This is the first publication on the distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in riverine and coastal sediments in South East Asia where the rapid transfer of land-based pollutants into aquatic environments by heavy rainfall and runoff waters is of great concern. Twenty-nine Malaysian riverine and coastal sediments were analyzed for PAHs (3-7 rings) by gas chromatography mass spectrometry. Total PAHs concentrations in the sediment ranged from 4 to 924 ng/g. Alkylated homologues were abundant for all sediment samples. The ratio of the sum of methylphenanthrenes to phenanthrene (MP/P), an index of petrogenic PAHs contribution, was more than unity for 26 sediment samples and more than 3 for seven samples for urban rivers covering a broad range of locations. The MP/P ratio showed a strong correlation with the total PAHs concentrations, with an r2 value of 0.74. This ratio and all other compositional features indicated that Malaysian urban sediments are heavily impacted by petrogenic PAHs. This finding is in contrast to other studies reported in many industrialized countries where PAHs are mostly of pyrogenic origin. The MP/P ratio was also significantly correlated with higher molecular weight PAHs such as benzo[a]pyrene, suggesting unique PAHs source in Malaysia which contains both petrogenic PAHs and pyrogenic PAHs. PAHs and hopanes fingerprints indicated that used crankcase oil is one of the major contributors of the sedimentary PAHs. Two major routes of inputs to aquatic environments have been identified: (1) spillage and dumping of waste crankcase oil and (2) leakage of crankcase oils from vehicles onto road surfaces, with the subsequent washout by street runoff. N-Cyclohexyl-2-benzothiazolamine (NCBA), a molecular marker of street dust, was detected in the polluted sediments. NCBA and other biomarker profiles confirmed our hypothesis of the input from street dust contained the leaked crankcase oil. The fingerprints excluded crude oil, fresh lubricating oil, asphalt, and tire-particles as major contributors.

Protein dynamics in the primary processes during the bacteriorhodopsin (BR) photocycle under physiological conditions were investigated by measuring picosecond time-resolved ultraviolet resonance Raman (UVRR) spectra of the BR suspended solution at ambient temperature. We used a 565 nm pump pulse to initiate the BR photocycle and two kinds of probe pulses with wavelengths of 225 and 238 nm to detect spectral changes in the tryptophan and tyrosine bands, respectively. The observed spectral changes of the Raman bands are most likely due to tryptophan and tyrosine residues located in the vicinity of the retinal chromophore, that is, Trp86, Trp182, Tyr57, and Tyr185. The 225 nm UVRR spectra exhibited bleaching of intensity for all the tryptophan bands within the instrumental response, followed by recovery with a time constant of 30 ps and no further changes up to 1 ns. This suggests that the stepwise structural changes in the tryptophan residues proceed in response to the retinal photoreaction. It is concluded that the initial intensity bleach arises from the J-intermediate formation and the 30 ps recovery is associated with the K-KL transition. The 30 ps process in the BR photocycle has been detected for the first time. In the 238 nm UVRR spectra, spectral features attributable to the K and KL intermediates were observed. The observed spectral changes showed that the temporal behaviors of the observed spectral changes in each Raman band of both tryptophan and tyrosine were different. This indicates that the spectral changes originated from structural changes of at least two tryptophan and two tyrosine residues.

