Effect of amino group protonation on the carboxyl group in aqueous glycine observed by O 1s X-ray emission spectroscopy.

The valence electronic structures of the amino acid glycine in aqueous solution were investigated in detail through X-ray emission spectroscopy at O 1s excitation under selective excitation conditions of the C[double bond, length as m-dash]O site in the carboxyl group. The X-ray emission spectra of glycine were similar to that of acetic acid (CH3COOH), suggesting a resemblance between the molecular orbitals associated with the carboxyl groups in the two molecules. The changes of O 1s X-ray emission spectra as a function of pH were investigated in detail. In addition to spectral changes due to protonation/deprotonation of the carboxyl group for lower pH-values around the pKa value (∼2.3), the spectra of glycine exhibited further changes in the higher-pH region near the pKb value of glycine (dissociation constant of amino group ∼9.5). These results show the effects of amino group protonation on the electronic state around the carboxyl group. X-ray emission spectroscopy might be a tool to investigate intramolecular interactions between functional groups in a molecule.

Core-hole-induced dynamical effects in the x-ray emission spectrum of liquid methanol.

We compute the x-ray emission spectrum of liquid methanol, with the dynamical effects that result from the creation of the core hole included in a semiclassical way. Our method closely reproduces a fully quantum mechanical description of the dynamical effects for relevant one-dimensional models of the hydrogen-bonded methanol molecules. For the liquid, we find excellent agreement with the experimental spectrum, including the large isotope effect in the first split peak. The dynamical effects depend sensitively on the initial structure in terms of the local hydrogen-bonding (H-bonding) character: non-donor molecules contribute mainly to the high-energy peak while molecules with a strong donating H-bond contribute to the peak at lower energy. The spectrum thus reflects the initial structure mediated by the dynamical effects that are, however, seen to be crucial in order to reproduce the intensity distribution of the recently measured spectrum.

Risk factors for mortality in patients with non-traumatic pontine hemorrhage.

OBJECTIVES: For patients with non-traumatic pontine hemorrhage (PH) who will survive, determining prognosis is vital for appropriate therapeutic planning in the acute stage. This study aimed to determine reliable prognostic factors of mortality in patients with PH. MATERIALS AND METHODS: The cases of a total of 118 consecutive PH patients were reviewed. We compared clinical and radiological characteristics between patients who died and survivors by the log-rank test and performed multivariate analysis by the Cox proportional hazards model using variables that were marginally or significantly associated with PH-related death on the log-rank test (P < 0.20). RESULTS: The median length of follow-up was 51 days (interquartile range: 7-742 days). Sixty-six patients (56%) died and 52 (44%) survived during follow-up period. Multivariate analysis showed that Glasgow Coma Scale score <9, hyperthermia (a core temperature of ≥39°C), maximum hematoma diameter more than 27 mm, and hematoma extension to midbrain and/or thalamus were significantly related to PH-related death. The Kaplan-Meier method showed that patients without these four factors had successively longer period at PH-related death (21 patients without factors: mean 2900 days; 97 patients with at least one of four factors: mean 820 days). CONCLUSIONS: Promptly identifying PH patients who are most likely die is important. The decision to stop life support in patients with PH is difficult, but factors, which are shown in this study, may be used to determine the level of care.

Pathology of embolic debris in carotid artery stenting.

BACKGROUND: The relationship between magnetic resonance (MR) plaque imaging and the pathology of distal embolic debris is unknown. We aimed to evaluate the relationship between the pathology of embolic debris in the embolic filter during carotid artery stenting (CAS), MR plaque imaging, and new ischemic lesions on diffusion-weighted imaging (DWI). METHOD: We prospectively reviewed the 36 patients who underwent CAS using a filter-type embolic protection device. Pathology of debris was categorized into thrombosis, inflammatory cells, elastic fiber, and calcification. We compared the clinical parameters, MR plaque imaging, and pathological characteristics of the embolic debris retained in the filter during CAS on univariate analysis. RESULTS: Eleven patients had and 25 patients did not have new lesion on DWI. All of DWI-high lesions were identified in affected side middle cerebral artery territory. Embolic debris was microscopically confirmed in 28 patients (78%); thrombosis in 11 (31%), inflammatory cells in 13 (36%), elastic fiber in 12 (33%), and calcification in 9 (25%). Proportion of asymptomatic carotid stenosis, intra-operative bradycardia/hypotension, and inflammatory cells of debris were significantly higher in patients with new DWI-high lesions. There was no significant relationship between the pathological characteristics and MR plaque imaging of distal embolic debris. CONCLUSIONS: Our study showed that new DWI-high lesions might be influenced by types of debris in the filter. The need for future studies specifically examine the association of pathology of debris and findings of MR plaque imaging with new DWI-high lesions during CAS is emphasized.

