Challenges and progress on the modelling of entropy generation in porous media: a review

Depending upon the ultimate design, the use of porous media in thermal and chemical systems can provide significant operational advantages, including helping to maintain a uniform temperature distribution, increasing the heat transfer rate, controlling reaction rates, and improving heat flux absorption. For this reason, numerous experimental and numerical investigations have been performed on thermal and chemical systems that utilize various types of porous materials. Recently, previous thermal analyses of porous materials embedded in channels or cavities have been re-evaluated using a local thermal non-equilibrium (LTNE) modelling technique. Consequently, the second law analyses of these systems using the LTNE method have been a point of focus in a number of more recent investigations. This has resulted in a series of investigations in various porous systems, and comparisons of the results obtained from traditional local thermal equilibrium (LTE) and the more recent LTNE modelling approach. Moreover, the rapid development and deployment of micro-manufacturing techniques have resulted in an increase in manufacturing flexibility that has made the use of these materials much easier for many micro-thermal and chemical system applications, including emerging energy-related fields such as micro-reactors, micro-combustors, solar thermal collectors and many others. The result is a renewed interest in the thermal performance and the exergetic analysis of these porous thermochemical systems. This current investigation reviews the recent developments of the second law investigations and analyses in thermal and chemical problems in porous media. The effects of various parameters on the entropy generation in these systems are discussed, with particular attention given to the influence of local thermodynamic equilibrium and non-equilibrium upon the second law performance of these systems. This discussion is then followed by a review of the mathematical methods that have been used for simulations. Finally, conclusions and recommendations regarding the unexplored systems and the areas in the greatest need of further investigations are summarized

Meta-analysis in Medicine: Implementation in Hypertension and Renal Disease in Diabetes Mellitus

This paper utilises meta-analysis and odds ratios to examine the relationship between hypertension and kidney disease in patients with diabetes (Type 1 or Type 2). Significant evidence is found to establish that our quantitative results (overall odds ratios) agree with the qualitative results of the literature, namely that hypertension has a close association with nephropathy and is a major risk factor for this renal disease. The results show that with hypertension diabetic patients have almost 3.5 times the risk of developing nephropathy than those diabetic patients without hypertension

Design of a Scanning Tunneling Microscope

1st Place in Engineering at the Denman Undergraduate Research Forum1st Place in the Local ASME Old Guard Oral Presentation1st Place in District B ASME Old Guard Oral PresentationApplications in nanotechnology require the use of tools that can help visualize and manipulate structures at the nanoscale. A scanning tunneling microscope (STM) is a visualization tool that utilizes the quantum mechanical phenomenon of electron tunneling to image features and structures at these small scales. Tunneling results when a metallic probe tip is brought sufficiently close to an electrically conducting, biased sample without making physical contact. A small current is drawn as electrons jump (tunnel) across the gap between the tip and the sample. This current is so small that the medium between the tip and the sample does not break down and become electrically conducting. Once a tunneling current is drawn between the tip and the sample, which are separated by a gap, feedback controls in conjunction with piezoelectric actuators adjust the gap distance in such a way as to maintain a constant tunneling current as the tip scans across the sample surface. STMs utilize this monitoring of the gap adjustment in order to produce images of the sample surface with potentially near atomic resolution. The first STM was developed by Binnig and Rohrer in 1981 and these microscopes are now commercially available. Commercial microscopes, however, are expensive, and not easily integrated with other experiments and processes in the laboratory. The goal of this work is to design and build a relatively inexpensive STM in order to serve as a basic laboratory research apparatus that could be utilized in nanotechnology research. This approach consists of using off-the-shelf components and instrumentation commonly found in a university laboratory (such as oscilloscopes and multimeters) to construct a STM. Automatic feedback controls serve to acquire data and control the piezoelectric actuators to sub-nanometer displacements in order to obtain and maintain a tunneling current. This data is then recorded and analyzed by imaging software developed in MATLAB in order to produce topographical images of samples. A commercially available gold grid is successfully imaged and used as a calibration tool to quantify images of other samples such as a gold film on an alumina substrate. This home-made instrument is potentially capable of imaging surfaces with resolution comparable to those attainable with commercial STMs if placed under vacuum. This work turns into reality the goal of rendering a STM a laboratory instrument as quotidian as an oscilloscope for nanotechnology research. Advisor: Vish SubramaniamThe College of EngineeringLockheed Martin Corporatio

Mouse hepatitis virus neurovirulence: evidence of a linkage between S glycoprotein expression and immunopathology.

