Serratia marcescens prosthetic joint infection: two case reports and a review of the literature.

BACKGROUND: Despite some studies on Gram-negative bacteria as difficult to treat pathogens in periprosthetic joint infections, there are no detailed analyses on Serratia periprosthetic joint infections. As such, we present two cases of Serratia periprosthetic joint infections and summarize all known cases to date in the course of a PRISMA criteria-based systematic review. CASE PRESENTATION: Case 1: a 72-year-old Caucasian female with Parkinson's disease and treated breast cancer developed periprosthetic joint infection caused by Serratia marcescens and Bacillus cereus, following multiple prior revisions for recurrent dislocations of her total hip arthroplasty. Two-stage exchange was performed, and the patient remained free of Serratia periprosthetic joint infection recurrence at 3 years. Case 2: an 82-year-old Caucasian female with diabetes and chronic obstructive pulmonary disease presented with a chronic parapatellar knee fistula after undergoing multiple failed infection treatments at external clinics. After performing two-stage exchange and gastrocnemius flap plastic for combined Serratia marcescens and Proteus mirabilis periprosthetic joint infection, the patient was released without any signs of infection, but was subsequently lost to follow-up. REVIEW: a total of 12 additional Serratia periprosthetic joint infections were identified. Merged with our two cases, the mean age of 14 patients was 66 years and 75% were males. Mean length of antibiotic therapy was 10 weeks with ciprofloxacin most commonly used (50%). Mean follow-up was 23 months. There was a total of four reinfections (29%), including one case of Serratia reinfection (7%). CONCLUSIONS: Serratia is a rare cause of periprosthetic joint infection affecting elderly with secondary diseases. While the overall reinfection rate was high, the risk of Serratia periprosthetic joint infection persistence was low. Treatment failure in patients may be attributable to the host, rather than the Serratia periprosthetic joint infection itself, thus challenging current concepts on Gram-negatives as a uniform class of difficult-to-treat pathogens. LEVEL OF EVIDENCE: Therapeutic level IV

Down-phase auditory stimulation is not able to counteract pharmacologically or physiologically increased sleep depth in traumatic brain injury rats

Modulation of slow-wave activity, either via pharmacological sleep induction by administering sodium oxybate or sleep restriction followed by a strong dissipation of sleep pressure, has been associated with preserved posttraumatic cognition and reduced diffuse axonal injury in traumatic brain injury rats. Although these classical strategies provided promising preclinical results, they lacked the specificity and/or translatability needed to move forward into clinical applications. Therefore, we recently developed and implemented a rodent auditory stimulation method that is a scalable, less invasive and clinically meaningful approach to modulate slow-wave activity by targeting a particular phase of slow waves. Here, we assessed the feasibility of down-phase targeted auditory stimulation of slow waves and evaluated its comparative modulatory strength in relation to the previously employed slow-wave activity modulators in our rat model of traumatic brain injury. Our results indicate that, in spite of effectively reducing slow-wave activity in both healthy and traumatic brain injury rats via down-phase targeted stimulation, this method was not sufficiently strong to counteract the boost in slow-wave activity associated with classical modulators, nor to alter concomitant posttraumatic outcomes. Therefore, the usefulness and effectiveness of auditory stimulation as potential standalone therapeutic strategy in the context of traumatic brain injury warrants further exploration

Global distribution and bioclimatic characterization of alpine biomes

Although there is a general consensus on the distribution and ecological features of terrestrial biomes, the allocation of alpine ecosystems in the global biogeographic system is still unclear. Here, we delineate a global map of alpine areas above the treeline by modelling regional treeline elevation at 30 m resolution, using global forest cover data and quantile regression. We then used global datasets to 1) assess the climatic characteristics of alpine ecosystems using principal component analysis, 2) define bioclimatic groups by an optimized cluster analysis and 3) evaluate patterns of primary productivity based on the normalized difference vegetation index. As defined here, alpine biomes cover 3.56 Mkm(2) or 2.64% of land outside Antarctica. Despite temperature differences across latitude, these ecosystems converge below a sharp threshold of 5.9 degrees C and towards the colder end of the global climatic space. Below that temperature threshold, alpine ecosystems are influenced by a latitudinal gradient of mean annual temperature and they are climatically differentiated by seasonality and continentality. This gradient delineates a climatic envelope of global alpine biomes around temperate, boreal and tundra biomes as defined in Whittaker's scheme. Although alpine biomes are similarly dominated by poorly vegetated areas, world ecoregions show strong differences in the productivity of their alpine belt irrespectively of major climate zones. These results suggest that vegetation structure and function of alpine ecosystems are driven by regional and local contingencies in addition to macroclimatic factors

