Fundamental to all living organisms is the capacity to coordinate cell division and cell differentiation to generate appropriate numbers of specialized cells. Whereas eukaryotes use cyclins and ...cyclin-dependent kinases to balance division with cell fate decisions, equivalent regulatory systems have not been described in bacteria. Moreover, the mechanisms used by bacteria to tune division in line with developmental programs are poorly understood. Here we show that Caulobacter crescentus, a bacterium with an asymmetric division cycle, uses oscillating levels of the second messenger cyclic diguanylate (c-di-GMP) to drive its cell cycle. We demonstrate that c-di-GMP directly binds to the essential cell cycle kinase CckA to inhibit kinase activity and stimulate phosphatase activity. An upshift of c-di-GMP during the G1-S transition switches CckA from the kinase to the phosphatase mode, thereby allowing replication initiation and cell cycle progression. Finally, we show that during division, c-di-GMP imposes spatial control on CckA to install the replication asymmetry of future daughter cells. These studies reveal c-di-GMP to be a cyclin-like molecule in bacteria that coordinates chromosome replication with cell morphogenesis in Caulobacter. The observation that c-di-GMP-mediated control is conserved in the plant pathogen Agrobacterium tumefaciens suggests a general mechanism through which this global regulator of bacterial virulence and persistence coordinates behaviour and cell proliferation.
Cooling of mechanical resonators is currently a popular topic in many fields of physics including ultra-high precision measurements, detection of gravitational waves and the study of the transition ...between classical and quantum behaviour of a mechanical system. Here we report the observation of self-cooling of a micromirror by radiation pressure inside a high-finesse optical cavity. In essence, changes in intensity in a detuned cavity, as caused by the thermal vibration of the mirror, provide the mechanism for entropy flow from the mirror's oscillatory motion to the low-entropy cavity field. The crucial coupling between radiation and mechanical motion was made possible by producing free-standing micromirrors of low mass (m 400 ng), high reflectance (more than 99.6%) and high mechanical quality (Q 10,000). We observe cooling of the mechanical oscillator by a factor of more than 30; that is, from room temperature to below 10 K. In addition to purely photothermal effects we identify radiation pressure as a relevant mechanism responsible for the cooling. In contrast with earlier experiments, our technique does not need any active feedback. We expect that improvements of our method will permit cooling ratios beyond 1,000 and will thus possibly enable cooling all the way down to the quantum mechanical ground state of the micromirror.
Increased β-synuclein (Sncb) expression has been described in the aging visual system. Sncb functions as the physiological antagonist of α-synuclein (Snca), which is involved in the development of ...neurodegenerative diseases, such as Parkinson’s and Alzheimer’s diseases. However, the exact function of Sncb remains unknown. The aim of this study was to elucidate the age-dependent role of Sncb in brain microvascular endothelial cells (BMECs). BMECs were isolated from the cortices of 5- to 9-d-old Sprague-Dawley rats and were cultured with different concentrations of recombinant Sncb (rSncb) up to 72 h resembling to some degree age-related as well as pathophysiological conditions. Viability, apoptosis, expression levels of Snca, and the members of phospholipase D2 (Pld2)/p53/ Mouse double minute 2 homolog (Mdm2)/p19(Arf) pathway, response in RAC-alpha serine/threonine-protein kinase (Akt), and stress-mediating factors such as heme oxygenase (decycling) 1 (Hmox) and Nicotinamide adenine dinucleotide phosphate oxygenase 4 (Nox4) were examined. rSncb-induced effects were confirmed through Sncb small interfering RNA (siRNA) knockdown in BMECs. We demonstrated that the viability decreases, while the rate of apoptosis underly dose-dependent alterations. For example, apoptosis increases in BMECs following the treatment with higher dosed rSncb. Furthermore, we observed a decrease in Snca immunostaining and messenger RNA (mRNA) levels following the exposure to higher rScnb concentrations. Akt was shown to be downregulated and pAkt upregulated by this treatment, which was accompanied by a dose-independent increase in p19(Arf) levels and enhanced intracellular Mdm2 translocation in contrast to a dose-dependent p53 activation. Moreover, Pld2 activity was shown to be induced in rSncb-treated BMECs. The expression of Hmox and Nox4 after Sncb treatment was altered on BEMCs. The obtained results demonstrate dose-dependent effects of Sncb on BMECs in vitro. For example, the p53-mediated and Akt-independent apoptosis together with the stress-mediated response of BMECs related to exposure of higher SNCB concentrations may reflect the increase in Sncb with duration of culture as well as its impact on cell decay. Further studies, expanding on the role of Sncb, may help understand its role in the neurodegenerative diseases.