Arterial stiffness as a risk factor for cerebral aneurysm.

OBJECTIVES: A low ankle-brachial index (ABI) is associated with increased mortality and risk of myocardial infarction and stroke in the general population. Arterial stiffness can be assessed non-invasively by the measurement of brachial-ankle pulse wave velocity (PWV), a simple and reproducible method. Because the importance of ABI and baPWV in the pathogenesis of cerebral aneurysms remains uncertain, we aimed to measure ABI and baPWV in patients with intracranial saccular and dissecting aneurysms to clarify whether these aneurysms are associated with arterial stiffness and atherosclerosis. MATERIALS AND METHODS: We prospectively investigated 78 patients diagnosed with intracranial saccular (n = 66) and dissecting (n = 12) aneurysms. The control group consisted of an age- and gender-matched normal population. We compared the clinical characteristics in patients with intracranial saccular aneurysms and controls, those with intracranial dissecting aneurysms and controls, and those who had cerebral aneurysms with and without subarachnoid hemorrhage. We also compared ABI and baPWV among saccular aneurysm locations and evaluated the correlation between the number of saccular aneurysms and ABI and baPWV. RESULTS: Multivariate logistic regression analysis shows that hypertension and higher baPWV (>1400 cm/s) are significantly associated with saccular aneurysms. Simple regression analysis revealed no correlation between the number of saccular aneurysms and ABI (r = -0.064, P = 0.611), and baPWV (r = 0.007, P = 0.956). CONCLUSIONS: The baPWV was associated with intracranial saccular aneurysms even after adjustment of hypertension and smoking. Assessment of the baPWV may aid the evaluation of the intracranial saccular aneurysm and the development of strategies for screening patients with intracranial saccular aneurysms.

Dynamics of oxygen Rydberg atom generation following O 1s inner-shell excitation of H2O.

The emission of low-energy electrons from H2O has been investigated at photon excitation energies in the vicinity of the O 1s ionization threshold. Neutral oxygen Rydberg atoms (O*) were found to form, and the correlation between the initial inner-shell excited state of H2O and the Rydberg state of O* was determined. The initially excited electron in a Rydberg orbital is shown to remain associated with O* even after the cleavage of two O-H bonds. We also show that the energy discrepancy between two Rydberg states of H2O and O* can be explained by the influence of the post-collision interaction, which becomes stronger as the excitation energy approaches the 1s ionization threshold.

Dynamics of hollow atom formation in intense x-ray pulses probed by partial covariance mapping.

When exposed to ultraintense x-radiation sources such as free electron lasers (FELs) the innermost electronic shell can efficiently be emptied, creating a transient hollow atom or molecule. Understanding the femtosecond dynamics of such systems is fundamental to achieving atomic resolution in flash diffraction imaging of noncrystallized complex biological samples. We demonstrate the capacity of a correlation method called "partial covariance mapping" to probe the electron dynamics of neon atoms exposed to intense 8 fs pulses of 1062 eV photons. A complete picture of ionization processes competing in hollow atom formation and decay is visualized with unprecedented ease and the map reveals hitherto unobserved nonlinear sequences of photoionization and Auger events. The technique is particularly well suited to the high counting rate inherent in FEL experiments.

Cascade Auger decays following Si KL23L23 Auger transitions in SiF4.

Cascade Si LVV Auger decays following KL(23)L(23) Auger transitions have been measured in SiF(4) molecule using an electron spectrometer combined with monochromatized undulator radiation. Molecular cascade processes from the two 2p holes states largely generate wide band structures in the spectra due to sequential electron emission leading to multiple valence holes. However, a peak with high yield is observed for the first time at about 103 eV, an energy being considerably higher than the energies of the normal LVV Auger electron, in the instance of the resonant excitation of Si 1s electron into the vacant molecular orbital. This peak is presumed to originate from the participator decay from the state with two 2p holes and one excited electron into the state with one 2p hole and one valence hole. A similar peak with less intensity is detected in the photoexcitation of the 1s electron into a Rydberg orbital. After the normal KL(23)L(23) Auger transition, the resultant cascade spectrum shows several peaks, e.g., 61 eV, 76 eV, and 82 eV. The former two peaks are assigned to the Auger transitions of Si atoms produced through molecular ion dissociation after cascade decays, and the latter is probably ascribed to the second step Auger decay into states having a 2p hole together with two valence holes.