A large ungated TPC with GEM amplification

A Time Projection Chamber (TPC) is an ideal device for the detection of charged particle tracks in a large volume covering a solid angle of almost . The high density of hits on a given particle track facilitates the task of pattern recognition in a high-occupancy environment and in addition provides particle identification by measuring the specific energy loss for each track. For these reasons, TPCs with Multiwire Proportional Chamber (MWPC) amplification have been and are widely used in experiments recording heavy-ion collisions. A significant drawback, however, is the large dead time of the order of 1 ms per event generated by the use of a gating grid, which is mandatory to prevent ions created in the amplification region from drifting back into the drift volume, where they would severely distort the drift path of subsequent tracks. For experiments with higher event rates this concept of a conventional TPC operating with a triggered gating grid can therefore not be applied without a significant loss of data. A continuous readout of the signals is the more appropriate way of operation. This, however, constitutes a change of paradigm with considerable challenges to be met concerning the amplification region, the design and bandwidth of the readout electronics, and the data handling. A mandatory prerequisite for such an operation is a sufficiently good suppression of the ion backflow from the avalanche region, which otherwise limits the tracking and particle identification capabilities of such a detector. Gas Electron Multipliers (GEM) are a promising candidate to combine excellent spatial resolution with an intrinsic suppression of ions. In this paper we describe the design, construction and the commissioning of a large TPC with GEM amplification and without gating grid (GEM-TPC). The design requirements have driven innovations in the construction of a light-weight field-cage, a supporting media flange, the GEM amplification and the readout system, which are presented in this paper. We further describe the support infrastructure such as gas, cooling and slow control. Finally, we report on the operation of the GEM-TPC in the FOPI experiment, and describe the calibration procedures which are applied to achieve the design performance of the device.Peer reviewe

Which treatment for low back pain? A factorial randomised controlled trial comparing intravenous analgesics with oral analgesics in the emergency department and a centrally acting muscle relaxant with placebo over three days [ISRCTN09719705]

BACKGROUND: About two thirds of adults suffer from backpain at some time during their life. In the emergency room many patients with acute back pain are treated with intravenous non-steroidal analgesics. Whether this treatment is superior to oral administration of non-steroidal analgesics is unknown. Intravenous administration, however, requires considerable amounts of resources and accounts for high workload in busy clinics. In the further course centrally acting muscle relaxants are prescribed but the effectiveness remains unclear. The objective of this study is on the one hand to compare the effectiveness of intravenous with oral non-steroidal analgesics for acute treatment and on the other hand to compare the effectiveness of a centrally active muscle relaxant with placebo given for three days after presentation to the ED (emergency department). METHODS/DESIGN: This study is intended as a randomised controlled factorial trial mainly for two reasons: (1) the sequence of treatments resembles the actual proceedings in every-day clinical practice, which is important for the generalisability of the results and (2) this design allows to take interactions between the two sequential treatment strategies into account. There is a patient preference arm included because patients preference is an important issue providing valuable information: (1) it allows to assess the interaction between desired treatment and outcome, (2) results can be extrapolated to a wider group while (3) conserving the advantages of a fully randomised controlled trial. CONCLUSION: We hope to shed more light on the effectiveness of treatment modalities available for acute low back pain

Dynamical locality and covariance: What makes a physical theory the same in all spacetimes?

