Charge-Induced Force Noise on Free-Falling Test Masses: Results from LISA Pathfinder.

We report on electrostatic measurements made on board the European Space Agency mission LISA Pathfinder. Detailed measurements of the charge-induced electrostatic forces exerted on free-falling test masses (TMs) inside the capacitive gravitational reference sensor are the first made in a relevant environment for a space-based gravitational wave detector. Employing a combination of charge control and electric-field compensation, we show that the level of charge-induced acceleration noise on a single TM can be maintained at a level close to 1.0 fm s^{-2} Hz^{-1/2} across the 0.1-100 mHz frequency band that is crucial to an observatory such as the Laser Interferometer Space Antenna (LISA). Using dedicated measurements that detect these effects in the differential acceleration between the two test masses, we resolve the stochastic nature of the TM charge buildup due to interplanetary cosmic rays and the TM charge-to-force coupling through stray electric fields in the sensor. All our measurements are in good agreement with predictions based on a relatively simple electrostatic model of the LISA Pathfinder instrument.

Sub-Femto-g Free Fall for Space-Based Gravitational Wave Observatories: LISA Pathfinder Results.

We report the first results of the LISA Pathfinder in-flight experiment. The results demonstrate that two free-falling reference test masses, such as those needed for a space-based gravitational wave observatory like LISA, can be put in free fall with a relative acceleration noise with a square root of the power spectral density of 5.2±0.1 fm s^{-2}/sqrt[Hz], or (0.54±0.01)×10^{-15} g/sqrt[Hz], with g the standard gravity, for frequencies between 0.7 and 20 mHz. This value is lower than the LISA Pathfinder requirement by more than a factor 5 and within a factor 1.25 of the requirement for the LISA mission, and is compatible with Brownian noise from viscous damping due to the residual gas surrounding the test masses. Above 60 mHz the acceleration noise is dominated by interferometer displacement readout noise at a level of (34.8±0.3) fm/sqrt[Hz], about 2 orders of magnitude better than requirements. At f≤0.5 mHz we observe a low-frequency tail that stays below 12 fm s^{-2}/sqrt[Hz] down to 0.1 mHz. This performance would allow for a space-based gravitational wave observatory with a sensitivity close to what was originally foreseen for LISA.

[In vitro activity of tigecycline on 760 bacterial strains isolated in the hospital university of Angers--2006-2009 TEST study]. / Activité in vitro de la tigécycline vis-à-vis de 760 souches bactériennes isolées au CHU d'Angers--le programme TEST 2006-2009.

Tigecycline (TGC), an antibiotic belonging to glycylcyclines, is active against Gram-positive bacteria, including multi-resistant bacteria, and most of the Gram-negative bacteria, including extended spectrum ß-lactamase-producers (ESBL) and Acinetobacter sp. TGC is not active on Pseudomonas aeruginosa. The microbiological laboratory from the university hospital of Angers participates in the Tigecycline Evaluation and Surveillance Trial (TEST) since 2006. The objective of this study is to evaluate the effectiveness of TGC and of various comparators against nosocomial and community-acquired pathogens. We also evaluated the effectiveness of TGC on a panel of strains isolated between 2006 and 2009 in the university hospital of Angers. Minimum inhibitory concentrations (MIC) were determined using the microdilution method. A total of 760 clinical strains were tested. TGC had a very good activity against Gram-positive bacteria, with 100 % of susceptibility for all the strains tested, irrespective of their resistance profile. Concerning Gram-negative bacteria, TGC was active against 93 % of Enterobacteriaceae, with a MIC 90 not exceeding 2mg/L. Whole of the 20 strains ESBL-producers tested were susceptible to TGC. Acinetobacter sp. were also inhibited at low concentrations of TGC, with a MIC 90 of 1mg/L. These results suggest that TGC can be a useful therapeutic alternative, especially for infections involving multiresistant bacteria.

Clustered cases of infections due to an uncommon methicillin-resistant Staphylococcus aureus originating in a maternity ward.

