Studying the interactions between nanoengineered materials and biological systems plays a vital role in the development of biological applications of nanotechnology and the improvement of our ...fundamental understanding of the bio-nano interface. A significant barrier to progress in this multidisciplinary area is the variability of published literature with regards to characterizations performed and experimental details reported. Here, we suggest a 'minimum information standard' for experimental literature investigating bio-nano interactions. This standard consists of specific components to be reported, divided into three categories: material characterization, biological characterization and details of experimental protocols. Our intention is for these proposed standards to improve reproducibility, increase quantitative comparisons of bio-nano materials, and facilitate meta analyses and in silico modelling.
Objective Aortic diameter as the primary criterion in the decision to repair abdominal aortic aneurysms (AAAs) has drawbacks as some rupture below size thresholds, whereas others reach extreme size ...without rupture. Predictions of static aortic wall stress have also failed to reliably predict rupture potential. The objective of this study was to computationally assess blood flow characteristics at the site of infrarenal AAA rupture. On the basis of the finite element literature correlating rupture location with high static local wall stress, we hypothesized that a computational fluid dynamics approach would also demonstrate rupture at regions of high pressure and wall shear stress (WSS). Methods Three-dimensional AAA geometry was generated from computed tomography angiography images of seven ruptured AAAs. Aortic blood flow velocity, pressure, and WSS were computationally determined. Flow characteristics at the site of rupture were determined and compared across all cases. Results AAA size at the time of rupture was 8.3 ± 0.9 cm. Only three of the seven AAAs ruptured at the site of maximal diameter. Blood flow velocity in the aneurysmal aorta showed dominant flow channels with zones of recirculation, where low WSS predominated. Regardless of aneurysm size or configuration, rupture occurred in or near these flow recirculation zones in all cases. WSS was significantly lower and thrombus deposition was more abundant at the site of rupture. Conclusions This computational study was the first to assess blood flow characteristics at the site of infrarenal AAA rupture in realistic aortic geometries. In contradiction to our initial hypothesis, rupture occurred not at sites of high pressure and WSS but rather at regions of predicted flow recirculation, where low WSS and thrombus deposition predominated. These findings raise the possibility that this flow pattern may lead to thrombus deposition, which may elaborate adventitial degeneration and eventual AAA rupture.
Purpose
Functional status and chronic health status are important baseline characteristics of critically ill patients. The assessment of frailty on admission to the intensive care unit (ICU) may ...provide objective, prognostic information on baseline health. To determine the impact of frailty on the outcome of critically ill patients, we performed a systematic review and meta-analysis comparing clinical outcomes in frail and non-frail patients admitted to ICU.
Methods
We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, PubMed, CINAHL, and Clinicaltrials.gov. All study designs with the exception of narrative reviews, case reports, and editorials were included. Included studies assessed frailty in patients greater than 18 years of age admitted to an ICU and compared outcomes between fit and frail patients. Two reviewers independently applied eligibility criteria, assessed quality, and extracted data. The primary outcomes were hospital and long-term mortality. We also determined the prevalence of frailty, the impact on other patient-centered outcomes such as discharge disposition, and health service utilization such as length of stay.
Results
Ten observational studies enrolling a total of 3030 patients (927 frail and 2103 fit patients) were included. The overall quality of studies was moderate. Frailty was associated with higher hospital mortality relative risk (RR) 1.71; 95% CI 1.43, 2.05;
p
< 0.00001;
I
2
= 32% and long-term mortality (RR 1.53; 95% CI 1.40, 1.68;
p
< 0.00001;
I
2
= 0%). The pooled prevalence of frailty was 30% (95% CI 29–32%). Frail patients were less likely to be discharged home than fit patients (RR 0.59; 95% CI 0.49, 0.71;
p
< 0.00001;
I
2
= 12%).
Conclusions
Frailty is common in patients admitted to ICU and is associated with worsened outcomes. Identification of this previously unrecognized and vulnerable ICU population should act as the impetus for investigating and implementing appropriate care plans for critically ill frail patients. Registration: PROSPERO (ID: CRD42016053910).
► Heat treatments produce two distinct TRIP microstructures: equiaxed and lamellar. ► 100
s bainite hold time produces highest level of retained austenite and strain at UTS. ► Lamellar microstructure ...has higher sustained work hardening rate in uniaxial tension. ► Sustained work hardening directly related to higher retained austenite stability.
