Arginine remarkably prolongs the lifetime of the M-intermediate in the bacteriorhodopsin photocycle at room temperature

AbstractThe lifetime of the M-intermediate in the bacteriorhodopsin photocycle was remarkably prolonged on drying a suspension of purple membrane, in arginine solution at alkaline pH. The M-intermediate could be completely accumulated under illumination (530 nm) at room temperature. The crystalline structure of purple membranes was retained after this treatment. The lifetime of the M-intermediate was found to be longer than 100 s and depended on the pH of the purple membrane suspension before drying. It was suggested that an interaction between the guanidium group of arginine and an amino acid residue played an important role in the prolongation

Fotoindukowana separacja ładunku pomiędzy porfiryną i chinonem przyłączonymi kowalencyjnie na przeciwnych końcach łańcucha poli(kwasu metakrylowego)

Badano proces fotoindukowanej separacji ³adunku pomiêdzy cz¹steczkami porfiryny (P) i benzochinonu (Q), kowalencyjnie przy³¹czonymi na przeciwnych koñcach ³añcucha poli(kwasu metakrylowego) (PMMA). Okreoelono wp³yw d³ugooeci ³añcucha, pH, si³y jonowej wodnych roztworów polimeru na wartooeæ sta³ej szybkooeci separacji ³adunku i wydajnooeci tworzenia pary rodniko-jonów P+• – Q–•.Photoinduced charge separation from porphyrin (P) to benzoquinone (Q) moieties covalently attached to the opposite chain ends of poly(methacrylic acid) (PMMA) was studied. The effect of polymer chain length, pH and ionic strength of the aqueous solution on the rate constant of charge separation and efficiency of P+•–Q–• radical ion pair formation was determined

Roles of bulk γ(L)-Bi₂MoO₆ and surface β-Bi₂Mo₂O₉ in the selective catalytic oxidation of C₃H₆

γ(L)-Bi₂MoO₆ (L: low temperature phase) catalysts, whose surface compositions have a Mo/Bi ratio above = 0.5, exhibited high selectivity in the partial oxidation of C₃H₆, while catalysts with Mo/Bi surface ratios near or below = 0.5 exhibited low selectivity. γ(L)-phase catalysts which have Mo/Bi surface ratios greater than = 0.5, were demonstrated to form β-Bi₂Mo₂O₉ on their surface. An interaction between the β- and γ(L)-phases was observed in these catalysts’ UV–vis spectra at 430 nm. The new β-phase material seems to grow along b-axis of γ(L)-phase, i.e., perpendicular to MoO₂–Bi₂O₂ layers. Structure visualizations revealed that the α-Bi₂Mo₃O₁₂, β-, and γ(H)-phases, which are selective catalysts, contain twin Mo tetrahedral structures, and that their Mo and Bi ions lie on the same plane. The pure γ(L)-phase does not contain this structure. A model for the very rapid transfer of oxygen between the γ(L)- and β-phases is discussed in relation to the kinetics of C₃H₆ oxidation.ArticleJournal of molecular catalysis. A, Chemical. 318(1-2):94-100 (2010)journal articl

The X-ray Jet in Centaurus A: Clues on the Jet Structure and Particle Acceleration

We report detailed studies of the X-ray emission from the kpc scale jet in the nearest active galaxy, Cen A. 41 compact sources were found within the jet, 13 of which were newly identified. We construct the luminosity function for the detected jet-knots and argue that the remaining emission is most likely to be truly diffuse, rather than resulting from the pile-up of unresolved faint knots. The transverse jet profile reveals that the extended emission has the intensity peak at the jet boundaries. We note that limb-brightened jet morphologies have been observed previously at radio frequencies in some jet sources, but never so clearly at higher photon energies. Our result therefore supports a stratified jet model, consisting of a relativistic outflow including a boundary layer with a velocity shear. In addition, we found that the X-ray spectrum of the diffuse component is almost uniform across and along the jet. We discuss this spectral behavior within a framework of shock and stochastic particle acceleration processes. We note some evidence for a possible spectral hardening at the outer sheath of the jet. Due to the limited photon statistics of the present data, further deep observations of Cen A are required to determine the reality of this finding, however we note that the existence of the hard X-ray features at outer jet boundaries would provide an important challenge to theories for the evolution of ultra-relativistic particles within the jets.Comment: 27page, 8 figures, ver2, accepted for publication in the Ap

Trimeric mutant bacteriorhodopsin, D85N, shows a monophasic CD spectrum

AbstractThe structure of mutant bacteriorhodopsin (bR), D85N, was examined by CD and X-ray diffraction at pH 7. The absorption maximum of D85N at pH 7 is located at 605 nm, which is similar to the acid-blue form of wild-type bR. D85N shows a monophasic CD band, the maximum of which is at 575 nm, although the crystalline arrangement and the trimeric structure is maintained. The acid-blue form of wild-type bR shows a biphasic CD despite the similarity in absorption spectra

Impact of the COVID-19 Pandemic on the Psychological Distress of Medical Students in Japan: Cross-sectional Survey Study