Hemiparesis resulting from stroke presents characteristic spatiotemporal gait patterns. This study aimed to clarify the spatiotemporal gait characteristics of hemiparetic patients by comparing them with height-, speed-, and age-matched controls while walking at various speeds. The data on spatiotemporal gait parameters of stroke patients and that of matched controls were extracted from a hospital gait analysis database. In total, 130 pairs of data were selected for analysis. Patients and controls were compared for spatiotemporal gait parameters and the raw value (RSI) and absolute value (ASI) of symmetry index and coefficient of variation (CV) of these parameters. Stroke patients presented with prolonged nonparetic stance (patients vs. controls: 1.01 ± 0.41 vs. 0.83 ± 0.25) and paretic swing time (0.45 ± 0.12 vs. 0.39 ± 0.07), shortened nonparetic swing phase (0.35 ± 0.07 vs. 0.39 ± 0.07), and prolonged paretic and nonparetic double stance phases [0.27 ± 0.13 (paretic)/0.27 ± 0.17 (nonparetic) vs. 0.22 ± 0.10]. These changes are especially seen in low-gait speed groups (<3.4 km/h). High RSIs of stance and swing times were also observed (–9.62 ± 10.32 vs. –0.79 ± 2.93, 24.24 ± 25.75 vs. 1.76 ± 6.43, respectively). High ASIs and CVs were more generally observed, including the groups with gait speed of ≥3.5 km/h. ASI increase of the swing phase (25.79 ± 22.69 vs. 4.83 ± 4.88) and CV of the step length [7.7 ± 4.9 (paretic)/7.6 ± 5.0 (nonparetic) vs. 5.3 ± 3.0] were observed in all gait speed groups. Our data suggest that abnormalities in the spatiotemporal parameters of hemiparetic gait should be interpreted in relation to gait speed. ASIs and CVs could be highly sensitive indices for detecting gait abnormalities.

Wash-off and sorptive behaviors of two benzothiazolamines (BTs) [i.e., 2-(4-morpholinyl)benzothiazole (24MoBT) and N-cyclohexyl-2-benzothiazolamine (NCBA)] have been investigated as possible molecular markersfortire debris and/or road dust transported in highway runoff water. Sum of dissolved and particulate 24MoBT and NCBA concentrations in runoff water ranged from 15 to 417ng/L and from 22to 508ng/L, respectively. Proportions of NCBA in particulate (>0.7microm) phase (<9-79%) were larger than that of 24MoBT (<1-14%), which was consistent with their experimentally determined octanol/water partition coefficients (Kow; 10(4.23+/-0.14) for NCBA; 10(2.42+/-0.03) for 24MoBT). The organic carbon-normalized in-situ partition coefficient (Koc') observed in runoff events (10(4.69+/-0.28) for NCBA; 10(3.42+/-0.23) for 24MoBT) were 1 order of magnitude higher than those expected from their Kow, indicating strong affinity of BTs to suspended particulate matter (SPM) in runoff water. Furthermore, in desorption experiments lasting 24 h, we observed almost the same levels of Koc' as those in runoff events, implying that significant fractions of BTs are strongly associated with runoff particles and not easily available to equilibrium partitioning. NCBA was ubiquitous in sediments from the Nogawa River receiving runoff from the Chuo Highway, whereas many of those samples had undetectable levels of 24MoBT. All of above results indicate that NCBA would be more suitable than 24MoBT as a molecular marker for runoff particles loading the aquatic environment. By using SPM-weighted mean concentration of particulate NCBA, at least 3.3+/-1.6% of the mass in the Nogawa sediments is estimated to be from runoff SPM.