Retained austenite is a metastable phase in transformation induced plasticity (TRIP) steels that transforms into martensite under local stress and strain. This transformation improves sheet formability, allowing this class of higher strength steels to be used for applications such as automotive structural components. The current work studies two distinct TRIP steel microstructures, i.e. equiaxed versus lamellar, and how microstructure affects the austenite transformation during uniaxial tensile loading. Different heat treatments were employed to obtain the two microstructures, and the bainite hold times of the treatments were varied to change the volume fraction of retained austenite. Based on uniaxial tensile response and magnetic saturation measurements, the bainite hold time of 100
s was determined to produce the best results in terms of largest strain at the ultimate tensile strength and highest volume fraction of retained austenite. The work hardening of the samples with a 100
s bainite hold was evaluated by calculating the instantaneous
n value as a function of strain. It was found that the lamellar microstructure has a lower maximum instantaneous
n value than the equiaxed microstructure, but has higher work hardening values for strain levels greater than 0.05 and up to the ultimate tensile strength. This difference in work hardening behaviour corresponds directly to the transformation rate of retained austenite in the two microstructures. The slower rate of transformation in the lamellar microstructure allows for work hardening to persist at high strains where the transformation effect has already been exhausted in the equiaxed microstructure. The different rates of transformation can be attributed to the location, carbon content, and size of the retained austenite grains in the respective TRIP microstructures.
Events in 2020 have sparked a reimagination of how both individuals and institutions should consider race, power, health, and marginalization in society. In a response to these developments, we ...examine the current and past limitations of the ways in which bioethicists have considered race and, more generally, discourses of marginalization. We argue that the foundational principle of justice necessitates that bioethics, as an institution, maintain an active voice against systemic injustice. To carry out this charge, bioethics as a field should promote alternative narratives-"counter storytelling"-to the mainstream voices that have traditionally been heard and accepted, largely without opposition. Additionally, we engage with both Post-Colonial and Critical Race Theory, which we believe are important tools for bioethics in pursuit of equity. Ultimately, we advocate for a proactive form of bioethics that actively resists and denounces injustice and which considers a much wider variety of voices about justice than bioethics has historically considered.
The human neocortex differs from that of other great apes in several notable regards, including altered cell cycle, prolonged corticogenesis, and increased size 1-5. Although these evolutionary ...changes most likely contributed to the origin of distinctively human cognitive faculties, their genetic basis remains almost entirely unknown. Highly conserved non-coding regions showing rapid sequence changes along the human lineage are candidate loci for the development and evolution of uniquely human traits. Several studies have identified human-accelerated enhancers 6-14, but none have linked an expression difference to a specific organismal trait. Here we report the discovery of a human-accelerated regulatory enhancer (HARE5) of FZD8, a receptor of the Wnt pathway implicated in brain development and size 15, 16. Using transgenic mice, we demonstrate dramatic differences in human and chimpanzee HARE5 activity, with human HARE5 driving early and robust expression at the onset of corticogenesis. Similar to HARE5 activity, FZD8 is expressed in neural progenitors of the developing neocortex 17-19. Chromosome conformation capture assays reveal that HARE5 physically and specifically contacts the core Fzd8 promoter in the mouse embryonic neocortex. To assess the phenotypic consequences of HARE5 activity, we generated transgenic mice in which Fzd8 expression is under control of orthologous enhancers (Pt-HARE5::Fzd8 and Hs-HARE5::Fzd8). In comparison to Pt-HARE5::Fzd8, Hs-HARE5::Fzd8 mice showed marked acceleration of neural progenitor cell cycle and increased brain size. Changes in HARE5 function unique to humans thus alter the cell-cycle dynamics of a critical population of stem cells during corticogenesis and may underlie some distinctive anatomical features of the human brain.
In contrast to injuries in the central nervous system, injured peripheral neurons will regenerate their axons. However, axotomized motoneurons progressively lose their ability to regenerate their ...axons, following peripheral nerve injury often resulting in very poor recovery of motor function. A decline in neurotrophic support may be partially responsible for this effect. The initial upregulation of glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF) by Schwann cells of the distal nerve stump after nerve injury has led to the speculation that they are important for motor axonal regeneration. However, few experiments directly measure the effects of exogenous BDNF or GDNF on motor axonal regeneration. This study provided the first direct and quantitative evidence that long-term continuous treatment with exogenous GDNF significantly increased the number of motoneurons which regenerate their axons, completely reversing the negative effects of chronic axotomy. The beneficial effect of GDNF was not dose-dependent. A combination of exogenous GDNF and BDNF on motor axonal regeneration was significantly greater than either factor alone, and this effect was most pronounced following long-term continuous treatment. The ability of GDNF, either alone or in combination with BDNF, to increase the number of motoneurons that regenerated their axons correlated well with an increase in axon sprouting within the distal nerve stump. Thus long-term continuous treatment with neurotrophic factors, such as GDNF and BDNF, can be used as a viable treatment to sustain motor axon regeneration.