The question of what it means for a theory to describe the same physics on all spacetimes (SPASs) is discussed. As there may be many answers to this question, we isolate a necessary condition, the SPASs property, that should be satisfied by any reasonable notion of SPASs. This requires that if two theories conform to a common notion of SPASs, with one a subtheory of the other, and are isomorphic in some particular spacetime, then they should be isomorphic in all globally hyperbolic spacetimes (of given dimension). The SPASs property is formulated in a functorial setting broad enough to describe general physical theories describing processes in spacetime, subject to very minimal assumptions. By explicit constructions, the full class of locally covariant theories is shown not to satisfy the SPASs property, establishing that there is no notion of SPASs encompassing all such theories. It is also shown that all locally covariant theories obeying the time-slice property possess two local substructures, one kinematical (obtained directly from the functorial structure) and the other dynamical (obtained from a natural form of dynamics, termed relative Cauchy evolution). The covariance properties of relative Cauchy evolution and the kinematic and dynamical substructures are analyzed in detail. Calling local covariant theories dynamically local if their kinematical and dynamical local substructures coincide, it is shown that the class of dynamically local theories fulfills the SPASs property. As an application in quantum field theory, we give a model independent proof of the impossibility of making a covariant choice of preferred state in all spacetimes, for theories obeying dynamical locality together with typical assumptions.Comment: 60 pages, LaTeX. Version to appear in Annales Henri Poincar

Modulated Martensite: Why it forms and why it deforms easily

Diffusionless phase transitions are at the core of the multifunctionality of (magnetic) shape memory alloys, ferroelectrics and multiferroics. Giant strain effects under external fields are obtained in low symmetric modulated martensitic phases. We outline the origin of modulated phases, their connection with tetragonal martensite and consequences for their functional properties by analysing the martensitic microstructure of epitaxial Ni-Mn-Ga films from the atomic to macroscale. Geometrical constraints at an austenite-martensite phase boundary act down to the atomic scale. Hence a martensitic microstructure of nanotwinned tetragonal martensite can form. Coarsening of twin variants can reduce twin boundary energy, a process we could follow from the atomic to the millimetre scale. Coarsening is a fractal process, proceeding in discrete steps by doubling twin periodicity. The collective defect energy results in a substantial hysteresis, which allows retaining modulated martensite as a metastable phase at room temperature. In this metastable state elastic energy is released by the formation of a 'twins within twins' microstructure which can be observed from the nanometre to millimetre scale. This hierarchical twinning results in mesoscopic twin boundaries which are diffuse, in contrast to the common atomically sharp twin boundaries of tetragonal martensite. We suggest that observed extraordinarily high mobility of such mesoscopic twin boundaries originates from their diffuse nature which renders pinning by atomistic point defects ineffective.Comment: 34 pages, 8 figure

The Plastid Genome of Eutreptiella Provides a Window into the Process of Secondary Endosymbiosis of Plastid in Euglenids

Euglenids are a group of protists that comprises species with diverse feeding modes. One distinct and diversified clade of euglenids is photoautotrophic, and its members bear green secondary plastids. In this paper we present the plastid genome of the euglenid Eutreptiella, which we assembled from 454 sequencing of Eutreptiella gDNA. Comparison of this genome and the only other available plastid genomes of photosynthetic euglenid, Euglena gracilis, revealed that they contain a virtually identical set of 57 protein coding genes, 24 genes fewer than the genome of Pyramimonas parkeae, the closest extant algal relative of the euglenid plastid. Searching within the transcriptomes of Euglena and Eutreptiella showed that 6 of the missing genes were transferred to the nucleus of the euglenid host while 18 have been probably lost completely. Euglena and Eutreptiella represent the deepest bifurcation in the photosynthetic clade, and therefore all these gene transfers and losses must have happened before the last common ancestor of all known photosynthetic euglenids. After the split of Euglena and Eutreptiella only one additional gene loss took place. The conservation of gene content in the two lineages of euglenids is in contrast to the variability of gene order and intron counts, which diversified dramatically. Our results show that the early secondary plastid of euglenids was much more susceptible to gene losses and endosymbiotic gene transfers than the established plastid, which is surprisingly resistant to changes in gene content