Due to seasonal upwelling, the upper ocean waters of the California Current System (CCS) have a naturally low pH and aragonite saturation state (Ωarag), making this region particularly prone to the ...effects of ocean acidification. Here, we use the Regional Oceanic Modeling System (ROMS) to conduct preindustrial and transient (1995–2050) simulations of ocean biogeochemistry in the CCS. The transient simulations were forced with increasing atmospheric pCO2 and increasing oceanic dissolved inorganic carbon concentrations at the lateral boundaries, as projected by the NCAR CSM 1.4 model for the IPCC SRES A2 scenario. Our results show a large seasonal variability in pH (range of ~ 0.14) and Ωarag (~ 0.2) for the nearshore areas (50 km from shore). This variability is created by the interplay of physical and biogeochemical processes. Despite this large variability, we find that present-day pH and Ωarag have already moved outside of their simulated preindustrial variability envelopes (defined by ±1 temporal standard deviation) due to the rapidly increasing concentrations of atmospheric CO2. The nearshore surface pH of the northern and central CCS are simulated to move outside of their present-day variability envelopes by the mid-2040s and late 2030s, respectively. This transition may occur even earlier for nearshore surface Ωarag, which is projected to depart from its present-day variability envelope by the early- to mid-2030s. The aragonite saturation horizon of the central CCS is projected to shoal into the upper 75 m within the next 25 yr, causing near-permanent undersaturation in subsurface waters. Due to the model's overestimation of Ωarag, this transition may occur even earlier than simulated by the model. Overall, our study shows that the CCS joins the Arctic and Southern oceans as one of only a few known ocean regions presently approaching the dual threshold of widespread and near-permanent undersaturation with respect to aragonite and a departure from its variability envelope. In these regions, organisms may be forced to rapidly adjust to conditions that are both inherently chemically challenging and also substantially different from past conditions.
Peripheral nerve injuries with substantial tissue loss require autologous nerve transplantation or alternatively reconstruction with nerve conduits. Axonal elongation after nerve transection is about ...1 mm/day. The precise time course of axonal regeneration on an ultrastructural level in nerve gap repair using either autologous or artificial implants has not been described. As peripheral nerve regeneration is a highly time critical process due to deterioration of the neuromuscular junction, this in vivo examination in a large animal model was performed in order to investigate axonal elongation rates and spider silk material degradation in a narrowly delimited time series (20, 30, 40, 50, 90, 120, 150 and 180 days) by using a novel spider silk based artificial nerve graft as a critical prerequisite for clinical translation. Autologous nerves or artificial nerve conduits based on spider silk of the spider species Trichonephila edulis were transplanted in a 6.0 cm nerve defect model in the black headed mutton. At each of the post-implant time point, electrophysiology recordings were performed to assess functional reinnervation of axonal fibers into the implants. Samples were analyzed by histology and immunofluorescence in order to verify the timeline of axonal regeneration including axonal regeneration rates of the spider silk implant and the autologous transplant groups. Spider silk was degraded within 3 month by a light immune response mainly mediated by Langhans Giant cells. In conjunction with behavioral analysis and electrophysiological measurements, the results indicate that the spider silk nerve implant supported an axonal regeneration comparable to an autologous nerve graft which is the current gold standard in nerve repair surgery. These findings indicate that a biomaterial based spider silk nerve conduit is as effective as autologous nerve implants and may be an important approach for long nerve defects.
Reconstruction of a 6.0 cm tibial nerve defect using a spider silk based artificial nerve implant lead to significant nerve regeneration in long term observation. Results indicate clinical and histological axonal regeneration throughout a critical nerve gap.
