The splenium of the corpus callosum:embryology, anatomy, function and imaging with pathophysiological hypothesis

Background and purpose The splenium of the corpus callosum is the most posterior part of the corpus callosum. Its embryological development, anatomy, vascularization, function, imaging of pathology, possible pathophysiological mechanisms by which pathology may develop and the clinical consequences are discussed. Methods A literature-based description is provided on development, anatomy and function. MR and CT images are used to demonstrate pathology. The majority of pathology, known to affect the splenium, and the clinical effects are described in three subsections: (A) limited to the splenium, with elaboration on pathophysiology of reversible splenial lesions, (B) pathology in the cerebral white matter extending into or deriving from the splenium, with special emphasis on tumors, and (C) splenial involvement in generalized conditions affecting the entire brain, with a hypothesis for pathophysiological mechanisms for the different diseases. Results The development of the splenium is preceded by the formation of the hippocampal commissure. It is bordered by the falx and the tentorium and is perfused by the anterior and posterior circulation. It contains different caliber axonal fibers and the most compact area of callosal glial cells. These findings may explain the affinity of specific forms of pathology for this region. The fibers interconnect the temporal and occipital regions of both hemispheres reciprocally and are important in language, visuospatial information transfer and behavior. Acquired pathology may lead to changes in consciousness. Conclusion The development, location, fiber composition and vascularization of the splenium make it vulnerable to specific pathological processes. It appears to play an important role in consciousness

Protein-mediated DNA Loop Formation and Breakdown in a Fluctuating Environment

Living cells provide a fluctuating, out-of-equilibrium environment in which genes must coordinate cellular function. DNA looping, which is a common means of regulating transcription, is very much a stochastic process; the loops arise from the thermal motion of the DNA and other fluctuations of the cellular environment. We present single-molecule measurements of DNA loop formation and breakdown when an artificial fluctuating force, applied to mimic a fluctuating cellular environment, is imposed on the DNA. We show that loop formation is greatly enhanced in the presence of noise of only a fraction of $k_B T$, yet find that hypothetical regulatory schemes that employ mechanical tension in the DNA--as a sensitive switch to control transcription--can be surprisingly robust due to a fortuitous cancellation of noise effects

Mid-term results after operative treatment of rockwood grade III-V Acromioclavicular joint dislocations with an AC-hook-plate

Acromioclavicular joint dislocations often occur in athletic, young patients after blunt force to the shoulder. Several static and dynamic operative procedures with or without primary ligament replacement have been described. Between February 2003 and March 2009 we treated 313 patients suffering from Rockwood III-V lesions of the AC joint with an AC-hook plate. 225 (72%) of these patients could be followed up. Mean operation time was 42 minutes in the conventional group and 47 minutes in the minimal invasive group. The postoperative pain on a scale from 1 to 10 (VAS-scale) was rated 2.7 in the conventional group and 2.2 in the minimal invasive group. Taft score showed very good and good results in 189 patients (84%). Constant score showed an average of 92.4 of 100 possible points with 89% excellent and good results and 11% satisfying results. All patients had some degree of pain or discomfort with the hookplate in place. These symptoms were relieved after removal of the plate. The overall complication rate was 10.6%. There were 6 superficial soft tissue infections, 1 fracture of the acromion, 7 redislocations after removal of the hook-plate. We observed 4 broken hooks which could be removed at the time of plate removal, 4 seromas and 2 cases of lateral clavicle bone infection, which required early removal of the plate. We can conclude that clavicle hook plate is a convenient device for the surgical treatment of Rockwood Grade III-V dislocations, giving good mid-term results with a low overall complication rate compared to the literature. Early functional therapy is possible and can avoid limitations in postoperative shoulder function

Melatonin in neuropaediatric MRI:a retrospective study of efficacy in a general hospital setting

