Intermittent transport of bacterial chromosomal loci

The short-time dynamics of bacterial chromosomal loci is a mixture of subdiffusive and active motion, in the form of rapid relocations with near-ballistic dynamics. While previous work has shown that such rapid motions are ubiquitous, we still have little grasp on their physical nature, and no positive model is available that describes them. Here, we propose a minimal theoretical model for loci movements as a fractional Brownian motion subject to a constant but intermittent driving force, and compare simulations and analytical calculations to data from high-resolution dynamic tracking in E. coli. This analysis yields the characteristic time scales for intermittency. Finally, we discuss the possible shortcomings of this model, and show that an increase in the effective local noise felt by the chromosome associates to the active relocations.Comment: 8 pages, 6 figures; typos added, introduction expanded, conclusions unchange

Reactive oxygen species, ageing and the hormesis police

For more than 50 years, the free radical theory served as the paradigm guiding most investigations of ageing. However, recent studies in a variety of organisms have identified conceptual and practical limitations to this theory. Some of these limitations are related to the recent discovery that caloric restriction and other experimental manipulations promote longevity by inducing hormesis effects in association with increased reactive oxygen species (ROS). The beneficial role of ROS in lifespan extension is consistent with the essential role of these molecules in cell signalling. However, the identity of specific forms of ROS that promote longevity remains unclear. In this article, we argue that in several model systems, hydrogen peroxide plays a crucial role in the induction of hormesis.The authors wish to thank Molly Burhans for preparing the figures. This work was supported by Fundacao para a Ciencia e Tecnologia (FCT) and COMPETE/QREN/EU (PTDC/BIA-MIC/114116/2009), a grant from the Roswell Park Alliance Foundation and by a National Cancer Institute Support Grant (P30CA016056) to Roswell Park Cancer Institute. Authors have no conflict of interest to declare

Behavioral and psychological effects of coronavirus disease-19 quarantine in patients with dementia

Background: In March 2020, the World Health Organization declared a global pandemic due to the novel coronavirus SARS-CoV-2 and several governments planned a national quarantine in order to control the virus spread. Acute psychological effects of quarantine in frail elderly subjects with special needs, such as patients with dementia, have been poorly investigated. The aim of this study was to assess modifications of neuropsychiatric symptoms during quarantine in patients with dementia and their caregivers. Methods: This is a sub-study of a multicenter nation-wide survey. A structured telephone interview was delivered to family caregivers of patients with diagnosis of Alzheimer disease (AD), dementia with Lewy bodies (DLB), frontotemporal dementia (FTD), and vascular dementia (VD), followed regularly at 87 Italian memory clinics. Variations in behavioral and psychological symptoms (BPSD) were collected after 1 month since quarantine declaration and associations with disease type, severity, gender, and caregiver\u2019s stress burden were analyzed. Results: A total of 4,913 caregivers participated in the survey. Increased BPSD was reported in 59.6% of patients as worsening of preexisting symptoms (51.9%) or as new onset (26%), and requested drug modifications in 27.6% of these cases. Irritability, apathy, agitation, and anxiety were the most frequently reported worsening symptoms and sleep disorder and irritability the most frequent new symptoms. Profile of BPSD varied according to dementia type, disease severity, and patients\u2019 gender. Anxiety and depression were associated with a diagnosis of AD (OR 1.35, CI: 1.12\u20131.62), mild to moderate disease severity and female gender. DLB was significantly associated with a higher risk of worsening hallucinations (OR 5.29, CI 3.66\u20137.64) and sleep disorder (OR 1.69, CI 1.25\u20132.29), FTD with wandering (OR 1.62, CI 1.12\u20132.35), and change of appetite (OR 1.52, CI 1.03\u20132.25). Stress-related symptoms were experienced by two-thirds of caregivers and were associated with increased patients\u2019 neuropsychiatric burden (p<0.0001). Conclusion: Quarantine induces a rapid increase of BPSD in approximately 60% of patients and stress-related symptoms in two-thirds of caregivers. Health services need to plan a post-pandemic strategy in order to address these emerging needs

INNOVATIONS in earthquake risk reduction for resilience: RECENT advances and challenges

