253 research outputs found
A multimodal network flow problem with product quality preservation, transshipment, and asset management
In this paper, we present an optimization model for a transportation planning problem with multiple transportation modes, highly perishable products, demand and supply dynamics, and management of the reusable transport units (RTIs). Such a problem arises in the European horticultural chain, for example. As a result of geographic dispersion of production and market, a reliable transportation solutions ensures long-term success in the European market. The model is an extension to the network ow problem. We integrate dynamic allocation, ow, and repositioning of the RTIs in order to nd the trade-o between quality requirements and operational considerations and costs. We also present detailed computational results and analysis
A multimodal network flow problem with product quality preservation, transshipment, and asset management
In this paper, we present an optimization model for a transportation planning problem with multiple transportation modes, highly perishable products, demand and supply dynamics, and management of the reusable transport units (RTIs). Such a problem arises in the European horticultural chain, for example. As a result of geographic dispersion of production and market, a reliable transportation solutions ensures long-term success in the European market. The model is an extension to the network ow problem. We integrate dynamic allocation, ow, and repositioning of the RTIs in order to nd the trade-o between quality requirements and operational considerations and costs. We also present detailed computational results and analysis
Pre-exposure embrittlement of sensitized alumimium-magnesium alloy, 5083-H116
Environment-sensitive fracture of aluminum-magnesium alloys containing above ~3 wt% magnesium historically has been considered under anodic-dissolution control. Information from more recent studies, however, suggests a hydrogen-related process is also often involved. Further evidence supporting the involvement of a hydrogen-related process of during Intergranular stress corrosion cracking (IGSCC) will be presented using information gleaned from smooth and pre-cracked test specimens, previously sensitized over a range of temperatures in both ‘dry’ and ‘wet’ conditions and then subjected to rising-load testing in a range of environments. A detailed evaluation of the IGSCC using X-ray computed tomography to provide 3-D images and ultra-high-resolution electron microscopy to characterize selected regions within intergranular stress corrosion cracks enables mechanistic insights
Helicobacter pylori infection is a significant factor risk for hyperhomocysteinemia in the patients with coronary artery disease
This work aimed to determine whether seropositivity to Helicobacter pylori infection was an independent risk factor for hyperhomocysteinemia patients with cardiovascular disease. The H. pylori IgG, IgA and homocystein levels in 96 patients with cardiovascular disease and 64 participants free of cardiovascular disease as control subjects were determined by ELISA assay. The results showed that seropositivity to H. pylori IgG and IgA levels of coronary artery disease (CAD)patients was significantly higher than the controls and CAD patients with H. pylori IgG and IgA negative antibodies. A significant correlation was found between the seropositivity to H. pylori IgG and homocysteine levels of CAD patients in comparison with the controls and CAD patients with seronegativity to H. pylori IgG and IgA (r = 0.233, P = 0.019). The involvement of H. pylori infection in atherosclerosis process was based on the chronic inflammation, which might facilitate the CAD-related pathologies. The effect of the presence of H. pylori infection on homocysteine levels elevation in the CAD patients (as a risk factor independent of other traditional factors) was remarkable
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Analysis of enriched rare variants in JPH2-encoded junctophilin-2 among Greater Middle Eastern individuals reveals a novel homozygous variant associated with neonatal dilated cardiomyopathy.
Junctophilin-2 (JPH2) is a part of the junctional membrane complex that facilitates calcium-handling in the cardiomyocyte. Previously, missense variants in JPH2 have been linked to hypertrophic cardiomyopathy; however, pathogenic "loss of function" (LOF) variants have not been described. Family-based genetic analysis of GME individuals with cardiomyopathic disease identified an Iranian patient with dilated cardiomyopathy (DCM) as a carrier of a novel, homozygous single nucleotide insertion in JPH2 resulting in a stop codon (JPH2-p.E641*). A second Iranian family with consanguineous parents hosting an identical heterozygous variant had 2 children die in childhood from cardiac failure. To characterize ethnicity-dependent genetic variability in JPH2 and to identify homozygous JPH2 variants associated with cardiac disease, we identified variants in JPH2 in a worldwide control cohort (gnomAD) and 2 similar cohorts from the Greater Middle East (GME Variome, Iranome). These were compared against ethnicity-matched clinical whole exome sequencing (WES) referral tests and a case cohort of individuals with hypertrophic cardiomyopathy (HCM) based on comprehensive review of the literature. Worldwide, 1.45% of healthy individuals hosted a rare JPH2 variant with a significantly higher proportion among GME individuals (4.45%); LOF variants were rare overall (0.04%) yet were most prevalent in GME (0.21%). The increased prevalence of LOF variants in GME individuals was corroborated among region-specific, clinical WES cohorts. In conclusion, we report ethnic-specific differences in JPH2 rare variants, with GME individuals being at higher risk of hosting homozygous LOF variants. This conclusion is supported by the identification of a novel JPH2 LOF variant confirmed by segregation analysis resulting in autosomal recessive pediatric DCM due to presumptive JPH2 truncation
A Global Perspective on H9N2 Avian Influenza Virus
H9N2 avian influenza viruses have become globally widespread in poultry over the last two decades and represent a genuine threat both to the global poultry industry but also humans through their high rates of zoonotic infection and pandemic potential. H9N2 viruses are generally hyperendemic in affected countries and have been found in poultry in many new regions in recent years. In this review, we examine the current global spread of H9N2 avian influenza viruses as well as their host range, tropism, transmission routes and the risk posed by these viruses to human health
Minor differences in body condition and immune status between avian influenza virus-infected and noninfected mallards: a sign of coevolution?