Using spectral domain optical coherence tomography (SD-OCT) the retina can be segmented automatically to visualize all retinal layers. In glaucoma chronically elevated intraocular pressure leads to a ...decline of retinal ganglion cells (RGC) which changes retinal architecture. The goal of these analyses was to gain insight into the changes induced by glaucoma within all macular layers using SD-OCT within a closely circumscribed glaucoma cohort.
SD-OCT measurements with automated retinal layer segmentation were performed in both eyes of primary open-angle glaucoma patients with a defined monocular absolute visual field scotoma in the central 10° of the visual field and in an age-matched healthy control group. Thickness of single retinal layers and entire retina were compared with special attention to the localization of the visual field scotoma in the glaucomatous eyes.
30 eyes of 15 glaucoma patients and 15 eyes of 15 healthy controls were included in this study. Statistical significant thickness differences were detected in the control group between superior and inferior retina for the retinal nerve fiber layer (RNFL), the outer plexiform layer (OPL) and the outer nuclear layer (ONL). In the glaucoma group thickness differences between worse and less affected eyes in the RNFL, the ganglion cell layer (GCL) and the inner plexiform layers (INL) were found. Comparison between healthy and diseased eyes revealed significant thickness differences in the RNFL, GCL, IPL and total retinal thickness but not the outer retinal layers.
Comparison between SD-OCT measurements of the macula between healthy and glaucomatous eyes in a closely circumscribed disease stage showed a pronounced disease impact on the inner but not the outer retina. These results provide evidence that GCL and IPL thickness seem to be good measures to discriminate between affected and unaffected eyes in testing for glaucoma.
The use of manure as a fertilizer in agriculture includes the risk of spreading pathogenic infectious agents to the environment, to animals and humans. The treatment of manure can help avoid or ...reduce these risks. Even if the treatment is dominated by economic considerations such as biogas production, ammonia stripping or phosphorous precipitation, the hygienic aspect should be kept in mind. Otherwise, new infection chains may be established by the use of insufficiently treated manure by-products such as fertilizers still containing infective pathogens. Treatment plants should use a concept according to HACCP principles that includes hazard analysis, risk assessment, the determination of process relevant CCPs and the validation of the process by determining the hygienizing efficiency using representative test organisms as well as microbial end product supervision. Treatment methods can be divided into physical, chemical and microbiological treatment, sometimes used in combination. For economical reasons, only composting or anaerobic treatment (biogas) or, to a minor extent, aerobic thermophilic stabilization (ATS) are used as routine preventive measures on a farm level. In cases of outbreaks of notifiable diseases both physical and chemical treatment of manure can lead to reliable disinfected/pasteurised end products which can be used in agriculture without long-lasting risks for soil fertility or the environment.
Purpose
A central diagnostic tool in adult glaucoma is the peripapillary retinal nerve fibre layer (pRNFL) thickness. It can be assessed by scanning laser polarimetry (SLP) or optical coherence ...tomography (OCT). However, studies investigating the relevance of pRNFL measurements in children are rare. This study aims to compare the glaucoma diagnosing ability of SLP and OCT pRNFL thickness measurements in a paediatric population.
Methods
This retrospective study included 105 children (glaucoma: 22 (21.0%); healthy glaucoma suspects: 83 (79.0%)) aged 4–18 years, examined with SLP (GDxPro/ECC, Carl Zeiss Meditec) and spectral-domain OCT (SPECTRALIS®, Heidelberg Engineering). The thickness of pRNFL sectors was compared between diseased and healthy participants. Areas under the receiver-operating characteristic curves (AUC) and logistic regression results were used to compare the glaucoma discriminative capacity between SLP and OCT measurements.
Results
Using OCT, pRNFL thickness was decreased in the superior, nasal, and inferior quadrants of glaucoma patients compared to healthy controls (
P
< 0.001, each). With SLP, such a difference was only observed in the inferior quadrant (
P
= 0.011). A correlation between glaucoma diagnosis and OCT-measured pRNFL thickness was found in all quadrants (
P
< 0.001) other than the temporal. With SLP, a correlation was found for the total average thickness (
P
= 0.037) and inferior quadrant (
P
= 0.0019). Finally, the AUCs of OCT measurements were markedly higher than those of SLP (e.g., inferior quadrant: OCT 0.83, SLP 0.68).