Amphiphilic lipids aggregate in aqueous solution into a variety of structural arrangements. Among the plethora of ordered structures that have been reported, many have also been observed in nature. ...In addition, due to their unique morphologies, the hydrophilic and hydrophobic domains, very high internal interfacial surface area, and the multitude of possible order−order transitions depending on environmental changes, very promising applications have been developed for these systems in recent years. These include crystallization in inverse bicontinuous cubic phases for membrane protein structure determination, generation of advanced materials, sustained release of bioactive molecules, and control of chemical reactions. The outstanding diverse functionalities of lyotropic liquid crystalline phases found in nature and industry are closely related to the topology, including how their nanoscopic domains are organized. This leads to notable examples of correlation between structure and macroscopic properties, which is itself central to the performance of materials in general. The physical origin of the formation of the known classes of lipidic lyotropic liquid crystalline phases, their structure, and their occurrence in nature are described, and their application in materials science and engineering, biology, medical, and pharmaceutical products, and food science and technology are exemplified.
The thermodynamics and physics underlying the self‐assembly of amphiphilic lipids are reviewed and then linked to Nature's deployment of these fascinating lyotropic liquid‐crystalline phases for specific biological functions. The harnessing of the unique properties of these structures to enable a range of technological, biomedical, and food applications is reviewed.
Abstract Purpose There is a need to obtain greater clarity regarding adolescents' e-cigarette use and the associations of use with a wider range of risk behaviors. This study examines the ...associations among past-month e-cigarette use only, traditional cigarette smoking only, dual use (i.e., concurrent e-cigarette use and cigarette smoking), school-related (i.e., truancy and poor academic performance) risk behaviors, and substance-related (i.e., alcohol use, binge drinking, marijuana use, illicit drug use, and nonmedical prescription drug use) risk behaviors. Methods Data were collected via self-administered questionnaires from a nationally representative sample of 8,696 high school seniors. Results An estimated 9.9% of U.S. high school seniors reported past-month e-cigarette use only, 6.0% reported past-month cigarette smoking only, and 7.3% reported past-month dual use. School- and substance-related risk behaviors had strong associations with past-month e-cigarette use. Adolescents who only used e-cigarettes had significantly greater odds of all school- and substance-related risk behaviors relative to nonusers. Dual users had significantly greater odds of frequent/daily e-cigarette use as well as all school- and substance-related risk behaviors relative to those who only used e-cigarettes. Finally, adolescents who engaged in frequent/daily e-cigarette use had significantly greater odds of binge drinking, marijuana use, other illicit drug use and nonmedical prescription drug use, relative to experimental e-cigarette users. Conclusions E-cigarette use is common among U.S. adolescents, and there are robust associations between e-cigarette use and school- and substance-related risk behaviors. There is evidence that e-cigarette use clusters with risk behaviors and appears to represent a problem behavior, especially dual use of e-cigarettes and traditional cigarettes.
Microstructure of Ordinary Portland Cement paste subjected to early age carbonation curing was studied to examine the effect of early carbonation on performance of paste at different ages. The study ...was intended to understand the mechanism of concrete carbonation at early age through the microstructure development of its cement paste. Early carbonation was carried out after 18-hour initial controlled air curing. The microstructure characterized by XRD, TGA,
29Si NMR and SEM was correlated to strength gain, CO
2 uptake and pH change. It was found that early carbonation could accelerate early strength while allowing subsequent hydration. The short term carbonation created a microstructure with more strength-contributing solids than conventional hydration. Calcium hydroxide was converted to calcium carbonates, and calcium–silicate–hydrate became intermingled with carbonates, generating an amorphous calcium–silicate–hydrocarbonate binding phase. Carbonation modified C–S–H retained its original gel structure. The re-hydration procedure applied after carbonation was essential in increasing late strength and durability.
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