An optimal and a heuristic algorithm for the single-item retrieval problem in puzzle-based storage systems with multiple escorts

Puzzle-based storage systems consist of densely stored unit loads on a square grid. The problem addressed in this paper is to retrieve a stored unit load from a puzzle-based storage using the minimum number of item moves. While previous research contributed optimal algorithms for only up to two empty locations (escorts), our approach solves configurations where multiple empty locations are arbitrarily positioned in the grid. The problem is formulated as a state space problem and solved to optimality using an exact search algorithm. To reduce the search space, we derive bounds on the number of eligible empty locations and develop several search-guiding estimate functions. Furthermore, we present a heuristic variant of the search algorithm to solve larger problem instances. We evaluate both solution algorithms on a large set of problem instances. Our computational results show that the algorithms clearly outperform existing approaches where they are applicate and solve more general configurations, which could not be solved to optimality before. The heuristic variant efficiently yields high-quality solutions for significantly larger instances of practically relevant size.     

Renal artery embolization in severe nephrotic syndrome

Introduction Severe nephrotic syndrome is associated with increased morbidity and mortality. Renal artery embolization (RAE) has been used in a number of renal diseases such as renal tumors, arteriovenous fistulas etc. However, data regarding benefits of RAE in patients with symptomatic severe proteinuria is limited. We decided to evaluate role of RAE in the setting of severe symptomatic nephrotic syndrome. Methods Eight patients who had undergone transcatheter renal artery embolization with polyvinyl alcohol (PVA) were included. Clinico‐demographic characteristics as well as baseline laboratory data including level of proteinuria, serum albumin, C‐reactive protein and LDL cholesterol levels were recorded for each patient. After RAE, outpatient clinic control laboratory values were also assessed. Findings All patients except one underwent bilateral RAE (four simultaneous or three sequential). Two patients experienced postembolization syndrome characterized by flank pain, fever, and leukocytosis, which was self‐limited and responded to analgesics in all patients. There was no technical complications associated with RAE procedure. All patients became anuric except one. Serum albumin levels increased and serum LDL‐cholesterol levels decreased considerably in treated patients. Discussion Renal artery embolization with the purpose of amelioration in nephrotic syndrome complications was effective and free of major technical complications in our patients.     

A software for simulating steady-state properties of passive dendrites based on the cable theory

In this study, a computer software, CableTeo, is introduced for simulating the steady-state electrical properties of passive dendrite based on the cable theory. The cable theory for dendritic neurons addresses to current-voltage relations in a continuous passive dendritic tree. It is briefly summarized that the cable theory related to passive cables and dendrites, which is a useful approximation and an important reference for excitable cases. The proposed software can be used to construct user-defined dendritic tree model. The user can define the model in detail, display the constructed dendritic tree, and examine the basic electrical properties of the dendritic tree using transfer impedance approach. The software addresses to ones who want to run simple simulations of the cable theory without need to any programming language skills or expensive software. It can also be used for educational purposes.     

Identification of common sensory features for the control of CNC milling operations under varying cutting conditions

The main focus of this study is to identify the most influential and common sensory features for the process quality characteristics in CNC milling operations—dimensional accuracy (bore size tolerance) and surface roughness—using three different material types (6061-T6 aluminum, 7075-T6 aluminum, and ANSI-4140 steel). The materials were machined on a vertical CNC mill, retrofitted with multiple sensors and data acquisition systems, to investigate the effects of variations in material types and machining parameters. The sensor data include cutting force measurements, spindle quill vibration, and acoustic emission, each of which further divided into measurable components, such as x, y, and z components in cutting force, x and y spindle quill vibration, DC, AC, and Count Rate for acoustic emission signals. Those components were filtered and analyzed to determine the sensory features that best correlate with process quality characteristics. Tool wear rate and machining characteristics appeared differently, depending on the material types, yet some components of the sensory data were found to be significant with relation to the variations in bore size and surface roughness for all three types of materials. This suggests that even under the varying cutting conditions involving different materials, the identified sensory features can be used for the reliable and accurate control of milling operations.     

Effects of sodium ascorbate and delayed bonding after bleaching on shear bond strengts of orthodontic brackets

Introduction: The aim of the study was to determine the effects of sodium ascorbate and delaying bonding for 4 weeks after bleaching on SBS of orthodontic brackets.