OBJECTIVE: We aimed to report a community outbreak of an uncommon methicillin-resistant Staphylococcus aureus (MRSA) originating in a maternity ward. PATIENTS AND METHODS: Cases were defined by epidemiological, clinical, and microbiological investigations. Microbiological investigations included phenotypic analysis, molecular typing, and whole-genome sequencing. To control the outbreak, we applied both national recommendations to prevent in-hospital transmission and the French High Council for Public Health guidelines on the management of community-acquired MRSA infections. RESULTS: Between March and July 2016, seven patients with MRSA infections were identified: six skin and soft tissue infections and one pulmonary infection, including six microbiologically confirmed infections. Infections occurred in community settings, but a link with the same maternity ward was found for all patients. All MRSA strains had a t690 spa type, were tetracycline-resistant, and produced Panton-Valentine leukocidin. All isolates belonged to the sequence type 88 (ST88). CONCLUSION: This outbreak highlights the largely underestimated risk of healthcare-associated infections in maternity wards. Healthcare workers should be aware of the importance of standard hygiene precautions and use of alcohol-based hand sanitizers for neonates and mothers.

[Retrospective study of serological tests for syphilis diagnosis at Nantes University hospital, between 1999 and 2006]. / Etude rétrospective des sérologies de syphilis au CHU de Nantes, de 1999 à 2006.

Since 2000, a resurgence of syphilis cases was observed in France and, particularly, in Paris area. The aim of this study was to evaluate the evolution of syphilis prevalence in Nantes area and its impact on our laboratory activity. Between 1999 and 2006, serological tests for syphilis performed at the laboratory were analysed according to the results of these tests, the age and patient sex and the wards. We treated about 32,000 serological tests, over an eight-year period. The number of tests increased by 7.5% per year and patients with a positive result were multiplied by three. These patients were men for 78%, with an average age of 43.4 years. The serological tests providing positive results were in general from two sectors, the anonymous and free detection center and the internal medicine ward and infectious diseases unit. Our study highlighted a strong increase in the number of positive tests, since 2001, with a clear orientation towards a sex male ratio in our area. This inclination currently did not show any decrease, at the opposite to what was observed by the InVS in Paris area.

"Open" structures of MurD: domain movements and structural similarities with folylpolyglutamate synthetase.

UDP-N-acetylmuramoyl-l-alanine:d-glutamate (MurD) ligase catalyses the addition of d-glutamate to the nucleotide precursor UDP-N-acetylmuramoyl-l-alanine (UMA). The crystal structures of Escherichia coli in the substrate-free form and MurD complexed with UMA have been determined at 2.4 A and 1.88 A resolution, respectively. The MurD structure comprises three domains each of a topology reminiscent of nucleotide-binding folds. In the two structures the C-terminal domain undergoes a large rigid-body rotation away from the N-terminal and central domains. These two "open" structures were compared with the four published "closed" structures of MurD. In addition the comparison reveals which regions are affected by the binding of UMA, ATP and d-Glu. Also we compare and discuss two structurally characterized enzymes which belong to the same ligase superfamily: MurD and folylpolyglutamate synthetase (FGS). The analysis allows the identification of key residues involved in the reaction mechanism of FGS. The determination of the two "open" conformation structures represents a new step towards the complete elucidation of the enzymatic mechanism of the MurD ligase.

Determination of the MurD mechanism through crystallographic analysis of enzyme complexes.

UDP -N- acetylmuramoyl- L -alanine: D -glutamate (MurD) ligase catalyses the addition of d -glutamate to the nucleotide precursor UDP -N- acetylmuramoyl- L -alanine (UMA). The crystal structures of three complexes of Escherichia coli MurD with a variety of substrates and products have been determined to high resolution. These include (1) the quaternary complex of MurD, the substrate UMA, the product ADP, and Mg2+, (2) the quaternary complex of MurD, the substrate UMA, the product ADP, and Mn2+, and (3) the binary complex of MurD with the product UDP - N- acetylmuramoyl- L -alanine- D -glutamate (UMAG). The reaction mechanism supported by these structures proceeds by the phosphorylation of the C-terminal carboxylate group of UMA by the gamma-phosphate group of ATP to form an acyl-phosphate intermediate, followed by the nucleophilic attack by the amino group of D-glutamate to produce UMAG. A key feature in the reaction intermediate is the presence of two magnesium ions bridging negatively charged groups.

Effect of analogues of diaminopimelic acid on the meso-diaminopimelate-adding enzyme from Escherichia coli.