Unique water-water coordination tailored by a metal surface.

At low coverage of water on Cu(110), substrate-mediated electrostatics lead to zigzagging chains along [001] as observed with STM [T. Yamada, S. Tamamori, H. Okuyama, and T. Aruga, "Anisotropic water chain growth on Cu(110) observed with scanning tunneling microscopy" Phys. Rev. Lett. 96, 036105 (2006)]. Using x-ray absorption spectroscopy we find an anomalous low-energy resonance at ~533.1 eV which, based on density functional theory spectrum simulations, we assign to an unexpected configuration of water units whose uncoordinated O-H bonds directly face those of their neighbors; this interaction repeats over trough sites with enhanced electron density and is analogous to the case of a hydrated electron.

Optimal prostate-specific antigen screening interval for prostate cancer.

BACKGROUND: To identify the optimal interval for repeat prostate-specific antigen (PSA) testing to screen for prostate cancer in healthy adults. PATIENTS AND METHODS: A retrospective cohort study was conducted on 7332 healthy males without prostate cancer at baseline from 2005 to 2008. Participants underwent annual health checkups including PSA testing at the Center for Preventive Medicine in Japan. Participants with high PSA (≥ 4.0 ng/ml) underwent further examination for prostate cancer. A subgroup analysis was conducted age group (<50 years, ≥ 50 years). RESULTS: Mean age was 50 years. Mean PSA at baseline was 1.2 ng/ml. In over 50-year group, for those with initial PSA of <1.0, 1.0-1.9, 2.0-2.9, and 3.0-3.9 ng/ml at baseline, the 3-year cumulative incidence of prostate cancer was 0%, 0.1%, 0.3%, and 5.7%, respectively. No prostate cancer was identified in those <50 years, regardless of PSA level. CONCLUSIONS: If PSA screening is recommended, males >50 years with PSA of 3.0-3.9 ng/ml at baseline should undergo rescreening at 2 years. For men with PSA <3.0 ng/ml, PSA rescreening at intervals of ≥ 3 years is appropriate. PSA screening may not be indicated in males of <50 years of age.

Super high resolution for single molecule-sequence-based typing of classical HLA loci at the 8-digit level using next generation sequencers.

Current human leukocyte antigen (HLA) DNA typing methods such as the sequence-based typing (SBT) and sequence-specific oligonucleotide (SSO) methods generally yield ambiguous typing results because of oligonucleotide probe design limitations or phase ambiguity for HLA allele assignment. Here we describe the development and application of the super high-resolution single-molecule sequence-based typing (SS-SBT) of HLA loci at the 8-digit level using next generation sequencing (NGS). NGS which can determine an HLA allele sequence derived from a single DNA molecule is expected to solve the phase ambiguity problem. Eight classical HLA loci-specific polymerase chain reaction (PCR) primers were designed to amplify the entire gene sequences from the enhancer-promoter region to the 3' untranslated region. Phase ambiguities of HLA-A, -B, -C, -DRB1 and -DQB1 were completely resolved and unequivocally assigned without ambiguity to single HLA alleles. Therefore, the SS-SBT method described here is a superior and effective HLA DNA typing method to efficiently detect new HLA alleles and null alleles without ambiguity.

Factors associated with lobar vs. non-lobar intracerebral hemorrhage.

