Time-resolved two-photon spectroscopy of photosystem I determines hidden carotenoid dark-state dynamics

We present time-resolved fs two-photon pump-probe data measured with photosystem I (PS I) of Thermosynechococcus elongatus. Two-photon excitation (λexc/2) 575 nm) in the spectral region of the optically forbidden first excited singlet state of the carotenoids, Car S1, gives rise to a 800 fs and a 9 ps decay component of the Car S1f Sn excited-state absorption with an amplitude of about 47 ( 16 % and 53 ( 10%, respectively. By measuring a solution of pure "-carotene under exactly the same conditions, only a 9 ps decay component can be observed. Exciting PS I at exactly the same spectral region via one-photon excitation (λexc) 575 nm) also does not show any sub-ps component. We ascribe the observed constant of 800 fs to a portion of about 47 ( 16 % "-carotene states that can potentially transfer their energy efficiently to chlorophyll pigments via the optically dark Car S1 state. We compared these data with conventional one-photon pump-probe data, exciting the optically allowed second excited state, Car S2. This comparison demonstrates that the fast dynamics of the optically forbidden state can hardly be unravelled via conventional one-photon excitation only because the corresponding Car S1 populations are too small after Car S2 f Car S1 internal conversion. A direct comparison of the amplitudes of the Car S1 f Sn excited-state absorption of PS I and "-carotene observed after Car S2 excitation allows determination of a quantum yield for the Car S1 formation in PS I of 44 ( 5%. In conclusion, an overall Car S2f Chl energy-transfer efficiency of∼69 ( 5 % is observed at room temperature with 56 ( 5 % being transferred via Car S2 and probably very hot Car S1 states and 13 ( 5 % being transferred via hot and “cold ” Car S1 states

The PPIP5K Family Member Asp1 Controls Inorganic Polyphosphate Metabolism in S. pombe

Inorganic polyphosphate (polyP) which is ubiquitously present in both prokaryotic and eukaryotic cells, consists of up to hundreds of orthophosphate residues linked by phosphoanhydride bonds. The biological role of this polymer is manifold and diverse and in fungi ranges from cell cycle control, phosphate homeostasis and virulence to post-translational protein modification. Control of polyP metabolism has been studied extensively in the budding yeast Saccharomyces cerevisiae. In this yeast, a specific class of inositol pyrophosphates (IPPs), named IP7, made by the IP6K family member Kcs1 regulate polyP synthesis by associating with the SPX domains of the vacuolar transporter chaperone (VTC) complex. To assess if this type of regulation was evolutionarily conserved, we determined the elements regulating polyP generation in the distantly related fission yeast Schizosaccharomyces pombe. Here, the VTC machinery is also essential for polyP generation. However, and in contrast to S. cerevisiae, a different IPP class generated by the bifunctional PPIP5K family member Asp1 control polyP metabolism. The analysis of Asp1 variant S. pombe strains revealed that cellular polyP levels directly correlate with Asp1-made IP8 levels, demonstrating a dose-dependent regulation. Thus, while the mechanism of polyP synthesis in yeasts is conserved, the IPP player regulating polyP metabolism is diverse

Tetryl Exposure: Forgotten Hazards Of Antique Munitions

Background: Older yet still abundant munitions such as tetryl present easily forgotten health hazards and associated needs for worker protection. Case presentation: Symptoms and findings from 22 workers who were exposed to tetryl are summarized. Conclusions: This study highlights the health hazards from exposure to tetryl. Occupational health professionals need to maintain vigilance to protect workers from the risks of handling older munitions

Enhanced effects of combined cognitive bias modification and computerised cognitive behaviour therapy on social anxiety

This study examines whether combined cognitive bias modification for interpretative biases (CBM-I) and computerised cognitive behaviour therapy (C-CBT) can produce enhanced positive effects on interpretation biases and social anxiety. Forty socially anxious students were randomly assigned into two conditions, an intervention group (positive CBM-I + C-CBT) or an active control (neutral CBM-I + C-CBT). At pre-test, participants completed measures of social anxiety, interpretative bias, cognitive distortions, and social and work adjustment. They were exposed to 6 × 30 min sessions of web-based interventions including three sessions of either positive or neutral CBM-I and three sessions of C-CBT, one session per day. At post-test and two-week follow-up, participants completed the baseline measures. A combined positive CBM-I + C-CBT produced less negative interpretations of ambiguous situations than neutral CBM-I + C-CBT. The results also showed that both positive CBM-I + C-CBT and neutral CBM-I + C-CBT reduced social anxiety and cognitive distortions as well as improving work and social adjustment. However, greater effect sizes were observed in the positive CBM-I + C-CBT condition than the control. This indicates that adding positive CBM-I to C-CBT enhanced the training effects on social anxiety, cognitive distortions, and social and work adjustment compared to the neutral CBM-I + C-CBT condition

La Plaque Console Du Radius : Une Alternative Dans L’ostéosynthèse Des Fractures De L’extrémité Supérieure De L’humérus ?

