Introducing a new formulation for the warehouse inventory management systems : with two stochastic demand patterns

This paper presents a new formulation for warehouse inventory management in a stochastic situation. The primary source of this formulation is derived from FP model, which has been proposed by Fletcher and Ponnambalam for reservoir management. The new proposed mathematical model is based on the first and the second moments of storage as a stochastic variable. Using this model, the expected value of storage, the variance of storage, and the optimal ordering policies are determined. Moreover, the probability of within containment, surplus, and shortage are computable without adding any new variables. To validate the optimization model, a Monte Carlo simulation is used. Furthermore, to evaluate the performance of the optimal FP policy, It is compared to (s*,S*) policy, as a very popular policy used in the literature, in terms of the expected total annual cost and the service level. It is also demonstrated that the FP policy has a superior performances than (s*,S*) policy

Computationally efficient calibration of WATCLASS Hydrologic models using surrogate optimization

International audienceIn this approach, exploration of the cost function space was performed with an inexpensive surrogate function, not the expensive original function. The Design and Analysis of Computer Experiments(DACE) surrogate function, which is one type of approximate models, which takes correlation function for error was employed. The results for Monte Carlo Sampling, Latin Hypercube Sampling and Design and Analysis of Computer Experiments(DACE) approximate model have been compared. The results show that DACE model has a good potential for predicting the trend of simulation results. The case study of this document was WATCLASS hydrologic model calibration on Smokey-River watershed

Study on the correlation between Vitamin D and HbA1c in type 2 diabetes mellitus

Background: Type 2 diabetes mellitus (DM) is associated with increased morbidity and mortality due to the development of complications, especially due to poor glycemic control. Besides its role in calcium homeostasis, Vitamin D has been involved in the pathophysiology as well as glycemic control of type 2 DM. Methods: 100 patients diagnosed with type 2 DM were included. Vitamin D levels along with glycosylated haemoglobin were measured in all the individuals. Results: Vitamin D deficiency was observed in 48% of the patients. Vitamin D levels were not associated with markers of glycemic control (HbA1c). Conclusions: Hypovitaminosis D was observed nearly in half of the patients with type 2 diabetes, suggesting a potential for vitamin D supplementation in type 2 DM patients

Study on Association between BMI and Vitamin D Levels in South Indian Rural Population

Introduction: Vitamin D deficiency is a global health problem worldwide and is considered to be a pandemic with implications for compromised bone health and other chronic diseases. A few studies have examined the association between vitamin D status and body mass index (BMI). However, prospective data using the biomarker serum 25-hydroxyvitamin D 25(OH) D3 are limited and therefore examined in the present study. This study aims to evaluate the level of vitamin D status among healthy individuals and also to examine the relation between BMI and 25(OH)D in a cross-sectional sample of 100 men and women ranging in age from 18-75 years. Methods: Participants were selected from subjects attending to Medicine Outpatient Department (OPD) in Sri Venkateshwara Medical College Hospital & Research Centre (SVMCH & RC) willing to participate in the present study between Jan 2020 to Dec 2020. Anthropometric measurements, personal, medical history questionnaire, food frequency questionnaire (FFQ) for vitamin D, and sun exposure questionnaire were collected from all the participants in the present study, blood samples for serum 25(OH)D3 were collected from all subjects. Results: Our study showed that the majority of healthy individual cases of the study i.e., 68.0% have a deficiency in vitamin D status, while 68.0% have ≤20 ng/dl in vitamin D, and 32.0% in >20 ng/dl. Moreover, the study showed a negative association between the level of circulating 25(OH) D3 and BMI. There is a statistically significant and inverse correlation between the level of circulating 25(OH) D3 and BMI. Conclusion: This study demonstrated that the association between BMI and 25(OH)D concentrations in populations from south India can be seen across different age groups and in both men and women. The study also exemplified that higher BMI leads to lower vitamin D status, providing evidence for the role of obesity as a causal risk factor for the development of vitamin D deficiency

The LOX-1 Scavenger Receptor and Its Implications in the Treatment of Vascular Disease