Background: Melatonin may offer a safe and cheap alternative to general anaesthesia and sedatives in neuropaediatric MRI. The purpose of our study was to evaluate its efficacy during a daily scanning programme and to assess its financial benefit. Methods: Neuro-MRI scans, performed in a general hospital setting after administration of melatonin in 64 children aged 10 months–5 years, were retrospectively reassessed by an experienced paediatric neuroradiologist, rating them as diagnostically contributing or as failed. The financial benefit was calculated. Results: 49/64 scans (77%) were diagnostically contributing, in 11 (22%) no movement artefact was seen in any sequence; 15/64 scans failed (23%), in 3/15 because of serious movement artefacts, in 12/15 the scan was not started. Repeat scans under general anaesthesia were performed in 17 cases (27%): in the 15 failed cases and in 2 cases initially assessed as failed, but were considered diagnostically contributing in the present study. The financial benefit at the time the scans were made was approximately 13,360 Euro. Conclusions: In this retrospective study, the use of melatonin in neuropaediatric MRI, made during a daily scanning programme with a remote waiting room, was associated with a high success rate in infants and young children. A minority of scans had no movement artefacts, indicating most children were not asleep. The sleep-inducing effect of melatonin could therefore not be proven, but the high success rate may be attributed to the sedative and/or anxiolytic effect of melatonin. Only a minority of scans had to be repeated under general anesthesia, leading to a reduction of scan related costs

Fast adiabatic transport of single laser-cooled 9^9Be+^+ ions in a cryogenic Penning trap stack

High precision mass and $g$-factor measurements in Penning traps have enabled groundbreaking tests of fundamental physics. The most advanced setups use multi-trap methods, which employ transport of particles between specialized trap zones. Present developments focused on the implementation of sympathetic laser cooling will enable significantly shorter duty cycles and better accuracies in many of these scenarios. To take full advantage of these increased capabilities, we implement fast adiabatic transport concepts developed in the context of trapped-ion quantum information processing in a cryogenic Penning trap system. We show adiabatic transport of a single $^9\mathrm{Be}^+$ ion initially cooled to 2 mK over a 2.2 cm distance within 15 ms and with less than 10\,mK energy gain at a peak velocity of 3 m/s. These results represent an important step towards the implementation of quantum logic spectroscopy in the \ppbar system. Applying these developments to other multi-trap systems has the potential to considerably increase the data-sampling rate in these experiments.Comment: 15 pages, 7 figure

Fungal Spore Dispersal by the Eastern Box Turtle (Terrapene carolina carolina)

Although spores from most macrofungi are wind- or water-dispersed, dispersal may also occur via biotic vectors. The Eastern box turtle (Terrapene carolina carolina) is a facultative mycovore that may play an important role in fungal spore dispersal although, to date, no information exists on fungi occurring in fecal samples of box turtles or on the ecological significance of box turtles as spore dispersal vectors. Consequently, a study of the potential for Eastern box turtles to act as vectors for spore dispersal was initiated by capturing wild turtles and collecting fecal samples. Serial dilutions from fecal samples were made to enumerate spores, quantify the number of spores per gram of fecal material and to isolate and identify fungi. Fungal spores were found to be extremely abundant throughout all samples. Fecal samples from 36 turtles yielded a total of 23 different fungal taxa in the Zygomycota, Ascomycota and Basidiomycota. Two yeasts that were isolated, Cryptococcus albidus and Rhodotorula mucilaginosa, are reported to naturally occur on Trifolium seeds found in fecal samples. A mold previously unreported from fecal material, Aspergillus wentii, was also found in fecal samples. Data collected suggests Eastern box turtles influence fungal spore dispersal by browsing on plant materials and defecating large numbers of fungal spores within their home ranges

Cryogenic 9Be+ Penning trap for precision measurements with (anti-)protons

Cooling and detection schemes using laser cooling and methods of quantum logic can contribute to high precision CPT symmetry tests in the baryonic sector. This work introduces an experiment to sympathetically cool protons and antiprotons using the Coulomb interaction with a 9Be+ ion trapped in a nearby but separate potential well. We have designed and set up an apparatus to show such coupling between two identical ions for the first time in a Penning trap. In this paper, we present evidence for successful loading and Doppler cooling of clouds and single ions. Our coupling scheme has applications in a range of high-precision measurements in Penning traps and has the potential to substantially improve motional control in these experiments