Differences in disease outcome between the highly neurovirulent MHV-JHM and mildly neurovirulent MHV-A59 have been attributed to variations within the spike (S) glycoprotein. Previously, we found that MHV-JHM neurovirulence was marked by diminished expression of interferon-gamma (IFN-gamma) mRNA and a reduced presence of CD8 T cells in the CNS concomitant with heightened macrophage inflammatory protein (MIP)-1 transcript levels and greater macrophage infiltration relative to MHV-A59 infection. Here, the ability of the S and non-spike genes to regulate these immune responses was evaluated using chimeric viruses. Chimeric viruses WTR13 and S4R22 were made on MHV-A59 variant backgrounds and, respectively, contained the S gene of MHV-A59 and MHV-JHM. Unexpectedly, genes other than S appeared to modulate events critical to viral replication and survival. Unlike unresolving MHV-JHM infections, the clearance of WTR13 and S4R22 infections coincided with strong IFN-gamma transcription and an increase in the number of CD8 T cells infiltrating into the CNS. However, despite the absence of detectable viral titers, approximately 40% of S4R22-infected mice succumbed within 3 weeks, indicating that the enhanced mortality following S4R22 infection was not associated with high viral titers. Instead, similar to the MHV-JHM infection, reduced survival following S4R22 infection was observed in the presence of elevated MIP-1alpha and MIP-1beta mRNA accumulation and enhanced macrophage numbers within infected brains. These observations suggest that the S protein of MHV-JHM influences neurovirulence through the induction of MIP-1alpha- and MIP-1beta-driven macrophage immunopathology

Race and gender-based perceptions of older septuagenarian adults

OBJECTIVES: Older adults face racism, sexism, and ageism. As the U.S. population ages, it is important to understand how the current population views older adults. METHODS: Participants recruited through Amazon\u27s Mechanical Turk provided perceptions of older Black and White models\u27 photographs. Using mixed-effect models, we assessed interactions between race and gender of participants and models. RESULTS: Among Participants of Color and White participants ( DISCUSSION: Participants had few biases toward older Black and White models, while gender biases favored men

Yeast Models of Prion-Like Proteins That Cause Amyotrophic Lateral Sclerosis Reveal Pathogenic Mechanisms

Many proteins involved in the pathogenic mechanisms of amyotrophic lateral sclerosis (ALS) are remarkably similar to proteins that form prions in the yeast Saccharomyces cerevisiae. These ALS-associated proteins are not orthologs of yeast prion proteins, but are similar in having long, intrinsically disordered domains that are rich in hydrophilic amino acids. These so-called prion-like domains are particularly aggregation-prone and are hypothesized to participate in the mislocalization and misfolding processes that occur in the motor neurons of ALS patients. Methods developed for characterizing yeast prions have been adapted to studying ALS-linked proteins containing prion-like domains. These yeast models have yielded major discoveries, including identification of new ALS genetic risk factors, new ALS-causing gene mutations and insights into how disease mutations enhance protein aggregation

A social relations analysis of young children's trust in their peers across the early years of school

Two hundred and five (103 female and 102 male) children enrolled in school years 1 and 2 in the United Kingdom (mean age 6 years 1 month at Time 1) were tested twice over a 1-year period. The children reported the promise keeping and secret keeping behaviours of classmates (all peers and same-gender peers) and provided friendship nominations (Time 2 only). Round robin social relations analyses for all peers and same-gender peers revealed: (a) perceiver variance, demonstrating consistent individual differences in trust beliefs in peers; (b) target variance, demonstrating consistent individual differences in eliciting trust from peers; and, (c) dyadic reciprocity, demonstrating reciprocal trust between individuals. Replicability across measures, stability, and cross-measure stability of these effects were found for all peers only. As hypothesised, the perceiver and target effects of trust were associated with the number of friendships. The findings support the concl usion that young children demonstrate multiple components of trust in dyadic relationships, which are associated with their social relationships

Cardiac dynamics: Alternans and arrhythmogenesis

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Identification of Two Independent COL5A1 Variants in Dogs with Ehlers-Danlos Syndrome.

The Ehlers-Danlos syndromes (EDS) are a heterogeneous group of heritable disorders affecting connective tissues. The mutations causing the various forms of EDS in humans are well characterized, but the genetic mutations causing EDS-like clinical pathology in dogs are not known, thus hampering accurate clinical diagnosis. Clinical analysis of two independent cases of skin hyperextensibility and fragility, one with pronounced joint hypermobility was suggestive of EDS. Whole-genome sequencing revealed de novo mutations of COL5A1 in both cases, confirming the diagnosis of the classical form of EDS. The heterozygous COL5A1 p.Gly1013ValfsTer260 mutation characterized in case 1 introduced a premature termination codon and would be expected to result in α1(V) mRNA nonsense-mediated mRNA decay and collagen V haploinsufficiency. While mRNA was not available from this dog, ultrastructural analysis of the dermis demonstrated variability in collagen fibril diameter and the presence of collagen aggregates, termed 'collagen cauliflowers', consistent with COL5A1 mutations underlying classical EDS. In the second case, DNA sequencing demonstrated a p.Gly1571Arg missense variant in the COL5A1 gene. While samples were not available for further analysis, such a glycine substitution would be expected to destabilize the strict molecular structure of the collagen V triple helix and thus affect protein stability and/or integration of the mutant collagen into the collagen V/collagen I heterotypic dermal fibrils. This is the first report of genetic variants in the COL5A1 gene causing the clinical presentation of EDS in dogs. These data provided further evidence of the important role of collagen V in dermal collagen fibrillogenesis. Importantly, from the clinical perspective, we showed the utility of DNA sequencing, combined with the established clinical criteria, in the accurate diagnosis of EDS in dogs