The aim of this study was to report the results of our experience in the treatment of proximal fractures with distal radius plate. This prospective study was conducted between January 2010 and December 2014. It took into account patients with a body mass index (BMI) not more than 25 kg/m2 in which the indication of conservative surgical treatment was decided and who did not have enough financial means to fulfill the required implants. The Neer classification was used to characterize fracture. To assess treatment outcomes, we used UCLA (University of California in Los Angeles) slightly modified score. There were 17 patients including 10 men and 7 women with a mean age of 32 years. According to Neer classification, six patients (35,29%) had stage I lesions, 5 others (29,42%) stage II and 6 patients (35,29%), stage III. There was no open fracture. There were three cases (17, 66%) of fracture-dislocations with one posterior variety. The average time of care was 13, 7 days (with a range of 2 to 29 days). The average time of healing was 117, 4 days with extremes of 81 days and 4 months 10 days. All patients were consolidated. The results at a mean of 15.31 months revealed excellent results in 29.41% and 29.41% poor results. In young patients whose treatment should be as conservative as possible, the distal radius plate could be an alternative if patient BMI does not exceed 25 kg/m2 and the epiphyseal screws are not too long. In case of comminuted fracture, it seems more desirable to postpone the osteosynthesis of weeks. However, only other subsequent studies on larger samples and longer followup, may lead to some conclusions about the usefulness of the distal radius plate in these lesions

Les Fractures De La Patella Chez L’adulte

Objectives: to determine the epidemiological aspects, the different techniques of surgical fixation of the patella fractures and the results. Patients and methods: this was a retrospective study from January 1, 2013 to December 31, 2017 and included the records of patients aged 15 years and older surgically treated for a patella fracture in our center. Results: The work involved 36 patients including 28 men (77.8%) and 8 women (22.2%) with a mean age of 35.9 years. High way trauma were the first cause of these fractures. Fractures were open in 44.4% of cases. Type II according to Ricard and Moulay classification was the most represented with 58.3% of cases. The majority of the patients, 80.5%, were treated by rigging. Five (5) cases of hematoma, one (1) postoperative infection, and three (3) cases of knee stiffness complicated the short- and medium-term follow-up. With an average follow-up of 2 years 6 months, radiologically, normal consolidation was achieved in 86.1% of cases. Two (2) cases of delayed consolidation and three (3) cases of nonunion have been noted. Three (3) cases of patellofemoral osteoarthritis appeared at two years. From the functional point of view, according to the Bosman score, 27.8% were excellent, 63.9% were good, 8.3% were bad, and the cable rigging seemed to give excellent and good results. Conclusion: the treatment of transverse fractures of the patella must be exclusively surgical. Guying is an osteosynthesis technique of choice. Nevertheless complications including knee stiffness, non-union and patellofemoral osteoarthritis are not uncommo

Oxidative Degradation of Glucose Adducts to Protein: Formation of 3-(N\u3csup\u3ee\u3c/sup\u3e-Lysino)-Lactic Acid from Model Compounds and Glycated Proteins

The chemistry of Maillard or browning reactions of glycated proteins is being studied in model systems in vitro in order to characterize potential reaction pathways and products in biological systems. In previous work with the Amadori rearrangement product N alpha-formyl-N epsilon-fructoselysine (fFL), an analog of glycated lysine residues in proteins, we showed that fFL was oxidatively cleaved between C-2 and C-3 of the carbohydrate chain to yield N epsilon-carboxymethyllysine (CML) and D-erythronic acid. We then detected CML in proteins glycated in vitro, as well as in human lens proteins and collagen in vivo (Ahmed, M. U., Thorpe, S. R., and Baynes, J. W. (1986) J. Biol. Chem. 261, 4889-4894). This work provided an explanation for the origin of CML in human urine and evidence for non-browning pathways of the Maillard reaction in vivo. In this report we describe the identification of a second set of products resulting from oxidative cleavage of fFL between C-3 and C-4 of the sugar chain, i.e. 3-(N epsilon-lysino)-lactic acid (LL) and D-glyceric acid. The formation of LL from fFL was increased at slightly acid pH, representing about 30% of the yield of CML at pH 6.4, compared with 4% at pH 7.4 in phosphate buffer. By gas chromatography-mass spectroscopy, LL was detected in proteins glycated in vitro and then identified as a natural product in human lens proteins and urine. Our results indicate that oxidative degradation of Amadori adducts toproteins occurs in vivo, leading to formation and excretion of CML and LL. These non-browning pathways for reaction of Amadori compounds may be physiologically relevant mechanisms for averting potentially damaging consequences of the Maillard reaction