Conclusion
pRNFL thickness measurements using both OCT and SLP, correlate notably with the presence of glaucoma. In general, the diagnostic performance of pRNFL thickness measurements seems higher for OCT than for SLP. Thus, pRNFL thickness measurements could provide important information, complementing conventional clinical and functional parameters in the diagnostic process of paediatric glaucoma.
Summary
The aim of our study was to evaluate the performance of different durations of active pre‐operative skin‐surface warming (pre‐warming) to prevent peri‐operative hypothermia and postoperative ...shivering. We randomly assigned 200 patients, scheduled for surgery of 30–90 min under general anaesthesia, to receive passive insulation or forced‐air skin surface warming for 10, 20 or 30 min. Body temperature was measured at the tympanic membrane. Shivering was graded by visual inspection. There were significant differences in changes of core temperature between the non‐pre‐warmed group and all the pre‐warmed groups (p < 0.00001), but none between the three pre‐warmed groups (p = 0.54). Without pre‐warming, 38/55 (69%) patients became hypothermic (< 36 °C) at the end of anaesthesia, whereas only 7/52 (13%), 3/43 (7%) and 3/50 (6%) patients following 10, 20 or 30 min pre‐warming, respectively, became hypothermic (p < 0.001 vs no pre‐warming). Shivering was observed in 10 patients without, and in three, three and one patients with pre‐warming in the respective groups (p = 0.02). Pre‐warming of patients for only 10 or 20 min before general anaesthesia mostly prevents hypothermia and reduces shivering.
The purpose of the study was to further scrutinize the potential of βB2-crystallin in supporting regeneration of injured retinal ganglion cell axons both in vitro and in vivo. Retinal explants ...obtained from animals after treatment either with lens injury (LI) alone or with combined LI 5 days or 3 days before or simultaneously with an optic nerve crush (ONC) were cultured for 96 h under regenerative conditions, and the regenerating axons were quantified and compared with untreated controls. These measurements were then repeated with LI replaced by intravitreal injections of γ-crystallin and β-crystallin at 5 days before ONC. Finally, bB2-crystallin-overexpressing transfected neural progenitor cells (bB2-crystallin-NPCs) in the eye were studied after crushing the optic nerve in vivo. Regeneration was monitored with the aid of immunoblotting of the retina and optic nerve both distal and proximal to the lesion site, and this was compared with controls that received injections of phosphate buffer only. LI performed 5 days or 3 days before ONC significantly promoted axonal outgrowth in vitro (p < 0.001), while LI performed alone before explantation did not. Intravitreal injections of β-crystallin and γ-crystallin mimicked the effects of LI and significantly increased axonal regeneration in culture at the same time intervals (p < 0.001). Western blot analysis revealed that crystallins were present in the proximal optic nerve stump at the lesion site in ONC, but were neither expressed in the undamaged distal optic nerve nor in uninjured tissue. bB2-crystallin-NPCs supported the regeneration of cut optic nerve axons within the distal optic nerve stump in vivo. The reported data suggest that bB2-crystallin-producing “cell factories” could be used to provide novel therapeutic drugs for central nervous system injuries.
Abstract
The demand of composites in the aviation and space industry has increased significantly in recent decades. This is due to the excellent properties of composite materials, especially their ...low density and design flexibility. However, the reuse and further utilization of composite structures and their materials provide new challenges for the recycling sector. In accordance with the ‘Green Deal’ of the European Commission, new pathways are required to ensure an effective and economic reuse of composite components at their end-of-life (EoL). We discuss a strategic approach for returning decommissioned parts of aviation composites back into the material cycle with a particular focus on waste reduction, as well as the decrease of the associated energy demand and emissions. Therefore, a sustainable strategy to exploit various circular possibilities was applied, consisting of the six R-strategies:
reuse, repair, refurbish, remanufacture, repurpose
and
recycling
. The Multi-Tiered System of Support is transferred to the introduced R6-strategy. The concept provides an approach to address the challenges of reintroducing EoL composites into the material chain. Based on the systematized R6-strategy it was possible to identify circular eco-subsystems for aviation composite components with minimal effort. Finally, this paper discusses a potential criterion used for assigning EoL aviation composites to the various eco-subsystems.
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