OBJECTIVES: The relationship between body mass index (BMI) and stroke subtypes has received more research attention than that between BMI and location of intracerebral hemorrhage (ICH). Lobar hemorrhage (LH) differs from non-LH primarily in terms of etiology, i.e. cerebral amyloid angiopathy is the main cause of LH. This study aimed to determine the relationship between BMI and ICH. MATERIALS AND METHODS: In this retrospective study involving 460 consecutive patients with ICH, BMI was significantly lower in LH than for other ICH locations. BMI categories were underweight (BMI < 18.5 kg/m(2)), normal weight (18.5-23.0 kg/m(2)), overweight (23.0-27.5 kg/m(2)), or obesity (≥27.5 kg/m(2)). Outcome at 1 year was evaluated by the modified Rankin Scale (mRS). We investigated the relationship of BMI and other clinical characteristics with LH and non-LH. RESULTS: LH was associated with age (>70 years), underweight, unfavorable outcome (mRS ≥3), and daily alcohol consumption. Hypertension and intraventricular bleeding were significantly less common in patients with LH than those with non-LH. CONCLUSIONS: Alongside risk factors conventionally thought to be related to LH, underweight may also be a LH-related factor, specifically in the elderly.

The inhomogeneous structure of water at ambient conditions.

Small-angle X-ray scattering (SAXS) is used to demonstrate the presence of density fluctuations in ambient water on a physical length-scale of approximately 1 nm; this is retained with decreasing temperature while the magnitude is enhanced. In contrast, the magnitude of fluctuations in a normal liquid, such as CCl(4), exhibits no enhancement with decreasing temperature, as is also the case for water from molecular dynamics simulations under ambient conditions. Based on X-ray emission spectroscopy and X-ray Raman scattering data we propose that the density difference contrast in SAXS is due to fluctuations between tetrahedral-like and hydrogen-bond distorted structures related to, respectively, low and high density water. We combine our experimental observations to propose a model of water as a temperature-dependent, fluctuating equilibrium between the two types of local structures driven by incommensurate requirements for minimizing enthalpy (strong near-tetrahedral hydrogen-bonds) and maximizing entropy (nondirectional H-bonds and disorder). The present results provide experimental evidence that the extreme differences anticipated in the hydrogen-bonding environment in the deeply supercooled regime surprisingly remain in bulk water even at conditions ranging from ambient up to close to the boiling point.

Projection of Si 1s photoexcited orbitals into resonant Auger electron spectra in KLL decays of Si(CH3)4 and SiF4.

Spectator resonant KL(23)L(23) Auger electron spectra have been measured in the Si 1s photoexcitation region of Si(CH(3))(4) using monochromatized undulator radiation combined with a hemispherical electron spectrometer. The broad peak with high intensity in a total ion yield spectrum, coming mainly from excitation of a 1s electron into the 6t(2) vacant orbital, induces a spectator Auger decay in which the excited electron remains in its excited orbital. The component on the higher energy side of this peak through 1s excitation into a Rydberg orbital produces resonant Auger decays in which the excited Rydberg electron moves into a slightly higher Rydberg orbital, or is partly shaken up to a significantly higher Rydberg orbital. These findings of Si(CH(3))(4) indicate a clear contrast to those for SiF(4), in which the 1s excitation into a Rydberg orbital induces a shake-down phenomenon as well as a shake-up one. The results of these molecules exhibit a clear splitting effect among excited orbitals which are smeared out by overlapping due to lifetime widths and due to densely populated levels in the 1s electron excitation spectrum. This is consistent with the calculation on photoexcitation within the framework of density functional theory.

The role of substrate electrons in the wetting of a metal surface.

We address how the electronic and geometric structures of metal surfaces determine water-metal bonding by affecting the balance between Pauli repulsion and electrostatic attraction. We show how the rigid d-electrons and the softer s-electrons utilize different mechanisms for the redistribution of charge that enables surface wetting. On open d-shell Pt(111), the ligand field of water alters the distribution of metal d-electrons to reduce the repulsion. The closed-shell Cu d(10) configuration of isostructural Cu(111), however, does not afford this mechanism, resulting in a hydrophobic surface and three-dimensional ice cluster formation. On the geometrically corrugated Cu(110) surface, however, charge depletion involving the mobile sp-electrons at atomic rows reduces the exchange repulsion sufficiently such that formation of a two-dimensional wetting layer is still favored in spite of the d(10) electronic configuration.

Evaluation of velopharyngeal function using high-speed cine-magnetic resonance imaging based on T2-weighted sequences: a preliminary study.