Methods: Sixty freshly extracted, noncarious, premolars were randomly assigned to 4 groups of 15 each. Orthodontic brackets were bonded with a composite resin and cured with a halogen light. After bonding, the shear bond strengths of the brackets were tested with a universal testing machine. Group I served as the control. In groups II, III, and IV, teeth were bleached with an office bleaching method. In group II, brackets bonded immediately after bleaching. In group III, teeth were immersed in artificial saliva of 4 weeks after bleaching before bonding brackets. In group IV, teeth were treated with 10% sodium ascorbate after bleaching before bonding brackets.

Results: One-way analysis of variance indicated a significant difference between groups (P < .001). The highest values for SBS were measured in group I (11.92 ± 0.81 MPa). The SBS was significantly lower in groups II, III, and IV than in group I (P < .001). There was no statistically significant difference between groups III and IV.

Conclusions: Bleaching significantly reduced the SBS of orthodontic brackets on human enamel. If bleaching is mandatory, teeth should be treated with sodium ascorbate before bonding.     

Derivation of machine tool error models and error compensation procedure for three axes vertical machining center using rigid body kinematics

Volumetric positional accuracy constitutes a large portion of the total machine tool error during machining. In order to improve machine tool accuracy cost-effectively, machine tool geometric errors as well as thermally induced errors have to be characterized and predicted for error compensation. This paper presents the development of kinematic error models accounting for geometric and thermal errors in the Vertical Machining Center (VMC). The machine tool investigated is a Cincinnati Milacron Sabre 750 3 axes CNC Vertical Machining Center with open architecture controller. Using Rigid Body Kinematics and small angle approximation of the errors, each slide of the three axes vertical machining center is modeled using homogeneous coordinate transformation. By synthesizing the machine's parametric errors such as linear positioning errors, roll, pitch and yaw etc., an expression for the volumetric errors in the multi-axis machine tool is developed. The developed mathematical model is used to calculate and predict the resultant error vector at the tool–workpiece interface for error compensation.     

Characterization of pyrolysis products of harbolite and Avgamasya asphaltites: comparison with solvent extracts

The products of pyrolysis at 525 and 840 °C of two asphaltites from South-Eastern Turkey have been analysed and compared with the bitumen obtained by solvent extraction. The yield of oil product is reasonably similar for all three treatments, with gas (hydrogen, ethene, C₁C₄ alkanes and hydrogen sulphide) being liberated during pyrolysis. Greater percentages of alkanes with shorter chain lengths (along with some alkenes), and of pentane-soluble aromatic oils with reduced molecular masses, are generated during pyrolysis, at the expense of asphaltenes. The extra alkanes are generated partly by the cracking of aromatic side-chains and also from kerogen. Pyrolysis reduces the number of sulphur linkages in the oil, but nitrogen- and oxygen-containing structures are liberated from kerogen during heating.     

Crosstalk between Sodium–Glucose Cotransporter Inhibitors and Sodium–Hydrogen Exchanger 1 and 3 in Cardiometabolic Diseases

Abnormality in glucose homeostasis due to hyperglycemia or insulin resistance is the hallmark of type 2 diabetes mellitus (T2DM). These metabolic abnormalities in T2DM lead to cellular dysfunction and the development of diabetic cardiomyopathy leading to heart failure. New antihyperglycemic agents including glucagon-like peptide-1 receptor agonists and the sodium–glucose cotransporter-2 inhibitors (SGLT2i) have been shown to attenuate endothelial dysfunction at the cellular level. In addition, they improved cardiovascular safety by exhibiting cardioprotective effects. The mechanism by which these drugs exert their cardioprotective effects is unknown, although recent studies have shown that cardiovascular homeostasis occurs through the interplay of the sodium–hydrogen exchangers (NHE), specifically NHE1 and NHE3, with SGLT2i. Another theoretical explanation for the cardioprotective effects of SGLT2i is through natriuresis by the kidney. This theory highlights the possible involvement of renal NHE transporters in the management of heart failure. This review outlines the possible mechanisms responsible for causing diabetic cardiomyopathy and discusses the interaction between NHE and SGLT2i in cardiovascular diseases.     

Numerical analysis of natural convection heat transfer from rectangular shrouded fin arrays on a horizontal surface

The main aim of this investigation is to discover the effects of clearance parameters on the steady-state heat transfer. In order to solve the three-dimensional elliptic governing equations, a finite volume based CFD code was used. The clearance gap between fin tips and shroud, the base and fin temperatures and the size and configuration of the finned surfaces were varied during the parametric study. The numerical results have been compared to existing experimental values from the literature and the comparison shows a good agreement. It is found that the heat transfer coefficient increases with the increase in the clearance parameter and it approaches to the value of heat transfer coefficient obtained for unshrouded fin arrays.