusion, cervical ultrasonography for ICA in infants during TH may be useful for the prediction of neurodevelopmental outcome.

Novel DCX mutation-caused lissencephaly in a boy and very mild heterotopia in his mother.

We describe a novel mutation in DCX in a family in which a proband boy had classical lissencephaly and his mother had extremely mild subcortical band heterotopia. No factors that would make the mother's symptoms milder, such as somatic mosaicism or skewed X chromosome inactivation, were observed. From this family, we conclude that a DCX mutation causes a pleiotropic phenotype in the female even if X chromosome inactivation pattern is not skewed, and the novel missense mutation in DCX produced relatively mild dysfunction of the doublecortin protein.

Successful combination therapy of propranolol and prednisolone for a case with congenital Kasabach-Merritt syndrome.

A male fetus was delivered by cesarean section with a large hemangioma on his right chest and thrombocytopenia. Clinically, Kasabach-Merritt syndrome (KMS) was suspected, and immediately he was treated with daily prednisolone (PSL) 1 mg/kg and recombinant thrombomodulin without response. Additional propranolol (1-3 mg/kg per day) and increased PSL 2 mg/kg per day therapy successfully controlled his disseminated intravascular coagulation and decreased the tumor size without serious side-effects. No relapse of KMS was observed after cease of PSL and propranolol. Combined use of propranolol and corticosteroid is expected as a candidate therapeutic tool for KMS.