Neutrophils were previously shown to digest oxidized carbon nanotubes through a myeloperoxidase (MPO)-dependent mechanism, and graphene oxide (GO) was found to undergo degradation when incubated with ...purified MPO, but there are no studies to date showing degradation of GO by neutrophils. Here we produced endotoxin-free GO by a modified Hummers' method and asked whether primary human neutrophils stimulated to produce neutrophil extracellular traps or activated to undergo degranulation are capable of digesting GO. Biodegradation was assessed using a range of techniques including Raman spectroscopy, transmission electron microscopy, atomic force microscopy, and mass spectrometry. GO sheets of differing lateral dimensions were effectively degraded by neutrophils. As the degradation products could have toxicological implications, we also evaluated the impact of degraded GO on the bronchial epithelial cell line BEAS-2B. MPO-degraded GO was found to be non-cytotoxic and did not elicit any DNA damage. Taken together, these studies have shown that neutrophils can digest GO and that the biodegraded GO is non-toxic for human lung cells.
In painful epicondylitis, previous studies reported deficiencies in elbow proprioception. In line, proprioceptive training of the lower limb has been reported substantial beneficial in a number of ...indications. Therefore, we have asked if a specified proprioceptive training using training devices that are capable of activating the deep musculature in the upper limb is able to reduce the symptoms of epicondylitis.
We included 71 patients with painful lateral epicondylitis > 3 months.
Group A: Proprioceptive training intervention with a Flexibar® (9 min daily for 12 weeks). Group B: at least 40 min running or walking/week with the XCO® in addition to the proprioceptive training with the Flexibar® (9 min daily for 12 weeks), follow-up for 12 weeks. Primary end point: Pain on visual analogue scale (VAS, 0-10); secondary end points: DASH-Score (0 = very good, 100 = very poor), grip strength according to Jamar dynamometer (kg), vibration sensation measured with a 128 Hz tuning fork.
The pain on VAS in group A was reduced significantly. 3.6 ± 2.0 to 2.4 ± 2.1 (-33%, p = 0.013), and from 3.7 ± 2.4 to 2.2 ± 1.9 (-41%, p = 0.004) in group B after 12 weeks. There was no significant difference between A and B (p = 0.899). In both groups, there was a significant improvement of the DASH-Score (A: 32 ± 15 to 14 ± 12, -56%, p < 0.001; B: 27 ± 12 to 12 ± 11, -55%, p = 0.001) without any difference between groups A and B (p = 0.339). Grip strength improvement in group A from 24 ± 12 to 33 ± 11 kg (+38%, p < 0.001), and from 29 ± 14 to 34 ± 11 kg (+15%, p < 0.001) in group B. In line, vibration sensation improved in both groups (A: 6.3 ± 0.6 to 6.5 ± 0.5, p = 0.0001; B: 6.3 ± 0.7 to 6.6 ± 0.5, p = 0.003).
A 12-week proprioceptive training with the Flexibar® improves pain, quality of life, grip strength and vibration sensation in patients with painful lateral epicondylitis.
Ib, randomised clinical trial TRIAL REGISTRATION: German Clinical Trials Register, DRKS00024857 , registered on 25 March 2021-retrospectively registered, http://apps.who.int/trialsearch/.
•Burn center volume does not affect mortality in Germany.•Patients treated in large volume burn centers received more surgeries.•Patients treated in large volume burn centers showed an increased ...length of hospital stay.
Hospital volume has been identified as an independent outcome parameter for a number of medical fields and surgical procedures, and there is a tendency to increase required patient numbers for center verification. However, the existing literature does not support a clear correlation between patient load and clinical outcome in adult burn care and recent data from Germany does not exist. We therefore evaluated the effect of patient volume in German burn centers on clinical outcome. Patient data was extracted from the German Burn Registry from 2015 to 2018. For better inter-center comparability, solely burn patients with a TBSA ≥ 10% were included. Mortality, number of surgeries and length of stay (LOS) were evaluated with respect to burn center patient volume. Burn center volume was divided into two and three groups. A total of 2718 patients with a TBSA ≥ 10% were admitted to the participating 17 burn centers. Independent from the division of patient data into either 2 or 3 groups, the TBSA and ABSI score-related severity of burn injuries were comparable between groups. There was no significant difference in mortality due to center size. Nevertheless, patients treated in large volume burn centers showed a significantly increased LOS (+4.5 days, 1.9–7.2 CI, p = 0.001) and required significantly more surgeries (+0.5 surgeries 0.2–0.8 CI, p = 0.002) when compared to the small volume centers. A similar phenomenon regarding mortality and LOS (p 0.001) was observed after dividing the centers into two groups. Interestingly a division into three groups showed significant differences with the best outcome for patients in medium-volume centers. Nevertheless, mortality did not differ significantly. Therefore, our data demonstrates that in contrast to many other medical fields, outcome and mortality are not automatically improved in burn care by simply increasing the patient load, at least in centers treating 20–100 BICU patients/year.
