Changes in frailty status after cardiac surgery. A prospective cohort study.

Background During the last years, the concept of frailty has become increasingly familiar in many surgical specialties, including cardiac surgery. One of the main characteristics of frailty is its potentially reversible nature. With the aim of reducing the incidence of complications after surgery, efforts are being made to preoperatively decrease the level of frailty, however, the effect that the surgery itself may have in the postoperative frailty status is still unknown. Methods A prospective cohort of 137 patients aged 70 or more undergoing cardiac surgery with the use of cardiopulmonary bypass were recruited at three university-affiliated hospitals in Spain. Frailty status was assessed preoperatively and six months after surgery using two different validated frailty measurements: The Fried frailty scale and the Clinical Frailty Scale. We analyzed the changes in these frailty scores and the transitions between frailty status after surgery. Results Prevalence of frailty was 27.5% with the Fried Frailty Scale and 11% with the Clinical Frailty Scale. Even though frail patients presented a higher incidence of postoperative major complications than their robust counterparts, up to 50% of frail patients improved their frailty status after surgery. The distribution of frailty groups at baseline and six months after surgery changed significantly, decreasing the overall burden of frailty after surgery. Besides, robust patients showed a slightly worsening of their previous frailty scores. Conclusions Frailty is a multifactorial and dynamic condition that can be significantly reduced after cardiac surgery, suggesting that cardiac pathology is an important contributor to the preoperative patient’s frailty status.

Rational Design of Programmable Monodisperse Semi-Synthetic Protein Nanomaterials Containing Engineered Disulfide Functionality

The reversible nature of disulfide functionality has been exploited to design intelligent materials such as nanocapsules, micelles, vesicles, inorganic nanoparticles, peptide and nucleic acid nanodevices. However, to our knowledge, there are no reports on design of semi-synthetic protein assemblies containing an engineered disulfide bond. Towards that end, herein, we disclose a new chemical methodology for the construction redox-sensitive protein assemblies using monodisperse facially amphiphilic protein-dendron bioconjugates. The disulfide functionality is strategically placed between the dendron and protein domains. The custom designed bioconjugates self-assembled into nanoscopic objects of a defined size dictated by the nature of dendron domain. The stimuli-responsive behavior of the protein assemblies is demonstrated using a suitable redox trigger.

Redefining the roles of UDP-glycosyltransferases in auxin metabolism and homeostasis during plant development

ABSTRACTThe levels of the important plant growth regulator indole-3-acetic acid (IAA) are tightly controlled within plant tissues to spatiotemporally orchestrate concentration gradients that drive plant growth and development. Metabolic inactivation of bioactive IAA is known to participate in the modulation of IAA maxima and minima. IAA can be irreversibly inactivated by oxidation and conjugation to Aspartate and Glutamate. Usually overlooked because its reversible nature, the most abundant inactive IAA form is the IAA-glucose (IAA-glc) conjugate. Glycosylation of IAA is reported to be carried out by the UDP-glycosyltransferase 84B1 (UGT84B1), while UGT74D1 has been implicated in the glycosylation of the irreversibly formed IAA catabolite oxIAA. Here we demonstrate that both UGT84B1 and UGT74D1 modulate IAA levels throughout plant development by dual IAA and oxIAA glycosylation. Moreover, we identify a novel UGT subfamily whose members modulate IAA homeostasis during skotomorphogenesis by redundantly mediating the glycosylation of oxIAA.

Water-Stable Hydrazone-Linked Porous Organic Cages

Although porous organic cages (POCs), particularly imine-linked (C=N) ones, have advanced significantly over the last decades, the reversible nature of imine linkages makes them prone to hydrolysis and structure collapse,...

Part II Introduction

The introduction of Part II of this book highlights that the polluter-pays, preventive, and precautionary principles described in Part I mark an epistemological shift between modern law, which rests on the fixed standards of traditional legal rule-making, and post-modern law, which emphasizes the pragmatic, gradual, unstable, and reversible nature of rules. Chapter 4 describes the paradigm shift from modern to post-modern law. Chapter 5 considers the various functions that the polluter-pays, preventive and precautionary principles may fulfil within a post-modern legal prospect, seeking to strike a balance among multiple and conflicting interests. Chapter 6 explains that the varying status of these principles does not deprive them of normative effect. Chapter 7 focuses on the conflict between environmental principles and free trade within the World Trade Organization (WTO). This four-stage approach enables us to demonstrate how the polluter-pays, preventive, and precautionary principles shape an ideal of rationality in a chaotic legal universe.

Heterochromatin: an epigenetic point of view in aging

Aging is an inevitable process of life. Defined by progressive physiological and functional loss of tissues and organs, aging increases the risk of mortality for the organism. The aging process is affected by various factors, including genetic and epigenetic ones. Here, we review the chromatin-specific epigenetic changes that occur during normal (chronological) aging and in premature aging diseases. Taking advantage of the reversible nature of epigenetic modifications, we will also discuss possible lifespan expansion strategies through epigenetic modulation, which was considered irreversible until recently.

Reconfigurable microbots folded from simple colloidal chains

To overcome the reversible nature of low-Reynolds-number flow, a variety of biomimetic microrobotic propulsion schemes and devices capable of rapid transport have been developed. However, these approaches have been typically optimized for a specific function or environment and do not have the flexibility that many real organisms exhibit to thrive in complex microenvironments. Here, inspired by adaptable microbes and using a combination of experiment and simulation, we demonstrate that one-dimensional colloidal chains can fold into geometrically complex morphologies, including helices, plectonemes, lassos, and coils, and translate via multiple mechanisms that can be varied with applied magnetic field. With chains of multiblock asymmetry, the propulsion mode can be switched from bulk to surface-enabled, mimicking the swimming of microorganisms such as flagella-rotating bacteria and tail-whipping sperm and the surface-enabled motion of arching and stretching inchworms and sidewinding snakes. We also demonstrate that reconfigurability enables navigation through three-dimensional and narrow channels simulating capillary blood vessels. Our results show that flexible microdevices based on simple chains can transform both shape and motility under varying magnetic fields, a capability we expect will be particularly beneficial in complex in vivo microenvironments.

Combined and uneven energy transitions: reactive decarbonization in Cuba and Venezuela

Mounting impacts of climate change have increased calls for a planetary energy transition, usually understood as the decarbonization of the global economy. All too often, however, these calls rely on technological or legislative measures, betraying an apolitical understanding of climate change and insufficient appreciation for the uneven global distribution of safety, risk, and power. Through an examination of recent events in Cuba and Venezuela, this article asks how prevailing calls for energy transitions to post-carbon futures reflect the combined and uneven present, replicating the inequalities of late carbon capitalism. By considering the 'Special Period in Times of Peace' in Cuba, as the decade following the collapse of the Soviet Union was known, and Venezuela's overlapping crises since 2014 as energy transitions, this article highlights difficulties along the path to more sustainable and just futures. It also calls to attention the intensely social, but potentially incomplete and reversible, nature of energy transitions.Keywords: Energy transitions, Cuba, Venezuela, Special Period, extractivism, decarbonization

Recent advances in supramolecular block copolymers for biomedical applications

Supramolecular block copolymers with a dynamically reversible nature and hierarchical microphase-separated structures can greatly enrich the library of pharmaceutical carriers and outline future research directions for biological applications.