Several analogues of diaminopimelic acid (A2pm) were tested as substrates or inhibitors of the meso-diaminopimelate-adding enzyme from Escherichia coli. They included lanthionine derivatives, a phosphonic analogue, heterocyclic compounds, 3-fluoro-A2pm, 4-methylene-A2pm and N-hydroxy-A2pm. The best substrates were, in decreasing order of specific enzyme activity, (2S,3R,6S)-3-fluoro-A2pm, meso-lanthionine sulfoxide and N-hydroxy-A2pm (mixture of stereoisomers). In those cases where all the stereoisomers were available, the specificity could be described as meso > > DD approximately to LL. N-Hydroxy-A2pm (mixture of stereoisomers) strongly inhibited the addition of radioactive meso-A2pm to UDP-N-acetylmuramoyl-dipeptide.

A comparative analysis of arranging in-flight oxygen aboard commercial air carriers.

INTRODUCTION: As air travel has become more commonplace in today's society, so too has air travel by oxygen-using individuals. Because there is little oversight or standardization of in-flight oxygen by the Federal Aviation Administration, individual airlines' policies and practices may vary greatly. On the premise that such variation may cause confusion by prospective air travelers, we undertook the current study to describe individual air carriers' policies and practices and to provide guidance to future air travelers. METHODS: Data were collected by a series of telephone calls placed by the study investigators to all commercial air carriers listed in the 1997 Cleveland Metropolitan Yellow Pages. The callers were registered respiratory therapists who identified themselves as inexperienced oxygen-requiring travelers wishing to arrange in-flight oxygen for an upcoming trip. Standard questions were asked of each carrier that included the following: Did the carrier have a special "help desk" to assist with oxygen arrangements? What oxygen systems, liter flow options, and interface devices were available? What was the charge for oxygen? How was the charged determined? What documentation from the physician was required? How much notification was required by the airline before the actual flight? In addition to recording these responses, the total amount of time spent on the telephone by the caller was logged along with the number of telephone calls and number of people spoken to in arranging in-flight oxygen. To compare oxygen charges between airlines, we calculated charges based on a "standard trip," which was defined as a nonstop, round-trip lasting 6 h in which the traveler used a flow rate of 2 L/min. RESULTS: Of the 33 commercial air carriers listed in the directory, 11 were US-based carriers and 22 were international-based carriers. Seventy-six percent of the airlines offered in-flight oxygen. For the 25 carriers offering in-flight oxygen, mean phone time required to make the arrangements was 9.96+/-4.8 min (range, 3 to 20 min). No more than two telephone calls were required to make oxygen arrangements. Most carriers required 48- to 72-h advance notice, with a single carrier requiring 1-month advance notice. Most carriers required some notification of oxygen needs by the traveler's physician. There was a great variation in oxygen device and liter flow availability. Liter flow options ranged from only two flow rates (36% of carriers) to a range of 1 to 15 L/min (one carrier). All carriers offered nasal cannula, which was the only device available for 21 carriers (84%). Actual charges for in-flight oxygen also varied greatly. Six carriers supplied oxygen free and 18 carriers charged a fee (range, $64 to $1,500). One airline allowed the traveler to bring one "E" cylinder with no fee assessed. For 14 of the 18 carriers that charged, the charge for the standard trip ranged from $100 to $250. CONCLUSIONS: (1) As expected from the lack of standard regulations, the availability, costs, and ease of implementing in-flight oxygen vary greatly among commercial air carriers. (2) Because the expense of in-flight oxygen is usually borne by the traveler (rather than by insurers), prospective travelers should consider charges for oxygen use when choosing an airline. (3) In the context that the current study shows substantial variation in oxygen policies, costs, and services among commercial air carriers and that such policies may change over time, our findings encourage the prospective air traveler needing in-flight oxygen to "shop around."

Shape coexistence and the N = 28 shell closure far from stability

The masses of 31 neutron-rich nuclei in the range A = 29-47 have been measured. The precision of 19 masses has been significantly improved and 12 masses were measured for the first time. The neutron-rich Cl, S, and P isotopes are seen to exhibit a change in shell structure around N = 28. Comparison with shell model and relativistic mean field calculations demonstrate that the observed effects arise from deformed prolate ground state configurations associated with shape coexistence. Evidence for shape coexistence is provided by the observation of an isomer in 43S.