Spacecraft observations have established that all known planets with an internal magnetic field, as part of their interaction with the solar wind, possess well-developed magnetic tails, stretching ...vast distances on the nightside of the planets. In this review paper we focus on the magnetotails of Mercury, Earth, Jupiter and Saturn, four planets which possess well-developed tails and which have been visited by several spacecraft over the years. The fundamental physical processes of reconnection, convection, and charged particle acceleration are common to the magnetic tails of Mercury, Earth, Jupiter and Saturn. The great differences in solar wind conditions, planetary rotation rates, internal plasma sources, ionospheric properties, and physical dimensions from Mercury’s small magnetosphere to the giant magnetospheres of Jupiter and Saturn provide an outstanding opportunity to extend our understanding of the influence of such factors on basic processes. In this review article, we study the four planetary environments of Mercury, Earth, Jupiter and Saturn, comparing their common features and contrasting their unique dynamics.
Plastic and reconstructive surgeons occasionally have to manage patients with the intake of immunosuppressive drugs while the individual risks for complications present unclear. This study aimed to ...analyze complication rates after surgery on patients with drug-induced immunosuppression.
Patients with a perioperative intake of immunosuppressive drugs who had undergone plastic surgery between 2007 and 2019 in our Department of Plastic, Aesthetic, Hand, and Reconstructive Surgery were analyzed retrospectively. Another cohort with the same or similar surgical procedures but without drug-induced immunosuppression was determined. A total of 54 immunosuppressed patients (IPs) were case-control matched with 54 comparable control patients (CPs). The 2 groups were compared for the outcome parameters of complication rate, revision rate, and length of hospital stay.
Matching achieved a 100% match for surgical procedures and sex. The mean age difference within paired patients was 2.8 years (0–10 years), while the mean age was 58.1 years in all patients. A total of 44% of IP showed signs of impaired wound healing in contrast to only 19% of CP (OR 3.440; 95%CI: 1.471–8.528; p = 0.007). The median hospital stay of IP was 9 days (range 1–110 days) compared to 7 days (range 0–48 days) of CP (p = 0.102). The revision operation rate was 33% in IPs and 21% in CPs (p = 0.143).
Patients with drug-induced immunosuppression who underwent plastic and reconstructive surgery have an increased risk for impaired wound healing in general. Additionally, our study showed a trend towards a longer hospital stay and operation revision rate. Surgeons have to consider these facts when treatment options are discussed in patients with drug-induced immunosuppression.
Ocean acidification will progress in an episodic manner, yet this has rarely been considered. Here, we investigate how the intensity, duration, and severity of episodic low aragonite saturation state ...events along the California continental shelf have changed since ~1750, and how they might change up to 2050 under the A2 scenario from the Special Report on Emissions Scenarios by the Intergovernmental Panel on Climate Change. Our model‐based results suggest that between 1750 and 2010, aragonite undersaturation events along the shelf have quadrupled in their number and lengthened in duration, but that even larger changes are bound to occur within the next 20 to 40 years. Undersaturation will become very likely the norm near the seafloor by 2030, and if atmospheric CO2 increases beyond ~500 ppm, this layer will become permanently undersaturated. Combined with a fourfold increase in intensity, the resulting increase in severity of low aragonite saturation state events will substantially affect the viability of calcifying organisms and will alter ecosystem structure.
Key Points
Globally applicable metrics to characterize low saturation state events
Metrics are applied to regional U.S. West Coast model simulations
Intensity, duration and severity increase rapidly from 2010 to 2050
Southern ocean carbon and heat impact on climate Sallée, J B; Abrahamsen, E P; Allaigre, C ...
Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences,
06/2023, Letnik:
381, Številka:
2249
Journal Article
Recenzirano
Odprti dostop
The Southern Ocean greatly contributes to the regulation of the global climate by controlling important heat and carbon exchanges between the atmosphere and the ocean. Rates of climate change on ...decadal timescales are therefore impacted by oceanic processes taking place in the Southern Ocean, yet too little is known about these processes. Limitations come both from the lack of observations in this extreme environment and its inherent sensitivity to intermittent processes at scales that are not well captured in current Earth system models. The Southern Ocean Carbon and Heat Impact on Climate programme was launched to address this knowledge gap, with the overall objective to understand and quantify variability of heat and carbon budgets in the Southern Ocean through an investigation of the key physical processes controlling exchanges between the atmosphere, ocean and sea ice using a combination of observational and modelling approaches. Here, we provide a brief overview of the programme, as well as a summary of some of the scientific progress achieved during its first half. Advances range from new evidence of the importance of specific processes in Southern Ocean ventilation rate (e.g. storm-induced turbulence, sea-ice meltwater fronts, wind-induced gyre circulation, dense shelf water formation and abyssal mixing) to refined descriptions of the physical changes currently ongoing in the Southern Ocean and of their link with global climate. This article is part of a discussion meeting issue 'Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities'.
We present a comprehensive study of the magnetic field and plasma signatures of reconnection events observed with the Cassini spacecraft during the tail orbits of 2006. We examine their “local” ...properties in terms of magnetic field reconfiguration and changing plasma flows. We also describe the “global” impact of reconnection in terms of the contribution to mass loss, flux closure, and large‐scale tail structure. The signatures of 69 plasmoids, 17 traveling compression regions (TCRs), and 13 planetward moving structures have been found. The direction of motion is inferred from the sign of the change in the Bθ component of the magnetic field in the first instance and confirmed through plasma flow data where available. The plasmoids are interpreted as detached structures, observed by the spacecraft tailward of the reconnection site, and the TCRs are interpreted as the effects of the draping and compression of lobe magnetic field lines around passing plasmoids. We focus on the analysis and interpretation of the tailward moving (south‐to‐north field change) plasmoids and TCRs in this work, considering the planetward moving signatures only from the point of view of understanding the reconnection x‐line position and recurrence rates. We discuss the location spread of the observations, showing that where spacecraft coverage is symmetric about midnight, reconnection signatures are observed more frequently on the dawn flank than on the dusk flank. We show an example of a chain of two plasmoids and two TCRs over 3 hours and suggest that such a scenario is associated with a single‐reconnection event, ejecting multiple successive plasmoids. Plasma data reveal that one of these plasmoids contains H+ at lower energy and W+ at higher energy, consistent with an inner magnetospheric source, and the total flow speed inside the plasmoid is estimated with an upper limit of 170 km/s. We probe the interior structure of plasmoids and find that the vast majority of examples at Saturn show a localized decrease in field magnitude as the spacecraft passes through the structure. We take the trajectory of Cassini into account, as, during 2006, the spacecraft's largely equatorial position beneath the hinged current sheet meant that it rarely traversed the center of plasmoids. We present an innovative method of optimizing the window size for minimum variance analysis (MVA) and apply this MVA across several plasmoids to explore their interior morphology in more detail, finding that Saturn's tail contains both loop‐like and flux rope‐like plasmoids. We estimate the mass lost downtail through reconnection and suggest that the apparent imbalance between mass input and observed plasmoid ejection may mean that alternative mass loss methods contribute to balancing Saturn's mass budget. We also estimate the rate of magnetic flux closure in the tail and find that when open field line closure is active, it plays a very significant role in flux cycling at Saturn.
Key Points
New plasma data show velocities for 29 kronian plasmoids
Reconnection at Saturn more commonly observed at dawn than dusk
Examples of both loop‐like and flux rope‐like plasmoids presented
PDF