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BackgroundAnkle–foot orthoses (AFOs) are frequently used to improve gait stability, toe clearance, and gait efficiency in individuals with hemiparesis. During the swing phase, AFOs enhance lower limb advancement by facilitating the improvement of toe clearance and the reduction of compensatory movements. Clinical monitoring via kinematic analysis would further clarify the changes in biomechanical factors that lead to the beneficial effects of AFOs. The purpose of this study was to investigate the actual impact of AFOs on toe clearance, and determine the best strategy to achieve toe clearance (including compensatory movements) during the swing phase.MethodsThis study included 24 patients with hemiparesis due to stroke. The gait performance of these patients with and without AFOs was compared using three-dimensional treadmill gait analysis. A kinematic analysis of the paretic limb was performed to quantify the contribution of the extent of lower limb shortening and compensatory movements (such as hip elevation and circumduction) to toe clearance. The impact of each movement related to toe clearance was assessed by analyzing the change in the vertical direction.ResultsUsing AFOs significantly increased toe clearance (p = 0.038). The quantified limb shortening and pelvic obliquity significantly differed between gaits performed with versus without AFOs. Among the movement indices related to toe clearance, limb shortening was increased by the use of AFOs (p < 0.0001), while hip elevation due to pelvic obliquity (representing compensatory strategies) was diminished by the use of AFOs (p = 0.003). The toe clearance strategy was not significantly affected by the stage of the hemiparetic condition (acute versus chronic) or the type of AFO (thermoplastic AFOs versus adjustable posterior strut AFOs).ConclusionsSimplified three-dimensional gait analysis was successfully used to quantify and visualize the impact of AFOs on the toe clearance strategy of hemiparetic patients. AFO use increased the extent of toe clearance and limb shortening during the swing phase, while reducing compensatory movements. This approach to visualization of the gait strategy possibly contributes to clinical decision-making in the real clinical settings.Trial registrationUMIN000028946. Registered 31 August 2017 (retrospectively registered).Electronic supplementary materialThe online version of this article (10.1186/s12984-018-0382-y) contains supplementary material, which is available to authorized users.

It is usually assumed that only amino acids located near the retinal chromophore are responsible for color tuning of rhodopsins. However, we recently found that replacement of Ala178 with Arg in the E-F loop of proteorhodopsin (PR), an archaeal-type rhodopsin in marine bacteria, shifts the lambda(max) from 525 to 545 nm at neutral pH [Yoshitsugu, M., Shibata, M., Ikeda, D., Furutani, Y., and Kandori, H. (2008) Angew. Chem., Int. Ed. 47, 3923-3926]. Since the location of Ala178 is distant from the retinal chromophore (approximately 25 A), the molecular mechanism of the unusual mutation effect on color tuning is intriguing. Here we studied this mechanism by using additional mutations and some analytical methods. Introduction of Arg into the corresponding amino acid in bacteriorhodopsin (BR, M163R mutant) does not change the absorption spectra, indicating that the effect is specific to PR. Introduction of Arg into the A-B or C-D loop yields little (3 nm) or no color change, respectively. T177R and P180R mutants exhibited absorption spectra identical to that of the wild type, while N176R and S179R mutants exhibit lambda(max) values of 528 and 535 nm, respectively. Therefore, the observed color change is position-specific, being fully effective at position 178 and half-effective at position 179. Salt affects the absorption spectra of wild-type and A178R PR similarly. FTIR spectroscopy at 77 K indicated similar chromophore structures for wild-type and A178R PR, and A178R PR pumps protons normally. We infer that the E-F loop has a unique structure in PR and the mutation of Ala178 disrupts the structure that includes the transmembrane region, leading to the observed changes in color and pK(a).

Several lines of evidence suggest that fine silicate crystals observed in primitive meteorite and interplanetary dust particles (IDPs) nucleated in a supersaturated silicate vapor followed by crystalline growth. We investigated evaporation of μm-sized silicate particles heated by a bow shock produced by a planetesimal orbiting in the gas in the early solar nebula and condensation of crystalline silicate from the vapor thus produced. Our numerical simulation of shock-wave heating showed that these μm-sized particles evaporate almost completely when the bow shock is strong enough to cause melting of chondrule precursor dust particles. We found that the silicate vapor cools very rapidly with expansion into the ambient unshocked nebular region; for instance, the cooling rate is estimated to be as high as 2000 K s −1 for a vapor heated by a bow shock associated with a planetesimal of radius 1 km. The rapid cooling of the vapor leads to nonequilibrium gas-phase condensation of dust at temperatures much lower than those expected from the equilibrium condensation. It was found that the condensation temperatures are lower by a few hundred K or more than the equilibrium temperatures. This explains the results of the recent experimental studies of condensation from a silicate vapor that condensation in such large supercooling reproduces morphologies similar to those of silicate crystals found in meteorites. Our results strongly suggest that the planetesimal bow shock is one of the plausible sites for formation of not only chondrules but also other cosmic crystals in the early solar system.