Background: The COVID-19 pandemic has negatively affected medical education. However, little data are available about medical students’ distress during the pandemic. Objective: This study aimed to provide details on how medical students have been affected by the pandemic. Methods: A cross-sectional study was conducted. A total of 717 medical students participated in the web-based survey. The survey included questions about how the participants’ mental status had changed from before to after the Japanese nationwide state of emergency (SOE). Results: Out of 717 medical students, 473 (66.0%) participated in the study. In total, 29.8% (141/473) of the students reported concerns about the shift toward online education, mostly because they thought online education would be ineffective compared with in-person learning. The participants’ subjective mental health status significantly worsened after the SOE was lifted (P Conclusions: Given our findings, the sudden shift to online education might have overwhelmed medical students. Thus, we recommend that educators inform learners that online learning is not inferior to in-person learning, which could attenuate potential depression and anxiety

The effectiveness of simulation-based education combined with peer-assisted learning on clinical performance of first-year medical residents: a case-control study

Background Simulation-based education and peer-assisted learning (PAL) are both known as useful educational methods. Previous research has reported that combining these two methods are effective for training medical residents in short-term evaluation. This study was aimed to evaluate the middle- to long-term effects of simulation-based education combined with PAL on the performance of medical residents during emergency department duties. Methods This study was designed as a case-control study and conducted over three years at Okayama University Hospital in Japan. Postgraduate-year-one medical residents were assigned to three groups: a simulation group that received simulation-based education, a lecture group that received traditional lecture-based education, and a control group that received no such prior trainings. Prior training in emergency department duties using PAL was performed as an educational intervention for the simulation and lecture groups during the clinical orientation period. The residents' medical knowledge was assessed by written examinations before and after the orientation. The performance of residents during their emergency department duties was assessed by self-evaluation questionnaires and objective-assessment checklists, following up with the residents for three months after the orientation period and collecting data on their 1st, 2nd, and 3rd emergency department duties. All the datasets collected were statistically analyzed and compared by their mean values among the three groups. Results A total of 75 residents were included in the comparative study: 27 in the simulation group, 24 in the lecture group, and 24 in the control group. The simulation and lecture groups obtained significantly higher written examination scores than the control group. From the self-evaluation questionnaires, the simulation group reported significantly higher satisfaction in their prior training than the lecture group. No significant differences were found in the emergency department performance of the residents among the three groups. However, when evaluating the improvement rate of performance over time, all three groups showed improvement in the subjective evaluation, and only the simulation and lecture groups showed improvement in the objective evaluation.ConclusionSimulation-based education combined with PAL is effective in improving the knowledge and satisfaction of medical residents, suggesting the possibility of improving work performance during their emergency department duties

Properties of the Disorder Induced in the Purple Membrane Structure by Iodination

Iodination induces disorder in the crystalline structure of purple membrane. The properties Of the disorder were examined by X-ray diffraction experiments on the iodinated purple membrane. The analysis of the intensity and the integral width of the Bragg reflections revealed that the disorder was well characterized by the second kind of disorder. The g value, which represents the extent of the second kind of disorder, is obtained for iodinated purple membrane with various extent of iodination. The g value and the wavelength at absorption maximum of iodinated PM are well correlated, indicating that the local change around retinal is reflected in the disorder in the crystalline structure of purple membrane

Angina Simultaneously Diagnosed with the Recurrence of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) mainly affects young adults and can have a potential impact on social functioning. As this syndrome is associated with endothelial dysfunction, the heart can be damaged via ischemia due to endothelial damage. This might potentially lead to heart failure, which accounts for approximately 20% of deaths among patients with ME/CFS. While cardiac ischemia is thought be a pathophysiologically important manifestation of this syndrome, this is not yet reported. Herein, we present a case of a young female with newly diagnosed vasospastic or microvascular angina and concurrent exacerbation of ME/CFS severity. Her anginal symptoms, including exertional chest pain and transient chest discomfort, mimicked those of ME/CFS but were relieved after the administration of a calcium channel blocker. We emphasize the possibility of concurrent angina and exacerbation of ME/CFS and the importance of detecting cardiac ischemia to avoid unfavorable outcomes

Clinical Relevance of Blood Glucose and Gastroesophageal Reflux Symptoms to Depressive Status in Patients with Type 2 Diabetes Mellitus

A relationship between diabetes and depression is apparent. To clarify the clinical relevance of diabetic patients’ gastroesophageal symptoms to their psychological status, we retrospectively analyzed the data from a Selfrating Depression Scale (SDS) and a Frequency Scale for Symptoms of Gastroesophageal reflux disease (FSSG) among 143 type 2 diabetic patients who visited a general medicine department. Among the 45 Japanese patients enrolled, the group with relatively high SDS scores (≥ 36) showed higher (FSSG) dysmotility symptom scores versus the low-SDS (< 36) group, although the 2 groups’ characteristics and laboratory data were not significantly different. Positive correlations of postprandial plasma glucose (PPG) levels with FSSG scores (R=0.321, p<0.05), particularly with reflux scores (R=0.455, p<0.01) were revealed. PPG and HbA1c levels were not correlated with SDS scores. The patients’ SDS scores were significantly correlated with their FSSG scores (R=0.41, p<0.01), suggesting that depressive status is linked to GERD-related manifestations. Considering that the patients’ PPG levels were correlated with GERD-related symptoms, diabetic patients’ blood glucose levels are associated with depressive status. Collectively, key symptoms related to GERD and glucose level values would be helpfu