Synthesis and biochemical evaluation of some novel N-acyl phosphono- and phosphinoalanine derivatives as potential inhibitors of the D-glutamic acid-adding enzyme.

A series of N-(5-phthalimidopentanoyl)-, N-[2-(2-ethoxy)acetyl]-, and N-(7-oxooctanoyl)-phosphono and phosphinoalanine derivatives has been synthesized and evaluated for inhibition of the D-glutamic acid-adding enzyme (MurD) of peptidoglycan biosynthesis.

Isotopic scaling and the symmetry energy in spectator fragmentation.

Isotopic effects in the fragmentation of excited target residues following collisions of 12C on (112,124)Sn at incident energies of 300 and 600 MeV per nucleon were studied with the INDRA 4pi detector. The measured yield ratios for light particles and fragments with atomic number Z < or = 5 obey the exponential law of isotopic scaling. The deduced scaling parameters decrease strongly with increasing centrality to values smaller than 50% of those obtained for the peripheral event groups. Symmetry-term coefficients, deduced from these data within the statistical description of isotopic scaling, are near gamma = 25 MeV for peripheral and gamma < 15 MeV for central collisions.

Synthesis of tritiated tuftsin and macrophage inhibitory tripeptide via acetylenic intermediates.

Acetylenic analogues of tuftsin (Thr-Dah-Pro-Arg) and of a macrophage inhibitory tripeptide (Thr-Dah-Pro) have been synthesized by conventional procedures in solution (Dah = 2,6-diamino-4-hexynoic acid). These acetylenic derivatives are intermediates for the preparation of structurally unmodified, tritiated peptides. Catalytic tritiation of Thr-Dah-Pro-Arg and of Thr-Dah-Pro has afforded the radioactive tetra- and tripeptides with specific activities of 11.4 Ci/mmol and 37 Ci/mmol, respectively.

Synthesis of analogs of the serum thymic nonapeptide, "facteur thymique serique" (FTS). Part I.

Analogs of FTS (Facteur Thymique Sérique), less than :formula: (see text), a circulating thymic factor, were prepared by replacing the amino acid residues in positions 1, 2, 8 and 9, or by shortening the nonapeptide chain at the N- or C-terminal end. These peptides were synthesized by two different schemes using the conventional synthesis in solution.

Hypercalcemia associated with dysregulation of 1,25-dihydroxyvitamin D in arthritis.

We describe an elderly man who presented with hypercalcemia associated with suppressed intact parathyroid hormone (PTH) levels. Despite renal insufficiency the circulating 1,25-dihydroxyvitamin D (1,25(OH)2D) was in the upper part of the normal range. Known causes of hypercalcemia were absent and mild hypercalcemia with suppression of intact PTH persisted until after bilateral hip replacement for severe arthritis (1 year after presentation). After hip replacement the ionized calcium normalized, intact PTH normalized, and 1,25(OH)2D decreased markedly. We believe the abnormalities in mineral homeostasis were related to production of 1,25(OH)2D by inflammatory mononuclear cells associated with arthritis.

Partial purification of rat and human serum factors inhibiting the G1-S transition in rat hepatocytes.

A low molecular weight compound, which inhibits the G1-S transition in rat hepatocytes, was purified from rat trypsin-treated serum by DEAE-cellulose chromatography and high-performance liquid chromatography on three different stationary phases. This procedure led to a 34500-fold purification with a 29% yield. Inactivation of the purified material by specific enzymes showed that the inhibitor is a glycopeptide containing a peptide moiety, N-acetylneuraminic acid and galactose residues. Amino acid analyses indicated the possible existence of a pentapeptide structure. The same purification procedure was applied to the corresponding human inhibitor. Inactivation by specific enzymes showed that it is also a glycopeptide.

Synthesis of analogs of the serum thymic nonapeptide, "facteur thymique serique" (FTS). Part II.

New analogs of FTS (Facteur Thymique Sérique), less than (Formula: see text), a circulating thymic factor, were prepared by replacing the amino acid residues in positions, 1, 3, 4, 5, 6 and 3 and 6 together. Five other analogs of C-terminal heptapeptide were prepared by replacing the amino acid residues in position 3 or 6. These peptides were synthesized using conventional synthesis in solution.