Cardiovascular disease is the leading cause of death. The disease is due to atherosclerosis which is characterized by lipid and fat accumulation in arterial blood vessel walls. A key causative event is the accumulation of oxidised low density lipoprotein particles within vascular cells, and this is mediated by scavenger receptors. One such molecule is the LOX-1 scavenger receptor that is expressed on endothelial, vascular smooth muscle, and lymphoid cells including macrophages. LOX-1 interaction with OxLDL particles stimulates atherosclerosis. LOX-1 mediates OxLDL endocytosis via a clathrin-independent internalization pathway. Transgenic animal model studies show that LOX-1 plays a significant role in atherosclerotic plaque initiation and progression. Administration of LOX-1 antibodies in cellular and animal models suggest that such intervention inhibits atherosclerosis. Antiatherogenic strategies that target LOX-1 function using gene therapy or small molecule inhibitors would be new ways to address the increasing incidence of vascular disease in many countries

Quantifying the phosphorylation timescales of receptor–ligand complexes: a Markovian matrix-analytic approach

Cells interact with the extracellular environment by means of receptor molecules on their surface. Receptors can bind different ligands, leading to the formation of receptor–ligand complexes. For a subset of receptors, called receptor tyrosine kinases, binding to ligand enables sequential phosphorylation of intra-cellular residues, which initiates a signalling cascade that regulates cellular function and fate. Most mathematical modelling approaches employed to analyse receptor signalling are deterministic, especially when studying scenarios of high ligand concentration or large receptor numbers. There exist, however, biological scenarios where low copy numbers of ligands and/or receptors need to be considered, or where signalling by a few bound receptor–ligand complexes is enough to initiate a cellular response. Under these conditions stochastic approaches are appropriate, and in fact, different attempts have been made in the literature to measure the timescales of receptor signalling initiation in receptor–ligand systems. However, these approaches have made use of numerical simulations or approximations, such as moment-closure techniques. In this paper, we study, from an analytical perspective, the stochastic times to reach a given signalling threshold for two receptor–ligand models. We identify this time as an extinction time for a conveniently defined auxiliary absorbing continuous time Markov process, since receptor–ligand association/dissociation events can be analysed in terms of quasi-birth-and-death processes. We implement algorithmic techniques to compute the different order moments of this time, as well as the steady-state probability distribution of the system. A novel feature of the approach introduced here is that it allows one to quantify the role played by each kinetic rate in the timescales of signal initiation, and in the steady-state probability distribution of the system. Finally, we illustrate our approach by carrying out numerical studies for the vascular endothelial growth factor and one of its receptors, the vascular endothelial growth factor receptor of human endothelial cells

Plasmin Inhibitor in Health and Diabetes: Role of the Protein as a Therapeutic Target

The vascular obstructive thrombus is composed of a mesh of fibrin fibers with blood cells trapped in these networks. Enhanced fibrin clot formation and/or suppression of fibrinolysis are associated with an increased risk of vascular occlusive events. Inhibitors of coagulation factors and activators of plasminogen have been clinically used to limit fibrin network formation and enhance lysis. While these agents are effective at reducing vascular occlusion, they carry a significant risk of bleeding complications. Fibrin clot lysis, essential for normal hemostasis, is controlled by several factors including the incorporation of antifibrinolytic proteins into the clot. Plasmin inhibitor (PI), a key antifibrinolytic protein, is cross-linked into fibrin networks with higher concentrations of PI documented in fibrin clots and plasma from high vascular risk individuals. This review is focused on exploring PI as a target for the prevention and treatment of vascular occlusive disease. We first discuss the relationship between the PI structure and antifibrinolytic activity, followed by describing the function of the protein in normal physiology and its role in pathological vascular thrombosis. Subsequently, we describe in detail the potential use of PI as a therapeutic target, including the array of methods employed for the modulation of protein activity. Effective and safe inhibition of PI may prove to be an alternative and specific way to reduce vascular thrombotic events while keeping bleeding risk to a minimum