Wildlife pathogens can alter host fitness. Low pathogenic avian influenza virus (LPAIV) infection is thought to have negligible impacts on wild birds; however, effects of infection in free-living birds are largely unstudied. We investigated the extent to which LPAIV infection and shedding were associated with body condition and immune status in free-living mallards (Anas platyrhynchos), a partially migratory key LPAIV host species. We sampled mallards throughout the species\u27 annual autumn LPAIV infection peak, and we classified individuals according to age, sex, and migratory strategy (based on stable hydrogen isotope analysis) when analyzing data on body mass and five indices of immune status. Body mass was similar for LPAIV-infected and noninfected birds. The degree of virus shedding from the cloaca and oropharynx was not associated with body mass. LPAIV infection and shedding were not associated with natural antibody (NAbs) and complement titers (first lines of defense against infections), concentrations of the acute phase protein haptoglobin (Hp), ratios of heterophils to lymphocytes (H:L ratio), and avian influenza virus (AIV)-specific antibody concentrations. NAbs titers were higher in LPAIV-infected males and local (i.e., short distance) migrants than in infected females and distant (i.e., long distance) migrants. Hp concentrations were higher in LPAIV-infected juveniles and females compared to infected adults and males. NAbs, complement, and Hp levels were lower in LPAIV-infected mallards in early autumn. Our study demonstrates weak associations between infection with and shedding of LPAIV and the body condition and immune status of free-living mallards. These results may support the role of mallards as asymptomatic carriers of LPAIV and raise questions about possible coevolution between virus and host
A synaptically connected hypothalamic magnocellular vasopressin-locus coeruleus neuronal circuit and its plasticity in response to emotional and physiological stress
The locus coeruleus (LC)-norepinephrine (NE) system modulates a range of salient brain functions, including memory and response to stress. The LC-NE system is regulated by neurochemically diverse inputs, including a range of neuropeptides such as arginine-vasopressin (AVP). Whilst the origins of many of these LC inputs, their synaptic connectivity with LC neurons, and their contribution to LC-mediated brain functions, have been well characterized, this is not the case for the AVP-LC system. Therefore, our aims were to define the types of synapses formed by AVP+ fibers with LC neurons using immunohistochemistry together with confocal and transmission electron microscopy (TEM), the origins of such inputs, using retrograde tracers, and the plasticity of the LC AVP system in response to stress and spatial learning, using the maternal separation (MS) and Morris water maze (MWM) paradigms, respectively, in rat. Confocal microscopy revealed that AVP+ fibers contacting tyrosine hydroxylase (TH)+ LC neurons were also immunopositive for vesicular glutamate transporter 2, a marker of presynaptic glutamatergic axons. TEM confirmed that AVP+ axons formed Gray type I (asymmetric) synapses with TH+ dendrites thus confirming excitatory synaptic connections between these systems. Retrograde tracing revealed that these LC AVP+ fibers originate from hypothalamic vasopressinergic magnocellular neurosecretory neurons (AVPMNNs). MS induced a significant increase in the density of LC AVP+ fibers. Finally, AVPMNN circuit upregulation by water-deprivation improved MWM performance while increased Fos expression was found in LC and efferent regions such as hippocampus and prefrontal cortex, suggesting that AVPMMN projections to LC could integrate homeostatic responses modifying neuroplasticity
Knowledge, attitude and practice of nuclear medicine staff towards radiation protection
Introduction: Ionizing radiation in medical imaging is one of the dominant sources of exposure, and correct knowledge of radiation protection, affects staff safety behaviors during procedures. This study aimed to assess the radiation protection Knowledge, Attitude and Practice (KAP) amongst nuclear medicine centers' staff in Iran. Methods: To evaluate the level of radiation protection KAP, a validated questionnaire was distributed between 243 participants considering demographic characteristics in different geographical regions in Iran from 2014 to 2015. Results: There were statistically significant differences in the level of nuclear medicine staff KAP radiation protection with gender (p0.05). Conclusion: Our findings have shown that radiation protection KAP level of nuclear medicine staff was inadequate in some regions. This might be due to the lack of continuous training and absence of adequate safety knowledge about ionizing radiation. It seems that awareness about radiation protection rules and regulations, along with continuous training and preparations has a direct effect on radiation practice leading to enhanced KAP of staff in nuclear medicine centers. © 2019 Tehran University of Medical Sciences. All rights reserved
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