The objective was to introduce a new technique for visualizing the three-dimensional (3D) movements of velopharyngeal-related muscles using high-speed cine-magnetic resonance imaging (MRI) based on T2-weighted sequences. The evaluation of phonation- and water swallowing-related events was performed in 11 healthy subjects. Specifically, whether cine-MRI could precisely visualize normal velopharyngeal function during these two events was examined. The 3D movements of the soft palate, superior pharyngeal constrictor muscles, and levator veli palatini muscles were visualized in all 11 subjects. A noteworthy finding was that the magnetic resonance signals of the superior constrictor pharyngeal muscles and the levator veli palatini muscles were significantly higher during phonation and during water swallowing than at rest. This initial study suggests that the 3D movements of velopharyngeal-related muscles can be successfully and precisely visualized without side effects. The magnetic resonance signal changes seen in the superior pharyngeal constrictor and levator veli palatini muscles using the technique described here should be useful to develop better methods of evaluation of velopharyngeal function.

Site-specific behavior in de-excitation spectra of F(3)SiCH(2)CH(2)Si(CH(3))(3) in the Si 1s excitation region.

Excitation (total ion yield) and de-excitation (resonant photoemission) spectra have been measured in the Si 1s photoexcitation region of the F(3)SiCH(2)CH(2)Si(CH(3))(3) molecule using monochromatized undulator radiation. Theoretical calculations within the framework of density functional theory have reproduced the observed total ion yield spectrum very well. The first peak at the lowest photon energy, coming from Si 1s excitation at the trimethyl side into a vacant orbital, induces spectator Auger decays in which the excited electron remains in its valence orbital. The second peak produced through excitation of Si 1s electron at the trifluoride side generates resonant Auger decays in which the excited valence electron remains predominantly also in the valence orbital or is partly shaken up into higher Rydberg orbitals. The third peak generated through Si 1s excitation at the trifluoride side produces resonant Auger decays in which the excited Rydberg electron remains or is partly shaken down to a lower lying valence molecular orbital. These findings exhibit a clear distinction between resonant Auger decays following photoexcitation of Si 1s electrons under different chemical environments.

Hydrogen bonding in acetone clusters probed by near-edge x-ray absorption fine structure spectroscopy in the carbon and oxygen K-edge regions.

Hydrogen bonding in acetone clusters was investigated using near-edge x-ray absorption fine structure (NEXAFS) spectroscopy and density functional theory calculations in the carbon and oxygen K-edge regions. The partial-ion-yield (PIY) curves of the cluster ions were measured as the NEXAFS spectra of acetone clusters. In the carbon K-edge region, the first resonance peak, which was assigned to the C(CO) 1s-->pi( *)(C=O) resonance transition, showed no substantial change in the PIY curves of the acetone clusters, while the C(CH3) 1s-->3ppi(CH(3)) excitation feature was found to be strongly suppressed. The selective suppression of the C(CH3) 1s-->3ppi(CH(3)) resonance transition can be explained by the change in the character of the 3ppi(CH(3)) orbital due to the C=O...H-C type of hydrogen-bonding interaction. On the other hand, the NEXAFS spectra of the acetone molecule and clusters were almost identical in the oxygen K-edge region, except for a small shift in the pi( *)(C=O) resonance of 0.13 eV, because the character of the pi( *)(C=O) orbital remained, regardless of the C=O...H-C hydrogen bonding interaction.

Adrenal function in patients with community-acquired pneumonia.

Adrenal insufficiency is believed to occur frequently in severe sepsis and septic shock. The aim of the present study was to determine whether adrenal function is also related to the severity of community-acquired pneumonia (CAP). In total, 64 Japanese patients with CAP were consecutively enrolled in the present study, which was carried out during 2005-2006. Serum adrenocorticotropic hormone (ACTH) and cortisol were measured in each subject, as was the response of cortisol secretion when 250 mug of cosyntropin was administered. Analyses were performed comparing these values with the score calculated according to the Pneumonia Patient Outcomes Research Team (PORT) cohort study, the number of in-hospital deaths and the length of hospital stay. As the PORT score increased, serum ACTH and cortisol also increased, while the response of cortisol secretion to the administration of cosyntropin decreased. In the analysis by receiver operating characteristic curves, adrenal dysfunction was related significantly to both the number of in-hospital deaths and the length of hospital stay. Adrenal dysfunction was shown to correlate with the Pneumonia Patient Outcomes Research Team score and the clinical outcomes, while adrenal insufficiency defined by the cosyntropin stimulation test was rare in the present study.