The Sendai Framework for Disaster Risk Reduction 2015-2030 (SFDRR) highlights the importance of scientific research, supporting the ‘availability and application of science and technology to decision making’ in disaster risk reduction (DRR). Science and technology can play a crucial role in the world’s ability to reduce casualties, physical damage, and interruption to critical infrastructure due to natural hazards and their complex interactions. The SFDRR encourages better access to technological innovations combined with increased DRR investments in developing cost-effective approaches and tackling global challenges. To this aim, it is essential to link multi- and interdisciplinary research and technological innovations with policy and engineering/DRR practice. To share knowledge and promote discussion on recent advances, challenges, and future directions on ‘Innovations in Earthquake Risk Reduction for Resilience’, a group of experts from academia and industry met in London, UK, in July 2019. The workshop focused on both cutting-edge ‘soft’ (e.g., novel modelling methods/frameworks, early warning systems, disaster financing and parametric insurance) and ‘hard’ (e.g., novel structural systems/devices for new structures and retrofitting of existing structures, sensors) risk-reduction strategies for the enhancement of structural and infrastructural earthquake safety and resilience. The workshop highlighted emerging trends and lessons from recent earthquake events and pinpointed critical issues for future research and policy interventions. This paper summarises some of the key aspects identified and discussed during the workshop to inform other researchers worldwide and extend the conversation to a broader audience, with the ultimate aim of driving change in how seismic risk is quantified and mitigated

Il Tecnezio: storia, usi e applicazioni.

To bring to the knowledge of all the Italian paternity of the discovery of the first artificial chemical element in history: the Technetium or Technetium (Tc)

Protein degradation sets the fraction of active ribosomes at vanishing growth.

Growing cells adopt common basic strategies to achieve optimal resource allocation under limited resource availability. Our current understanding of such "growth laws" neglects degradation, assuming that it occurs slowly compared to the cell cycle duration. Here we argue that this assumption cannot hold at slow growth, leading to important consequences. We propose a simple framework showing that at slow growth protein degradation is balanced by a fraction of "maintenance" ribosomes. Consequently, active ribosomes do not drop to zero at vanishing growth, but as growth rate diminishes, an increasing fraction of active ribosomes performs maintenance. Through a detailed analysis of compiled data, we show that the predictions of this model agree with data from E. coli and S. cerevisiae. Intriguingly, we also find that protein degradation increases at slow growth, which we interpret as a consequence of active waste management and/or recycling. Our results highlight protein turnover as an underrated factor for our understanding of growth laws across kingdoms

Novel pathogenic TGFBR1 and SMAD3 variants identified after cerebrovascular events in adult patients with Loeys-Dietz syndrome

INTRODUCTION: Loeys-Dietz syndrome (LDS) is an autosomal dominant connective tissue disorder due to heterozygous pathogenic variants in transforming growth factor beta (TGFβ) signaling-related genes. LDS types 1-6 are distinguished depending on the involved gene. LDS is characterized by multiple arterial aneurysms and dissections in addition to variable neurological and systemic manifestations. Patient 1: a 68-year-old man was admitted due to an aphasic transient ischemic attack (TIA). Brain CT-scan and CT angiography revealed a chronic and asymptomatic right vertebral artery dissection. Stroke diagnostic panel was unremarkable. His history showed mild stroke familiarity. At age of 49, he was treated for dissecting-aneurysm of the ascending aorta and started anticoagulation therapy. Seven years later, he underwent surgery for dissecting aneurysm involving aortic arch, descending-thoracic aorta, left subclavian artery, and both iliac arteries. Patient 2: a 47-year-old man presented a left hemiparesis due to right middle cerebral artery (MCA) and anterior cerebral artery (ACA) occlusion caused by right internal carotid artery (ICA) dissection after sport activity. Despite i.v. thrombolysis and mechanical thrombectomy, he developed malignant cerebral infarction and underwent decompressive hemicraniectomy. Digital subtraction angiography showed bilateral carotid and vertebral kinking, aneurysmatic dilatation on both common iliac arteries and proximal ectasia of the descending aorta. His father and his uncle died because of an ischemic stroke and a cerebral aneurysm rupture with a subarachnoid hemorrhage (SAH), respectively. DISCUSSION: in both cases, considering the family history and the multiple dissections and aneurysms, LDS molecular analysis was performed. In patient 1, the novel NM_005902.3 (SMAD3): c.840T > G; p.(Asn280Lys) likely pathogenic variant was identified, thus leading to a diagnosis of LDS type 3. In patient 2, the novel NM_004612.2 (TGFBR1): c.1225T > G; p.(Trp409Gly) likely pathogenic variant was found, allowing for a diagnosis of LDS type 1. CONCLUSION: LDS is characterized by genetic and clinical variability. Our report suggests that this genetically-determined connective tissue disorder is probably underestimated, as it might firstly show up with cerebrovascular events, although mild systemic manifestations. These findings could lead to identify people at risk of severe vascular complications (i.e., through genetic consult on asymptomatic relatives), in order to perform adequate vascular assessments and follow-up to prevent complications such as stroke